Note: Descriptions are shown in the official language in which they were submitted.
CA 02446705 2010-07-26
COMPOSITIONS OF QUINOXALINE-BASED THERAPEUTIC
AGENTS AND FATTY ACIDS HAVING ENHANCED
PHARMACOKINETIC CHARACTERISTICS
to Background of the Invention
The present invention relates to compositions
containing therapeutic components, hereinafter TCs, for
example, alpha-2-adrenergic agonists. More
particularly, the invention relates to such compositions
15 including such TCs, and advantageously one or more other
components, in which compositions the TCs preferably
have enhanced pharmacokinetic characteristics.
A TC includes any chemical entity, such as a
compound, an ion, a complex and the like, which is
20 effective to act on and/or bind to receptors and provide
a therapeutic effect. The TC may .be an agonist, an
antagonist, precursors thereof, metabolites thereof and
combinations thereof.
A continuing challenge in providing compositions
25 having TCs is to be able to render such compositions
more effective. One way to render the TCs more
effective is to enhance their pharmacokinetic
dispositions. For example, the dispensed or
administered TCs should advantageously be permeable
30 through lipid cell membranes so that the agonist may
reach the target receptor to impart a therapeutic
effect. One possible reason for why certain TCs
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permeate poorly through a lipid membrane is that these
components may be charged ions at physiological pH.
Although the term "enhancement of pharmacokinetic
disposition" as used herein may mean an enhancement in
permeability, an enhancement of pharmacokinetic
disposition may also mean an enhancement in, for
example, bioavailability, sequestration and/or release
characteristics of the TCs.
Ion pairing, or complexation, between cations and
anions to enhance the movement of ionizable molecules
across biologic membranes has been suggested. Nash et
al. Skin Pharmacol 5:160-170 (1992) and Ogawa et al. Jpn
J Ophthalmol 37:47-55 (1993). However, prior ion
complex systems may be inappropriate for use to deliver
TCs to certain biological environments, for example, the
ophthalmic environment.
There continues to be a need for new compositions
that increase the efficacy of therapeutic components.
Summary of the Invention
New TC-containing compositions have been
discovered. In accordance with the invention, the
present compositions contain certain materials which are
effective in enhancing the efficacy of the TCs of the
compositions. Without limiting the invention to any
particular theory or mechanism of operation, it is
believed that the efficacy of the TCs is enhanced
because of improved pharmacokinetics, for example,
increased permeability of the TCs through lipid
bilayers. In one embodiment, these materials enhance
the bioavailability of the TCs in the eye. Preferably,
the materials are able to enhance the pharmacokinetics
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of the TCs under physiological conditions, for example
at pHs of about 6.5 to about 9.
The TCs are advantageously ionized or ionizable at
physiological pHs, for example, about pH 6.0 to about pH
9Ø In one embodiment, the TCs are ionized or
ionizable at about pH 7.
TCs employed in the present, compositions include
those compounds, mixtures of compounds, mixtures of
other materials, which are useful to provide a
io therapeutic benefit or effect when administered to a
patient, e.g. a human patient. The TCs useful in this
invention include, without limitation, NMDA antagonists,
antibacterials, antihistamines, decongestants,
antiinflammatory, antiparasitics, miotics,
anticholinergics, adrenergics, antivirals, local
anesthetics, antifungals, amoebicidals,
trichomonocidals, analgesics, mydriatics, antiglaucoma
drugs, neuroprotective agents, antiaugiogenic agents,
ophthalmic diagnostic agents, ophthalmic agents used as
adjuvants in surgery, chelating agents, antineoplastics,
antihypertensives, muscle relaxants, diagnostics and the
like and mixtures thereof. Specific examples of such
TCs are conventional and well known in the art.
The TCs may include alpha-2-adrenergic agonists.
Alpha-2-adrenergic agonists include imino-imidazolines,
imidazolines, imidazoles, azepines, thiazines,
oxazolines, guanidines, catecholamines, biologically
compatible salts and esters and mixtures thereof. The
alpha-2-adrenergic agonist may include quinoxaline
components. Quinoxaline components include quinoxaline,
biologically compatible salts thereof, esters thereof,
other derivatives thereof and the like, and mixtures
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thereof. Non-limiting examples of quinoxaline
derivatives include (2-imidozolin-2-ylamino)
quinoxaline, 5-bromo-6-(2-imidozolin-2-ylamino)
quinoxaline, and biologically compatible salts thereof
and esters thereof, for example, the tartrate of 5-
bromo-6-(2-imidozolin-2-ylamino) quinoxaline, and the
like and mixtures thereof. Hereinafter, 5-bromo-6-(2-
imidozolin-2-ylamino) quinoxaline is referred to as
"brimonidine", and the tartrate of 5-bromo-6-(2-
imidozolin-2-ylamino) quinoxaline is referred to as
"brimonidine tartrate."
The alpha-2-adrenergic agonists, such as those
listed above, may be specific for the alpha-2A-
adrenergic receptors, alpha-2B-adrenergic receptors
and/or alpha-2D-adrenergic receptors or any combination
thereof.
Materials which enhance the pharmacokinetics of the
TCs include efficacy enhancing components, hereinafter
EECs. In one embodiment, the EEC includes fatty acids,
saturated and/or unsaturated. The fatty acids of the
present invention may have more than 12 carbons, for
example docosahexanoic acid and linolenic acid. In one
embodiment, the fatty acids of the present invention
comprise about 12 carbons to about 26 carbons. In
another embodiment, the fatty acids of the present
invention comprise about 16 carbons to about 24 carbons.
In one embodiment, the EECs themselves are effective to
provide at least one therapeutic effect.
The TC and the EEC form and/or are present in the
form of a complex in the compositions of the present
invention. In one embodiment, the TC and the EEC form a
complex in solution, for example, a complex may be
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formed in a solution at a pH of about 5 to about 9, for
example, about pH 7 to about pH 9. In one embodiment,
the EEC and the TC form a complex that is an ion pair,
for example, in an aqueous component. In one
embodiment, the TC and EEC are able to form a complex
present as a separate phase, for example a salt-like
material and or oil phase, outside of a solution.
The present compositions may include carrier
components. In one embodiment, the compositions have
pHs of about 7 or greater. For example, the
compositions may have pHs of between about 7 and about
9, and preferably are ophthalmically acceptable.
In a useful embodiment, a solubilizer component may
be included in the present compositions. The
solubilizer component is present in an amount effective
to enhance the solubility of the complexes in the
present compositions. Although any suitable solubilizer
component may be employed, the solubilizer component is
advantageously nonionic. Non-limiting examples of
useful solubilizer components include poly(oxyethylene)-
poly(oxypropylene) block polymers, polysorbate 80,
polyvinyl alcohol, polyvinylpyrrolidine,
hydroxypropylmethyl cellulose and the like and mixtures
thereof.
Still further in accordance with the invention, the
present compositions may include an effective amount of
a nonionic tonicity component. Nonlimiting examples of
useful nonionic tonicity components are mannitol,
glycerine and mixtures thereof.
The EEC and TC advantageously are present in
amounts so that the ratio of electrical charge from the
EEC to electrical charge from the TC is in range of
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about 0.9 to about 1.5. In a preferred embodiment, the
ratio of electrical charge from the EEC to electrical
charge from the TC is in a range of about 0.95 to about
1.4, for example, about 1.0 to about 1.3.
The present compositions may include a buffer
component. Although any suitable buffer component may
be employed, it is advantageous to employ a buffer
component which is effective at reduced concentrations,
for example, to assist in reducing the ionic
concentration in the present compositions. In one
embodiment, the buffer component is present in a range
of about 0.001 molar or about 0.005 molar to about 0.05
molar about 0.1 molar. In one useful embodiment, the
buffer component is a phosphate buffer component.
