MULTIFUNCTIONAL TRANSDERMAL DRESSING FOR WOUNDS

PANSEMENT TRANSDERMIQUE MULTIFONCTIONNEL POUR PLAIES

English Abstract

A multifunctional polymer-free clay products having a clay, a zwitterion, a silver compound, and, an analgesic. The multifunctional polymer-free clay product provides antimicrobial and pain relieving properties. Method of treatment of bums using the multifunctional polymer-tree clay product having antimicrobial and pain relieving properties. Methods of preparing multifunctional polymer-free clay products having a clay, a zwitterion, a silver compounds and, an analgesic.

French Abstract

La présente invention concerne un produit d'argile sans polymère multifonctionnel présentant une argile, un ion bipolaire, un composé d'argent, et un analgésique. Le produit d'argile sans polymère multifonctionnel présente des propriétés antimicrobiennes et de soulagement de la douleur. La présente invention concerne également un procédé de traitement de brûlures utilisant le produit d'argile sans polymère multifonctionnel présentant des propriétés antimicrobiennes et de soulagement de la douleur. La présente invention concerne des procédés de préparation de produits d'argile sans polymère multifonctionnels présentant une argile, un ion bipolaire, des composés d'argent et un analgésique.

Claims

WHAT IS CLAIMED IS:
1. A multifunctional polymer-free clay product comprising a clay, a
zwitterion, an
antimicrobial agent, and, an analgesic, wherein the multifunctional polymer-
free clay product
provides antimicrobial and pain relieving properties, wherein the clay is
selected from the group
consisting of mommorillonite, kaolinite, smectite, and bentonite, wherein the
antimicrobial agent
is selected from the group consisting of silver ion, copper, silver-containing
compounds, and,
copper containing compounds, and, wherein the analgesic is selected from the
group consisting
of opioid analgesics, nonsteroidal anti-inflammatory drugs (NSAIDs) and
adjuvant analgesics,
capsaicin, clonidine, ketamine, Morphine, fentanyl, Buomorphine, fentanyl
base, lidocaine
base, loperainide base, cannabinoids, and combinations thereof.
2 The multifunctional polymer-free clay product of claim 1, wherein the
zwitterion is
selected from the group consisting of betaine, betaine hydrochloride, choline
chloride, 3-Benzyl-
5-(2-hydroxymethyl)-4-methylthiazolium chloride, 3-Benzyl-5-(2-hydroxymethyl)-
4-
methythiazolium bromide, 3-Benzyl-5-(2-hydroxymethyl)-4-methylthiazolium
fluoride, [2-
(Metbaciyloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide, [2-
(Methacryloyloxy)ethylldimethyl-(3-sulfopropyl) ammonium chloride and 3-Benzyl-
5-[2-
hydroxmethyl)-4-methyithiazolium iodide
3. The multifunctional polymer-free clay product of claim 1, wherein a
thickness of the
multifunctional polymer-free clay product ranges from about 1 micrometer to
about 500
micrometer.
59

4. The multifunctional polymer-free clay product of claim 1, wherein the
polymer-free
day product achieves a bending radius of curvature. ranging from about 0.4
millimeter to about
centimeters.
5. The multifunctional polymer-free clay product of claim 1, wherein the
polymer-free
clay product has greater than 50 percent absorption of visible light.
6 The multifunctional polymer-free clay product of claim 1, wherein the
polymer-free
clay product does not incorporate a polymer
7. A multifunctional dressing comprising the multifunctional polymer-free clay
product
of claim 1.
8. A method of treating bums comprising administering the multifunctional
polymer-free
clay product of claim 1
9. A method of preparing a multifunctional polymer-free clay product
comprising an
antimicrobial agent and an analgesic, the method comprising:
a) mixing a clay, the antimicrobial aunt and water to form a first slurry;
b) washing the slurry of step a) with water to obtain a washed second slurry;
c) adding a zwitterion and water to the washed second slurry of step b) to
obtain a third
clay slurry;
d) casting the third clay slurry of step c) onto a substrate to obtain a first
dried product;
e) adding drops of the analgesic in a non-aqueous solvent onto the first dried
product of
step d) to obtain a resultant product,
f) drying the resultant product to obtain a second dried product;
g) separating the second dried product of step f) from the substrate of step
d);

wherein the second dried product of steps t) and g) is the multifunctional
polymer-free
clay product which provides both antimicrobial and pain relieving properties,
wherein the clay is
selected from the group consisting of montmorillonite, kaolinite, smectite,
and bentonite,
wherein the antimicrobial agent in the multifunctional polymer-free clay
product is selected from
the group consisting of silver ion, copper, silver-containing compounds, and,
copper containing
compounds, and, wherein the analgesic is selected from the group consisting of
fentanyl base,
lidocaine base, loperamide base, and combinations thereof.
10. The method of claim 9, wherein the substrate is selected from the group
consisting of
a silicone sheet, a fabric, and a glass surface.
11. The method of claim 9, wherein the zwitterion is selected from the group
consisting
of betaine, betaine hydrochloride, choline chloride, 3-Benzyl-5-(2-
hydroxymethyl)-4-
methylthiazolium chloride., 3-Benzyl-5-(2-hydroxymethyl)-4-methylthiazolium
bromide, 3-
Benzyl-5-(2-hydroxymethyl)-4-methylthiazolium fluoride and 3-Benzyl-5-(2-
hydroxymethyl)-4-
methylthiazolium iodide.
12. A multifunctional polymer-free clay product prepared by the method of
claim 9.
13. A method of preparing a multifunctional polymer-free organo modified clay
product
comprising an antimicrobial agent and an analgesic, the method comprising:
a) mixing a clay, the antimicrobial agent and water to form a first slurry;
b) washing the first slurry of step a) with water to obtain a washed second
slurry;
c) adding a mixture of water and non-aqueous solvent containing betaine and an

analgesic to the washed second slurry of step b) to obtain a third clay
slurry;
d) casting the third clay slurry of step c) onto a substrate to obtain a dried
product,
61

e) separating the dried product of step d) from the substrate to obtain a
separated dried
product, wherein the separated dried product is the multifunctional polymer-
free clay product,
wherein the multifunctional polymer-free clay product provides antimicrobial
and pain relieving
properties, wherein the clay is selected, from the group consisting of
montmorilonite, kaolinite,
smectite, and bentonite, wherein the antimicrobial agent is selected from the
group consisting, of
silver ion, copper, silver-containing compounds, and, copper containing
compounds, and,
wherein the analgesic is selected from the group consisting of fentanyl base,
lidocaine base,
loperamide base, and combinations thereof.
14. The method of claim 13, wherein the substrate is selected from the group
consisting
of a silicone sheet, a fabric, and a glass surface.
15. The method of claim13, wherein the zwitterion is selected from the group
consisting
of betaine, betaine hydrochloride, choline chloride, 3-Benzyl-5-(2-
hydroxymethyl)-4-
methylthiazolium chloride, 3-Benzyl-5-(2-hydroxymethyl)-4-methylthiazolium
bromide, 3-
Benzyl-5-(2-hydroxymethyl)-4-methylthiazolium fluoride, [2-
(Methacryloyloxy)ethyl]dimethyl-
(3-sulfopropyl) ammonium hydroxide, [2-(Methacryloyloxy)ethyl]dimethyl-(3-
sulfopropyl)
ammonium Chloride and 3-Benzyl-5-(2-hydroxymethyl)-4-methylthiazolium iodide.
16. A multifunctional polymer-free clay product prepared by the method of
claim 13.
17. A multifunctional antimicrobial and analgesic dressing comprising a
backing film
and a multifunctional polymer-free clay product, wherein the multifunctional
polymer-free clay
product comprises a clay, a zwitterion, an antimicrobial agent, and, an
analgesic, whereby the
multifunctional polymer-free clay product provides antimicrobial and pain
relieving properties,
and the backing film is a polymeric film impermeable to liquid water.

62

18. The multifunctional antimicrobial and analgesic dressing of claim 17
further
comprising a diffusion control membrane, wherein the diffusion control
membrane provides
controlled release of the analgesic in the multifunctional polymer-free clay
product.
19. A multifunctional antimicrobial and analgesic dressing comprising a
backing film
and more than one multifunctional polymer-free clay product, wherein each of
the
multifunctional clay product in the more than one multifunctional polymer-free
clay product
comprises a clay, a zwitterion, an antimicrobial agent, and, an analgesic,
wherein the multifunctional antimicrobial and analgesic dressing provides
antimicrobial
and pain relieving properties, wherein the backing film is a polymeric film
impermeable to liquid
water.
20. The multifunctional antimicrobial and analgesic dressing of claim 19
further
comprising a diffusion control membrane, wherein the diffusion control
membrane provides
controlled release of the analgesic from the multifunctional polymer-free clay
product.

63

Description

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
MULTIFUNCTIONAL TRANSDERMAL DRESSING FOR WOUNDS
[0001] This Application claims the benefit of US, Appl. Ser. No.
62/253,503, filed
November 10, 2015, and, is a continuation-in-part of co-pending U.S. Appl.
Ser. No. 14/210,082,
filed March 13, 2014, which claims benefit of U.S. App.!. Ser. No. 61/794420
filed March 15,
2013, which are incorporated in entirety by reference.
[0002] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR
DEVELOPMENT
[0003] This work was supported by the Government of the United States of
America
under Contract No. W81XWF1-14-C-0130, awarded by the United States Department
of Defense.
The Government of the United States of America has certain rights in this
invention.
[0004] Field
[0005] This disclosure relates to a inultifiinctional bandage for wounds.
Disclosure
provides a bandage based on claymat with antimicrobial property. A mat based
on silver
containing claymat with analgesic property is provided. A bandage based on
claymat with both
antimicrobial and analgesic properties in the same product is provided. A
transdermal delivery
product based on claymat for analgesics is provided. A. transdemial delivery
product based on
claymat for local anesthetic is provided.
BACKGROUND
[0006] in this section, we discuss several aspects of related work,
including background
and conventional technologies.
[00071 Burns are among the most painful and debilitating battlefield
wounds faced by the
US warfitihter. Burn wounds turn deadly when infection sets in. Since military
operations began

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
in Iraq in March 2003, hundreds of US military personnel have sustained burn
injuries from
explosions and other implements of war such as 1ED's [EK.Renz et al. Long
Range Transport
of War-Related Burn Casualties, J Trauma. 64, Si 36-5145 (2008)]. Acute burn
injury pain is a
source of immense suffering, and it has been linked to debilitating chronic
pain and stress-related
disorders. Severe pain is felt during acute treatment and rehabilitation,
especially during dressing
changes, debridemenes, and skin grafting, and continues through long-term
follow-up. The
backbone of burn analgesia is opioid therapy, typically administered via oral
or paremeral routes-.
The systemic use of opioid medications in burn patients is complicated by the
side effects such
as tolerance, hyperalgesia, hemodynamic instability, respiratory depression,
and dependence.
Therefore, besides the systemic administration of analgesics, attempts have
been made to control
the pain locally using topical analgesics which have shown encouraging results
[T. Long, T.
Cathers, R. Willman, T. O'Donnell, N. Garrig.,ues, T. Jones, Morphine-Infused
Silver
Sulfadiazine Cream for Burn Analgesia: A Pilot Study, Journal of Burn Care &
Rehabilitation,
22, 118-123, (2001)]. Such topical dressings can be used to protect the bum
wound from
infection and thereby aid in wound healing if antimicrobial properties can be
imparted to them.
Topical antimicrobial-analgesic dressings can also be used to treat major
irritation/pain problems
such as abrasions, friction irritations and pressure sores (blisters).
[0008] Fentanyl, an opioid analgesic was incorporated into an
antimicrobial wound
dressing based on silver containing clay mats. This fentanyl-loaded silver
containing clay mat
can provide controlled delivery of analgesic drugs to wounds while assisting
in wound healing
with its antimicrobial properties. Silver containing clay mats were prepared
and evaluated in
vitro for their antimicrobial activity and their ability to provide controlled
release of fentanyl,
2

