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Patent 1143289 Summary

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(12) Patent: (11) CA 1143289
(21) Application Number: 336744
(54) English Title: MICROPARTICLE DRUG DELIVERY SYSTEM
(54) French Title: SYSTEME DE LIBERATION DE MEDICAMENTS SOUS FORME DE MICROPARTICULES
Status: Expired
Bibliographic Data
(52) Canadian Patent Classification (CPC):
  • 167/159
(51) International Patent Classification (IPC):
  • A61K 9/50 (2006.01)
  • A61K 9/00 (2006.01)
  • A61K 9/16 (2006.01)
  • A61K 31/56 (2006.01)
  • A61K 39/00 (2006.01)
  • C07K 16/00 (2006.01)
  • C12N 11/04 (2006.01)
  • A61K 38/00 (2006.01)
(72) Inventors :
  • BECK, LEE R. (United States of America)
  • TANWUARY, ALBERT C. (United States of America)
  • COWSAR, DONALD R. (United States of America)
  • FLOWERS, CHARLES E. (United States of America)
(73) Owners :
  • STOLLE RESEARCH AND DEVELOPMENT CORPORATION (United States of America)
(71) Applicants :
(74) Agent: MEREDITH & FINLAYSON
(74) Associate agent:
(45) Issued: 1983-03-22
(22) Filed Date: 1979-10-01
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): No

(30) Application Priority Data:
Application No. Country/Territory Date
967,380 United States of America 1978-12-07
952,109 United States of America 1978-10-17

Abstracts

English Abstract






ABSTRACT OF THE DISCLOSURE

Antibody or antigen containing microparticles for the
active or passive immunization of the internal femal reproduc-
tive organs, comprising microparticles of an antigen or anti-
body incorporated in a matrix material which is biocompatible
and biologically degradable, said microparticles capable of
being transported after deposition in the vagina by the natural
transport mechanism of the internal female reproductive organs
across the cervix into the uterus. A contraceptive composition
capable of being directly delivered to the uterus and fallopian
tubes comprising microparticles of a biodegardable and bio-
compatible matrix material having sperm surrogate activity and
containing a contraceptive agent and a transport inducing hormone
which when released stimulates the transport of the microparticles
across the cervix into the uterus and fallopian tubes with the
proviso that the contraceptive agent and hormone are different
when the contraceptive agent is a hormone.


Claims

Note: Claims are shown in the official language in which they were submitted.



The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:


1. Antigen or antibody containing microparticles for
the active or passive immunization of the internal female
reproductive organs, which comprise:
microparticles containing an amount of antigen or
antibody sufficient to elicit a response incorporated in a
matrix material which is biocompatible and biologically degrad-
able, said microparticles capable of being transported after
deposition in the vagina by the natural mechanism of the internal
female reproductive organs across the cervix into the uterus.


2. The microparticles of Claim 1, wherein said micro-
particles are of a size ranging from 20 to 70 µm and said matrix
material is polylactic acid, polyglycolic acid, or copolymers
of glycolic and lactic acids.


3. The microparticles of Claim 1, wherein said micro-
particles contain from 10 wt.% to 6-0 wt.% of said antigen or
antibody.


4. The microparticles of Claim 1, Claim 2 or Claim 3,
wherein said antigen is derived from a bacterial or viral
pathogen and said antibody is one which responds to an antigen
from a viral or bacterial pathogen.



5. The microparticles of Claim 1, Claim 2 or Claim 3,
wherein said microparticles are formulated in a composition as
a suppository, cream, jelly, foam or a liquid with a pharmaceuti-
cally acceptable excipient.



48


6. Antigen or antibody containing microparticles
for the active or passive immunization of the internal female
reproductive organs, which comprises:
microparticles of a particle size ranging from
20 to 70 µm containing an amount of antigen or antibody
sufficient to elicit a response incorporated in a matrix
material which is biocompatible and biodegradable, said micro-
particles capable of being transported after deposition in
the vagina by the natural mechanism of the internal female
reproductive organs across the cervix into the uterus.


7. The micropartieles of Claim 1 wherein said matrix
is selected from the group consisting of poly-d,l-lactic acid,
polyglycolic acid, copolymers thereof and glycerol mono- or
distearate.


8. The microparticles of Claim 6, wherein said micro-
particles contain from 10 wt.% to 60 wt.% of said antigen or
antibody.


9. Microparticles containing contraceptive agent
capable of being transported by the natural transport mechanism
of the internal female reproductive organs into at least the
uterus, which comprises:
a cycle regulatory hormone and contraceptive agent
incorporated in a biocompatible and biodegradable matrix
material as microparticles which possess sperm surrogate
activity with the proviso that when said contraceptive agent
is a hormone, the contraceptive hormone and cycle regulatory
hormones are different, said cycle regulatory hormone being
capable of stimulating said natural transport mechanism after
said microparticles have been deposited in the vagina.


49


10. The microparticles of Claim 9, wherein said micro-
particles range in size from 20 to 70 µm and said biodegradable
and biocompatible matrix material is a polymer selected from
the group consisting of polyglycolic acid, polylactic acid,
and mixtures thereof.


11. The microparticles or Claim 9 or Claim 10,
wherein said transport inducing compound is an estrogen or a
progestin.


12. The microparticles of Claim 9 or Claim 10,
wherein said contraceptive agent is a hormone selected from
the group consisting of progesterone, estradiol, norethindrone,
norgestrel, ethynodiol diacetate, lynestrenol, medroxy-
progesterone acetate, dimethisterone, megestrol acetate,
chlormadinone acetate, ethinyl estradiol and mestranol.


13. Microparticles containing contraceptive agent
capable of being transported by the natural transport mechanism
of the internal female reproductive organs into at least the
uterus, which comprises:
a cycle regulatory hormone and contraceptive agent
incorporated in a biocompatible and biodegradable matrix material
as microparticles of a particle size ranging from 20 to 70 µm
which possess sperm surrogate activity with the proviso that
when said contraceptive agent is a hormone, the contraceptive
hormone and cycle regulatory hormones are different, said
cycle regulatory hormone being capable of stimulating said
natural transport mechanism after said microparticles have been

deposited in the vagina.





14. The microparticles of Claim 13 wherein the matrix
material is selected from the group consisting of poly-d,1-
lactic acid, polyglycolic acid, copolymers thereof and glycerol
mono- or distearate.


15. The microparticles of Claim 13 or Claim 14,
wherein said contraceptive agent is a hormone selected from
the group consisting of progesterone, estradiol, norethindrone,
norgestrel, ethynodiol diacetate, lynestrenol, medroxy-
progesterone acetate, dimethisterone, megestrol acetate,
chlormadinone acetate, ethinyl estradiol and mestranol.

51

Description

Note: Descriptions are shown in the official language in which they were submitted.


11:
~ 3;289

MICROPARTICLE DRUG DELIVERY SYSTEM

; BACKGROUND OF TIIE INVENTION
~ '
Field of the Invention:
~:
The present invention relates to a method for introducing
therapeutic or medicinal agents into the uterus and fallopian
r, . ' tubes of the internal female reproductive organs.
''

Description of the Prior Art:
.