Any feature or combination of features described
herein are included within the scope of the present
invention provided that the features included in any
such combination are not mutually inconsistent as will
be apparent from the context, this specification, and
the knowledge of one of ordinary skill in the art.
Additional advantages and aspects of the present
invention are apparent in the following detailed
description and claims.
Detailed Description of the Invention
Compositions comprising therapeutic components,
TCs, and efficacy enhancing components, EECs, are
provided. The EECs employed in the present compositions
may be effective in enhancing the pharmacokinetics of
the TCs. For example, the EEC may enhance the
therapeutic effect of the therapeutic component. In one
embodiment, the present compositions may further include
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liquid carrier components and have the characteristics
of liquid, for example, aqueous liquid, solutions.
In one embodiment, the TC and the EEC form
complexes. The complexes formed may be a "loose" ion
pair or a "tight" ion pair. In one useful embodiment,
the complex of the present invention is a "tight" ion
pair. For example, the complexes of this invention are
adequately "tight" as to not dissociate in high
dielectric constant solvent, such as water or aqueous
solutions. One advantage of such a "tight" ion pair
complex is that the complex may be contained in an
aqueous solution, for example saline, which may be used
in an ophthalmic environment.
In one embodiment, the complex is able to
dissociate under certain conditions. For example, after
the complex crosses the lipid layer, the TC may activate
a targeted molecule more effectively if it is not
complexed to an EEC. Therefore, in one embodiment, the
TC and the EEC exist as a complex for the purpose of
enhancing the pharmacokinetic disposition of the TC and
thereafter dissociate to allow the TC to act more
effectively at a receptor.
In one embodiment, a single TC may form a complex
with more than one EEC, for example two or three EECs.
In another embodiment, a single EEC may form a complex
with more than one TC, for example two or three TCs.
In one embodiment, a single TC molecule may form a
complex with one or more EEC molecules, for example,
one, two or three EEC molecules may form a complex with
one TC molecule. In another embodiment, a single EEC
molecule may form a complex with more than one TC
molecules, for example, two or three TC molecules may
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form a complex with one EEC molecule.
The presently useful TCs preferably are chosen to
benefit from the presence of the EECs. In general, the
TCs are provided with enhanced ability to cross a lipid
membrane when they complex with the EECs. In one
embodiment, the TCs are basic molecules. In another
embodiment, the TCs are cations.
Examples of TCs which may be included in the
present compositions include, but are not limited to,
NMDA antagonists; antibacterial substances such as beta-
lactam antibiotics, such as cefoxitin, n-
formamidoylthienamycin and other thienamycin
derivatives, tetracyclines, chloramphenicol, neomycin,
carbenicillin, colistin, penicillin G, polymyxin B,
vancomycin, cefazolin, cephaloridine, chibrorifamycin,
gramicidin, bacitracin and sulfonamides; aminoglycoside
antibiotics such as gentamycin, kanamycin, amikacin,
sisomicin and tobramycin; nalidixic acid and its analogs
such as norfloxacin and the antimicrobial combination
fluoroalanine/pentizidone, nitrofurazones and analogs
thereof; antihistaminics and decongestants such as
pyrilamine, chlorpheniramine, tetrahydrazoline,
antazoline and analogs thereof; mast-cell inhibitors of
histamine release, such as cromolyn; anti-
inflammatories such as cortisone, hydrocortisone,
hydrocortisone esters, betamethasone, dexamethasone,
dexamethasone sodium phosphate, prednisone,
methylprednisolone, medrysone, fluorometholone,
prednisolone, prednisolone sodium phosphate,
triamcinolone, indainethacin, sulindac, its salts and
its corresponding sulfides, and analogs thereof; miotics
and anticholinergics such as echothiophate, pilocarpine,
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physostigmine salicylate, diisopropylfluorophosphate,
epinephrine, dipivaloylepinephrine, neostigmine
echothiopate iodide, demecarim bromide, carbamoyl
choline chloride, methacholine, bethanechol, and analogs
thereof; mydriatics such as atrophine, homatropine,
scopolamine, hydroxyamphetamine, ephedrine, cocaine,
tropicamide, phenylephrine, cyclopentolate,
oxyphenonium, eucatropine; and the like and mixtures
thereof. Other TCs are: antiglaucama drugs, for
example, timolol, and especially its maleic salt and R-
timolol and a combination of timolol or R-timolol with
pilocarpine; other adrenergic agonists and/or
antagonists such as epinephrine and an epinephrine
complex, or prodrugs such as bitartrate, borate,
hydrochloride and dipivefrine derivatives; carbonic
anhydrase inhibitors such as acetazolamide,
dichlorphenamide, 2-(p-hydroxyphenyl)-thiothiophene-
sulfonamide, 6-hydroxy-2-benzothiazolesulfonamide, and
6-pivaloyloxy-2-benzothiazolesulfonamide; antiparasitic
compounds and/or anti-protozoal compounds such as
ivermectin, pyrimethamine, trisulfapidimidine,
clindamycin and corticosteroid preparations; compounds
having antiviral activity such as acyclovir, 5-iodo-2'-
deoxyuridine (IDU), adenosine arabinoside (Ara-A),
trifluorothymidine, interferon, and interferon-inducing
agents such as poly I:C; antifungal agents such as
amphotericin B, nystatin, flucytosine, natamycin and
miconazole; anesthetic agents such as etidocaine
cocaine, benoxinate, dibucaine hydrochloride, dyclonine
hydrochloride, naepaine, phenacaine hydrochloride,
piperocaine, proparacaine hydrochloride, tetracaine
hydrochloride, hexylcaine, bupivacaine, lidocaine,
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mepivacaine and prilocaine; ophthalmic diagnostic
agents, such as: (a) those used to examine the retina
such as sodium fluorescein, (b) those used to examine
the conjunctiva, cornea and lacrimal apparatus, such as
fluorescein and rose bengal and (c) those used to
examine abnormal pupillary responses such as
methacholine, cocaine, adrenaline, atropine,
hydroxyamphetamine and pilocarpine; ophthalmic agents
used as adjuncts in surgery, such as alpha-chymotrypsin
and hyaluronidase; chelating agents such as
ethylenediaminetetraacetic acid (EDTA) and deferoxamine;
immunosuppressants and anti-metabolites such as
methotrexate, cyclophosphamide, 6-mercaptopurine and
azathioprine and combinations of the compounds mentioned
above, such as antibiotics/antiinflammatories
combinations such as the combination of neomycin sulfate
and dexamethasone sodium phosphate and combinations
concomitantly used for treating glaucoma, for example, a
combination of timolol maleate and aceclidine; and the
like and mixtures thereof.
In a preferred embodiment, the useful TCs include
adrenergic agonists. The adrenergic agonists may be
molecules containing amines. Also, the adrenergic
agonists may be amine-containing molecules with pKa's of
greater than 7, preferably about 7 to about 9.
In one embodiment, the useful TCs include alpha-
adrenergic agonists. Examples of alpha-adrengergic
agonists include, but not limited to, adrafinil,
adrenolone, amidephrine, apraclonidine, budralazine,
clonidine, cyclopentamine, detomidine, dimetofrine,
dipivefrin, ephedrine, epinephrine, fenoxazoline,
guanabenz, guanfacine, hydroxyamphetamine, ibopamine,
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indanazoline, isometheptene, mephentermine, metaraminol,
methoxamine, methylhexaneamine, metizolene, midodrine,
naphazoline, norepinephrine, norfenefrine, octodrine,
octopamine, oxymetazoline, phenylephrine,
phenylpropanolamine, phenylpropylmethylamine,
pholedrine, propylhexedrine, pseudoephedrine,
rilmenidine, synephrine, tetrahydrozoline, tiamenidine,
tramazoline, tuaminoheptane, tymazoline, tyramine,
xylometazoline, and the like and mixtures thereof.