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
The antimicrobial properties of both silver containing claymats without
Fentanyl and with
Fentanyl loading were demonstrated using Kirby-Bauer assay tests. After
optimizing the kinetics
of the opi.oid delivery in vitro, the efficacy of silver containing claymats
with fentanyl as a
topical analgesic dressing was tested using a standard hot plate animal model.
The Hot Plate test,
in a rodent model, clearly demonstrated the ability of silver containing
claymats with fentanyl
patches to elicit cutaneous antinocictption activity due to regional delivery
of subtherapeutic
doses of fentanyl. Pain and Infection are the two major complications
associated with second-
degree burn injuries. Silver containing claymats with fentanyl mat is a single
patch device that
can be used to alleviate pain and prevent infection in burn injuries,
[0009] Burn Injury Pain and Action of Analgesics
[001.0] The description of the pain pathway as provided by Kehlet et al.
[H. Kehlet, J.B.
Dahl, The value of "multimodal" or "balanced analgesia" in postoperative pain
treatment.
Anesth. Analg;77,1049 (1993)1 and Gottschalk et al. [H. Kehlet, LB. Dahl, The
value of
"multimodal" or "balanced analgesia" in postoperative pain treatment. Anesth
Analg;77,1049
(1993)] is as follows: "Both the peripheral and the central nervous systems
(CNS) are involved
in the perception of pain. The transmission of burn wound pain stimuli begins
with peripheral
nociceptors. The pain message from the nociceptors is transmitted via A-delta
and C fibers to the
dorsal horn of the spinal cord [P. Richardson,. L. Mustard, The management of
pains in the burns
unit, .Bums, 35, 921-936, (2009)1. The sensitivity of nociceptors is limber
enhanced by many
tissue factors and inflammatory chemicals released in the course of tissue
injury." Therefore, the
baseline pain management must include treatment of both nociceptive and
neuropathic

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
components. Nociceptiv-e receptors can be controlled by local medication while
neuropathic parts
will require systemic administration of analgesics.
[0011) Action of Topical Analgesics
[0012] Treatment -for reducing pain involves the use of common and opioid
analgesics,
nonsteroidal anti-inflammatory drugs (NSAIDs) and adjuvant analgesics P&P.
Flores, A.P.
Rocha de Castro., J.S. Nascimento, Topical Analgesics, Revista Brasileira de
Annesesiologie, .62,
244-252, (2012)]. Pharmacologically, it is known that the main mechanism of
analgesics is to act.
at specific sites located in the CNS and periphery. This observation led the
topical administration
of pain reliever drugs such as NSAID's, local anesthetics, capsaicin,
tricyclic. antidepressants,
ketamine, clonidi.ne, opioids, and. cannabinoids... For example, .fentanyl
transdenual patches are
used to treat chronic pain from cancer or in the post-operative setting [M.
Lane, The transdermal
delivery of fentanyl, European journal of Pharmaceutics and Biopharmacentics,
84, 449455,
(2013)]. The topical application of these drugs allows high concentrations in
peripheral effector
sites. Thus, undesirable side effects are less likely to occur compared to
delivering these drugs
systemically.
[0013] Human skin consists of three main layers: the epidermis, dermis,
and hypodermis.
An applied drug must traverse these structural layers, encounteringseveral
lipophilic. and
hydrophilic domains on the way to the (fermis where absorption into systemic
circulation is rapid
due to large capillary beds [L. Margetts, R. Sawyer, Transdemial Drug
Delivery: Principles and
Opioid Therapy, Continuing Education in Anesthesia, Critical Care & Pain, 7,
171-176, (2007)].
Therefore, the action of transdermal supply of analgesic will take more time
than systemic
administration of the same drug. For example, after initial application,
fentanyl concentrations in
4

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
blood increase gradually, generally leveling off between 12 and 24 h. In the
case of a burn injury,
the drug absorption rate through the skin will also be affected by various
other factors such as the
degree of burn, thickness of skin. and body temperature. The conventional
wisdom is that even
though -opioid drugs are applied locally on the skin, the main analgesic-
action of opioids occurs
only in the spinal cord. This will require the drug to be absorbed into the
blood, and travel from
the skin surface to the spinal cord. The treatment of severe pain with opioids
has thus far been
limited by their unwanted central side effects.
[001.4] Recent pioneering work by Stein et al. and others promises the
possibility of
opioid analgesic action outside the CNS. Recently, plaid receptors have been
identified on
peripheral processes of sensory neurons. Opioids can attenuate the
excitabibty.of peripheral
nociceptor terminals, reduce the conduction of pain, signals- and the release
of excitatory
pminflammatory .neuropeptides (substance P. calcitonin gene-related peptide)
from peripheral
sensory nerve endings. in other words, areas with injury or burns generate
chemical substances
that irritate nerve endings even more and cause pain. Opioids apparently
decrease the formation
of these substances and decrease the response of nerve fibers to these
substances. The
modulating effect of fentanyl on the nerve endings can be translated into a
clinically significant
effect on pain relief.
[OW 5] Clays as a drug delivery medium
[0016] Fentanyl loaded silver containing clay.mat patches were prepared
using
montmorillonite clay as the matrix for Fentanyl. Clays are common ingredients
in
pharmaceutical products. Clay minerals are naturally occurring inorganic
cationic exchangers
that can undergo ion exchange with basic drugs in solution. In addition to ion-
exchange, organic

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
molecules can bond to clays via physical adsorption and ion-dipole
interactions of acidic. and
non-ionized molecules. For example, Wai and Banker demonstrated the loading:
of alkaloids in
montrnorillonite clay [K.N. Wai, G.S. Banker, Some physicochemical .properties
of the
montmorillonites. J. Pharm, Sci. 55, 1215 1220 (1966)]..Onemajor advantage of
using clays to:
deliver drugs compared to other delivery systems is the very low risk of 'dose
dumping*.
Common topical medical dressings such as gauze, membranes and textiles can be
subjected to
dose dumping easily due to external forces. Thus, a material of high chemical
and mechanical
resistance is required to develop a safe, high potency opioid transdermal drug
delivery vehicle
Aguzzi, P. Cerezo, C. Viseras, C. Caramella, Use of clays as drug delivery
systems:
Possibilities and limitations, Applied Clay Science, 36,22-36, (2007)1 Clays
are the most
optimum storage and delivery systems for analgesics because of their
mechanical and chemical
stability. Fentanyl has been loaded into a metakaolin clay, which provided a
mechanically strong
sustained drug release medium [K.N. Wai, GS. Banker, Some physicochemical
properties of the
montmorillonites. 3. Pharm. Sci. 55, 1215- 1220 (1966)1 The multifunctional
patch can be used
in skin graft patients, for pain management at the skin donor site.
[0017] The transdermal absorption of opiaid drugs like fentanyl may take
up to 8-12 h to
take action. However, the injured patient requires the drugs to provide
immediate relief One
approach is to use local anesthetics.such as Lidocaine base or Loperamide base
instead of
Fentanyi or in combination with Fentanyl.
[0018] Lidocaine hydrochloride molecules strongly bound to the claymat
through at
intercalation process. For example, Kevadiya et al. intercalated Lidocaine
hydrochloride into
montmorillonite clay by ion exchange and investigated the controlled drug
release [B.D.
6

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
Kevadiya, G.V. Josh, H.M. Mody, RC. Bajaj, Biopolymer-clay hydrogel composites
as drug
carrier: Host-guest intercalation and in vitro release study of lidocaine
hydrochloride, Applied
Clay Science, 52, 364-367 (201 01 The in vitro release experiments showed that
lidocaine
release from montmotillonite clay was controlled by pH of the extracting
liquid medium.
Lidocaine was released faster at alkaline or neutral pH. Abdel-Mohsen et al.
studied the ionic
state of lidocaine as a function of pH [KG, Abitel-Mohsen, HA., Mohamed,
H.M.A. Wadood,
Study of the effect of montmorillonite and Florite on the dissociation
constant, release and local
anesthetic activity of lidocaine, STP Pharma Sciences, 4, 295 300 (2001)].
They also
demonstrated that Lidocaine hydrochloride release in water is affected by the
pH indicating the
interaction of lidocaine cations With the clay surface. Conditions, for
transdermal drug delivery is
different from in vivo drug delivery or in vivo drug release. The transdermal
delivery of drugs
occurs in a dry state without a major amount of fluids. in comparison, drug
delivery through oral
administration occur in the presence of a large amount of bodily fluids and
strongly depends on
the pH of the medium.
[0019] The availability of fluids on the skin surface to extract the drug
from the drug
delivery transdermal patches is very small or even absent on dry skins.
Therefore, the
transdermal mat should allow free mobility of the drug through the patch. This
flow will be
restricted if the polymers are used in the preparation of claymati.
[0020] The -ammonium (4-N11- and +N(C2115)2-) groups on lidocaine
hydrochloride
interact strongly with the clay surface. No leaching of lidocaine
hydrochloride was from the mats
observed due to the strong binding of lidocaine hydrochloride with the.
claymat and silver
containing claymat samples. Therefore, it was decided to use lidocaine base
instead of lidocaine
7

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
hydrochloride. This resulted in an increase in the release of lidocaine base
from the clay-mat and.
silver containing claymat samples during the drug release testing.
SUMMARY
[0021] The disclosed teachings provide making of a pain relieving device
based on clay
mat. The disclosure provides a device based on clay mats with combined
antimicrobial and pain
relieving properties. The disclosure provides clay mat loaded with silver and
analgesics.
[00221 The disclosed teachings provide making of a pain relieving device
based on clay
mat. The disclosure provides a device based on clay mats with combined
antimicrobial and pain
relieving properties. The disclosure provides clay mat loaded with an
antimicrobial agent and
analgesics. The disclosure provides clay mat loaded with silver and fentanyl.
Some
embodiments provide a multiftmctional topical wound dressing capable of both
antimicrobial
action while delivering pain medication.
[0023] Some embodiments provide a multi fiinctional polymer-free clay
product having
clay, a zwitterion, an antimicrobial agent, and, an analgesic. The
multifunctional polymer-free
clay product provides antimicrobial and pain relieving properties. The clay
can be
montmorillonite, kaolinite, smectite, and bentonite. The antimicrobial agent
can be silver ion,
copper, silver-containing compounds, or, copper containing compounds. The
zwitterion can be
betaine, betaine hydrochloride, chol.ine chloride, 3-Benzy1-5-(2-
hydroxymethyl)-4-
mettrylthiazolium chloride, 3-13enzy1-5-(2-hydroxymethy1)-4-1nethylthiazolium
bromide, 3-
Benzy1-5-(2-hydroxymethyl)-4-methylthiazolium fluoride, [2-
(Methacryloyloxy)ethyl]climethyl-
(3-;sulfopropyl) ammonium hydroxide; [2-(Methacryloyloxy)ethylidimethyl-(3-
sulfopropyl)
all1MOTthITII chloride and 3-Benzy1-5-(2-hydroxriethyl)-4-methylthiazolium
iodide. The
8

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
analgesic. can be opioid analgesics, nonsteroidal anti-inflammatory drugs
(NSAIDs) and adjuvant
analgesics, capsaicin, clonidine, ketamine, _Mnrphine, fentanyl,
Buprenorphine, fentanyl base,
lidocaine base, loperamide base, cannabinoids, and combinations thereof The
thickness of the
multifunctional polymer-free clay product ranges from about 1. micrometer to
about 500
micrometers. In some embodiments, the thickness of the multifunctional polymer-
free clay
product ranges from about 1 micrometer to about 100 micrometers, The polymer-
free clay
product achieves a bending radius of curvature ranging from about 0.4
millimeters to about 10
centimeters. The polymer-free clay product can have greater than 50 percent
absorption of
visible light. The polymer-free clay product does not incorporate a polymer.
Some
embodiments provide a multifunctional dressing having a multifunctional
polymer-free clay
product
[0024] Some embodiments provide a method of treating bums by
administering a
multifunctional polymer-free clay product having antimicrobial and pain
relieving properties.
[0025] Some embodiments provide a method of preparing a multifunctional
polymer-free
clay product having an antimicrobial agent and an analgesic. The method
includes mixing clay,
an antimicrobial agent, and water to form a first clay slurry. Washing the
first clay shirty with
water to obtain a washed second clay slurry. Next, adding a zwitterion and
water to the. Washed
second slurry to obtain a third clay slurry. Then casting the third clay
slurry onto a substrate to
obtain a first dried product. Then adding drops of an analgesic in a non-
aqueous solvent onto the
first dried product to obtain a resultant product. Then drying the resultant
product to obtain a
second dried product. Then separating the second dried from the substrate. The
second dried
product is the multifunctional polymer-free clay product. The multifunctional
polymer-free day
9