In the past, the methods of generally treating the internal
reproductive organs of the female have included principally the
oral ingestion or the injection of drugs into the patient in
order to treat diseases and to regulate the female reproductive
cycle. Few methods are known by which the female reproductive
organs can be treated by delivery of a therapeutic agent directly
to the uterus. One technique which achieves the direct delivery
of a contraceptive steroid to the uterus is the progestert
device which is a medicated intrauterine device. The device is
described in U.S. Patent No. 3,699,951 and No. 3,777,015 by
Zaffaroni. The disadvantage of the insertable device is that it
requires a trained physician to place the device in the uterus.
There exists still, therefore, a need for an improved method of
delivering a contraceptive agent as well as other medicinal



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11~3Z89



agents such as antigens and antibodies which can be self-adminis-
-~ tered.

Several techniques are known by which contraceptive agents
~ in the form of microcapsules can be introduced into the vagina,
however, in these techniques transport of the microcapsules
across the cervix into the uterus does not occur. For instance,
U. S. Patent Nos. 3,918,452 and 3,921,636 show techniques in
which a pharmaceutical agent is released from microparticles in
a tampon which is placed in the vagina.
,. , ,

The technique shown by Zaffaroni in U. S. Patent Nos.
3,699,951 and 3,777,015 describes an intrauterine device designed
to release progesterone directly into the uterus for the purpose
of contraception. This device, however, is non-biodegradable
and it must be placed in the uterus and removed from the uterus
following use by a trained physician. Accordingly, the utility
of the device is limited by the fact that it cannot be self-
- administered.
'

Eaxly studies have been conducted to investigate the scope
of possible particulate materials which will migrate across the
cervix into the uterus after deposi~ion in the vagina. Thus, it
,
,
... . .

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1 11"

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.
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has been shown that carbon particles from a cap containing a
suspension of carbon particles, when placed over the cervix,
can be recovered from the uterus after coitus (Amersbach,
~ "Sterilitat Und Frigiditat," Muchen. Med. Wchnschr. 77: 225,
5 ~ 1930). J. Trapl, "Neuve Anschauunger uber den Fi-und Samen-
transport in den Geschlechtsteilen de Frau," Zentralbl. Gynak.
67: 547, 1943, has shown that even without the use of a cervical
cap, carmine particles migrate thus demonstrating that non-
motile particIes other than carbon also migrate.
',,

Still further, R. Krehbiel and H. P. Carstens, "Roentgen
Rabbit", Am. J. Physiol. 125: 571, 1959, have shown that the
,.": .
: passage of a radio-opaque oil, when placed in the vagina of a
!" ' rabbit was blocked until after the vulva was stimulated, while
other investigators have shown that graphite and dyes in gelatin
were not transported across the cervix. The implication of the
data is that the nature of the particles affects the transport
process and that transport is assisted by muscular contractions.
Hartman, in "How Do Sperms Get Into the Uterus?" Fertil. and
Steril 8: 403, 1957, concluded that in the transport of sperm
_
in the reproductive tract, transport occurs principally by
. .

Z89

cooperation of the particles with the musculature of the
female reproductive tract. G. M. Duncan and D. R. Kalkwarf,
"Sustained Release Systems for Fertility Control," in
Human Reproduction: Conception and Contraception, edited by
E. S. E. Hafez and T. N. Evans, Harper and Row, New York,
1973, have concluded from experiments that non-motile particles
which are about the size of the head of the sperm migrate
directionally through the cervix to the fallopian tubes.
However, the article shows that progesterone containing
microcapsules of cellulose acetate butyrate and of a size
ranging from 5 to 1400 ~m do not migrate across the cervix
into the uterus, but are transported in the reverse direction.
Therefore, the reference clearly suggests that microcapsules
of a size greater than 5 ~m will not migrate inward to the
internal female reproductive organs.



SUMMARY OF THE INVENTION


Accordingly, the present invention seeks to provide
a means by which medicinal and therapeutic agents can be
locally administered to the vagina and transported through
the cervix into the uterus to treat the internal female
reproductive organs.
The present invention also seeks to provide micro-
particles containing a pharmaceutical agent, which, when
deposited in the vagina, can be transported across the
cervi~ into the uterus by the natural transport mechanism
of the internal reproductive organs.




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1143Z89
Briefly, these aspects and other aspects of the
present invention as hereinafter will become more readily
apparent, are provided in one aspect by antigen or antibody
containing microparticles for the active or passive immuni-

zation of the internal female reproductive organs, whichcomprise, microparticles containing an amount of antigen or
antibody sufficient to elicit a response incorporated in a
matrix material which is biocompatible and biologically
degradable, the microparticles capable of being transported
after deposition in the vagina by the natural mechanism of
the internal female reproductive organs across the cervix
into the uterus.
Another aspect of the invention comprehends microparticles
containing contraceptive agent capable of being transported
by the natural transport mechanism of the internal female
reproductive organs into at least the uterus, the micro-
particles comprises, a cycle regulatory hormone and contra-
ceptive agent incorporatedinabiocompatible and biodegradable
matrix material as microparticles which possess sperm surrogate
activity with the proviso that when the contraceptive agent
is a hormone, the contraceptive hormone and cycle regulatory
hormones are different, the cycle regulatory hormone being
capable of stimulating the natural transport mo~lanism after the
microparticles have been deposited in the vagina.

BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the present invention and
many of the attendant advantages thereof will be readily
obtained as the same becomes better understood by reference
to the following detailed description when considered in
connection with the accompanying drawings, wherein:
FIGURE l shows microparticles of a monolithic structure


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containing a pharmaceutical agent;
FIGURE 2 shows microparticles formed of a core of pharma-
ceutical agent in a matrix material surrounded by a shell of
matrix material; ..
FIGURE 3 shows microparticles formed of a core of pharma-
ceutical agent surrounded by a shell of matrix material;
FIGURE 4 shows microparticles of an onion-skin structure
. of alternating layers of matrix material and pharmaceutical
agent;
. FIGURE 5 shows microparticles formed of a core of one
particular pharmaceutical agent surrounded by a shell of matrix
material containing a second type of pharmaceutical aqent;
FIGURE 6 shows monolithic microparticles of contraceptive
. agent and cycle regulatory hormone in a matrix material;
FIGURE 7 shows microparticles of a core of contraceptive
agent and cycle regulatory hormone surrounded by a shell of
matrix material
' FIGURE 8 shows microparticles of a core of contraceptive
agent and cycle regulatory hormone in a matrix material surrounde I
by a shell of matrix material;

~1~3Z8~3

:' .~ ' .
: . FIGURE 9 shows microparticles of a core of contraceptive
agent in a matrix material surrounded by a shell of cycle regu-
latory hormone in matrix material;
. FIGURE 10 shows multi-layered microparticles in which
contraceptive agent and cycle regulatory hormone are dispersed
throughout different layers;
FIGURES llA and llB show the blood levels of progesterone
and estradiol in baboons treated intramuscularly and intra-
. vaginally respectively with 7.87 mg of progesterone;
FIGURE 12 is a series of photomicrographs showing the
. histological appearance of baboon endometrium;
FIGURE 13 is a series of photomicrographs showing the
morphology of the uterine epithelialsurface of baboons;
. FIGURES l~A and 14B show thb blood levels of progesterone
and estrogen in baboons treated intramuscularly and intra-
vaginally respectively with 1.57 mg of progesterone;
FIGURE 15 is a series of photomicrographs showing the
surface epithelial morphology of baboon endometrium
~ FIGURES 16A and 16B are recordings of the contractile
activity of two female baboons one of which was treated with
.'