In one useful embodiment, the TCs include alpha-2-
adrenergic agonists. As used herein, the term "alpha-2
adrenergic agonist" includes chemical entities, such as
compounds, ions, complexes and the like, that may
produce a net sympatholytic response, resulting in
increased accommodation, for example, by binding to
presynaptic alpha-2 receptors on sympathetic
postganglionic nerve endings or, for example, to
postsynaptic alpha-2 receptors on smooth muscle cells.
A sympatholytic response is characterized by the
inhibition, diminishment, or prevention of the effects
of impulses conveyed by the sympathetic nervous system.
The alpha-2 adrenergic agonists of the invention may
bind to the alpha-2 adrenergic receptors
presynaptically, causing negative feedback to decrease
the release of neuronal norepinephrine. Additionally,
they also may work on alpha-2 adrenergic receptors
postsynaptically, inhibiting beta-adrenergic receptor-
stimulated formation of cyclic AMP, which contributes to
the relaxation of the ciliary muscle, in addition to the
effects of postsynaptic alpha-2 adrenergic receptors on
other intracellular pathways. Activity at either pre-
or postsynaptic alpha-2 adrenergic receptors may result
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in a decreased adrenergic influence. Decreased
adrenergic influence results in increased contraction
resulting from cholinergic innervations. Alpha-2
adrenergic agonists also include compounds that have
neuroprotective activity. For example, 5-bromo-6-(2-
imidozolin-2-ylamino) quinoxaline is an alpha-2-
adrenergic agonist which has a neuroprotective activity
through an unknown mechanism. Without limiting the
invention to the specific groups and compounds listed,
the following is a list of representative alpha-2
adrenergic agonists useful in this invention: imino-
imidazolines, including clonidine, apraclonidine;
imidazolines, including naphazoline, xymetazoline,
tetrahydrozoline, and tramazoline;,imidazoles, including
detomidine, medetomidine, and dexmedetomidine; azepines,
including B-HT 920 (6-allyl-2-amino-5,6,7,8 tetrahydro-
4H-thiazolo[4,5-d]-azepine and B-HT 933; thiazines,
including xylazine; oxazolines, including rilmenidine;
guanidines, including guanabenz and guanfacine;
catecholamines and the like.
Particularly useful alpha-2-adrenergic agonists
include quinoxaline components. In one embodiment, the
quinoxaline components include quinoxaline, derivatives
thereof and mixtures thereof. The derivatives of
quinoxaline include, without limitation, (2-imidozolin-
2-ylamino) quinoxaline. In one embodiment, the
derivatives of quinoxaline include 5-halide-6-(2-
imidozolin-2-ylamino) quinoxaline. The "halide" of the
5-halide-6-(2-imidozolin-2-ylamino) quinoxaline may be a
fluorine, a chlorine, an iodine, or preferably, a
bromine, to form 5-bromo-6-(2-imidozolin-2-ylamino)
quinoxaline.
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Other useful quinoxaline derivatives are well
known. For example, useful derivatives of a quinoxaline
include the ones disclosed by Burke et al U.S. Patent
No. 5,703,077. See also Danielwicz et al 3,890,319.
The quinoxaline and derivatives thereof, for
example brimonidine, are amine-containing and preferably
have pKa's of greater than 7, preferably about 7.5 to 9.
Analogs of the foregoing compounds that function as
alpha-2 adrenergic agonists also are specifically
intended to be embraced by the invention.
The alpha-2-adrenergic agonists, for example the
ones listed above, may be effective toward activating
one or more of alpha-2A-adrenergic receptors, alpha-2B-
adrenergic receptors and alpha-2D-adrenergic receptors.
In one embodiment, the composition of the present
invention includes a TC other than an alpha-2-adrenergic
agonist. For example, a composition in accordance with
the present invention may include a TC which is not a
quinoxaline such as 5-bromo-6-(2-imidozolin-z-ylamino)
quinoxaline (brimonidine).
Other useful TCs include ocular hypotensive agents
(Woodward et al U.S. Patent No. 5,688,819),
pyranoquinolinone derivatives (Cairns et al U.S. Patent
No. 4,474,787), compounds having retinoid-like
activities (Chandraratna U.S. Patent No. 5,089,509),
ketorolac/pyrrole-l-carboxylic acids {Muchowski et al
U.S. Patent No. 4,089,969), ofloxacins/benzoxazine
derivatives (Hayakawa et al U.S Patent No. 4,382,892),
memantines (Lipton et al U.S. Patent No. 5,922,773).
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In one useful embodiment, the amount of TC in the
present composition is in the range of about 0.05% to
about 30% (w/v). The amount of TC may be in the range
s of about 0.1% (w/v) to about 10% (w/v) . For example,
the amount of TC may be in the range of about 0.1% (w/v)
to about 0.6% (w/v). In one embodiment, the TC is an
adrenergic agonist and is present in the composition in
the range of about 0.1% (w/v) to about 0.6% (w/v), for
io example, about 0.13%.
Any suitable EECs may be employed in accordance
with the present invention. In one embodiment, the EECs
are acidic molecules. In another embodiment, the EECs
are anions. In one embodiment, EECs include fatty acids
is or derivatives thereof. The fatty acids may possess a
long hydrophobic carbon chain and a terminal carboxyl
group. The chain may be saturated, or it may have one
or more double bonds. Moreover, fatty acids may contain
triple bonds. Fatty acids may differ, for example, in
20 length and in the number and position of their
unsaturated bonds. Non-limiting examples of saturated
fatty acids include lauric acid, myristic, palmitic,
stearic, arachidic, lignoceric, derivatives thereof, and
the like and mixtures thereof. Non-limiting examples of
25 unsaturated fatty acids include palmitoleic, oleic,
linoleic, linblenic, arachidonic, derivatives thereof,
and the like :and mixtures thereof. Other examples of
some unusual fatty acids include trans-Vaccenic acid,
lactobacillic, tuberculostearic, cerebronic, derivatives
30 thereof, and the like and mixtures thereof.
In one embodiment, the EEC includes a
docosahexanoic acid. In another embodiment, the EEC
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includes a linolenic acid.
In one embodiment, the fatty acids of the present
invention comprises about 12 carbon atoms to about 26
carbon atoms. In another embodiment, the fatty acids of
the present invention comprises about 16 carbon atoms to
about 24 carbons.
In one embodiment, the EEC has a direct therapeutic
effect. For example, an EEC may include eicosanoids,
such as prostanoids. A prostanoid is any group of
complex fatty acids derived from arachidonic acid, being
carbon in length with an internal 5 or 6 carbon ring,
for example prostaglandin, protanoic acid and
thromboxanes. Prostanoids are known to reduce intra-
ocular pressure. In one embodiment, a composition
15 according to the invention comprises a complex having a
TC and a therapeutically effective EEC. For example, a
composition according to the present invention may
comprise a complex of an adrenergic agonist and a
prostanoid. Both the adrenergic agonist and the
20 prostanoid may act, via different mechanisms, to provide
an additive therapeutic effect, for example, to reduce
intra-ocular pressure. The EEC may exert its therapeutic
effects when it is still bound to a complex, or the EEC
may exert its effects when it is free from the complex.
Although fatty acids are preferred as counter ions
to form complexes with TCs, such as the adrenergic
agonists, other molecules may be used as counter ions to
form complexes with the TCs. In one embodiment, the
complexes formed are able to enhance the movement of the
TCs across lipid layers. In one embodiment, these
complexes are able to solubilize the TCs in solution,
preferably solutions with pHs of about 7 to about 10.
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EECs other than fatty acids include anionic
polymers derivatives thereof, and the like and mixtures
thereof. In one embodiment, the anionic polymers are
added to a solution containing TCs to form a complex
with the TCs therein. Preferably, the anionic polymer
is ophthalmically acceptable at the concentrations used.