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
product provides both antimicrobial and pain relieving properties. The
antimicrobial in the
multifunctional polymer-five clay product can be silver ion, copper, silver-
containing
compounds, and, copper containing compounds. In some embodiments, the silver
compound is
silver nitrate. The analgesic can be fentanyl base, -lidocaine base,
loperamide base, and
combinations thereof. The substrate can be a silicone sheet, fabric, and a
glass surface. The clay
can he montmorillonite, kaolinite, smectite, and. bentonite. Thezwitterion can
be betaine, beta inc
hydrochloride, thane chloride, 3-Benzy1-342-hydroxymethyl)-4-methylthiazolium
chloride, 3-
Benzyl-5-(2-hydroxymethyl)-4-methylthiazolium bromide, 3-Benzy1-5-(2-
hydroxymethyl)-4-
methylthiazolium fluoride, [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)
ammonium
hydroxide, [2-(Methactyloyloxy)ethylidimethyl-(3-sulfopropyl) ammonium
chloride and 3-
Benzyl-5-(2-hydroxymethyl)-4-methylthiazolium iodide.
[0026] In another embodiment of the method of preparing a
nutititimctional polymer-free
clay product having an antimicrobial and an analgesic, the method includes
mixing clay, an
antimicrobial agent, and water to form a first clay slurry. Then washing the
first slurry with
water to obtain a washed second clay slurry. Then adding a mixture of water
and a non-aqueous
solvent containing hetaine and an analgesic to the washed second slurry to
obtain a third clay
slurry. Next, casting the third clay slurry onto a substrate to obtain a dried
product. Next,
separating the dried product from the substrate to obtain a separated dried
product. The
separated dried product is the multifunctional polymer-free clay product:,
which provides
antimicrobial and pain relieving properties. The antimicrobial agent can be
silver ion, copper,
silver-containing compounds, or, copper containing compounds. hi some
embodiments, the

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
silver compound is silver nitrate. The analgesic can be fentanyl base,
lidocaine base, loperamide
base, and combinations thereof.
[0027] Some embodiments provide a multifunctional antimicrobial and
analgesic
dressing having a backing film and a multifunctional polymer-free clay
product. The
multifunctional polymer-free clay product includes a clay, a zwitterion, an
antimicrobial agent,
and, an analgesic. The multifunctional polymer-free clay product provides
antimicrobial and
pain relieving properties. The backing film is polymeric film impermeable to
liquid water.
[00281 Some embodiments provide a multifunctional antimicrobial and
analgesic
dressing having a backing film, a multifunctional polymer-free clay product,
and a diffusion
control membrane. The multifunctional polymer-free clay product includes a
clay, a mitterion,
an antimicrobial agent, and, an analgesic. The .multifunctional polymer-free
clay product
provides antimicrobial and pain relieving properties. The backing film is
polymeric film
impermeable to liquid water. The diffusion control membrane is a porous layer
that provides
controlled release of the analgesic in the multifunctional polymer-free clay
product.
[0029] Some embodiments provide a multifunctional antimicrobial and
analgesic
dressing having a backing film and more than one multifunctional polymer-free
clay product.
Each of the multifunctional clay product includes a clay, a zwitterion, an
antimicrobial agent,
and, an analgesic. The multifunctional antimicrobial and analgesic dressing
provides
antimicrobial and pain relieving properties. The backing film is a polymeric
film impermeable
to liquid water.
[00301 Some embodiments provide a multifunctional antimicrobial and
analgesic
dressing having a backing film, more than one multifunctional polymer-free
clay product, and a
11.

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
diffusion control membrane. Each of the multifunctional clay product includes
a clay, a
zwitterion, an antimicrobial. agent, and, an analgesic. The multifunctional
antimicrobial and
analgesic dressing provides antimicrobial and pain relieving properties. The
backing film is a
polymeric film impermeable to liquid water. The diffusion control membrane is
a porous layer
that provides controlled release of the analgesic. from the multifunctional
polymer-free clay
product.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG_ 1 provides photographs of 'Photographs of (A) A roll of
silver containing,
claymat loaded with fentanyl demonstrating the flexibility of the mat. (B) A
large sheet of silver
containing claymat loaded with fentanyl with 10-inch width. and 15-inch
length.
[0032] FIG. 2 provides a schematic diagram of ion-exchange of silver ions
and
intercalation of betaine followed by the addition of analgesic drug fentanyl.
[0033] FIG. 3 provides a schematic diagram of ion-exchange of silver ions
and the
addition of a mixture containing both betaine and a local anesthetic lidocaine
base.
[0034] FIG. 4 provides the amount Of fentanyl (nanogram per sq.cm)
permeated across
the cadaver skin from the multifunctional claymat patch loaded with 80
micrograms per sq, cm
of fentanyl.
[0035] FIG. 5 provides the amount of fentanyl (microgram per sq. cm)
penetrated in the
skin after different time points
0036] FIG. 6 provides the hot plate testing with. 80 micrograms per sq.
cm Fentanyl
loaded silver containing claymat patches: Antinociception attion of fentanyl
'delivered topically
from. Fentanyl loaded silver containing claymat. FIG. 6A Shows that fentanyl
increased the paw
12

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
withdrawal latencies in left hind, paw compared to left paw of the untreated.
rat. FIG. 6 B shows
that right hind paw treated with a silver containing claymat patch labeled as
"R-blank" showed a
decrease in the paw withdrawal latencies as compared to the untreated right
hind paw of the
animal
[0037] Fla 7 provides Kirby-Bauer agar diffusion assay of silver
containing claymat
(S), Fentanyl-loaded Silver containingelaymat (F) and pristine claymat (C)
samples along with a
positive control (A).
[0038] FIG. 8 provides the lidocaine base amounts in microgam per square
centimeter
detected on the skin as a function of time.
[0039] FIG. 9 provides the Paw Withdrawal Latency (PWL) of rats treated
with pristine
claymat (without out silver) patch and control without any patch applied on
the plantar surface. of
the hind limbs.
[0040] FIG. 10 provides the Paw Withdrawal Latency (PWL) of rats-treated
with pristine
claymat (without out silver) patch and lidocaine base loaded claymat patch
applied on the plantar
surface of the hind limbs.
[0041] FIG. I I provides the Paw Withdrawal Latency (PWL) of rats
treated. with silver
containing claymat patch and lidotaint base loaded silver containing claymat
patch applied on
the plantar surface of the hind limbs.
[0042] Fla 12 provides the Paw Withdrawal Latency (PWI.) of rats treated
with silver
containing cla)anat patch and a mixture of lidocaine base and fentanyl loaded
silver containing
claymat patch applied on the plantar surface of the hind limbs.
13

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0043] FIGS. 13 A and B provide a schematic diagram of analgesic loaded
silver
containing claymat patches. FIG. 13A is a simple patch without the drug
diffusion controller
layer. FIG. 13B includes a drug diffusion controller membrane on top of the
analgesic loaded
silver containing-claymat.
[0044] FIG, 14 provides the schematic diagram of a multiftmetional
dressing consisting
of more than one silvercontaining claymat. Each silver containing claymat is
loaded with a
different drug (for example, Fentanyl loaded silver containing claymat, L
Lidocaine base
loaded silver containing claymat).
DETAILED DESCRIPTION OF THE INVENTION
[0045] Clay Films or Sheets
[0046] The disclosure relates to preparation, properties, and
applications of thin clay
sheets.
[0047] Montmorillonite clay has excellent adsorbent as well as particle
clumping
properties: Cations such as sodium, lithium, and potassium reside in the gap
between. these layers
known as the gallery or the interlayer. The gallery allows for 3 processes to
occur: hydrophobic
modification, intercalation, and exfoliation.
[0048] Intercalation is when an organic component is inserted in between
the gallery,
causing expansion, yet still maintaining a well-defined spatial relationship
between the layers.
Intercalation causes the gallery to expand. up to Ito 2 angsuunt Exfoliation
is a. delaminating
process where the gallery expands to the point where the layers completely
separate from each.
other. Thisis. accomplished through the adsorption of desired molecules.
During exfoliation,
packets of clay platelets separate from one another. Platelets at the
outermost region of each
14

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
packet cleave off, exposing more platelets for separation. The gallery expands
up to 20 to 30.
angstroms in the case of exfoliation, almost 20 times more than
intercalation..
[0049] The initial question that arose was how to create a clay film that
does not fall
apart and does not make use of significantly large polymers. Montmotillonite
clay naturally
forms stacks of plate-like structures called platelets, with each platelet.
being less than 10
angstroms thick. The gallery spaces between the platelets can he tilled with
monomers,
oligomers, or polymers to increase the distance between the platelets. The
clay must expand but
not enough to lose its stack organization because if it becomes exfoliated, it
will fail to form an
intact film.
[0050] in some embodiments organo-modified clay sheet made by using
zwitter ions
(ionic compounds containing both positive and negative ions in the same
molecule) such as
Betaine, Betaine hydrochloride, Choline chloride, [2-
(Methacryloyloxy)ethyl}dimethyl-(3-
sulfopropy1) ammonium hydroxide, 1.2-(Methacry1oylox0ethy1idimethy143-
sulfopropyl)
ammonium chloride, 3-Benzy1-5-(2-hydroxymethyl)-4-methylthiazolium chloride
and bromide,
chloride, fluoride and iodide salts of tetraheptylammonium and
cetyltrimethylammonium
cations; all of them haying a very high charge density to intercalate the clay
layer intergalleiy.
[0051] Solvents that can be used for making the clay and organo-modified
clay may
include water, alcohols, organic solvents such as toluene, dimethyl thrmamide,
dimethyl
carbonate, chloroform, and acetonitrile. The drying times required for
formation of clay and
organo-modified films ranges from about 0 to about 24 days. In some
embodiments, the drying
time ranges from about I minute to about 24 hours. In some embodiments, the
drying time
ranges from about 5 to about 12 hours. The curing can be accelerated by
heating using a

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
microwave, or Ultra Violet radiation or Infrared radiation or conventional
heat source. Low
humidity can also accelerate the curing.
[0052] The disclosed teachings provide preparation of clay in the form of
thin film, cut
into desirable sizes. The organo-modified clay product is a film,-a sheet, a
mat, a patch or a
membrane. The disclosed orgatio-modified clay product is referred to as
polymer-free because
polymer is not added for preparation of the clay product. Others disclose day
products made
using polymeric materials which are commonly known as "polymer-clay
composites." In
products referred to as polymer-clay composites, the polymers act as a medium
to disperse clay
particles and to provide mechanical stability to the polymer-clay composite
sheets. The polymer-
clay composite use various polymeric materials such as polyaniline, polymethyl
methacrylate
(PM MA), poly (styrene-co-acrylonitrile), polyaniline, polypyrrole,
polysullone,polyacrylates,
.polyimide, epoxy, polyamide, polypropylene, polypropylene, polyethylene,
polystyrene,
polyvinylchloride, acrylonitrile butadiene styrene (ABS) polymer, Polyethylene
terephthalate
(PET), ethylene-vinyl acetate copolymer (EVA), polyacrylonitrile,
polycarhonate, polyethylene
oxide (PEO), epoxy resin, polyimide, polylactide, polycaprolactone, phenolic
resin, poly p-
phenylene vinylene, polypyrrole, rubber, starch, polyurethane, and
polyvinylpyridine (PVP).
cellulose acetate, vinyl acetate resins, acrylic resins,styrene resins, vinyl
thletride resins,
melamine resins, silicones, polyurethane, polysulphones, polyphenylerte
ethers,polybutylene
terephthalate, and polyethersulfones in their preparation (Fengge Gao,
Clay/polymer composites:
the story, Materials Today, Volume 7, Issue 11, Pages 50-55,2004). The
disclosed
embodiments are referred. to as polymer-free because the disclosed products do
not require
polymers as described above.
16

CA 03007747 2018-06-07
WO 2017/083227
PCT/US2016/060830
[0053] The
disclosure provides fabrication of a clay film covered with mesh and put
onto the adhesive material that serves as the base of the bandage,
[0054] Some embodiments use clay film in -a wound dressing. Some
embodiments use
clay film in a bum wound dressing. Some embodiments use clay film in an
antimicrobial
dressing for gram negative and gram positive bacteria. Some embodiments use
clay film in a
hemostatic dressing,
[0055] Some embodiments use clay film as a permeable and semipermeable
membrane.
[0056] The disclosure relates to the synthesis of organo-modified clay
films that can be
incorporated with metal and non-metallic. cations and able to make small to
large dimension free
standing clay films and membranes upon drying.
[0057] Some embodiments prepare clay sheets withottrusing polymers.
Because in
transdermal drug delivery application, the polymer can hinder or reduce the
permeation or
diffusion of moisture, chemicals, drugs, analgesics, and local anesthetics
through the clay sheets.
It is also preferable to have a continuous sheet clay uninterrupted by the
polymer matrix. In this
way, special properties of clay particles such as adsorption, permeability to
drugs and water, high
temperature stability, ion-exchange property, chemical permeation property,
drug delivery
property, chemical diffusion property, hemostasis property, and wound healing
property Can be
filly utilized without being disturbed. or hindered by the properties of the
polymer.
[0058] Some embodiments use clay film as a UV-resistant, i12-resistant.,
hydrophobic and
hydrophilic coating materials.
17