` 11~3Z89
, . .
` .~.. . . .~.
' . . ,

microparticles containing estradiol and the other of which was

not treated with hormone-containing microparticles.
~., ~ ~ '
DET~ILED DESCRIPTION OF THE PREFERRED E~IBODIMENTS
~ _ ~
~ In its broadest terms the objective of the present inven-
5 ~ tion is to provide microparticles containing at least one
medicinal agent which when deposited in the vagina are trans-
ported by the natural transport mechanism across the cervix into
at least the uterus and possibly the fallopian tubes where
release of the medicinal agent occurs. In one aspect of the
present invention the microparticle delivery is employed to
convey various antibodies or antigens directly to the internal
~` reproductive organs to obviate systemic introduction of antigens
or antibodies for the treatment of the reproductlve organs.
. ~ Systemic introduction, in fact, cannot be used as a means for
15~ administering many antigens and antibodies into the body for
- treatment of the reproductive organs. In a second major aspect
of the present invention a method is provided for the introduc-
tion of contraceptive agent containing microparticles into the
vagina followed by transport of the same across the cervix into
th uterus. The dire~t and local int-oduction of the contracep-




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~ .


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,............ . .
`.,
tive agent has the advantage that substantially smaller dosagesof many types of contraceptive agents can be self-administered
; to achieve virtually the same contraceptive effect achieved
with larger amounts of drug introduced systemically. While the
5~ method of the present invention is effective for the delivery
of contraceptive agent containing microparticles under normal
circumstances in which a woman is regularlv cycling, the present
method can be modified so that a woman who is not regularly
cycling can be regulated and at the same time the internal
organs can be rendered increasingly susceptible to transport of
the microparticles containing contraceptive agent across the
cervix into the uterus and fallopian tubes. The desired effect
can be accomplished by incorporating a menstrual cycle reaula-
; tory and cervical transport promoting hormone which is normally
an estrogen or progestin in the microparticles in addition to
the contraceptive agent.
:~' .
There are two basic ways in which the role of antibodies
can be stimulated in the body to counteract the effects of
antigens. One technique is active immunization while the other
is passive immunization. In order to actively immunize a subject,


` ` ` ` 1~43Z89`
`.`:' ., ', ~
. . .
.
the subject is administered an antigen to induce the formation
~ ofj endogeneous antibodies. Normally, this technique requires up
- to two weeks before a sufficiently good level of antlbody~ response is achieved. Because of the delay involved, the
,5 ~ active immunization technique imposes limitations for the treat-
-` ment of infectious diseases which have a short incubation-time,
~for the treatment of a disease actively in progress and for
reversing or modifying the effects of drugs, toxins, hormones,
~ and enzymes. The second basic immunization technique is passive
immunization whereby antibodies are administered in order to
~'; achieve temporary immune protection. Passive immunization has
the advantage that the biological effects are immediate and can
be effectively used in patients suffering from lmmunodeficienoy
~ diseases. Moreover, active immuhization is not limited to the
use of non-toxic antigens because animal species can be used as
the source of the protective antibodies. Transport of the micro-
particles is controlled by the cyclic changes in the endo~enous
ovarian steroid hormones, estradiol and progesterone. During
the first 14 days of the menstrual cycle or the follicular or
estrogenic phase of the cycle, the ovaries produce estradiol
~ which has a stimulating effect on the cervical muscle contraction


`

~; ~ ~
~r'.``~ The frequency and amplitude of the cervical contractions during
the follicular phase steadlly increase from day zero to day 14
at which time ovulation occurs and the cycle enters the lutial
phase or progestational phase when the ovaries be~in to secrete
5 i progesterone. Progesterone has an inhibitory effect on the con-
;~ tractile activity of the cervix or alternatively a muscle relax-
ing effect on the cervix. The ovarian hormones also exhibit an
opposing effect in the cells of the cervix in that estradiol
causes an accumulation of secretory products in the cells of
lO ~`~ the cervix while progesterone promotes the release of these
products in the cervical lumen. The interactions described are
the mechanism by which changes in the viscosity of cervical fluic
' ` occur.
"'ii'` ' ' . .
;~ The fluid or mucous of the cervix is dynamic and is an
5;~ aqueous type of hydrogel. The transport of microparticles as
well as sperm is dependent upon the permeability of the cervical
mucous to the microparticles as well as the propulsion provided
by estrogen induced contractions of the cervix. The most appro-
priate time for transport of microparticles across the cervix
O occurs when the uterus exhibits maximum contractile activity and.,
.
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~ ~ cervical mucous permeability. Accordingly, the greatest rate of
~ ~ transport of sperm or microparticles through the cervix should :.
: l occur between day 12 a~d day 16 of the menstrual cycle, although
. the actual day of ovulation may vary from four to six days in
5:~ different individuals with some transport occurring in some
persons before day 12 of the cycle. Normally, the cervix is not
`~ very receptive to transport during the first twelve days of the
menstrual cycle as well as between days 16 and 28. Thus, in
order to deliver microparticles containing antigen, antibody or
. contraceptive agent into the cervix, the microparticles in an
: appropriate dosage need only to be deposited in the vagina prior
to day 16 of the cycle, preferably before day 12.

,
In a major embodiment of the present invention advantage

: can be taken of the fact that estrogen and progestin hormcnes

lS; have a transport stimulating effect on the internal organs. Thus,

. microparticles containing either an estrogen or progestin and

` medicinal agent or estrogen or pro~estin containing micro-

~-~ particles with microparticles containing a medicinal agent can

~ be introduced into the vagina to regulate the menstrual cycle of

a woman who is not cycling regularly or to stimulate the cervix

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to transport microparticles across the cervix into the uterus
and fallopian tubes. The locally absorbed progestin or estro-

~- gen in a biologically effective amount induces the necessary
secretory changes in the endometrium of the cervix and promotes
~5 the contractile activity of the cervix necessary for micro-
, particle transport. Once transport activity has begun, the
microparticles are conveyed across the cervix into the uterus.
Both estrogen and progestin in proper amounts will stimulate
transport. However, a progestin at too high a level of concen-
tration will have an adverse effect on microparticle transport
because the progestins have a muscle relaxing effect on the
, tissues of the cervix. However, the adverse effect of the
administered progestin can be reversed by the administration
of a sufficient concentration of an estrogen via estrogen con-

taining microparticles such as estradiol which as discussed
supra induces contratile activity of the tissues of the cervix.
Normally, when estradiol is delivered locally by way of the
microparticles, the amount of microparticles administered should
be sufficient to deliver from 0.1 to 1 mg per day over a 7-14
day period. On the other hand, when progesterone is incorporated
.

J

11~3'~8'~
. .
,~ .
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in the microparticles, the amount of microparticles administered
should be sufficient to deliver from 0.5 to 2 mg per day over
a 7-14 day period.