Additionally, the anionic polymer may include one or
more, for example, two (2) or three (3), anionic (or
negative) charges. Furthermore, anionic polymers with
more than 1 anionic site may be employed to reduce the
osmotic pressure of a solution containing TCs. For
example, a solution having a complex wherein several TCs
complex to a single anionic polymer has a lower osmotic
pressure than a similar solution wherein the TCs are not
complexed.
Examples of anionic polymers which may have
multiple anionic charges include:
metal carboxymethylstarchs
metal carboxymethylhydroxyethylstarchs
hydrolyzed polyacrylamides and polyacrylonitriles
heparin
homopolymers and copolymers of one or more of:
acrylic and methacrylic acids
metal acrylates and methacrylates
alginic acid
metal alginates
vinylsulfonic acid
metal vinylsulfonate
amino acids, such as aspartic acid, glutamic
acid and the like
metal salts of amino acids
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p-styrenesulfonic acid
metal p-styrenesulfonate
2-methacryloyloxyethylsulfonic acids
metal 2-methacryloyloxethylsulfonates
3-methacryloyloxy-2-hydroxypropylsulfonic
acids
metal 3-methacryloyloxy-2-
hydroxypropylsulfonates
2-acrylamido-2-methylpropanesulfonic acids
to metal 2-acrylamido-2-methylpropanesulfonates
allylsulfonic acid
metal allylsulfonate and the like
cellulose derivatives:
carboxymethylcelluloses
metal carboxymethylhydroxyethylcelluloses
hydroxypropylmethylcelluloses
In another embodiment, the anionic polymers
include anionic polysaccharides which tend to exist in
ionized forms at higher pHs, for example, pHs of about 7
or higher. The following are some examples of anionic
polysaccharides which may be employed in accordance with
this invention.
Polydextrose is a randomly bonded condensation
polymer of dextrose which is only partially metabolized
by mammals. The polymer may contain a minor amount of
bound sorbitol, citric acid, and glucose. Chondroitin
sulfate also known as sodium chondroitin sulfate is a
mucopolysaccharide found in human tissue, specifically
cartilage, bones, tendons, ligaments, and vascular
walls. This polysaccharide has been extracted and
purified from the cartilage of sharks. Carrageenan is a
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linear polysaccharide having repeating galactose units
and 3,6 anhydrogalactose units, both of which can be
sulfated or nonsulfated, joined by alternating 1-3 and
beta 1-4 glycosidic linkages. Carrageenan is a
hydrocolloid which is heat extracted from several
species of red seaweed and irish moss. Maltodextrins
are water soluble glucose polymers which are formed by
the reaction of starch with an acid and/or enzymes in
the presence of water. Other anionic polysaccharides
found useful in the present invention are hydrophilic
colloidal materials and include the natural gums such as
gellan gum, alginate gums, i.e., the ammonium and alkali
metal salts of alginic acid and mixtures thereof. In
addition, chitosan, which is the common name for
deacetylated chitin is useful. Chitin is a natural
product comprising poly-(N-acetyl-D-glucosamine).
Gellan gum is produced from the fermentation of
Pseudomonas elodea to yield an extracellular
heteropolysaccharide. The alginates and chitosan are
available as dry powders from Protan, Inc., Commack,
N.Y. Gellan gum is available from the Kelco Division of
Merk & Co., Inc., San Diego, Calif. Generally, the
alginates can be any of the water-soluble alginates
including the alkali metal alginates, such as sodium,
potassium, lithium, rubidium and cesium salts of alginic
acid, as well as the ammonium salt, and the soluble
alginates of an organic base such as mono-, di-, or tri-
ethanolamine alginates, aniline alginates, and the like.
Generally, about 0.2% to about 1% by weight and,
preferably, about 0.5% to about 3.0% by weight of
gellan, alginate or chitosan ionic polysaccharides,
based upon the total weight of the composition, are used
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to obtain the gel compositions of the invention.
The anionic polysaccharides may be cyclized. The
cyclized anionic polysaccharides may include less than
ten monomer units. For example, the cyclized
polysaccharides include less than six monomer units.
In one embodiment, a, particularly useful group of
cyclized anionic polysaccharides includes the
cyclodextrins. Examples of the cyclodextrin group
include, but are not limited to: a-cyclodextrin,
derivatives of a-cyclodextrin, 0-cyclodextrin,
derivatives of (3-cyclodextrin, y-cyclodextrin,
derivatives of y-cyclodextrin, carboxymethyl-p-
cyclodextrin, carboxymethyl-ethyl-p-cyclodextrin,
diethyl-p-cyclodextrin, dimethyl-p-cyclodextrin, methyl-
p-cyclodextrin, random methyl-p-cyclodextrin, glucosyl-p-
cyclodextrin, maltosyl-p-cyclodextrin, hydroxyethyl-p-
cyclodextrin, hydroxypropyl-p-cyclodextrin,
sulfobutylether-p-cyclodextrin, and the like and
mixtures thereof. Sulfobutylether-p-cyclodextrin is a
preferred cyclized anionic polyasaccharide in accordance
with the present invention. It is advantageous that the
EECs, including the above mentioned cyclodextrins,
employed in this invention be, at the concentration
employed, non-toxic to a mammal, for example a human. As
used herein, the term "derivatives," as it relates to a
cyclodextrin, means any substituted or otherwise
modified compound which has the characteristic chemical
structure of a cyclodextrin sufficiently to function as
a cyclodextrin component, for example, to enhance the
solubility and/or stability of active components and/or
reduce unwanted side effects of the active components
and/or to form inclusive complexes with active
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components, as described herein.
Although cyclodextrins and/or their derivatives may
be employed as EECs, one embodiment of the invention may
include EECs other than cyclodextrins and/or their
derivatives.
A particularly useful class of anionic polymer
includes anionic cellulose derivatives. Anionic
cellulose derivatives include metal carboxymethyl-
celluloses, metal carboxymethylhydroxyethylcelluloses
and hydroxypropylmethylcelluloses and derivatives
thereof.
In one embodiment, a complex of a TC and a EEC may
exist as a salt-like material and/or an oil phase
outside of a solution. For example, a complex of
is brimonidine and linoleic acid may be a powder.
Furthermore, this complex may be added to a solution,
for example a saline solution. Preferably, the TC and
the EEC still remain as a complex. In one embodiment,
the solution containing the complex, for example a
complex of brimonidine and linoleic acid, is
administered to the eye to treat glaucoma. In one
embodiment, the complex remains intact at the site where
the therapeutic component may exert a therapeutic
effect. In a preferred embodiment, the complex
dissociates at or near the site where the therapeutic
component may exert a therapeutic effect. For example,
a complex of brimonidine and linolenic acid may
dissociate to release brimonidine at or near the ciliary
body in the eye, wherein the brimonidine can act on
receptors located on the ciliary body to reduce the
production of aqueous solutions, thereby treating
glaucoma.
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In another embodiment, a EEC is added to a solution
containing TC to form a complex with the TC therein. In
one embodiment, the complex is formed only in solution.
The amount of EEC added is such that the
s pharmacokinetics of the TC is at least somewhat
increased. Such amount should be effective to perform
the desired function or functions in the present
composition and/or after administration to the human or
animal. In one embodiment, one or more EECs, which may
io include an anionic polymer, are present in an amount
sufficient to form a complex with at least a portion or
substantially all of the TC present in a present
composition. Advantageously, the EEC is present in an
effective amount, but less than the amount required to
is form an emulsion, for example, with the water present in
the composition. In one useful embodiment, the complex
is not present in an emulsion, for example, an EEC/water
emulsion. The present compositions preferably includes
no emulsions, for example, as described herein. At
20 least about 10% or about 30% or about 50% or about 70%
of the TC in the present compositions preferably is
present in the form of a complex with the EEC(s). More
preferably, more preferably about 80% or about 90% to
about 100% of,the TC present is in such a complex.