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0059] Organomodified clay can be exchanged with any group I
(monocationic), group II
(dicationie), group Ill (tricot-ionic), alkali metal, alkaline earth metal or
a combination of groups
I, II and III metal species and ions, and nano and micro sized particles form.
[0060] Organo-modified clay can be exchanged with any transition metal,
late transition
metal, lanthanide Metal, heavy elements in ionic and nano and micro sized
particles form.
[0061] Organo-modified clay can be exchanged with organic molecules -
including but not
limited to pharmacological drugs, vitamins, and nutrients
[0062] Some embodiments use clay sheets to provide controlled delivery of
analgesic
drugs to burn wounds while assisting in wound healing with its antimicrobial
and moisture
control properties.
[0063] Some embodiments use clay sheets to provide transdennal delivery
of nutrients
and pharmacological agents.
[0064] The disclosure provides a polymer-free organo-modified clay
product. The
orstano-modified clay product has clay and an organic compound. The organo-
modified clay
product is alternatively referred to in the disclosure as a film, a sheet, a
mat, a patch or a
membrane. The disclosed organo-modified clay product is referred to as polymer-
free because
the polymer is not added for preparation of the clay product. The clay is
montmorillonite,
kaolinite, smectite, and bentonite. The organic compound is betaine, betaine
hydrochloride,
choline chloride, 3-Benzy1-5-(2-hydroxymethyl)-4-methylthiazolium chloride, 3-
Benzy1-5(2-
hydroxymethyl)-4-methylthiazolitun bromide, 3-Benzy1-542-hydroxymethyl)-4-
methylthiazol ium fluoride, [2-(Methaciyloyloxy)ethyl]dimethyl-(3-sulfopropyl)
ammonium
18

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
hydroxide, [2-(4ethacry1oyloxy)ethyl1dimethy1-(3-sulfopropyl) ammonium
chloride or 3-
Benzy1-5424hydtwzyrathyl.)-4-methylthiazolium iodide.
[0065] In some embodiments, a thickness of the polymer-free organo-
modified clay
product ranges from about I micrometer to about 500 micrometers: In some
embodiments, a
thickness of the polymer-free organo-modified clay product ranges from about 1
micrometer to
about 100 micrometers. In some embodiments, a thickness ofthe polymer-free
organo-modified
clay product ranges from about 20 micrometers to about 60 micrometers. In some
embodiments,
a thickness of the polymer-free organo-modified clay product ranges from about
60 micrometers
to about 100 micrometers. In some embodiments, a thickness of the polymer-free
organo-
modified clay product. is about 80 micrometers.
[0066] In some embodiments, the polymer-free organo-modified clay product
achieves a
bending radius of curvature ranging front about 0.4 millimeters to about 10
centimeters. The
bending radius of curvature is achieved without breaking the polymer-free
oreano-modified clay
product. In some embodiments, the polymer-free oreano-modified clay product
achieves a
bending radius of curvature ranging from about 0.3 millimeters to about 10
millimeters. In some
embodiments, the polymer-free organo-modified clay product achieves a bending
radius of
curvature of about 0.5 millimeters. In some embodiments, the polymer-free
organo-modified
clay product achieves a bending radius of curvature of about 0.4 millimeters.
[0067] In some embodiments, the polymer-free ortzano-modified clay
product has greater
than 50 percent absotption of visible light. In some embodiments, the polymer-
free organo-
modified clay product is non-transparent. In some embodiments of the polymer-
free organo-
modified clay product, when the thickness of the product was about 50
micrometers, the film had
19

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
greater than 50 percent absorption of visible light. In some embodiments, When
the organo-
modified clay product was fbrther modified, by the addition of silver, the
film absorbed greater
than 82 percent of the visible light.
[00681 In some embodiments, the polymer-free organo-niodified clay
product does not
incorporate a polymer. In some embodiments, the organo-modified clay product
is a polymer
free composite.
Antimicrobial Wound Dressing Application of Clay Sheets
[0069) The disclosed organo-modified clay materials stand out from the
rest, as till date
there is no available literature on synthesis of free-standing organo-modified
or unmodified clay
films that are prepared without. using polymers or binders-. Clay tends to
swell when water is
drawn into the interlayer space, allowing the cations to. become easily
exchangeable. En some
embodiments, an N,N,N-trimethylglycine, also known as Betaine is intercalated
into the clay.
The hydroxyl groups of clay attach to the Betaine, expanding the clay. The
silver ions in silver
nitrate exchange with the sodium cations and take their place within the
interstitial space as well.
The silver ions in silver nitrate, the component added to the Montmorillonite
gallery, is the main
driving force for eliminating the microbes. Silver ions tend to have
antiseptic properties used for
controlling burn and eye 'infections. Silver ions have the ability to disrupt
the bacterial cell wall,
penetrate the cell and disrupt, the physiological function of cell,
respiration and metabolites. In
addition, silver is bactericidal against more than 150 species of bacteria,
viruses, yeast and ftmgi,
including MRSA, MDR., Klebsiella and Pseudomonas species.

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0070] Water acts as an essential component in the antimicrobial bandage
as well.
Although most of it evaporates after the clay film is cast some of it may
remain within the clay
film to provide moisture to the wound.
[0071] Organo-modified Silver-clay film can be used as an antimicrobial
wound
dressing. The bare clay and organo-modified clay films that can be used as
burn and or wound
bandages with membranes and adhesive patches can also be .used to stop
bleeding hence can be
used as a hemostatic agent or bandage against wound bleeding and healing in 0-
100 minutes time
interval. The purpose of this product is to fulfill the function of a bandage
as well as kill
microbes when applied to the wound. The product achieves its purpose of
eliminating bacteria in
less than $ min-32 hour depending on the bacterial colony size.
[0072] The bandages can be made available in three different film sizes
ranging from 0.1
cm by 0.1 cm to 100 meter by 100 meter sizes. These sizes are produced to
cater to small,
medium or large wounds. In some embodiments, the larger film products are also
referred to as
sheets. In some embodiments, if the size of the wound is small, a smaller size
of the film product
is cut and is referred to as a mat.
[0073] The silver clay sheet may also work effectively in eliminating
other different
types of microbes such as fungi or algae as well,
[0074] Silver-clay sheets serve multiple purposes in the burn and scar
healing process.
Clay has well-known property to retain moisture and has been used as a
promoter for hemostasis.
Clay with optimal silver concentrations can reduce the cost without
compromising the efficacy
of the silver.
21

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0075] There is a large amount of clinical evidence to support. the use
of hydrogel
dressings in the treatment Of hypertropbic scars. It may be due to the
hydrogel dressings ability
to hydrate the damaged tissue and allow oxygen to permeate to the surface of
the skin. This will.
help in a localized increase in oxygen concentration leading to a down-
regulation of signals that
stimulate growth near the Skin surface, thus preventing or reducing scar
formation. In some
embodiments, the multifunctional polymer-free clay product isox.ygen permeable
In some
embodiments, the multifiinctional polymer-free clay product is oxygen
transport rate of at least
100 cubic centimeters per 100 square inches per day.
[0076] The final product was easily contoured as a bandage (strip or
roll) with a silicone-
based hydrogel adhesive. The bandage served as a bum andwound care product,
which has a
huge commercial market for military and civilian casualties. The wound
dressing can be applied
to numerous applications, such as burn, wound, and surgical care, and also in
water filtration
systems and for food packaging.
[0077] In some embodiments, the polymer-free organo-modified clay product
includes an
antimicrobial agent. The antimicrobial agent can be silver ion, copper,
iodine, prollavine,
silver-
containing compounds, copper containing compounds, quaternary ammonium
compounds, or
quaternary phosphonium compounds. Silver-containing compounds include but are
not limited to
silver sulfadiazine, silver nitrate, :silver oxide, and silver carbonate;
copper containing
compounds include but not limited to copper oxide, copper sulfate, copper
acetate, and copper
nitrate; quaternary ammonium compounds include but not limited to benzalkonium
alkyl
chloride, methyl trialkyl ammonium chloride, and alkyl dimethyl benzyl
ammonium chloride and
.?")

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
quaternary .phosphonium compounds include but not limited to alkyl trimethyl
phosphonium
chloride and dialkyl dimethyl phosphonium bromide.
[0078] in some embodiments, the polymer-free organo-modified clay product
includes an
analgesic. The analgesic can be opioid analgesics, nonsteroidal anti-
inflammatory drugs
(NSA1Ds) and adjuvant analgesics, capsaicin, clonidine, ketamine, Morphine,
fentanyl,
Buprenorphine or cannabinoids.
[0079] Some embodiments provide an antimicrobial dressing having the
polymer-free
organo-modified clay product. Some embodiments provide a bum wound dressing
having the
polymer-free organo-moditied clay product.
[0080] Some embodiments provide a method ofarttimicrobial treatment by
administering
the polymer-free organo-modified clay product.
[0081] Some embodiments provide a method of treating bums by
administering the
polymer-free organo-modified clay product.
[0082] Some embodiments provide a method of preparing a. polymer-free
organo-
modified clay product.. The method includes mixing a clay particle and an
organo-containing
solution to form a slurry. Then the slurry is casted on a substrate to obtain
a slurry casted on a
substrate. Then the slurry casted on the substrate is dried to obtain a dried
product of the slurry
on the substrate. Then the dried slurry product is separated from the
substrate. The separated
dried slurry product. is the polymer-free organo-moditied clay product. The
polymer-free organo-
modified clay product can be a film, a sheet, a mat or a patch or a membrane.
In some
embodiments, if the substrate is glass, then the dried slurry product has to
be removed from the
glass substrate. In some embodiments, if the substrate is fabric or nylon, the
dried slurry product
23

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
need not be removed from the fabric ornylon. The resulting dried shiny product
on the fabric or
nylon substrate can together form part of a wound dressing product. Thus,
dried-sluny need.nof
be removed from a nylon or fabric substrate. In this disclosed methods, no
polymer has been
added to the clay for preparing the product. In some embodiments ofthe method,
the substrate
can be a silicone sheet, fabric or a glass surface. In some embodiments, the
fabric is nylon.
[0083] In some embodiments of the method when the product is prepared at
a
temperature of about 25 degree C., the viscosity of the slurry prepared for
spreading on the
substrate ranges from about 2 centipoise to about 20 centipoise. In some
embodiments of the
method when the product is prepared at a temperature of about 25 degree C, the
viscosity of the
slurry prepared for spreading on the substrate-rang-es from 'about 5
centipoise to about 10
centipoise. In some embodiments drying the slurry casted on- the Substrate is
performed .under
conditions of slow, air. In some embodiments drying the slurry casted on the
substrate is
performed at 20-25 degrees Centigrade under ambient, room temperature
conditions.
[00841 In some embodiments, the polymer-free organo-modified clay product
has greater
than 16 grams per square meter per hour water vapor transport rate (WVTR) at
40 degree C..
[0085] Some embodiments provide a method of preparing a polymer-free
organo-
modified clay product. The method includes mixing a clay particle and an
organo-containing
solution to form a shiny. Then the slurry is casted on a substrate to form a
slurry casted on a
substrate product. Then the slurry casted on the substrate is dried to obtain
the polymer-free
organo-modifted clay product. The organo-modified clay product can be a film,
a sheet, a mat or
a patch or a membrane.
24

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0086] Some embodiments provide a method of preparing a polymer-free
organo-
modified clay product having an antimicrobial agent. The method includes
mixing a clay particle
and an organo-containing solution. Then an antimicrobial agent containing
solution is added to
obtain a slurry. The slurry is casted onto a substrate. The casted slurry and
substrate are subjected
to drying, and a dried slurry is obtained on the substrate. The dried slurry
is separated from the
substrate to obtain the organo-modified clay product containing the
antimicrobial agent.
[0087] Some embodiments provide a method of preparing a polymer-free
organo-
modified clay product having an analgesic. The method includes mixing a clay
particle and an
organo-containing solution. Then an analgesic containing solution is added,
and a slurry is
obtained. The slurry is casted on a substrate and dried to obtain a dried
slurry on the substrate.
The dried slurry is separated from the substrate to obtain the polymer-free
organo-modified clay
product having the analgesic compound.
[00881 Some embodiments provide an antimicrobial wound dressing that also
has
analgesic properties. The wound dressing has a polymer-free organo-modified
clay product
having an antimicrobial agent. The wound dressing has successive layers of the
tbllowin.g: a
hydrogel adhesive with a hydrophobic backing; a polymer-free organo-modified
clay product
having an antimicrobial agent and analgesic; and, a nylon membrane.
10089.1 Some embodiments provide a method of preparing an antimicrobial
wound
dressing having analgesic properties. The method includes successively
layering the following: a
hydrogel adhesive with a hydrophobic backing; a polymer-free organo-m.odified
clay product
having an antimicrobial agent; and, a nylon membrane. In some embodiments, the
method
includes successively layering the following: a nylon membrane, then a polymer-
free organo-
2 5