As alluded to above the microparticles of the preseht
5, invention can provide the feasibility of locally administering a
contraceptive agent,antigen or antibody to the cervix while sim-
ultaneously exogenously activating a menstrual cycle in a non-
cycling woman by the administration of an appropriate ovarian
, hormone and stimulating the cervix for microparticle transport.
Hence, estrogen containing microparticles can be administered
, , such that,estradiol or a synthetic estrogen is released at the
,; cervix for a fourteen day period thus duplicating the first half
of the menstrual cycle. When transport of the microparticles
occurs across,the cervix, medicinal agent in the microparticles
lS or in separate microparticles is delivered to the uterus. Four-
; teen days after administration of the estrogen containing micro-
, particles, progesterone containing micro,particles optionally
containing antibody or antigen are then administered. Thus, the
complete natural menstrual cycle can be duplicated while pro-
viding antibody or antigen protection. Of course, it is also


~3289
: ,:;
`~ . .
'~,, .
within the scope of this invention to deliver microparticles
containing estrogen or progestin into the cervix to regulate
the cycle and thereafter administer antigen or antibody contain-
ing microparticles at the period of the cycle when the cervix is
receptive to transport. In the artificially induced cycle maximum
transport across the cervix is achieved between days 12 and
16. Since the cycle regulatory hormones are administered locally
in the present technique, effective estradiol activity can be
achieved at dosage rates between 0.01 and 0.07 mg per day,
while effective progesterone activity can be attained a-t dosage
rates of 0.04 to 0.14 mg per day. Estradiol and progesterone
are the regulatory hormones of choice. However, it is evident
that other well known synthetic estrogens and progestins can be
employed as substitutes for estradiol and progesterone, respect-
ively. Suitable estrogens include estrone, mestranol, ethinyl
estradiol, 2-methoxyestrone, 2-hydroxyestrone and estriol. Suit-
able progestins include norethindrone, dimethisterone, ethyno-
diol diacetate, norethynodiol, norethindrone acetate and norges-
trol. When the synthetic compounds are employed, the dose
employed depends entirely upon the biological potency of the
synthetic estrogen or progestin compound.
.
Microparticles containing a medicinal agent such as antibod r~
antigen or contraceptive agent and/or menstrual cycle regulating

~ ` ~1~a3Z89
`.. .' '' '` '.
~: ' .
"'

hormone can be formed in a variety of configurations. In
perhaps the simplest situation shown in FI~URES 1 and 6 micro-
particles of a monolithic structure are prepared in which the
desired antigen or antibody 2 on the one hand, or contraceptive
agent 21 and cycle regulatory hormone 22 on the other hand,is
distributed throughout a matrix material 1 (or 23) which is
biodegradable and biocompatible. Once the microparticles are
deposited in the vagina they begin to slowly deteriorate thereby
continuously releasing the desired drug to achieve the desired
daily dosagé of drug over a prolonged period of time from the
` ~ time they are deposited in the vagina until well after the micro-
, particles have been conveyed across the cervix and deposited in
the uterus. When the microparticles contain a cycle regulatory
hormone, continuous release of the hormone regulates the ~ro-
perties of the cervical mucous and the contractile activity
of the cervix. Since the microparticles of this particular
embodiment continually release their active constituents from
the time of deposition in the vagina, it is evident that most
convenient results are achieved if the microparticles are formed
such that they have an effective lifetime close to the period
of the menstrual cycle so that microparticles need only be

.- `
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~ :" ` 1143289
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. , .

administered once during the cycle. How-ver, this is only a
preferred embodiment because the microparticles can be adminis-
tered as many times as desired to achieve contraceptive and
; cycle regulatory effects.
, :,. . ` '.
-5 ~` FIGURE 2 shows another embodiment of the microparticles
of a monolithic structure wherein antigen or antibody 2 i5
incorporated within matrix material 1 which in turn is surrounde
by an envelope 3 of a drug free matrix material. This type of
microparticle configuration wher~in the particles are of a size
such that they possess sperm surrogate activity, is desirable
where reIease of drug is to be delayed for some period of time
'' ` after deposition of the microparticles in the vagina. The
~ delayed release of drug obtained by using the above microparti-

; cles, for instance, would allow sufficient time for the micro-
particles to be deposited in the vagina, transported across
~; the cervix and deposited in the uterus before the microparticles
deteriorate to the point where the outer wall is essentially
eliminated and drug release commences.
, . `.
- FIGURE 7 shows microparticles in which a

core 25 of contracepti~e agent 21 and cycle regulatory hormone

"' :'

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1~3289



22 is encapsulated in a shell 27 of matrix material 24. This
particular configuration of microparticles would be desirable
where it is necessary to delay release of the active con-
stituents of the deposited microparticles as described above
for the microparticles of FIGURE 2.



In still another microparticle configuration as shown
in FIGURE 3, the microparticles can be designed for the
sudden release of a large amount of antibody or antigen. To
achieve this purpose the microparticles can be formed such
th~t a core 5 of antigen or antibody is encapsulated in a
shell matrix material l. Microparticles containing a core of
drug would be particularly well suited in situations where an
endogenous factor for disrupting the outer shell of the
microparticles is exploited. For example, the difference in
pH of the mucosal fluids in the vagina on the one hand, and
the cervix and uterus on the other hand, can be exploited
such that deterioration of the outer shell occurs when the
microparticles reach the area of the cervix or uterus. In
this situation, the acidic pH of the vagina would have
little or no effect on the shell of the microparticles.
However, when t~he mic~o~articles are conveyed into the




, _ . .

~1~3289



cervix where they are exposed to the neutral pH therein,
breakdown of the outer shell would commence eventually re-
sulting in the sudden release of drug which is advantageous
where it is desirable to deliver a substantial amount of anti-

body to a patient suffering from an acute infection or havinga high concentration of toxin. This procedure would be
particularly desirable where it is desired to administer a
booster response after an individual has already received a
primary immunization.



In the treatment of patients for some disorders it is
advantageous to be able to administer antigen or antibody in
an intermittent fashion. This could be accomplished by the use
of microparticles having the configuration shown in FIGURE 4
where alternate layers of drug alone or dispersed in matrix
material 7 and drug free matrix material 1 are formed in con-
centric layers. When such microparticles are deposited in the
vagina, release of drug does not occur until the outer layer
of the microparticles disintegrates. Once the underlying layer
is exposed drug release starts and continues until the layer
disintegrates or releases the drug. Drug release ceases as the
next underlying drug free layer is reached. In this manner in-
termittent release of the drug is achieved. An example of the




-20-

~ ` ~3289
~, .
.,
. .` :~ , . . ` '
~; ~ applicability of this technique can be found in active immuniza-
tion where the outermost drug layer releases antigen for a
sustained period which is followed by a period for instance of
a week or two, in which no drug is released. After the non-
5~ drug containing layer disintegratesj a second period of antigen
' ~ release starts. In this manner on~ could in a single adminis-

'',!~,S'~` tration of microparticles provide a primary immunization dose~
followed by a booster dose.
'~' . ' . ' .
~; When it is desired to not only convey an antigen or anti-
10~ ~ body to the uterus through the cervix but also adminis er cycle
regulatory hormone in order to activate or regulate thenatural
, transport mechanism, it is possible to administer microparticles
~, of a monolithic structure aa shown in FIGURE 1 in which both
antigen or antibody and cycle regulating hormone are dispersed
15 ~ through a matrix material. In this manner, once the micro-
particles are deposited in the vagina, release of both hormone
and antigen or antibody starts and eventually the microparticles
are conveyed across the cervix into the uterus. A perhaps more
selective regimen of administration could be provided by micro-
particles which have an outermost matrix layer containing cycle
'
.