25 In one useful embodiment, the amount of EEC, for
example, an anionic polymer, in the present composition
is in the range of about 0.1% to about 30% (w/v) or more
of the composition. For example, the amount of EEC is
in the range of about 0.2% (w/v) to about 10% (w/v). In
30 one embodiment, the amount of EEC is in the range of
about 0.2% (w/v) to about 0.6% (w/v). In another
embodiment, the EEC is carboxymethylcellulose and is
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present in the composition in the range of about 0.2%
(w/v) to about 0.6% (w/v). One useful concentration of
carboxymethylcellulose in the present compositions is
about 0.5%.
In one embodiment, the TCs and the EECs form
complexes at pHs of greater than 7. Preferably, the
TCs and the EECs form complexes at pHs between about 7
to about 10.
Without wishing to limit the present invention to
any particular theory or mechanism of operation, it is
believed that at least one element which contributes to
complex stabilization and/or inhibition of complex
disassociation is an interaction of the non-polar or
hydrophobic hydrocarbon portion or tail of the EEC with
1s the TC. This interaction may act in combination with
the ionic interaction between the EEC and the TC to
enhance complex stabilization and/or inhibit complex
disassociation. This interaction may also be involved
in enhancing complex formation. The effects of the
hydrophobic interaction and ionic interaction may be
synergistic in nature.
Compositions of the present invention may
advantageously include solubilizer components which at
least assist in maintaining the TC-EEC complex in
solution or dispersed in the composition. For example,
a solubilizer component may be useful to maintain the
TC-EEC complex in solution under conditions which, in
the absence of a solubilizer component, would result in
insolubility and/or precipitation of the TC-EEC complex.
These conditions include one or more of certain pH
values, certain concentrations of the TC and/or EEC,
certain ionic concentrations and the like. The presence
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of a solubilizer component preferably reduces the
solubility sensitivity of the present complexes to these
conditions and allows .for more flexibility in
formulating the present compositions.
The inclusion of ions or ionic species in the
present compositions may weaken the bonding between the
TC and the EEC. in the complexes, disadvantageously
resulting in a lowered concentration of intact TC-EEC
complexes. Therefore, in one useful embodiment, the
solubilizer component is nonionic to reduce the ionic
concentration in the present compositions and still
provide the benefits to be attained from the solubilizer
component. Examples of nonionic solubilizer components
include, without limitation, poly(oxyethylene)-
poly(oxypropylene) block polymers, polysorbate 80,
polyvinyl alcohol, polyvinylpyrrolidine,
hydroxypropylmethyl cellulose and the like and mixtures
thereof.
In one embodiment, the complex according to the
present invention may serve as a delay release system
for the TCs and/or the EECs. For example, a TC may be
pharmacologically inactive when it is part of a complex.
However, as the complex disassociates, for example,
slowly disassociates over time in a biological
environment, it releases, for example, slowly releases
the TC. A slow and/or delayed release of a
pharmacologically active TC may be advantageous. For
example, such delayed release may be helpful in
providing appropriate dosing.
In one embodiment, the complexation of TCs with
EECs may further help to solubilize the TCs in solution
and preferably reduces irritation when the TCs are
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administered to sensitive tissues. For example, an eye
drop solution having a pH of about 7 may contain
insoluble TC ions, such as brimonidine tartrate ions.
If such a solution is administered to the eye, a
sensitive tissue, the insoluble TC ions may cause
discomfort and irritation. However, a complex of TC and
EEC may help solubilize the TC in such a solution. In
one embodiment, the solution containing a solubilized TC
results in less irritation as the solution is applied to
a sensitive tissue, for example the eye. In a more
preferred embodiment, the solution containing solubilize
TC results in little or no irritation when the solution
is administered to a sensitive tissue.
In one embodiment, the compositions may also
include preservative components or components which
assist in the preservation of the composition. The
preservative components selected so as to be effective
and efficacious as preservatives in the present
compositions, that is in the presence of EECs, and
preferably have reduced toxicity and, more preferably,
substantially no toxicity when the compositions are
administered to a human or animal.
Preservatives or components which assist in the
preservation of the composition which are commonly used
in pharmaceutical compositions are often less effective
when used in the presence of solubilizing agents or
solubilizing component. In certain instances, this
reduced preservative efficacy can be compensated for by
using increased amounts of the preservative. However,
where sensitive or delicate body tissue is involved,
this approach may not be available since the
preservative itself may cause some adverse reaction or
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sensitivity in the human or animal, to whom the
composition is administered.
Preferably, the present preservative components or
components which assist in the preservation of the
composition, for example, the TCs and/or EECs therein,
are effective in concentrations of less than about 1%
(w/v) or about 0.8% (w/v) and may be 500 ppm (w/v) or
less, for example, in the range of about 10 ppm(w/v) or
less to about 200 ppm(w/v). Preservative components in
accordance with the present invention preferably
include, but are not limited to, those which form
complexes with the anionic polymer, or EEC, to a lesser
extent than does benzalkonium chloride.
Very useful examples of the present preservative
components include, but are not limited to oxidative
preservative components, for example oxy-chloro
components, peroxides, persalts, peracids, and the like,
and mixtures thereof. Specific examples of oxy-chloro
components useful as preservatives in accordance with
the present invention include hypochlorite components,
for example hypochlorites; chlorate components, for
example chlorates; perchlorate components, for example
perchlorates; and chlorite components. Examples of
chlorite components include stabilized chlorine dioxide
(SCD), metal chlorites, such as alkali metal and
alkaline earth metal chlorites, and the like and
mixtures therefore. Technical grade (or USP grade)
sodium chlorite is a very useful preservative component.
The exact chemical composition of many chlorite
components, for example, SCD, is not completely
understood. The manufacture or production of certain
chlorite components is described in McNicholas U.S.
CA 02446705 2010-08-11
Patent 3,278,447. Specific examples of useful SCD
Products include that sold under the trademark Dura Klor*
by Rio Linda Chemical Company, Inc., and that sold under
the trademark Anthium Dioxide by International Dioxide,
Inc. An especially useful SCD is a product sold under
the trademark PuriteT by Allergan, Inc. Other examples
of oxidative preservative components includes peroxy
components. For example, trace amounts of peroxy
io components stabilized with a hydrogen peroxide
stabilizer, such as diethylene triamine penta(methylene
phosphonic acid) or 1-hydroxyethylidene-1,1-diphosphonic
acid, may be utilized as a preservative for use in
components designed to be used in the ocular
is environment. Also, virtually any peroxy component may
be used so long as it is hydrolyzed in water to produce
hydrogen peroxide. Examples of such sources of hydrogen
peroxide, which provide an effective resultant amount of
hydrogen peroxide, include sodium perborate decahydrate,
20 sodium peroxide and urea peroxide. It has been found
that peracetic acid, an organic peroxy compound, may not
be stabilized utilizing the present system. See, for
example, Martin et al U.S. Patent No. 5,725,887.
Preservatives other than oxidative preservative
components may be included in the compositions. The
choice of preservatives may depend on the route of
administration. Preservatives suitable for compositions
to be administered by one route may possess detrimental
properties which preclude their administration by
another route. For nasal and ophthalmic compositions,
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preferred preservatives include quaternary ammonium
compounds, in particular the mixture of alkyl benzyl
dimethyl ammonium compounds and the like known
generically as "benzalkonium chloride." For
compositions to be administered by inhalation, some
preferred preservatives are chlorbutol and the like.
Other preservatives which may be used, especially for
compositions to be administered rectally, include alkyl
esters of p-hydroxybenzoic acid and mixtures thereof,
to such as the mixture of methyl, ethyl, propyl, butyl
esters and the like which is sold under the trade name
"Nipastat."