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
modified clay product having an antimicrobial agent and analgesic; and, then a
hydrogel
adhesive with a hydrophobic backing
[0090j Some embodiments provide an analgesic wound dressing. The
analgesic wound
dressing includes a polymer-free organo-modified clay product having an
analgesic. The wound
dressing has successive layers of the following: a hydrogel adhesive with a
hydrophobic backing;
a polymer-free organo-modified clay product having an analgesic and, a nylon
membrane. Some
embodiments provide a transdermal wound dressing. Some embodiments provide a
method of
preparing a transdemial wound dressing.
[0091] Some embodiments provide a method of preparing an analgesic wound
dressing.
The method includes successively layering the following: a hydrogel adhesive
with a
hydrophobic backing; then a polymer-free orstano-modified.clay product having
an analgesic
and, then a nylon membrane. Alternatively, the successive layering can be as
follows: nylon
membrane, then a polymer-free ortiano-modified clay product having an
analgesic followed by a
hydrogel adhesive with a hydrophobic backing.
[0092] The disclosure relates to a multifunctional device which could be
a patch or
bandage or dressing capable providing pain release while acting as
antimicrobial.
[00931 Silver ions from silver nitrate, exchange with the sodium cations
present in clay,
within the interstitial space. The silver exchanged. clay gallery is the main
driving force for
eliminating the microbes or bacteria. The organo-modified Silver-Betaine-Clay
film is
conformable to various shapes and sizes and garners anti-microbial properties.
FIG. IA Shows a
photograph of silver containing clay mat demonstrating the flexibility of the.
mat. Large size
samples, for example, having 10 inches width and 15 inches length of silver
containing claymat
26

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
such as in FIG. I B can be made by the disclosed processes. Continuous rolls
of mats also can be
made by increasing the drying, rate using higher temperature and air flow over
the mats.
[0094] Some embodiments are a clay mat loaded with silver and fentanyl.
Some
embodiments provide a clay mat loaded with silver and Lidocaine base. Some
embodiments
provide a clay mat loaded with silver and loperamide base. Some embodiments
provide a
multifunctional product containing more than one type of clay mat loaded with
silver and
analgesics. Some embodiments provide a multifunctional product containing both
clay mat
loaded with silver and fentanyl and clay mat loaded with silver and Lidocaine
base. Some
embodiments provide a multifunctional product containing both clay mat loaded
with silver and.
tentanyl and clay mat loaded with silver and Loperamide base.
[0095] The disclosed teachings provide making of a pain relieving device
based on clay
mat. The disclosure provides a device based on clay mats with combined
antimicrobial and pain
relieving properties. The disclosure provides clay mat loaded with silver and
analgesics.
[0096] The disclosed teachings provide making of a pain relieving device
based on clay
mat. The disclosure provides a device based on clay mats with combined
antimicrobial and pain
relieving properties. The disclosure provides clay mat loaded with silver and
analgesics. The
disclosure provides clay mat loaded with silver and femanyl.
[0097] Some embodiments provide a multifunctional topical wound dressing
capable of
both antimicrobial action while delivering pain medication.
[0098] Some embodiments provide a multifunctional polymer-free clay
product having a
clay, a zwitterion, an antimicrobial agent, and, an analgesic. The
multifunctional polymer-free
clay product provides antimicrobial and pain relieving properties. The clay
can be

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
montmorillonite, kaolinite, smectite, and 'bentonite. The antimicrobial agent
can be silver ion,
copper, silver-containing compounds, and, copper containing compounds. Silver;-
containing
compounds include but not limited to silver sulfadiazine, silver nitrate,
silver oxide, and silver
carbonate. The silver provides antimicrobial properties. The zwitterion can be
betaine, betaine
hydrochloride, cholirte chloride, 3-Benzy1-5-(2-hydroxymethyl)-4-
methylthiazolium chloride, 3-
Benzy1-5(2-hydroxymethyl)-41-methylthiazolium bromide, 3-Benzyl-5-
(24ydroxymethyl)-4-
methyltbiazolium. fluoride, [2-(Methacryloyloxy)ethyl]dimethyl-(3-sullopropyl)
ammonium
hydroxide, [2-(Methacryloyloxy)ethyljdimethyl-43-sulfopropyl) ammonium
chloride and 3-
Benzy1-5-(2-hydroxymethy0-4-methylthiazolium iodide. The analgesic can be
plaid analgesics,
nonsteroidal anti-inflammatory drugs (NSAIDs) and adjuvant analgesics,
capsaicin, clonidine,
ketamine. Morphine, fentanyl, Buprenorphine, fentanyl base, lidocaine base,
loperamide base,
cannabinoids, and combinations thereof The thickness of the multifunctional
polymer-free clay
product ranges from about 1 micrometer to about 500 micrometers. In some
embodiments, the
thickness of the multifunctional polymer-free clay product ranges from about 1
micrometer to
about 100 micrometers. The polymer-free clay product achieves a bending radius
of curvature
ranging from about 0.4 millimeters to about 10 centimeters. The polymer-free
clay product can
have greater than 50 percent absorption of visible light. The polymer-free
clay product does not
incorporate a polymer. Some embodiments provide a multifunctional dressing
having a
multifunctional polymer-free clay product.
[0099] Some embodiments provide a method of treating burns by
administering a
multifunctional polymer-free clay product having antimicrobial and pain
relieving properties.

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0100] Some embodiments provide a method of preparing a multirimctional
polymer-free
clay product having an antimicrobial and an analgesic. The method includes
mixing a clay,. an
antimicrobial agent, and water to form a first clay slurry. Washing the first
clay slurry with
water to obtain a washed second clay slurry. Next, adding a zwitterion'and
water to the washed
second slurry to obtain a third clay Slurry. Then casting the third clay
slurry onto a substrate to
obtain a first dried product.. Then adding drops of analgesic in a non-aqueous
solvent onto the
first dried product to obtain a resultant. product. Then drying the resultant
product to obtain a
second dried product. Then separating the second dried from the substrate. The
second dried
product is the multifunctional polymer-free clay product. The multifunctional
polymer-free clay
product provides both antimicrobial and pain relieving properties.. The
antimicrobial. in-the
multifunctional polymer-free clay product can be silver ion, copper, silver-
containing
compounds, and, copper containing compounds. In some embodiments, the silver
compound is
silver nitrate. The analgesic can be fentanyl, lidocaine base, loperamide
base, and combinations
thereof The substrate can be a silicone sheet, fabric, and a glass surface.
The clay can be
montmorillonite, kaolinite, smectite, and bentonite. The zwitterion can be
beanie, betaine
hydrochloride, choline chloride, 3-Benzy1-5(2-hydroxymethyl)-4-
methylthiazolium chloride, 3-
Benzy1-542-hydrolcymethyl)-4-methylthiazohum bromide, 3-Benzy1-5-(2-
hydroxymethy0-4-
methylthiazolitun fluoride, [2-(Methamloyloxy)ethylidimethyl-(3-Sulfoprop.y1)
ammonium
hydroxide, [2-(Methacryloyloxy)ethyljdimethyl-(3-stdfopropyl) ammonium
chloride and 3-
Benzy1-5-(2-hydroxymethyl)-4-methylthiazolium iodide.
1.01011 In another embodiment of the method of preparing a multifunctional
polymer-free
clay product having an antimicrobial and an analgesic, the method includes
mixing a clay, an
29

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
antimicrobial agent, and water to form a first clay slurry. Then washing the
first slurry with
water to obtain a washed second clay slurry. Then adding a mixture of water
and. a non-aqueous
solvent containing betaine and an analgesic to the washed second slurry to
obtain a third clay
slurry. Next, casting the third clay slurry onto a substrate to obtain a dried
product. Next,
separating the dried product from the substrate to obtain a separated dried
product. The
separated dried product is the multifunctional polymer-free clay product,
which. provides
antimicrobial and pain relieving properties. The antimicrobial agent can be
silver ion, copper,
silver-containing compounds, and, copper containing compounds. In some
embodiments, the
silver compound is silver nitrate. The analgesic can be fentanyl, lidocaine
base, loperamide base,
and combinations .thereof Fentanyl compounds include but not limited to
fentanyl base, fentanyl
citrate, and fentanyl hydrochloride (R. S. Vardanyan, V.3. 1-Iruby, Fentanyl-
related compounds,
and derivatives: current status and future prospects for pharmaceutical
applications. Future
medicinal chemistry, 6(4), 385-412, 2014),
['0102] Some embodiments provide a method of preparing a. multifunctional
wound
dressing as shown FIG. 13A. The method includes successively layering of the
following: a
hydrophobic backing film; a multifunctional polymer-free organo-modified clay
product having
both an antimicrobial agent and an analgesic..
[0103] Backing Layer
[0104] In some embodiments, a backing layer may be present. The backing
layer is
typically a layer farthest from the wound. The backing layer provides support
to the
multifunctional claymat and can increase the mechanical strength of the wound
dressing.

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
Preferably the backing layer is conformable to animal anatomical surfaces and
impermeable to
liquid water.
[0105] The backing layer can be an occlusive.dressing that is impermeable
to analgesics,
and anesthetics and other drugs. The backing layer can be a plastic sheet
laminated with metallic
foil.
[01.06] The backing layer can be a. transparent, opaque, conformable,
elastomeric,
moisture vapor permeable film. The backing film is preferably impermeable to
liquid water. The
backing films may be permeable to water vapor. The dressing is preferably
conformable to
anatomical surfaces and stretches to the movement of skin and contracts back
to the same size as
befoat stretching. The backing layer may further include a pressure sensitive
adhesive layer to
enhance adhesion to the first absorbent layer. The backing .film may be made
up using a
hydrogel. The backing film may be hydrophobic and repel water.
[0107] in some embodiment of the invention, the backing layer can be a
dressing such as
that sold under the trademark Tegaderm (3M, St. Paul Minnesota). The backing
layer can be
used to cover and protect dressing and wounds, to maintain a moist environment
for wound
healing, as a protective cover over the wound site.
[0108] Backing layer could be non-woven fabrics, natural fiber (e.g.,
cotton) fabrics,
synthetic resin fabrics, synthetic min films, gauze dressing, synthetic resin
foams, woven
fabrics, and knit fabrics. Pressure-sensitive adhesive sheets, pressure-
sensitive adhesive
dressings, hydrogel dressings, can also be used as a backing layer.
[0109] Some embodiments provide a multifunctional antimicrobial and
analgesic
dressing having a backing film and a multifunctional polymer-free clay
product. The
31

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
multifunctional polymer-free clay product includes a clay, a zwitterion, an
antimicrobial agent.,
and, an analgesic. The multifunctional polymer-free clay product provides
antimicrobial and
pain relieving properties. The backing film is polymeric film. impermeable to
liquid water.
[0110] Some embodiments provide a multifunctional wound dressing consists
of
successively layering of the following: a hydrophobic backing film; a polymer-
free nano-
modified clay product having both silver and fentanyl..
[0111] Some embodiments provide a multifunctional wound dressing consists
of
successively layering of the following: a hydrophobic backing film; a polymer-
free organo-
modified clay product having both silver and lidocaine base.
[0112] Diffusion Control Membrane
[011.3] The multifunctional dressing can include a porous diffusion
control layer to
provide a controlled release-of analgesic from multifunctional clay mat to the
wound site.
[0114] The diffusion barrier membrane allows transport of analgesic from
the
multifunctional clay mat to wound site. The diffusion barrier membrane also
allows moisture,
perspiration and wound exudates from the wound to the multifunctional claymat.
This diffusion
layer allows isolation of wound site from other components of the dressing.
The diffusion control
membrane is preferably soft, flexible, and conformable. It should also be non-
irritating to skin or
wound. Typically; polymeric membranes are used to control the rate of drug
release in
transdermal patches. Polymeric membranes can be made of a polymer such as but
TIOt limited to
nylon, polyurethane, Polytetrafluoroethylene, polyethylene, polypropylene,
polyamide or
polyester materials. Further, the diffusion control membrane may be in the
form of moisture
vapor permeable films, perforated films, porous films, films with micron-sized
holes, films with
32

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
nano-sized holes, track-etched polymer membranes, woven-, non-woven or knit
webs, or scrims.
Some embodiments of the diffusion membrane are a nylon membrane. In some
embodiments,
the diffusion control membrane can be a thin perforated polymeric film such as
that sold wider
the trademark Delnet manufactured by Applied Extrusion Technologies, Inc., of
Middletown
Delaware.
[0115] Some embodiments provide a method of preparing a. multifunctional
wound
dressing as shown in FIG. BB. The method includes successively layering of the
following: a
hydrophobic backing film; a multifunctional polymer-free organo-modified clay
product having
both an antimicrobial agent and an analgesic. and, a diffusion control
membrane.
[0116] Some embodiments provide a multifunctional antimicrobial and
analgesic
dressing having a backing film, a multifunctional polymer-free clay product
and a diffusion
control membrane. The multifunctional polymer-free clay product includes a
clay, a. zwitterion,
an antimicrobial awnt, and, an analgesic. The multiftmetional polymer-free
clay product
provides antimicrobial and pain relieving properties. The backing film is
polymeric film
impermeable to liquid water. The diffusion. control membrane is a porous layer
that provides
controlled release of the analgesic in the multifunctional polymer-free clay
product.
[0117] Some embodiments provide a multiftmetional wound. dressing. The
multifunctional wound dressing includes a polymer-free organo-modified clay
product having
both an antimicrobial agent and an analgesic. The wound dressing has
successive layers of the
following: a hydrogel adhesive with a hydrophobic backing; a polymer-free
organo-modified
clay product having both an antimicrobial and. an analgesic and, a nylon
membrane. Some
33