. .
''

-21-

~-~

` 1143;~:89
` : :
~: :.
"',`.`~"
regulatory hormone and an inner core of matrix material contain-
ing antigen or antibody. When such microparticles are adminis-
tered, the sustained release of cycle regulatory hormone occurs,
~1~ and when the cervix is receptive to transport, the microparticles

5,~; are transported across the cervix into the uterus. Release of., r, .the antigen or antibody will occur in the cervix or uterus as


the underlying antigen or antibody core of the microparticles
is exposed. FIGURE 5 shows microparticles of the structure dis-
; cussed above in which outer cycle regulatory hormone containing
lQ layer 9 encapsulates inner antigen or antibody containing core
11. The antigen or antibody alone can constitute the core of the
microparticles or the antibody or antigen can be dispersed in the
matrix material to form core 11, However, outer layer or shell
~ - 9 is formulated by dispersing a menstruaL cycle regulatory
hormone in a matrix material.
,'' ' ~ ~ ~ ' . .
From the above discussion it is evident that antibody or
antigen alone or in combination with a cycle regulatory hormone
can be incorporated in microparticles in a variety of configura-
tions depending upon how the drug or drugs are to be released.

Moreover, while multi-layered microparticles such as the types
shown in FIGURES 2, 4 and 5 are normally formed of a single
type of matrix material, it is possible, if not desirable under

~` . ' .
:. ~,,''

"",'~'''' . .
~- -22-
.
''~''`'~

1~3289
.
" :
.
~some circumstances, to formulate contiguous layers of the micro-
particles from different matrix materials. Still further, it is
;~ possible that under some circumstances, it`may be desirable to
deliver more than one antibody or antigen to the internal repro-
5~ ductive organs to treat more than one condition. Thus, for
; ~instance, monolithic microparticles could be prepared and
delivered containing two different antibodies to passively treat
,~ two different diseases. In fact, it may be desirable under some
circumstances to actively immunize a patien~ against one dis-
order and simultaneously passively immunize the patient against
a second disorder with antigen or antibody delivered in the
same microparticles. Of course, when more than one antigen and/
or antibody is combined in one microparticle where they may be
in contact and not in different layers of a microparticle, they
must not react with each other.
'',

Still another microparticle configuration is shown in
FIGURE 8 wherein compatible, i.e. mutually non-re~ctive, con-
traceptive agent 21 and cycle regulatory hormone 22 are dispersed
in matrix material 23 to form a core 25. The microparticles are
completed by encapsulating the particles of drug containing




.

`` li~32~39

'~; .
,''~', , .

matrix material in a shell 27 of matrix material 24. The matrix
material 23 and 24 of the inner core 25 and shell 27 can be the
same material or different material. The use of different matrix
materials is especially useful where it is desired to take
advantage of the different rates of deterioration of the matrix
materials or the different rates of diffusion of the drug through
the matrix materials. Release of the contraceptive agent and
cycle regulatory hormone does not occur until the shell of matrix
material 24 has deteriorated.
,, . ~ .
10-~ ~ FI~,URE 9 shows a microparticle structure wherein a core
; 25 of contraceptive agent 21 in matrix material 23 is formed
; and then in turn core 25 is surrounded by a shell 27 of matrix
;~ material 25 containing cycle regulatory hormone 22. The micro-
~ particles of this particular configuration are especially use-
15~ ful where it is deslred to deposit microparticles in the vagina
;~ to achieve the initial gradual release of only cycle regulatory
hormone 22 which regulates the monthly cycle and stimulates
transport of the microparticles across the cervix. In this
manner regulation of the monthly cycle and at least initial
transport of the microparticles can be initiated by the time the
inner core 25 is sufficiently exposed to permit release of
encapsulated contraceptive agent 21. Of course,the contraceptive


~3~89
`.`` . ` '.
`' ':'
`.`
agent can be encapsulated alone or dispersed throughout a eore
matrix material which can be the same as or different from
shell matrix material 24.
, .
: A multiply layered microparticle configuration is shown
: in FIGURE 10. These microparticles possess an inner core 25 of
. a eontraceptive agent 21 alone or dispersed in a matrix material
23. The core 25 is encapsulated in a shell 27 of a matrix
. material 24 which in turn is eneapsulated in an outer shell 31
of matrix material 29 containing cycle regulatory hormone 28.
10. Microparticles of this particular coniguration would be useful
in those situations where it is desirable to administer cycle
regulatory hormone after deposition of the microparticles in
the vagina. After all of the cycle regulatory hormone has been
released, release of the contraceptive agent would be delayed
until inner shell 27 has deteriorated to a sufficient extent
: to permit release of contraceptive agent from core 25. In the
~meantime, transport of the microparticles will occur thus achiev-
. ing delayed release of the contraceptive agent until the bulk of
the microparticles has been conveyed into the uterus.

With regard to the physical shape of the

11 . .

~ ` li~3'~




microparticles, the microparticles can assume any possible
shape ranging from ordered shapes such as spherical or oval to
irregular shapes. The shape of the microparticles is not a
factor in microparticle transport. Normally, the medicinal
agent diffuses from the microparticles by gradual deterioration
of the matrix material and/or by permeation of the agent from
the matrix material.
., ., .
The size of the microparticles is important insofar as
the microparticles must possess sperm surrogate activity such
that they can be conveyed by the natural transport mechanism of
the reproductive organs upward from the cervix into the uterus
and eventually into the fallopian tubes. If the microparticles
are too large, they will cause contractions of the cervix which
will expel the microparticles. Microparticles which are too
'small will not be conveyed upward into the internal reproductive
organs. Usually, the microparticles range in size from 20 to 70 u~ ,
preferably 20-60 ~m.
".'
The matrix material from which the microparticles are
formed and in which the contraceptive aqent and cycle regulatory
hormone are dispersed is important not only from the viewpoint
.




-26-

.
. .


~143289
.
'~: . .
, ~ , ' .
of sperm surrogate aetivity but also from the biocompatibility
standpoint. In order for a material to be aceeptable as a
matrix material it should have no adverse effect on the internal
female reproductive organs. The matrix material should also be
biocompatible in that it should not irritate the tissues of the
eervix or uterus, it should not be eareinogenie and it should
not induce inflammation in body tissues. The matrix material
should be compatible with body tissues and it must be miscible
with the cervical mucous. Another factor of importance is that
the matrix material must be biodegradable in that body chemical
processes must be able to eventually breakdown the polymer
so that it does not accumulate in the body. The matrix material
should also have the ability, when in microparticle form, to
slowly deteriorate over a period of time which at least
eorresponds to the female monthly menstrual cycle. Suitable
examples of polymer materials include polyglycolic acid, ~
poly~actiie acid, copolymers thereof, and the like. Other useful
matrix materials include such materials as glycerol mono- and
distearate. Other matrix materials include those which will
deeompose in the neutral environment of the cervix.

In the preparation of the antibody or antigen containing
microparticles essentially any known antigen or antibody can be



I

11~3289



incorporated in the microparticles although those of par-
ticular use in the treatment of conditions and diseases of
the internal reproductive organs are preferably used.
Suitable types of antigens which can be incorporated in the
present microparticles include bacterial and viral pathogens
of man and animals, however, enzymes and other biological
factors involved in the reproductive process can also be used.
Suitable pathogenic antigens include Neisseria gonorrhea,
Mycobacterium tuberculosis, Herpes virus (humonis, types 1
and 2), Candida albicans, Candida tropicalis, Trichomonas
vaginalis, Haemophilus vaginalis, Group B streptococcus ecoli,
Microplasma hominus, Hemophilus ducreyi, Granuloma inguinale,
Lymphopathia venereum, Treponema pallidum, Brucella abortus,
Brucella melitensis, Brucella suis, Brucella canis,
Campylobacter fetus, Campylobacter fetus intestinalis,
Leptospira pomona, Listeria monocytogenes, Brucella ovis,
Equine herpes virus l, Equine arteritis virus, IBR-IBP virus,
BVD-MB virus, Chlamydia ps.ittaci, Trichomonas foetus, Toxo-
plasma gondii, Escherichia coli, Actinobacillus equuli,
Salmonella abortus ovis, Salmonella abortus equ.i, Pseudomonas
aeruginosa, Corynebacterium equi, Corynebacterium pyogenes,
Actinobaccilus seminis, Mycoplasma bovigenitalium,
Aspergillus fumigatus, Absidia ramosa, Trypanosoma equiperdum,
Babesia caballi, Clostridium tetani.