In one broad embodiment, compositions are provided
which comprise a TC-EEC complex, a preservative
1s component in an effective amount to at least aid in
preserving the compositions and a liquid carrier
component. Preferably, the preservative components
include oxy-chloro components, such as compounds, ions,
complexes and the like which (1) do not substantially or
20 significantly detrimentally affect the TC in the
compositions or the patients to whom the compositions
are administered, and (2) are substantially biologically
acceptable and chemically stable. In one embodiment,
compositions in accordance with the present invention
25 comprise a complex of alpha-2-adrenergic agonist-
linolenic acid, an oxy-chloro component, and a liquid
carrier component, for example, an aqueous component.
The carrier components useful in the present
invention are selected to be non-toxic and preferably
30 have no substantial detrimental effect on the present
compositions, on the use of the compositions or on the
human or animal to whom the compositions are
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administered. In one embodiment, the carrier component
is a liquid carrier. In a preferred embodiment, the
carrier component is a liquid carrier component, for
example, an aqueous component. A particularly useful
liquid carrier component is that derived from saline,
for example, a conventional saline solution or a
conventional buffered saline solution. The liquid
carrier preferably has a pH in the range of about 6 to
about 9 or about 10, more preferably about 6 to about 8,
and still more preferably about 7.5. The liquid medium
preferably has an ophthalmically acceptable tonicity
level, for example, of at least about 200 mOsmol/kg,
more preferably in the range of about 200 to about 400
mOsmol/kg. In an especially useful embodiment, the
osmolality or tonicity of the carrier component
substantially corresponds to the tonicity of the fluids
of the eye, in particular the human eye. In another
useful embodiment, nonionic tonicity components are
used.
In one embodiment, the carrier components
containing the EECs and the TCs may have viscosities of
more than about 0.01 centipoise (cps) at 25 C, for
example, more than about 1 cps at 25 C or, for example,
more than about 10 cps at 25 C. In one embodiment, the
composition has a viscosity of about 50 cps at 25 C and
comprises a conventional buffer saline solution, a
carboxymethylcellulose and a brimonidine tartrate. In
one useful embodiment, in place of saline, a nonionic
tonicity component is used.
In order to insure that the pH of the liquid
carrier component, and thus the pH of the composition,
is maintained within the desired range, the liquid
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carrier component may include at least one buffer
component. Although any suitable buffer component may
be employed, it is preferred to select such component so
as not to produce a significant amount of chlorine
dioxide or evolve significant amounts of gas, such as
CO. The buffer component may be inorganic. Alkali
metal and alkaline earth metal buffer components are
advantageously used in the present invention. For
example, phosphate buffers may be used in accordance
io with the present invention. One or more buffer
components may be used in a composition of the present
invention.
As used herein, the term "complex" refers to a
close association between one or more EECs and one or
1s more TCs. For example, the electrical charge of an TC
in solution may maintain one or more EECs comprising an
opposite electrical charge in close association. In one
embodiment, the present complexes are ion pair complexes
in which the electric charge of the EECs and the TC are
20 substantially or even completely balanced. It should be
noted, however, that the present invention is not
intended to be limited to only such ion pair complexes.
Rather, any complex or related combination of EEC(s)
and TC component(s) which preferably remain
25 substantially intact in an aqueous environment, and
which exhibit one or more of the enhanced effects. set
forth herein, is to be considered within the scope of
the present invention.
The formation of an TC-EEC complex may produce an
30 overall diminishment in the net electrical charge of the
TC. To promote the formation of intact TC-EEC
complexes, it may be advantageous to provide a
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relatively large amount of EEC. For example, the ratio
of electrical charge from the' EEC to electrical charge
from the TC may be in the range of about 0.9 to about
1.5, preferably, in the range of about 1.0 to about 1.3.
For example, an EEC may have one negative charge per
molecule and a TC may have two positive charges per
molecule. In this case, a molar ratio of EEC to TC of 2
in a composition will result in a ratio of electrical
charge of 1.
In one embodiment, the concentration of EEC in a
composition of the invention* is less than required to
form an emulsion, for example, an EEC/water emulsion in
the composition. In other words, the amount of EEC is
preferably controlled so that enough EEC is present to
complex with substantially all of the TC present, and
less EEC is present than that needed to form an emulsion
in the composition.
As noted above, high concentrations, of ionic
species may lower the concentration of intact TC-EEC
complexes present in the compositions of the present
invention. Conversely, a low concentration of ionic
species may increase the concentration of intact TC-EEC
complexes. In one embodiment, in order to maintain a
low concentration of ionic species, compositions of the
present invention include a reduced concentration of
buffer component. For example, concentrations of buffer
component, for example, phosphate buffer, may be present
in compositions of the present invention in an amount in
a range of about 0.0001 molar to about 1.0 molar.
However, in order to reduce the ionic concentration
present in the compositions, the buffer component
preferably is present in a concentration in a range of
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about 0.001 molar to about 0.1 molar or about 0.2 molar,
more preferably in a range of about 0.005 molar to about
0.1 molar.
Any suitable ophthalmically acceptable tonicity
component or components may be employed, provided that
such component or components are compatible with the
other ingredients of the liquid carrier component and do
not have deleterious or toxic properties which could
harm the human or animal to whom the present
compositions are administered. In one embodiment, the
tonicity component is selected from inorganic salts and
mixtures thereof. Examples of useful tonicity
components include sodium chloride, potassium chloride,
and mixtures thereof.
In order to reduce the ionic concentration of the
present compositions, and thereby promote the
maintenance of intact EEC-TC complexes, it is preferred
that nonionic tonicity components'be used in the present
compositions. Examples of such nonionic tonicity
components include, without limitation, mannitol,
dextrose, glycerin, propylene glycol and the like and
mixtures thereof.
The present compositions may conveniently be
presented as solutions or suspensions in aqueous liquids
or non-aqueous liquids, or as oil-in-water or water-in-
oil liquid emulsions. The present compositions may
include one or more additional ingredients such as
diluents, flavoring agents, surface active agents,
thickeners, lubricants, and the like, for example, such
additional ingredients which are conventionally employed
in compositions of the same general type.
The present compositions in the form of aqueous
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suspensions may include excipients suitable for the
manufacture of aqueous suspensions. Such excipients are
suspending agents, for example, sodium carboxymethyl-
cellulose, methylcellulose, hydroxypropylmethyl-
cellulose, sodium alginate, polyvinylpyrrolidone, gun
tragacanth and gun acacia; dispersing or wetting agents
may be a naturally occurring phosphatide, for example,
lecithin, or condensation products of ethylene oxide
with long chain aliphatic alcohols, for example,
io heptadecaethylene-oxycetanol, or condensation products
of ethylene oxide with partial esters derived from fatty
acids and a hexitol such as polyoxyethylene sorbitol
mono-oleate, or condensation products of ethylene oxide
with partial esters derived from fatty acids and hexitol
anhydrides, for example, polyoxyethylene sorbitan mono-
oleate, and the like and mixtures thereof. Such aqueous
suspensions may also contain one or more coloring
agents, one or more flavoring agents and one or more
sweetening agents, such as sucrose, saccharin, and the
like and mixtures thereof.
The present compositions in the form of oily
suspensions may be formulated in a vegetable oil, for
example, olive oil, sesame oil or coconut oil, or in a
mineral oil such as liquid paraffin. Such suspensions
may contain a thickening agent, for example beeswax,
hard paraffin or cetyl alcohol. Sweetening agents, such
as those set forth above, and flavoring agents may be
added to provide a palatable oral preparation.
The present compositions may also be in the form of
oil-in-water emulsions. The oily phase may be a
vegetable oil, for example, olive oil or arachis oil, or
a mineral oil, for example, liquid paraffin, and the
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like and mixtures thereof. Suitable emulsifying agents
may be naturally-occurring gums, for example, gum acacia
or gum tragacanth, naturally-occurring phosphatides, for
example, soya bean lecithin, and esters or partial
esters derived from fatty acids and hexitol anhydrides,
for example, sorbitan mono-oleate, and condensation
products of the said partial esters with ethylene oxide,
for example, polyoxyethylene sorbitan mono-oleate. The
emulsions may also contain sweetening and flavoring
agents.