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
embodiments provide a transdemial wound dressing. Some embodiments provide a
method of
preparing a transdertnal wound dressing.
[01181 Some embodiments provide a multifunctional wound dressing. The
multifunctional wound dressing includes a polymer-free organo-modified clay
product having
both silver and fentanyl. The wound dressing has successive layers of the
following: a hydrogel
adhesive with a hydrophobic backing; a polymer-free organo-modified clay
product having both
having both silver and fentanyl and, a nylon membrane. Some embodiments
provide a
transdennal wound dressing. Some embodiments provide a method of preparing a
transdermal
wound dressing.
[0119] Some embodiments provide a multifunctional wound dressing. The
multifunctional wound dressing includes a polymer-free. organo-modified clay
product having
both silver and lidocaine base. The wound dressing has successive. layers of
the following: a
hyelrogel adhesive with a hydrophobic backing; a polymer-free organo-modified
clay product
having both having both silver and lidocaine base and, a nylon membrane. Some
embodiments
provide a .transdermal wound dressing. Some embodiments provide a method of
preparing a
transdemial wound dressing.
[0120] Some embodiments provide a method of making day mat with
analgesics. Some
embodiments are a method of making clay mat with fentanyl. Some embodiments
are a method
of making clay mat with Lidocaine base. Someembodiments are a method of making
clay mat
with Loperamide base. Some embodiments provide a multiftinctional wound
dressing. The
multifunctional wound dressing includes a polymer-free silver containing clay
product having a.
pain relieving drug. Some embodiments provide a multifunctional wound dressing
containing
34

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
more than one type of polymer-free silver containing clay product having a
pain relieving drug,
where the pain relieving drug could be an analgesic such as tentanyl, morphine
but not limited to
and a local anesthetic such as lidocaine base or loperamide base but limited
to. One embodiment
is represented in FIG. 14. FIG. 14 shows a multifunctional dressing that has
more than one
multifunctional polymer-free clay product. Some of the multifunctional polymer-
free clay
products have .lentarryl (shown as F). Some of the multifunctional polymer-
free clay products
have lidocaine (indicated as .L).
[01211 Some embodiments provide a multifunctional antimicrobial and
analgesic
dressing having a backing film and more than one multifunctional polymer-free
clay product.
Each of the multifunctional clay product. includes a clay, a zwitterion, an
antimicrobial agent,
and, an analgesic. The multifunctional antimicrobial and analgesic dressing
provides
antimicrobial and pain relieving properties. The backing film is a polymeric
film impermeable
to liquid water.
[01221 Some embodiments provide a multifunctional antimicrobial and
analgesic
dressing having a backing .film, more than one multifunctional polymer-free
clay product, and a
diffUsion control membrane. Each of the multifunctional clay product includes
a clay, a
zwitterion, an antimicrobial agent, and, an analgesic. The multifunctional
antimicrobial and
analgesic dressing provides antimicrobial and pain relieving properties. The
backing film is a
polymeric film impermeable to liquid water. The diffusion control membrane is
a porous layer
that provides controlled release of the analgesic from the multifunctional
polymer-free clay
product.
3 5

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0123] Some embodiments provide multiftmctional topical wound dressing
capable of
both. antimicrobial action while delivering pain medication,
[0124] Processes in which analgesic such as but not limited to femanyl,
and morphine
and local anesthetics such as but not limited to lidocaine base and loperamide
base is
incorporated into the clay mat is provided.
[0125] in. one embodiment, the silver containing claymats can be dipped
in. analgesic or
local anesthetic drug dissolved in a non-aqueous solution for a. period of
time. In this process, the
drug was absorbed by the silver containing claymat.
[0126] In another embodiment, drops of a non-aqueous solution of
analgesic or local
anesthetic, drug were placed on the silver containing claymat to allowed to be
absorbed into the
claymat. Then the solvent was evaporated to produce drug-loaded silver
containing claymat
[0127] In another embodiment, silver ion-exchanged clay particles were
treated with a
mixture of water and. a non-aqueous solvent containing both betaine and
analgesic or local
anesthetic drugs. Then the resulting slurry will be casted onto a substrate
and allowed to dry. The
resulting dried product is the silver containing drug loaded clay mat.
[0128] One embodiment of preparation of silver containing claymats is as
follows.
Montmorillonite clay slurry was formed by ion-exchanging sodium ions in the
clay with silver
ions,, followed by intercalating with anhydrous trimethylglycine (Betaine)
molecules, into the
interIayer galleries of clay particles. Further drugs such as fentanyl base
can be loaded onto the
mat to obtain the multifunctional fentanyl base containing clay mat product.
[0129] Schematic representation method of the preparation of silver
containing claymat
is provided in FIG. 2.
36

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0130] It was determined that the sequence of steps involved in the
mixing of clay with
betaine and silver ions is critical for loading analgesics such. as fentanyl.
[0131] The order could be the montmorillonite clay ion-exchanges with
silver ions first
followed by interaction with betaine, or the montmotillonite clay particles
were first exfoliated
with betaine molecules and then the slurry was treated with silver nitrate.
[0132] There is a distinct difference that-can be observed cm the Silver
containing mats
obtained from these two sequential routes. The first process yielded a brown
sheet probably due
to the formation of nano-silver particles inside the galleries of clay layers.
In the second process,
bulk silver (or micro-sized silver particles) was deposited on the Silver
containing claymat
resulting in a gray colored product. The Higher amount of Fentanyl was
incorporated into the
samples, which were formed by first silver ion exchange followed by Betaine
loading. If this
order is reversed no drug was incorporated into the silver containing claymat.
[0133] Another embodiment of a process for incorporating an analgesic
drug into silver
containing claymat is as follows.
[0134] According to one process, the equilibration of silver containing
clay patches in
fentanyl solution yielded patches with a maximum fentanyl loading of
micrograms per sq.cm
The fentanyl loading process was modified in order to increase the loading
level of analgesic. in
a modified process silver containing claymat patches were first wetted with
fentanyl solution in
methanol. The fentanyl liquid was absorbed immediately into the claymat due to
its porous
nature. The solvent was evaporated under ambient conditions leaving fentanyl
loaded into the
silver containing claymats (Fentanyl is non-volatile with melting point of¨
87.5 degree% Using
37

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
this modified method, fentanyl loading levels as high as ¨80 micrograms per
sq.cm have been
achieved.
[0135] A process for loading -large quantities of die-analgesic drug into
a silver
containing claymat is as follows. The transdermal absorption olopioid
analgesics such as
fentanyi may take up to 8-12 h to take pain relieving action. However, the
injured patient
requires the dnius to provide immediate. relief One approach is. to use local
anesthetics such as
Lidocaine or loperamide instead of or in combination with opioid analgesics
like Fentanyt
[0136] The lidocaine patch 5 percent (for example, Lidoderm, Endo
Pharmaceuricals,
inc., Chadds Ford, PA) is a targeted peripheral analgesic, designed to treat
peripheral
neuropathic pain with minimal risk of systemic adverse effects.. The patch
facilitates lidocaine
diffusion across the skin, where the drug binds to sodium channels that are
present in abnormally
high numbers on hyperactive or damaged nociceptors. When bound to these sodium
channels,
lidocaine reduces the abnormal ectopic discharges produced by damaged and
dysfunctional
peripheral nerves and interrupts conduction of the pain signal, thus
alleviating pain. This system
prevents lidocaine from. entering the plasma in any clinically meaningful
concentrations.
[0137] The commercially available lidocaine patch typically consists of a
10 x 14 cm,
nonwoven, polyethylene backing and Medication-containing adhesive of 5 percent
lidocaine (700
mg patch) and other inactive ingredients. The lidocaine base amount in these
patches is
relatively much higher than Fentanyl patches. This could be due to the milder
analgesic action of
Lidocaine compared to Fentanyl. Therefore, it was decided to prepare silver
containing clay-mat
patches with lidocaine with higher loading.
38

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0138] Fentanyl solution was dropped onto Silver containing claymat
directly, and the
solvent was evaporated to form a dry Fentanyl-loaded Silver containing
claymat. This-method
allowed loading of up to 80 microgramicm2 of fentanyl onto Silver containing
claymat. This.
method is not suitable to load 5000 microgram/sq.= (5 milligrams per sq. cm or
5 percent) of
Lidocaine base typically used in commercial lidocaine patch. Therefore, an
alternate method was
investigated to load higher amount of lidocaine onto silver containing
claymat. According to the
new method, the drug was added during the preparation clay.mats along with
betaine as shown in
Fig. 3. FIG. 3 shows ion-exchange of silver ions and intercalation of betaine
mixed together
with lidocaine base to obtain a multifunctional lidocaine base loaded silver
containing clay mat
product.
[0139) Mixtures of silver nitrate and montmorillonite Clay-dressing were
prepared with
different lidocaine hydrochloride compositions. Increasing the lidocaine
hydrochloride content in
the formulation decreased the stability of claymat formation. Higher level
loading of lidocaine
hydrochloride (greater than 7.5 weight percent) resulted in flocculation or
precipitation of the
clay, resulting in claymats that were cracked and poor in quality.
Flocculation can be reduced by
ion-exchanging silver ions for sodium ions in the clay. However, all these
mats were very fragile,
broken easily and had. poor bending strength. The flexibility of the films can
be improved by
increasing the betaine content in the film from 15 weight percent to 25 weight
percent at the
lidocaine hydrochloride loading of 7.5 weight percent..
[0140] Since silver-exchanged clays provided better claymats after
lidocaine
hydrochloride loading, further optimization was carried out using these
compositions. The skin
penetration of Lidocaine hydrochloride continued to increase with time up to
2.5 hours.
39

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
However, the amount of drug released was very low, 4 microgram per sq. cm
after 2.5 hours.
Lidocaine hydrochlotide molecules were strongly bound to the elaymat through
an intercalation
process. This strong binding probably is the reason fir non-leaching of
lidocaine hydrochloride
from the silver containing claymat samples. Therefore, a neutral lidocaine
base was used instead
of lidocaine hydrochloride to increase the release of lidocaine from the
claymats and silver
containing claymats.
[014.1] In vivo animal studies:
[01421 A prototype topical dressing. was tested with an animal (rat) pain
model (Hot plate
test). Pain response in animals can be measured with the hot plate test. This
test can also be used
to test the efficacy of analgesics by observing the reaction to pain caused by
heat. The main
behavioral reaction to heat-induced pain in rats in this system is licking of
the hind paws (in.
response to moderate heat, 48.5 degree C.). The delay in time before a rat
exhibits this behavior
after exposure to heat is labeled as the paw withdrawal latency (PWL). A
higher PWL value
indicates less pain (or increased delay of pain) felt by the animal. The test
equipment consists of
a thermo-regulated hot plate upon which a glass enclosure was placed to keep
the rat over the
heated surface. The rat was placed on the hot plate and the percentage of time
the animal stayed
on the hot plate was measured. The animal was able to stay for a longer
duration due to the local
anesthetic action of fentanyl.
[01431 About 112 percent increase in the PWL for rats treated with
fentanyl loaded silver
containing claymat was observed compared to an untreated animal. It should
also be noted that
the blank silver containintt claymat patch without the fentanyl exhibited
about a 25 percent
decrease in PWL values. Without wishing to bound by any theory, the reason for
this behavior

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
could be the result of silver in the patch, coating the hind paw surface and
making the skin more
conductive-to...heat. Interestingly; a longer latency was observed with
.fentanyl Waded silver
containing claymat patch despite the fact that silver increases thermal
conductivity, making the
argument even stronger that local delivery of fentanyl works as an analgesic.
[0144] in summary, the feasibility of silver loaded claymat to act as a
topical dressing for
the delivery of opioid analgesic, femanyl has been clearly demonstrated. Both
in-vitro
(permeation testing with Franz cell) as well as hot plate rat. model testing
showed that fentanyl
can be loaded onto silver containing claymat and can be released in a
controlled manner via the
skin. Most notable observation is that fentanyl topical patch can be used for
local pain relief.
[0145] Evaluation of Antinociceptive Activity of lidocaine base loaded
silver containing
claymat patches:
[0146] Plain patches of-size 10X10 mm were cut and weighed. 20 microliter
of 250 mg
per niL (5mg per sq.cnt) of lidocaine base solution in methanol was loaded
carefully by adding
dropwise using micropipette for each patch. Methanol was allowed to evaporate
at room
temperature. In. one batch of patches, Fentanyl was also loaded similarly. Paw
Withdrawal
Latency (PWL) of the silver containing claymat loaded with Lidocaine base
group was reduced
by about 52 percent. On the other side, in the case of plain clay patch
(without Silver), there was
no significant increase in the PWL. However, in the case of plain clay patch
(without silver)
loaded with lidocaine base PWI., increased by about 62 percent. The PWI.,
increased about 103
percent as anticipated in the silver containing claymat patch loaded with
Lidocaine base (5
milligrams per sq.cm) and Fentanyl (1 milligram per sq.cm) which was
comparable to the
41