-28-





Suitable examples of enzymes that may be involved in
the reproductive process include ribonuclease, neuramidinase,
trypsin, glycogen phosphorylase, sperm lactic dehydrogenase,
sperm hyaluronidase, adenosinetriphosphatase, alkaline
phosphatase, alkaline phosphatase esterase, amino peptidase,
trypsin chymotrypsin, amylase, muramidase, acrosomal
proteinase, diesterase, glutamic acid dehydrogenase, succinic
acid dehydrogenase, beta-glycophosphatase, lipase, ATP-ase
alpha-peptate gamma-glutamylotrans peptidase, sterol-3-beta-

ol-dehydrogenase, DPN-di-aprorase.



Suitable examples of hormones acting as antigens
include human chorionic gonadotrophin hormones, human
placental lactogen, progesterone, estradiol and the like.
Other antigens include those known as embryonic cellular
antigens which occur on the cellular surface of the tropho-
blast and are unique to the trophoblast. In addition to the
above mentioned pathogens, mixtures of pathogens which can
infect the female reproductive organs also can be incorporated
in microparticles.



Examples of antibodies for passive immunization which can
-




-29-


. .
. . _. .

11~3~39
. . ..




be incorporated in microparticles include those which correspond
to all of the above described antigens which are effective for
active immunization. Antibodies which are effective against
sperm, eggsl products of conception and the like can also be
5 ~ employed.
, '
When the antigen or antibody containing microparticles
are administered to a subject, they are administered in an
amount such that the desired daily dosage level of antigen or
antibody is delivered in an amount sufficient to elicit the
desired response over the desired Period of time, which for
antigen would be about 0.5 to 1 mg of antigen per day over a
7-14 day period. The dosage range re~uired for a booster
immunization would vary from 0.5 to 1 mg per day over a 24
hour time span. With regard to passive immunization via antibody
lS administration, the weight of antibody administered does not
necessarily directly relate to the therapeutic effect realized.
The important factor in terms of dosage for passive immunization
is the titer of the antibody or the biological potency. The
titer of an antibody refers to the maximum dilution of the anti-
body which elicits an effect in a test situation. Two different

Il

11~3;~B9




preparations of antibody are not equally comparable on a weight
basis because they have different biological potencies. An
immunological titer of 1:500 is the minimum biological potency
for any antibody to be administered by the process of the
~5 present invention. Moreover, the rate at which the immunoglobu-
lin or antibody should be delivered to the cervix, uterus and
fallopian tubes should not exceed 0.1 mg of antibody per day.
Any dose rate less than this level which is effective in elicit-
ing a therapeutlc response is acceptable.

The antigen, antibody or contraceptive agent containing
microparticles can be conveniently prepared by any well known
procedure used in the past for the preparation of microparticles
containing a pharmaceutical material. While the amount of
antigen or antibody, and cycle regulatory hormone, if it is to
lS be present, is not critical, normally, the microparticles contain
from about 10 wt.% to 60 wt.% preferably 10 wt.% to 50 wt.%,
most preferably 10 wt.% to 25 wt.% of antibody or antlgen.
,.
The primary limitation for the generation of passive
immunization in a subject by the administration of antibodies
in clinical medicine is that antibodies produced in animals quite
often cause serum sickness or anaphylaxis when injected into
.
''

1143Z89



human recipients. However, the local delivery technique of the
present invention circumvents this problem because not only
are smaller dosages of antibodies required, but also systemic
~dministration of antibodies is avoided.



In some instances active immunization is more advantageous
than passive immunization such as for permanent protection
against infectious diseases. Thus, when an antigen is delivered
to the uterus and fallopian tube by the present technique,
antibodies are secreted which not only provide the desired
immunological effect, but also are structurally and fundamental-
ly unique from the type of antibody produced in response to
systemic immunization. Systemic antibodies are not secreted by
the reproductive organs, and it is for this reason that
systemic immunization is not an effective way of generating
antibodies in the fluids of the cervix, uterus and fallopian
tubes.



Another aspect of active immunization pertains to fertility.
In this case, sperm antigens are delivered by transport of anti-
gent containing microcapsules into the cervix, uterus and fallo-
pian tubes. The antigen which is slowly released over a sustained
period of time, stimulates the secretory tissues of the organs




-32-
,,.

: ~ ~ Z85~
. ` .
,
~`"'' .
to secrete protective antibodies in the fluid layer which coats
the internal organs which essentially are the cervix, uterus and
fallopian tubes. After copulation and deposition of sperm in
the vagina, antibodies in the cervical mucous cause agglutinatior
of the sperm in the cervix and prevent further transport of the
sperm into the uterùs. Antibodies against sperm also inactivate
sperm by techniques other than agglutination.
. ., ' , . .:
; ~ ~ For the contraceptive agent containing microparticles of
~ the invention any type of contraceptive agent which has the
desired contraceptive effect, especially in mammals, can be
formulated in the present microparticles. Suitable examples of
contraceptive agents include spermicidal compounds such as
nonylphenoxypolyoxyethylene ethynol, Benzethonium chloride
; (benzyldimethyl [(2-(1, 1, 3,3-tetramethylbutyl-phenoxy) ethoxy)
ethyl~ ammonium chloride), Chlorindanol (7-chloro-4-indanol)
and the like; and natural and synthetic hormones such as
Progesterone (a 4-pregnene-3, 20-dione), Estradiol (estradiol
3, 17~ -dicypionate), Norethindrone (17-hydroxy-19-nor-17~ -
pregn-4-en-20-yn-3-one), Norgestrel (d, 1-13~ ethyl-17~ -ethynyl
17~ - hydroxy -4~en-3-one), Ethynodiol diacetate (3~ , 17~ -
.,.'

1143Z89



diacetoxy-17~ -ethynyl-4-estrene), Lynestrenol (17~ -ethy-
nylestr-4-en-17~ -ol), Medroxy-progresterone acetate (17~
-hydroxy-6a -methylpregn-4-ene-3, 20-dione), Dimethisterone
(173 -hydroxy-6a -methyl-17-1-propynyl-androst-4-en-3-one),
Megestrol acetate (17a -hydroxy-6-methylpregn-4, 6-diene-3,
20 dione acetate), Chlormadinone acetate (6-chloro-17-hydroxy-
pregna-4, 6-diene-3, 20-dione acetate), Ethinylestradiol
(17a cthinyl-1,3,5(10)-estratriene 3~ -diol), Mestranol
(3-methoxy-19-nor-17~ -pregna-1,3,5(10)-trien-20-yn-17-ol)
and the like. Another class of compounds within the scope of
the present invention are those which induce early abortion
in mammals. Suitable examples of compounds possessing
abortifacient activity inciude antihistamines, cytotoxic drugs,
ergot alkaloids, hormones, prostaglandins such as Prosta-
glandins E2 and F2a (lla,-15(S)-dihydroxy-9-keto-prosta-5-
cis-13-trans-dienoic acid and 9~, lla -15 (S)-trihydroxy-
prosta-5-cis-13-trans dionoic acid, respectively), sympatho-
lytic compounds, and the like. Of course, mixtures of various
contraceptive agents where the individual compounds are bio-
logically compatible can also be used.