The present compositions in the form of syrups and
elixirs may be formulated with sweetening agents, for
example, as described elsewhere herein. Such
formulations may also contain a demulcent, and flavoring
is and coloring agents.
The specific dose level for any particular human or
animal depends upon a variety of factors including the
activity of the active component employed, the age, body
weight, general health, sex, diet, time of
administration, route of administration, rate of
excretion, drug combination and the severity of the
particular condition undergoing therapy.
The following non-limiting examples illustrate
certain aspects of the present invention.
EXAMPLE 1
Effects of Brimonidine-linoleic acid on Intra Ocular
Pressure
The data below shows the percent change with time
of Intra Ocular Pressure after administration of
Brimonidine-linoleic acid at time 0. The treatment is
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an ion pair formulation of 0.131% Brimonidine and
0.126% linoleic acid.
0 hr 0.0 mm Hg (administration of
complex)
1 hr -10.4 mm Hg
2 hr -16.0 mm Hg
4 hr -9.5 mm Hg
6 hr -9.4 mm Hg
EXAMPLE 2
Relative sedative effects of various compounds
The relative sedative effects of Brimonidine-
linoleic acid (compound 65) was compared to saline
(compound 62) and Brimonidine tartrate (compound 60).
This study involved cross overs and a one-week wash out
in between the administration of the various compounds.
As done in a previous experiments, the following
method was followed:
1. 6 trained monkeys were placed in chairs and
allowed to acclimate for approximately 30
minutes.
2. Individual monkeys were brought into the
"testing room" where they were allowed to
adjust to the new environment for
approximately 2 minutes. After this
adjustment time the monkey were observed for
1-2 minutes after which a sedation score was
given. Sedation scores were recorded on an
observation sheet.
3. The monkey were returned to the group of
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animals assigned to this study.
4. 2 baseline readings were done at T-0.5 and 0
hour. After the 0 hour reading one drop of
the test compound was administered to the
right eye.
5. Steps 2 & 3 were repeated at T=0.5, 1, 2, 3
and 4 hour.
6. Animals were monitored until they recover from
effects of the drug.
7. Scoring of Sedation was based on the following
scale:
,S=O Monkey is quiet, but slightly active
S=1 Monkey is quiet, easy to handle for
reading
S=2 Monkey is quiet, relaxed but very low in
activity
S=3 Monkey is blinking eyes and yawning
S=4 Monkey is sleepy and inactive, eyes are
heavy
8. The test compounds were coded: 62-Saline, 65-
Brimonidine tortrate, 60-Brimonidine-linoleic
acid.
9. Test Compound Administration:
animal #1 week 1 week 2 week 3
19 62 65 60
24 62 65 60
42 65 60 62
50 65 60 62
57 60 62 65
58 60 62 65
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The scoring was conducted for each animal for the
different test compounds. The average results are shown
on table 1.
Table 1
Comparison of the sedative effects of Brimonidine-
Linoleic Acid ion pair complex (0.2%) to Brimonidine
Tartrate (0.2%) and saline.
Brimonidine-Linoleic Acid Ion Pair Complex
TIME (HR) SEDATION SCORE
-0.5 0.7
0 1.0
0.5 1.2
1 1.5
2 1.8
3 1.6
4 1.6
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Brimonidine Tartrate
TIME (HR) SEDATION SCORE
-0.5 0.7
0 0.8
0.5 0.8
1 1.7
2 2.6
3 2.5
4 2.7
Saline Vehicle
TIME (HR) SEDATION SCORE
-0.5 0.7
0 1.0
0.5 1.0
1 1.0
2 1.2
3 1.3
4 1.3
The first reading after dosing, 0.5 hr-time point,
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the monkeys were quiet and easy to handle. In general,
the animals started to show low activity when brought
into the test room at the lhr time.
Half the monkeys given test compound Brimonidine-
linoleic showed low activity (1 hour post dose), with
the exception of monkey #19. Monkey #19 did not appear
to be sleepy, inactive or have heavy eyes and seemed to
react similarly to all test compounds. She seems to be
very comfortable in the chair, and when there were no
distractions she tended to close her eyes and relax.
The dosing with Brimonidine-linoleic acid complex
appear to cause more sedation in the monkeys than dosing
with saline. In general when the monkeys were dosed
with saline, they were quiet and easy to handle for all
is readings. However, dosing with Brimonidine tartrate
causes more sedation than dosing with Brimonidine-
linoleic acid. When the monkeys were dosed with
Brimonidine tartrate, on average they became sleepy and
inactive with heavy eyes. This observation was seen
usually at the 2-hour time point and most of the animals
remained this way through the end of observations.
Without wishing to limit the invention to any
mechanism or theory of operation, it is believed that
one of the reasons that Brimonidine-linoleic acid
complex causes less sedation than Brimonidine tartrate
is that it partitions more in the lipid compartments.
In other words, the Brimonidine-linoleic acid complex is
more trapped in the lipid compartments, and are not as
available to circulate in the blood stream to eventually
travel to the brain to cause sedation.
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Example 3
Effects of Brimonidine-linoleic acid ion pair complex
(0.2%) on rabbit intraocular pressure
In this study, the animals were placed into three
groups consisting of a mix of age,~size and sex.
Group Number of Animals Number of Animals
Number Males Females
1 4 4
2 4 4
3 4 4
One group of animals (both sexes) were used per
screening study. The test compound (20iL of 0.2%
Brimonidine-linoleic acid ion pair complex) was
administered to the surface of the cornea using an
automatic pipette or an appropriate device.
is
The following general procedure for administering
the test compound employed in this study is presented
below:
1. Make sure that the 0.25% proparacaine
Opthetic mixture (topical local anesthetic),
test compounds, and commercially available
treats are available.
2. Turn on the Digilab Modular OneTM Pneuma
Tonometer (pneumatonometer) [BioRad,
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Cambridge, MA]; it needs approximately 15
minutes to warm up. Turn on gas supply or air
pump.
3. Hold probe vertically with the point tip down
and press "calibration check" for "zero".
4. Wipe the pneumatonometer probe with an alcohol
swab, and inspect the tip membrane for holes.
5. Set the external calibration device (air or
water manometer) to 25 mm Hg, place the
pneumatonometer probe in the calibration
device to an ensure that it corresponded to
25 2mm Hg.
6. Obtain a rabbit. Make sure the recording data
sheets are at hand.
7. Gently restrain the rabbit via a commercial
restrainer or a cotton towel. Measure the
pupil diameter with the specialized ruler for
each eye and record the values on the sheets
provided. If the eyes are too dark to obtain
a value by this method, a specialized penlight
may be used. Obtain a pupil diameter
measurement by shining the penlight on the
cornea for one second.
8. Slide the upper eyelid up the thumb and
visually
assess and score the degree of ocular surface
redness. Record the value for each eye on the
sheet provided.
9. Put one drop of 0.25% proparacaine Opthetico
(50:50 mix of 0.5% proparacaine Opthetico +
Cellufresh ) on the surface of each eye. Wait
one or more minutes for ophthetic to take
CA 02446705 2003-10-31
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effect.
10. Place the pnematonometer tip on one eye
at the site where the curvature of the cornea
is greatest. Let the probe shank travel to
the black line, not the red line. Persist
until a stable reading with the standard
deviation below 1.0 is obtained. Repeat the
procedure for the contralateral eye. Record
the data. (Note: If the animal is upset by
the restraint, the reading will be
artificially high and cannot be used. Use
gentle restraint).