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
positive control commercial Lidodemi patch which resulted in an increase of
about 96 percent in
the PWL
[0147] Antimicrobial Testing of Fentanyl loaded silver containing clarnat
samples:
[0148] Kirby-Bauer agar-diffusion assay for the following samples was
conducted using
four strains E. coli, Salmonella Typhimurium, Staphylococcus wrens, and
Streptococcus
pyogenes, (a) Positive control (AmoxicillinklavWanic acid 30ug - BBL sensidisc
Product
number 231628), (b) Pristine montmorillonite claymat (c) silver containing
clay and (d)
Fentanyl-loaded Silver containing claymat
[0149] The positive control, silver containing clay and fentanyl4oaded
silver containing
claymat samples exhibited a zone of inhibition for all 4 bacteria tested.
Further, no significant
difference was observed between silver containing clay and fentanyl-loaded
silver containing
claymat samples. This has clearly demonstrated that antimicrobial action of
Silver ion was not
detrimentally affected by the fentanyl-loading. The pristine clay material did
not show any zone
of inhibition, indicating that the montmorillonite clay was not antimicrobial.
However, it is
important to note here that montmorillonite clay can be replaced with clays
that have an inherent.
antimicrobial property, such as Cloisite 20A and Cloisite 30B [Si. Hong and J
.W. Rhim,
Antimicrobial activity Of organically modified nano-clays. J. Nanosci
Nanoteehnol. 8, 5818-24
(2008).].
[0150] It will be readily understood by the skilled artisan that numerous
alterations may
be made to the examples and instructions given herein. These and other objects
and features of
present invention will be made apparent from the following examples. The
following examples
as described are not intended to be construed as limiting the scope of the
present invention.

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0151] Other modifications and variations to the invention will be
apparent to those
skilled in the art from the foregoing disclosure and teachings. Thus, while
only certain.
embodiments of the invention have been specifically described herein, it will
be apparent that
numerous modifications may be made thereto without departing from the spirit
and scope of the
invention.
[0152] EXAMPLES
[0153] Example I
[0154] 15 g of montmorillonite clay, L53 g silver nitrate, and 250mL
distilled water were
mixed in a plastic bottle and then placed in a ball mill. After the mixture
had been agitated for at
least 18 hours on the ball mill, it was then centrifuged and. washed four
times with. distilled
water. The mixture was then put back into the plastic bottle with 2.6 g of
Betaine (Sigma-
Aldrich, Saint Louis, MO, CAS number 107,43-7; product number 61962), and.
enough distilled
water added to equal a total of 300 grams of solution and then placed in a
ball mill for at least
another 18 hours. The mixture was caste(' onto a silicone mat and allowed to
dry. The dried
silver containing claymat was used for loading analgesic drugs.
[0155] Example 2
[0156] Loading of Fentanyl base onto Silver containing Claymats
[0157] The elaymats were cut into definite size. They were weighed and
immersed in 1
mg/mliFentanyl base solution (5 ml) (Sigma-Aldrich, Saint Louis, MO, CAS
number 437-38-7,
product number .E-013) in a well-sealed container and allowed to equilibrate
for 24 hours. The
patches were washed off using methanol to get rid of the surface drug
completely. The patches
were then dissolved in water, centrifuged and the supernatant was collected
The supernatant was
43

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
filtered :through 0.22-micron filter and then the amount Of fentanyl base in
the sample was
quantitated,:
[0158] Table 1. The amount of drug loaded in thinner Silver containing
claymat patches
Product code Fentanyl base per unit area Fentanyl base per unit
weight I
(megimg) (mcgtem2,)
:MM1-1413 033 0.18 1.99 0,73
MM1-1414 0.54 0,16 3.4S 0.91
MM1-1415 0.02 0.008
MMI-1416 0.03 0.005
[01591 The Higher amount of Fentanyl base was incorporated into the
samples MAII-
1413 and MM1-1414, which were formed by first silver ion exchange followed by
Betaine
loading. If this order is reversed: no drug was incorporated into the claymat.
[0160] The equilibration 0Si:1w:containing claymat patches in fentanyl
base solution
yielded patches with: a maximum fentanyl loading of ¨8 micrograms per
sq...crn, 'Fhe fentanyl
baseloading prOCOSWO.plodifiedin Order tO inot'easethe loading level of
fentanyl base, ht 010'
modified process Fentanyl base loaded silver containing claymat patches WOre
first wetted, with
fentanyl base solution in methanol. The fentanyl base liquid was absorbed
immediately into the
silver containing claymat due to its porous nature. The solvent was evaporated
under ambient
44

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
conditions leaving fentanyt base loaded into the Silver containing claymats
(Fentanyl base is tlein,
volatile witti:inOting:Ofint of¨ 87,5 degitee); Using this modified method,
fentanyl loading:
levels as high as nicecrn2 have been achieved.
[0161] Table 2. The amount of Fentanyl base loaded in silver containing
clayinat patches
(mcg¨ micmgram)
Product Thickness Fentanyl base loading
Fentanyl per unit
code (micromete method weight (incgkin2)
MMI-1413 40 Equilibrating patch with .99 0.73
Fentanyl base solution
MMI-1414 40 Equilibrating patch with 3.45k0.91
Fentanyl base solution
MM1-1440 80 Equilibrating patch with 8.35+-2.18
Fentanyl base solution
MM1-1441 100 Addition of Fentanyl base 84.54-111.14
solution onto the claymat,
followed by solvent removal
[0162] Example 3
[0163] In-vitro Drug Release Studies
[0164] Initial trials were performed using Franz diffusion cells. The
film$:(MMI-1415:
and M MI-1414) dissolved in water and buffer. Therefore, we performed the
release studies using
methanol. The films were immersed in 4 ml methanol. 200 microliters of
methanol were sampled

CA 03007747 2018-06-07
WO 2017/083227
PCT/US2016/060830
at each:time point and the resemOitwas replaced with same volume eit6h tittle
The amount of
drug:WM*0W was (1-00-ii*ed by RPLC Tht amounts Of fentaaA !i.eto*04, into the
otution
wetv provided in Table 3 and 4.
[0101 Table 3 Drug release per unit area of the Fentanyl loaded
sityer:oentaining
claymat mat
Time iN4MI-1413 MMI-1414
(h) (mcgicm2) (me Wm') sd sd
IIII 0.09 IIIMMEIM 0,09
1 .._
0.84 1.45 0.02 0.02
1111111.11111111.1=1 0.62
[OW] Table 4. Drug rejeaSp. Or unit Weight of the Fentanyi loaded
silver=sontainiog
elaymat mat
Time MMI-1413 MMI-1414
(h) (megfcm2) (mcglcm2) sd sd
0 , 0.014 0.06 0.002 0.02
1.5 0.13 0.19 0.02 0.014
3 0,28 0,37 0,19 0.04
0.32 0.52 0.20 0.13
7 0.33 0.54 0.18 0.16
46

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0167] Example 4
[0168] .Fentanyl base loading of thicker silver containing claymat
patches
[0169] The patches were cut into definite size. They were weighed and
immersed in 10
mg/ml Fentanyl base solution (5 ml) in a well-sealed container and allowed to
equilibrate for 2.4
hours. The patches were washed using methanol to get rid, of the surface drug
completely. The
patches were then dissolved in water, -centrifuged and the supernatant was
collected. The
supernatant was filtered through 0.22-micron filter, and then the amount of
fentanyl in the
sample was quantitated. The amounts of fentanyl base released into the
solution were provided
in Table 5 and 6.
[0170] Table 5. The amount of drug loaded in thicker Fentanyl loaded
silver containine,
claymat patches
Product code Fentanyl base per unit weight Fentanyl base per unit area
(mcitimg) (mcwcml
MMI-1440
(80-micron 0.28 0.06 8.35 2.18
thick patch)
[0171] Example 5
[0172] Drug Release Studies
[0173] The films were immersed in 4m1 methanol. 2.00 microliters of
methanol were
sampled at each time point, and the reservoir was replaced with same volume
each time. The
amount of drug in methanol was quantitated by HPLC,
[0174] Table 6. Drug release data of the thicket fentanyl loaded silver
containing clay-mat
patch (Meg microgram)
47

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
Time (h) Cumulative release per unit Cumulative release
per unit
weight (mcalmg) area (ircaisq. cm)
0
0.004 0.001 0,11+0.02
1.5
0.15 0.06 4.63+1.91
3
0.25i0.03 7.48+1.23
0,24 0.06 l7.3527
[0175] The 80-micrometer thick silver containing claymat samples were
loaded with
fentanyl base using the same method described in example 2. The load per unit
weight did not
change much. The load per surfa.ce area were doubled due to increase in the
thickness from 40
microns to 86 microns. The equilibration of Fentanyl base loaded silver
containit4elaymat
patches in fentanyl base solution yield patches with a maximum fentanyl base
loading of 8
ineWSqcm. The fentanyl base loading process was modified in order ti.-
?:increaSeithe loading
level offentanyl bast: In the modified process Fentanyl base loaded silver
containing clayind
patches were first wetted with fentanyl base solution in methanol. The solvent
was evaporated
under ambient conditions to form dry fentanyl base-loaded silver containing
claymats. Using this
modified method, fentanyl base loading levels as high as 80 mcglcm2 has been
achieved,
[0176] Example 6
[0177] Invitro FentattYI hase Permeation Testing on Human *in 80
mcgten14Pe.ntanYl:
loaded silver containing claymat Patch
[0178] Since the fentanyl base permeation from the 8 meg/0112 Fentanyl
:lbaded silver
containing claymat patches resulted in the very low amount of fentanyl base
diffusion through
the human skin, we decided to treat Fentanyl loaded silver containing claymat
patches with 10X
48

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
higher loading of fentanytbast The data of higher femanyl base-loaded Fentanyl
loaded silver
cOntairiing elayttlat poto pros vied in Table 7,
[0179] Table 7, Loading amount of feutanyl base in Fentanyl loaded silver
containing
claymat used in Human Skin Permeation Testing
Product code Fentanyl base per unit area (microgram
per
cm)
1440 (80-100micron 84.54,01.14
thickness)
[0180] Drutz. Permeation Studies
[0181] Method: The drug loaded Fentanyl loaded silver: containing claymat
patch was:
placed on the backing film with an adhesive. The drug transport of drug from
the Fentanyl
loaded silver containing claymat patch across the microtomed human cadaver
skin (0,25 mm)
was:performed using Franz diffUsion cell setup. The patch was overlaid on the
human skin:With
clay patch facing the epidermis side of the skin placed on a tubber ring. The
skin samples were
previously tested for integity by using electrical resistivity equipment and
Transepidermal water
loss (Delfin Technologies) equipment, The second tubber ring was placed on the
patch and
mounted on the Fran diffusion cell. The receiver compartment was filled with
pH 7,4 buffer. The
receiver compartment fluid was withdrawn at 2 hours interval and analyzed for
Fentanyl base
content by MU:.
[01.8.2] Results: The permeation across the skin was found to have a lag
time 16 It After
12 hours, the drug was detectable in.,thmeeiver compartment. The amount of
fentanvi base
(ngistixm) permeated across the cadaver skin from the clay patch loaded with
80 micrograms per
49