The amount of microparticles deposited in the vagina
depends upon the amount of contraceptive agent that must be




-34-

Il .

~1~3'~89
:"
'


delivered to the uterus and fallop~ian tubes to achieve the
desired contraceptive effect. In the case of hormones which
produce a contraceptiv~e effect, the dosage of hormone which
should be administered ranges from 20 ug to 1000 ug per day.
In the case of spermicidal contraceptive agents it is not
necessary to administer a daily dosage over most of the days
' of the menstrual cycle. It is only necessary to administer
spermicidal agent for several days around midcycle when concep-
tion is possible at a dosage level sufficient to prevent con-
ception. Normally, a dosage of 25 ug to 1000 ug per day for 7
days about midcycle will achieve the desired effect. Other
types of contraceptive agents which can be used as discussed
above include abortifacient drugs. These abortifacient drugs
should be administered immediately following a missed menstrual
period for three to five days at a dose of 1 to 500 mg per day.
. .
In the manufacture of the microparticles containing
antigen or antibody and for a menstrual cycle regulatory hormone,
any conventional method of forming the microparticles can be
used. ~he selection of a particular method chiefly depends upon
the technical requirements of the matrix material and the
. .




' ' '

119~32~39
. , .

. .
~' . .
particular manner in which the microparticles are intended to
be used. Generally, microencapsulation processes can be
classified according to the three principal types, (1) phase-
separation methods including aqueous and organic phase separa~
5~ tion processes, melt dispersion and spray drying; (2) inter-
facial reactions including interfacial polymerization, in situ
polymerization and chemical vapor depositions; and (3) physical
methods, including fluidized-bed spray coating, multi- and
single-orifice centrifugal coating, electrostatic coating and
physical vapor deposition.
~ . .
Microparticles containing medicinal or therapeutic agents
can be delivered to the vagina by a variety of methods. The
preferred method is to incorporate a fixed number o microParti-
cles into a container designed for easy hand insertion into the
15 ~ vagina. The insertion container should be made of a biodegradable
material that dissolves within minutes after placement in the
vagina, thus, releasing the microparticles.Pharmaceutical type
gelatin capsules can be conveniently used as a delivery system
for the microparticles.The dose level can be varied by increasing
or decreasing the number of micropar-ticlesin the delivery device.




-36-
.~

` " 1~43'~8~

. '

Of course, any number of other methods of variatiohs, or this
preferred method might be used. For examPle the microparticles
could be molded into a solid vaginal suppository which affords
the simplest most direct method of applying the microparticles
by using an appropriate suspension medium such as gelatin.
Creams, jellies, foams, or liquids might be used as a suspension
medium for microparticles.Preparations of this type could be
placed in the vagina using a loadable syringe or some type of
pressurized vaginal inserter such as an aerosol device or a
1~ squeeze tube or bulb. A variety of different types of applicators
for administering pharmaceutical agents to the vagina and
rectum are in common use. A gelatin capsule is also a convenient
vehicle for the delivery of microparticles.

~ Having now generally described the invention, a more com-
lS plete understanding can be obtained by reference to certain
specific examples which are included for purposes of illustra-
tion only and are not intended to be limiting unless otherwise
specified.
,~

~1~3~89



EXAMPLE 1

Preparation of Progesterone Containing
Polylactic acid Microcapsules

A 2.5 g amount of progesterone and 10.0 grams of
d,l-polylactic acid were dissolved in 38 grams of methylene
chloride. The resulting viscous solution was poured into a
250 ml kettle containing 120 ml of a 5 wt.% aqueous poly-
vinylalcohol solution. The dispersion obtained was stirred
at about 200 rpm until a stable emulsion had formed with the
droplets being in the range of 50 to 100 ~-m in diameter. A
vacuum was applied to the emulsion until it began to foam and
then the rate of stirring was reduced to 600 rpm. After two
hours, most of the methylene chloride had evaporated. More-
over, continuous stirring was not required to prevent the
embryonic microcapsules from agglomerating. Thereafter, the
emulsion was centrifuged, the aqueous polyvinylalcohol
solution was decanted and the microcapsules were resuspended
in 150 ml of deionized water. For about 18 hours thereafter a
vacuum was continually applied to the stirred aqueous sus-

pension. Thereafter, the suspension was centrifuged and themicrocapsules obtained were washed with water and then col-
lected by vacuum filtration. The microcapsules were dried at
room temperature under a hard vacuum overnight, and then they




-38-


1~3289


were sieved whereby a fraction ranging between 43 and 61 ~m
was obtained. By this procedure microcapsules containing
22 + 1.5 wt.% progesterone were obtained.

EXAMPLE 2
Preparation of Progesterone Containing
Glycerol Monostearate Microcapsules i

A 1.0 gram amount of progesterone was added to 4 grams
of molten glycerol monostearate and a portion of the molten
mixture was poured into the reservoix of a melt sprayer and
heated to 167C. The flow of nitrogen into the device to
effect cooling was 60 liters per minute, while the flow of
nitrogen into the sprayer to aerosolyze the molten mixture
was adjusted to the maximum rate of 5.75 liters per minute.
The aerosol was sprayed intermittently, and microcapsules
were collected and sieved, whereby a size fraction ranging
between 43 and 61 ~m was collected. The microcapsules pro-
duced by this procedure were spherical and contained a 20 wt.
% theoretical loading of progesterone.

EXAMPLE 3

Four female baboons were injected with d,l polylactic




-39-

-

11~3289



microcapsules containing 7.87 mg of progesterone while five
baboons were treated with d,l-polylactic microcapsules con-
taining 7.87 mg of progesterone by the vaginal route of
administration. All baboons were treated on day 5 and
uterine biopsies were taken on day 12. Daily blood levels of
estradiol and progesterone were also obtained. The results
of the daily determinations are shown in FIGURE 11 wherein
FIGURE llA shows the level of progesterone and estradiol for
the intramuscular injection of microcapsules while FIGURE llB
shows the levels of progesterone and estradiol for the
vaginal administration of microcapsules. It is apparent that
higher blood level concentrations of progesterone are found
in the intramuscularly injected baboons than in vaginally
treated baboons. There are two possibilities to account for
this: (1) not all of the microcapsules placed in the vagina
remain in the body over the 7-day period of treatment; (2)
not all progesterone released from the microcapsules following
placement in the vagina reaches the bloodstream. Both of
these possibilities probably contribute to the differences in
the systemic levels of progesterone between the two treatment
groups. If systemic delivery of progesterone is considered




-40-

~1~3289




alone and the possibility of local delivery directly to the
uteris in the intravaginally treated animals is excluded, it
is logical to expect a more intense progestational effect
in baboons treated by injection than in those treated
vaginally. The results from dose-response experiments
support this expectation. Comparative histological examin-
ation of the endometrial biopsies of the baboons, however, do
not support this assumption. Histological examination re-
veals no significant reduction in the level of progesterone-

induced secretory activity in baboons treated by intravaginaladministration when compared to those treated by intra-
muscular injection. This is somewhat unexpected on the
basis of the difference in the systemic levels of progesterone.
This seemingly contradictory finding actually supports the
possibility for local delivery of progesterone in the
vaginally treated baboons. FIGURES 12a and 12b show the
histological appearance of the endometrium of a baboon
treated by the intravaginal administration of microcapsules
containing 7.87 mg of progesterone (H & F stained tissue at
20x and lOOx magnification, respectively). FIGURES 12c and
12d represent the same tissue (PAS stained) at 20 x and lOOx




-41-


-
:


1143289


magnification, respectively.