11. At the end of the 0, 6, 24, 30, 48, 54, 72, 78
and 96 hour measurements, use an automatic
pipette to apply 20,uL of the test compound to
the surface of the cornea of one eye. After
the 102 hour measurements, the eyes will be
washed out with Refresh and Prefrin .
12. Give the animal a treat and return the animal
to its cage.
13. Repeat steps 7 to 11 on the remaining animals
in the group.
The following general procedure for measuring the
effects of the test compound employed in this study is
as follows: a reading is conducted at 0, 2, 4, 6, 24,
26, 28, 30, 48, 50, 52, 54, 72, 74, 76, 78, 96, 98, 100,
and 102 hours. The pneumatonometer is calibrated before
use with a manometer and the probe tip is wiped with an
alcohol swab. One drop of 0.25% proparacaine Opthetic ,
a corneal anesthetic, is placed on the cornea. Allow
sufficient time (approximately 1 minute) for it to
anesthetize the cornea before placing the probe on the
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eye. The eye is gently opened by the person doing the
tonometer reading. The probe is placed on the cornea at
the point of greatest curvature and a stable reading is
obtained. The probe is held parallel to the floor and
perpendicular to the line of the rabbit's sight. The
reading is repeated until a reasonable reading can be
obtained. The piston should be between the red and
black lines or at the black line on the probe.
The effects of Brimonidine-linoleic acid ion pair
complex is shown on Table 2. It appears that the
complex is able to reduce intraocular pressure in a
rabbit's eye for at least 6 hours. For example, 6 hours
after the administration at times 0 hr, 24hr, 48hr, 72
hr, and 96 hr, the intraocular pressure remained below
the initial time. However, it also appears that the
effect of the complex is less than 18 hrs. For example,
18 hrs after administration of the complex at time 6 hr,
the intraocular pressure returned to about the same
initial level.
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TIME (HR) INTRAOCULAR PRESSURE
(mmHg)
0* 25.8 * 1.2
2 17.1 * 1.0
4 21.1 1.0
6* 23.9 1.0
24* 25.6 * 0.5
26 19.9 0.6
28 22.9 0.8
30* 23.0 1.1
48* 26.5 1.0
50 20.4 0.6
52 23.4 * 0.7
54* 24.1 0.8
72* 26.8 0.9
74 21.1 0.8
76 23.9 1.1
78* 25.2 0.9
96* 27.9 * 1.1
98 20.1 1.3
100 23.9 0.7
102 25.3 1.6
*Brimonidine-linoleic acid ion pair were administered at
these time points.
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Values are mean S.E.M. n=8.
Example 4
The following composition is prepared by mixing
together the specified amounts of the ingredients.
Ingredient Amount
Brimonidine Base 1.32 mg
Linolenic Acid 1.25 mg
1.0 molar Phosphate Buffer (pH 7.5) 1.0 ml
Polysorbate 80 90 mg
Purified Water q.s. to 10 ml
This composition is formulated for and is
effective for the treatment of disorders of the eye.
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Example 5
The following composition is prepared by mixing
together the specified amounts of.the ingredients.
Ingredient Amount
Brimonidine Base 1.32 mg
Linolenic Acid 1.27 mg
1.0 molar Phosphate Buffer (pH 7.5) 1.0 ml
Polysorbate 80 90 mg
Purified Water q.s. to 10 ml
This composition is formulated for and is
effective for the treatment of disorders of the eye.
Example 6
The following composition is prepared by mixing
together the specified amounts of the ingredients.
Ingredient Amount
Brimonidine Base 1.32 mg
Linolenic Acid 1.25 mg
Mannitol 0.2 g
Purified Water q.s. to 10 ml
This composition is formulated for and is
effective for the treatment of disorders of the eye.
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Example 7
The following composition is prepared by mixing
together the specified amounts of the ingredients.
Ingredient Amount
Brimonidine Base 1.32 mg
Linolenic Acid 1.25 mg
Glycerine 0.12 g
Purified Water q.s. to 10 ml
This composition is formulated for and is
effective for the treatment of disorders of the eye.
is Example _8
The following composition is prepared by mixing
together the specified amounts of the ingredients.
Ingredient Amount
Brimonidine Base 1.32 mg
Linolenic Acid 1.25 mg
1.0 molar Phosphate Buffer (pH 7.5) 0.1 ml
Purified Water q.s. to 10 ml
This composition is formulated for and is
effective for the treatment of disorders of the eye.
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Example 9
The following composition is prepared by mixing
together the specified amount of the ingredients.
Ingredient Amount
Brimonidine Base 1.32 mg
Linolenic Acid 1.25 mg
1.0 molar Phospate Buffer (pH 7.5) 1.0 ml
Polysorbate 80 0.1 mg
Purified Water q.s. to 10 ml
This composition is formulated for and is
effective for the treatment of disorders of the eye.
Example 10
The following composition is prepared by mixing
together the specified amount of the ingredients.
Ingredient Amount
Brimonidine Base 1.32 mg
Linolenic Acid 1.25 mg
1.0 molar Phospate Buffer (pH 7.5) 1.0 ml
Polyvinylpyrrolidone 0.1 g
Purified Water q.s. to 10 ml
This composition is formulated for and is
effective for the treatment of disorders of the eye.
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Example 11
The following composition is prepared by mixing
together the specified amount of the ingredients.
Ingredient Amount
Brimonidine Base 1.00 mg
Linolenic Acid 1.26 mg
1.0 molar Phosphate Buffer (pH 7.5) 0.1 ml
Polyvinyl Alcohol 0.1 g
io Purified Water q.s. to 10 ml
This composition is formulated for and is effective
for the treatment of disorders of the eye. This
composition exemplifies a linolenic acid to brimonidine
molar ratio of 2.0 resulting in a ratio of electrical
charge from the linolenic acid to electrical charge from
the brimonidine of 1Ø
Example 12
The following composition is prepared by mixing
together the specified amount of the ingredients.
Ingredient Amount
Brimonidine Base 1.00 mg
Linolenic Acid 1.39 mg
1.0 molar Phosphate Buffer (pH 7.5) 0.1 ml
Poly(oxyethylene) Poly(oxypropylene)
Block Polymer 0.1 g
Purified Water q.s. to 10 ml
This composition is formulated for and is effective
for the treatment of disorders of the eye. This
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composition exemplifies a linolenic acid to brimonidine
molar ratio of 2.2 resulting in a ratio of electrical
charge from the linolenic acid to electrical charge from
the brimonidine of 1.1.
Example 13
The following composition is prepared by mixing
together the specified amount of the ingredients.
Ingredient Amount
Brimonidine Base 1.00 mg
Linolenic Acid 1.51 mg
1.0 molar Phosphate Buffer (pH 7.5) 0.1 ml
Glycerine 10 mg
Polyvinylpyrrolidone 0.1 g
Purified Water q.s. to 10 ml
This composition is formulated for and is effective
for the treatment of disorders of the eye. This
composition exemplifies a linolenic acid to brimonidine
molar ratio of 2.4 resulting in a ratio of electrical
charge from the linolenic acid to electrical charge from
the brimonidine of 1.2.
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E&Wle 24
The rollowing composition is prepared by mixing
together the specified amount of the ingredients-
Zagre4Lant amount
s Brimonidine Base 1.00 mg
Linolenic Acid 1.64 mg
1.0 molar E'hospnate buffer (pH 7.5) = 0.1 ma.
Polysorbate 90 90 mg
Mannitol 0.2 g
Purified Water 9.8. to 10 MI
This composition is formulated for and is effective
for the treatment of disorders of the eye. This
composition exemplifies a linolenic acid to brimonidine
is molar ratio of 2.6 resulting in a ratio of electrical
charge from the linolenic acid to electrical charge from
the brimonidine of 1.3.
While this invention has been described with
respect to various specific examples and embodiments, it
is to be understood that the invention is not limited
thereto and that it can be variously practiced with the
scope of the following claims-
so