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
square cm per patch is provided in FIG. 4. As seen in FIG. 4, about 0.2
nanograms per square
centimeter of fentanyl base was found to have permeated after about 12 h,
about 1.9 nanograms
per square centimeter of .fentanyl base was found to have permeated after
about 16 h, about 3.6
nanograms per square centimeter of fentanyl base was found to have permeated
after about 20
hours, about 4,1 nanograms per square centimeter of fentanyl base was found to
have permeated
after about. 24 hours, about 5.1 nanograms per square centimeter of fentanyl
base was found to
have permeated after about 36 hours, and about 4.9 nanograms per square
centimeter of fentanyl
base was found to have permeated after about 48 hours.
[0183] Drug Penetration Studies
[0184] Method: The set up was similar that set up for skin permeation
studies. However,
in this study, the skin was removed at different time points, the active
diffusion area of the skin
was biopsy punched, the surface was washed with water 3 times and wiped with a
kimwipe. The
skin was dissolved in 1N sodium hydroxide by incubating overnight. The sodium
hydroxide
solution was centrifuged after overnight incubation; IN perchloric acid was
incorporated to
precipitate the proteins. The mixture was centrifuged again, and the
supernatant was diluted (1:1)
with phosphate buffer and injected into HPLC for quantitation. Three trials
were run for each
time point for 8 hours.
[0185] Results: The cumulative amount of drug penetrated into the skin
increased with
time is provided in FIG. 5. The amount of drug after 2 hours and 4 hours was
about 1.53 and
3.30 meg/4cm respectively (FIG. 5). The amount of drug in 8th hour and 12th
hour were 4.90
and 6.92 mcg/cm2 respectively.
[0186] Example 7

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0187] After in-vitro optimization of the analgesic delivery from
fentanyl base loaded
silver containing claymat, the prototype topical dressing was tested with an
animal (rat) pain.
model (Hot plate test). Pain response in animals can be measured with the hot
plate test. This test
can also be used to test the efficacy of analgesics by observing the reaction
to pain caused by
heat. The main behavioral reaction to heat-induced pain in rats in this system
is licking of the
hind paws-(in response to moderate heat., 48.5 deareeC). The delay in time
before a rat exhibits
this behavior after exposure to heat is labeled as the paw withdrawal latency
(PWL). A higher.
PWL value indicates less pain (or increased delay of pain) felt by the animal.
[0188] The test equipment consists of a thermo-regulated hot plate upon
which a glass
enclosure was placed. to keep the rat over the heated surface. The rat was
placed on the hot plate
and the percentage of time the animal stayed on the hot plate was measured.
The animal was able
to stay for a longer duration due to the local anesthetic action of fentanyl
base. Male., 8 weeks
old Sprague-Dawley Rats were purchased from Harlan Laboratories (South Easton,
MA).
Fentanyl base loaded silver containing clapnat patch (80 micrograms per square
centimeter
fentanyl base concentration) was placed on the plantar aspect of the left hind
foot (test limb) and
blank silver containing claymat (no fentanyl base) referred as 4R-blank" in
FIG. 613 was placed
on the plantar aspect of the right hind foot (control hind limb) of the same
rat. The patches were
secured. to the hind limbs using an adhesive backing film After 12 hours
exposure time, both
patches were removed, and after 30 minutes the rat was subjected to hot plate
analgesia testing
using a hot plate analgesia meter um Life Science Inc., Woodland Hill, CA).
Hot plate
analgesia tests were carried out at 48.5 degreeC. Each test was recorded using
a hand-held video
camera. Video footages were analyzed to determine the paw withdrawal time
(PWL, the time it
5.1

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
took for the rat to lift and start licking its control or test limb) for each
hind. paw. The paw
withdrawal latency (.PWL) values are plotted in FIG. 6A and FIG. 68. We
observed a -111
percent increase in the PWL for Fentanyl loaded silver containing claymat-
treated rat compared
to an untreated animal. It should also be noted that the blank Silver
containing claymat patch (R
blank) without the fentanyl base exhibited a --25 percent decrease in PWL
values. The reason for
this behavior could be the result of silver in. the patch, coating the hind
paw surface and making
the skin more conductive to heat. Interestingly, a longer latency was observed
with Fentanyl
loaded silver containing claymat patch despite the fact that silver increases
thermal conductivity
making the argument even stronger that local delivery of Fentanyl base works
as an analgesic.
Anomalous data in Rat #7 could be due to the uncertainty in the application of
the patch because
the patch. was chewed off by the animal.
[0189] Example 8
[0190] Antimicrobial Testing of Fentanyl loaded silver containing claymat
Samples
[01911 Kirby-Bauer agar diffusion assay for the following samples was
conducted using
four strains E. coli, Salmonella Typhimurium, Staphylococcus aureus, and
Streptococcus
pyogenes.
[0192] (a) Positive control (Amoxicilliniclavulanic acid - 3Oug - BBL
sensidisc
Product number 231628).
[0193] (b) Pristine montmorillonite clay
[0194] (c) Silver containing montmorillonite clay and
[0195] (d) Fentanyl-loaded silver containing montmorillonite clay

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0196] The zone Of inhibition values in:centimeters are provided iruTable
8, and the data
IS: plotted in FIG. 7.
[0197] Table 8. TablefOt Zone Of inhibition
Bacteria. Number Of .Zone of inhibition (en))
Replicates
Antibtoti Claymat Silver- Fentanyl-
c (No silver loaded loaded
+ Control added) clay- Silver
(Silver
containing
containing claymat
claymat)
. .
,
E. coli 1 1.5 0 0.7 0.8
,
' 7 1.5 . 0 0.8 0,7
3 1.5 0 0.9 0.6
Salmonella 1 1,9 0 0.6 0,6
Typhimurium , .
.
.4.. 1.8 0 0.6 0.6
...,
.J 2.1 0 0.7 0,5
Staphylococcus 1 1.5 0 ' 0,6 0.8
aureus
7 1.5 0 0.7 0.7
3 1.6 0 0.7 0.6
Streptococcus 1 2.1 0 0.9 ' 0,7
pyogenes
.-) 2,2 0 0.8 0,6
.
.
3 2 0 0.7 0,6
, ............................................................................

[019811 The positive control, silver containing montmorillonite claymat
and fentanyl
loaded silver containing montinorilionite claymat samples exhibited a zone of
inhibition for all 4
bacteria.tested. Farther, no significant difference was observed between
silver containing
montmorilionite claymat and fentanyl loaded silver containing montmorillonite
claymat samples.
This has clearly demonstrated that fentanyl-loading did not affect the
antimicrobial action of
53

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
silver ion detrimentally. FIG. 7 shows the plot of zones of inhibition on
claymat C, silver
containing claymat S. fentanyl-loaded silver containing claymat F, and
antibiotic positive (-Ive)
control A. when tested with E.coli, salmonella typhimuriutn, staphylococcus
aureus and
streptococcus pyogenes.
[0199] Example 9
[02001 synthesis of lidocaine base
[0201] In a typical synthesis, 10 g of lidocaine hydrochloride was
dissolved in 50 niL of
acetonitrile. Then 14 g of potassium carbonate was added and stirred at 50
degreeC for 1h. Then
the reaction mixture was filtered using a Buettner funnel and the filtrate was
rotoeyaporated to
yield Lidocaine Base product itt>95percent yield. Silver containing claymats
and plain clay-mats
were loaded with lidocaine base, and their drug release study was conducted.
[0202] Example 10
[0203] Mixtures of silver nitrate and montmorillonite claymats were
prepated,
centrifuged, and washed following the same procedure as described in example I
with different
compositions as listed in the table below. After centrifugation and washing,
various
concentrations of lidocaine base and hetaine were added to each mixture in a
plastic bottle as
shown in Table 9.
54

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0204] Table. 9. Various compositions of claymat precursor solution
Lidoeaine Betaine I Total Clay AgNO3 Betaine
Lidocaine
base Concentration Mass of (8) (g) (.0 base (g)
Concentration (weight Solution
(weight percent) (g)
percent)
7.5 15 120 6 0.617 0.9 0.45
7.5 20 120 6 0.612 1.2 0.45
7.5 25 120 6 0.612 1.5 0.45
I

7.5 30 120 6 0.612 1.8 0.45
[02051 All bottles were capped and placed in a ball mill overnight. After
agitation on the
ball toil.eacb bottled mixture. was uncapped and placed in a desiccator with
&vacuum pump
attached to it to extract all the bubbles out of solution. Each dressing
mixture was then poured
onto a baking mat to dry. Clay Malta were fatly dried in 2-3 days. `['he area
of the clay mat was
approximated (368 square centimeters). Even though Lidocaine base
concentration in the
precursor solution was 7,5 weight percent, the lidocaine base loading was
about 1.2 milligram
per square centimeter based on the size of the mat.
[02061 Example Ii
[02071 Skin penetration studies
[0208] A 10x lOmm lidocaine base (5 milligrams per squareventimeter)
containing Silver
containing claymat patch was secured onto the stratum comeum with the help of
a backing
membrane. The receptor compartment was filled with 5 mr,.. of phosphate buffer
(pH 7.4). The
cells with skin and lidocaine hydrochloride patch were mounted on the
diffusion apparatus. 'The

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
receptor solution (Phosphate buffer saline pH 7.4) in contact with the
underside of the skin was
stirred magnetically at 600rpm and its temperature maintained to achieve a
skin surface
temperature of 32.0 1.00 degreeC. At time intervals of 0,5, 1,1.5, 3-and 6 h
clay patch was
removed from the skin, the skin was washed with purified water, and tape
stripped one. time
using 3M's adhesive tape to remove any adhering drug from the skin surface.
The biopsy sample
of the active diffusion area of the skin (0,64 square-centimeters) was cut and
subjected to
extraction of lidocaine hydrochloride content for measurement.
[0209) Sample Analysis
[0210] Lidocaine base was extracted from skin that was cut into small
pieces using I mi.
of water. The skin sample was vortexed with water for 10 min. These samples
were kept for
shaking for 1 hr and centrifuged for 15 min at 13000 Tin; The supernatant was
subjected to
analysis by HPLC.
Results: There was an increasing trend in the amount of drug loaded into the
skin with time. FIG.
8 shows that the total amount of drug loaded in the skin were about 18.7
micrograms per square
centimeter in 0.5 h, about 29.5 micrograms per square centimeter in 1.5 h,
about 47 micrograms
per square centimeter in 3 h, about 59.6 micrograms per square centimeter in
4.5 h, and about 69
micrograms per square centimeter in 6 hours.
[0211] Evaluation of Antinociceptive Activity of Drug Loaded Clay patches
(Hot Plate
Test)
[0212] Patch preparation: Plain patches of size 10X10 mm were cut and
weighed.
20microliter of 250mg/mL (5mtt per square centimeter) of Lidocaine base
solution in methanol
was loaded carefully by adding dropwise using micropipette for each patch.
Methanol was
56

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
allowed to evaporate at room temperature. In one batch of patches, Fentanyl
was also loaded
similarly.
[0213] Grouping: Male Sprague dawley rats (250-300 g) were be used for
the study.
They were randomly groupedinto fourgroups of four animals each as mentioned
below:
[0214] Group I: Silver containing claymat patch only
[021.5] Group IL Silver containing claymat patch loaded with Lidocaine
base
[0216] Group III: Silver containing claymat patch loaded with Lidocaine
base and
Fen tanyl
[0217] Group IV: Clay/Betaine Patch loaded with Lidocaine
[0218] Group Plain clay patch only
[02193 Method: The animals were allowed tbr several days of
acclimatization for
handling Two days prior -to experimentation they were allowed acclimatize for
baseline thermal
latency. On the day of the experiment, the patches were applied on the plantar
surface of the hind.
limbs. The patches were secured to the hind limbs using an adhesive bandage.
After 6 hrs, the
patches were removed, and the animals were subjected to hot plate analgesia
testing using a hot
plate analgesia meter (IITC Life Science Inc., Woodland Hill) CA). Hot plate
analgesia tests
were carried out at. 48.5 degree C. Each test was recorded using a hand-held
video camera. Video
footages were analyzed -to determine the paw withdrawal time (PWL, the time it
took for the rat
to lift and start licking its control or test limb) for each hind paw. A cut-
off period of 60 s was
given to avoid any potential thermal injury to the rat's paw. A minimum of
three replicates was
run on each rat. The mean and SD was calculated for each group.
57

CA 03007747 2018-06-07
WO 2017/083227 PCT/US2016/060830
[0220] Results: The Paw Withdrawal Latency (PWL) data in seconds for test
animals is
plotted in FIG. 9, FIG. 10, FIG. 1 1 and FIG. 12. Paw Withdrawal Latency (PWL)
of the plain
Silver containing claymat patch applied rats was reduced by -28percent.
interestingly, the PWL
data provided in FIG. ii show that for the Silver containing clarnat loaded
with Lidocaine base
(Group II) was also reduced by ¨52percent. On the other side, in the case of
plain clay patch,
there was no significant increase in the PWL as shown in FIG, 9, However, in
the case of clay
patch loaded with lidocaine PWL increased by about 62percent as shown in FIG.
10. From these
two sets of data, it is evident that presence of silver in silver containing
claymat increases the
conductivity of the skin overcoming the local anesthetic effect of lidocaine.
The PAIL increased
-103percent as anticipated in the silver containing clarnat patch loaded with
lidocaine base
(5inglem2) and Fentanyl (Inigicrn2) as shown in FIG. 12 which was comparable
to the positive
control commercial lidocaine patch which resulted in an increase in the MI.. -
96 percent.
58