A second line of histological evidence which provides
support for the local delivery of progesterone in the
vaginally treated animals comes from the observation that
progesterone-induced alterations in endometrial histology are
distributed evenly throughout the endometrium in baboons
treated by injections; whereas, in baboons treated by intra-
vaginal deposition of the microcapsules, the effects are
localized and vary from gland to gland with a notable
intensity of stimulation in the superficial glands under-
lining the surface epithelium (FIGURE 12). The absence of
subnuclear vacuoles in the superficial glands in baboons
treated by injection and the abundant presence of subnuclear
vacuoles in the superficial glands of baboons treated intra-

vaginally provides evidence of the local intrauterinedelivery of progesterone in the intravaginally-treated
baboons.



A comparative examination of the surface epithelial
morphology by scanning electron microscopy provides further
evidence for localized progestational effects following intra-
vaginal treatment with the microcapsules. FIGURE 13 compares




42-


1143'~89


the morphology of the uterine epithelial surface of: normal
non-treated day 12 baboon endometrium (FIGURE 13a); normal
non-treated day 20 endometrium (FIGURE 13b); treated day 12
endometrium (intramuscular injection of microcapsules con-

taining 7.87 mg of progesterone, FIGURE 13c); and treated day12 endometrium (intravaginal deposition of microcapsules con-
taining 7.87 mg of progesterone, FIGURE 13d).



Progesterone induces the formation of distinct micro-
villus projections on the luminal surface of the glandular
epithelial cells. Microvilli are not normally present before
ovulation (see day 12 control) but become quite conspicuous
after ovulation (see day 20 control). Continuous progesterone
treatment between days 5 and 12 induces the formation of
numerous microvillus projections. Microvilli occur in an even
distribution on the epithelial surfaces of baboons treated by
injection. However, in baboons treated intravaginally the
microvilli occur in distinct patches. The patchy uneven
distribution of microcapsules occurs between areas in which
the epithelial cells lack microvilli and other areas in which
the microvilli vary in size. This uneven distribution of a
progesterone-induced alteration in the morphology of the
surface epithelium is indicative of localized areas
of progesterone stimulation. Following systemic delivery,




-43-

lL

` ~3Z89
.~ .
.:~'.`. .: .
~:
A all areas of the endometrium receive a uniform ~ose of drug,
whereas with local delivery, some areas may receive higher or
lower doses depending on where the microcapsules are located
' within the uterus. ,
~' . .
FIGURES 14A and 14B compare the mean progesterone and
estradiol levels between baboons treated by either intramuscular
injection ,(FIGURE 14A) or intravaginal administration (FIGURE
14B) with a dose of microcapsules containing 1.S7 mg of proges-
terone under the conditions described above. This low dose of
10~ mic~ocapsules has a slight inhibiting effect on the estradiol
levels when administered by injection and no effect when
administered intravaginally. Exogenous progesterone is present
~,~, in low levels in the blood between days 5 and 12 in baboons
treated by injection. However, in baboons treated by the vaginal
15 ~ route, exogenous progesterone could not be detected in the blood
within the sensitivity range of the assay technique between
' ~days 5 and 12.
`,

On the basis of the comparative hormone data shown in
FIGURE 14 and excluding the possibility for local delivery, it
~ seem logical to expFct the histology of the endometrium of the ~'

'` , `.
' .
.:'.,

-44-


,

,


~43'~39
, . ' .
.' .
vaginally-treated baboons to resemble the pattern observed in
normal non-treated controls. The rationale for this expectation
is that the blood levels of both progesterone and estradiol
in baboons treated by the intravaginal route with the low dose
of microcapsules is identical to that which occurs normally.
Therefore, on the basis of endocrine data, there is little
reason to expect hormone-induced alterations in the endometrial
histology. The same rationale, however, does not hold for the
animals treated by injection because following the treatment,
detectable progesterone levels were found in the blood between
days 5 and 12. Moreover, the estradiol levels appear to be
somewhat depressed when compared to the normal controls. Again,
the histological findings are contrary to the expected results.
In spite of the lack of measurable systemic progesterone in
baboons treated by the vaginal route, the endometrium exhibits
distinct progestational effects.
''; .
Examination of the surface epithelial morphology by
scanning electron microscopy reveals the fre~uent occurrence
of microvilli providing clear evidence for progesterone stimula-
tion as shown in FIGVRE 15. In particular, FIGURES 15a and 15b




.' 11 .

D

3289
. . ,' , .
~,~.''"
are low magnification (9600) and high magnification (18240)
micrographs of the surface epithelium of the treated baboon on
day 12 of the menstrual cycle. FIGURE 15c is a micrograph of
the epithelium which shows microcapsules containing progesterone
on the surface of the epithelium while FIGURE 15d is a photo-
micrograph of the microcapsules themselves. Although the pro-
gesterone-induced alterations in the endometrial histology
might-occur in response to systemic progesterone that is too
low to measure by the assaying system employed, a more likely
explanation is that the progesterone-induced changes result
from direct local intrauterine delivery of progesterone.
. .
The most important point to emphasize is that with a
low dose of microcapsules (i.e., 7.87 mg of progesterone)
secretory changes were induced in the endometrium. Moreover,
a dose response associated with the changes has been demonstrated
suggesting that by increasing the dose it should be possible to
achieve a level of effect sufficient to inhibit reproductive
function.
.''. ..
FIGURES 16A and 16B compare the pattern of cervical muscle
contractile activity between two baboons on the same day of the

~ 3'~89



menstrual cycle. A special transducer constructed as described
by W. n. slair and L. R. seck in Ovum Transport and Fertility
Regulation, 1976r pp. 41-74, Scriptor Publication (Copenhagen)
placed in the cervix of each baboon was used to measure the
pattern of the cervical contractions shown in the Figures. The
transducer was connected to a strip chart recorder. FIGURE 16A
shows the results obtained from a baboon treated by placing
microparticles containing estradiol into the vagina while FIGURE
16B shows the results obtained from a control baboon untreated
10 ~ with microparticles. The results show that the treatment stimu-
lates both the frequency and the amplitude o~ the cervical
contractions. These contractions move the microparticles through
the system.

Having now fully described the invention, it will be
lS apparent to one of ordinary skill in the art that many changes
and modifications can be made thereto without departing from the
spirit or scope of the invention as set forth herein.




_47_

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Administrative Status

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Administrative Status

Title Date
Forecasted Issue Date 1983-03-22
(22) Filed 1979-10-01
(45) Issued 1983-03-22
Expired 2000-03-22

Abandonment History

There is no abandonment history.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $0.00 1979-10-01
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
STOLLE RESEARCH AND DEVELOPMENT CORPORATION
Past Owners on Record
None
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Drawings 1994-01-25 8 407
Claims 1994-01-25 4 124
Abstract 1994-01-25 1 27
Cover Page 1994-01-25 1 18
Description 1994-01-25 46 1,625