Screening of anti-fertility agents.powerpointt

1. Screening of drugs used for
contraception
PRESENTER : DR MOHAMED AJEEM
MODERATOR : DR PRAMOD

2. Contents
 Introduction
 Mechanism
 Types
 Anti ovulatory activity
 Estrogenic activity
 Progestional activity
 Anti-implantation activity
 Androgenic activity
 Conclusion

3. INTRODUCTION
 Contraception: Interception of birth process at any stage ranging from
ovulation to ovum implantation
 Anti fertility agents are substances which prevents reproduction by
interfering with normal reproductive agents in both male and female

4. Contraceptives currently in use
 Estrogens
 Natural: Estradiol, Estriol and
Estrone
 Synthetic: Ethinyl-estradiol,
Mestranol
 Progestins
 Natural: Progesterone, 17 α
hydroxyprogesterone
 Synthetic: Levonorgestrel,
Desogestrel,
Medroxyprogesterone acetate

5. Mechanism of Anti-fertility
 Inhibition of ovulation.
 Prevention of fertilization.
 Interference with transport of ova from oviduct to endometrium of the
uterus.
 Interference with the implantation of fertilized ovum.
 Distraction of early implanted embryo.

6. Screening methods (Female)
Anti Ovulatory
 HCG induced ovulation in
rats
 Cupric acetate induced
ovulation in rabbits
Estrogenic
 Vaginal Opening
 Vaginal Cornification
 Uterine weight assay
 Chick oviduct method
Progestional
 Pregnancy maintenance
test
 Clauberg Mcphail test
 Endometrial carbonic
anhydrase

7. Screening methods(male)
 Chicken comb method
 Weight of ventral prostate, seminal vesicles
and musculus levator ani

8. Anti-ovulatory Activity
Female albino rats
24-26 days old
treated with Test
dose followed by
HCG
After 2 days,
animals are
sacrificed, ovaries
are dissected out
preserved in 10%
buffered formalin
and subjected to
histopathological
evaluation
HCG induced ovulation in rats
Principle: Human chorionic gonadotropin (HCG) induces follicle maturation,
followed by spontaneous ovulation 2 days later

9. Anti-ovulatory Activity
Cupric acetate-induced ovulation in rabbits
Principle : rabbits ovulates within a few hours after an i.v.
injection of cupric acetate (0.3 mg/ kg using 1% cupric acetate
in 0.9% saline). Injection of anti-ovulatory drugs, 24 h before
the induction procedure prevents ovulation.

10. Anti-ovulatory Activity
 Procedure:
 Sexually mature female albino rabbits, weighing 3–4 kg
 Animals kept in isolation for at least 21 days
 Test drug, and 24 h later an i.v. injection of cupric acetate is given.
 The rabbits are sacrificed and the ovaries are examined 18–24 h later.
 The total number of ovulation points

11. Vaginal Cornification (Estrogenic Activity)
 Rats and mice exhibit cyclic ovulation and associated changes in hormones
 Adult female albino rats are used for the study
 Changes in vagina is observed by taking vaginal smears examining for
cornified cells, leucocytes and epithelial cells
 Any drug which changes animals to estrus stage is considered to have
estrogenic activity

12. Seven-day old pullet
chicks are injected s.c
twice daily with test
compound in various
doses X 6 days
Standard doses
estradiol-17β
between 0.02
and 0.5 μg
Animals are
sacrificed and
weight of the
body and oviduct
determined
 Chick Oviduct Method:
 principle: The weight of the oviduct of
young chicken is increased dose-
dependently by natural and synthetic
estrogens

13. Uterine weight assay
Principle: Repeated administration of
estrogens induces a dose-dependent increase
of uterine weight in castrated female rats.
Immature female
Sprague-Dawley
rats (55 g) are
ovariectomized
Test compound -
Orally or S.C in 0.5%
Solution of
carboxymethylcellulose
or in cotton seed
Oil
On the 8th day,
the animals are
sacrificed and
uterine weights
determined

14. Clauberg (McPhail) test in rabbits
(Progestional activity)
Immature female rabbits (weighing 550–650 g) receive daily
injections of 5.0 μg estradiol benzoate for 6 days
7th -12th day the rabbits are administered the test
drug or the standard (0.02, 0.08 and 2.0 mg
progesterone) s.c
15th day, animals are sacrificed, uterus removed and fixed
in 10% formalin. Sections are made from the middle part
of each horn for histological examination

15. Clauberg (McPhail) test in rabbits
(Progestional activity)

16. Pregnancy maintenance test (progestional)
Day 1
• Mature Sprague-
Dawley female
rats inseminated
by being placed
with males
overnight
8-13 days
• ovariectomized if
found pregnant
and test
compounds are
administered once
daily, s.c
21 th day
• Animals are
sacrificed and
presence or
absence of
implantation sites
are noted

17. Anti-implantation Activity
 Female albino in proestrous or estrous stage are mated with matured male rats (female 3:1
male)
 examined for the presence of spermatozoa in the early morning vaginal smear
 Drug is administered orally to the animals once daily
 10th of pregnancy, the animals are laparotomized ; number of implants present in both the
uterine horns each ovary is counted. The animals are allowed to complete the gestation period
(21-23 days) and the number of litters delivered

19. Animals are divided in
to group of 8 animals
Surface area of
Individual comb is
measured
The capons
are injected daily i.m
for 5 consecutive
days test compound
or the standard in 1 ml
olive oil
Surface area of
Individual comb is
remeasured 24 hrs
after the last injection
Chicken comb method
(Androgenic activity)

20. Weight of ventral prostate, seminal vesicles
and musculus levator ani
 Principle: In the rat, the growth of the ventral prostate, the seminal vesicles and the
musculus levator ani is dependent on the presence of male sexual hormones. Weight
increase of the musculus levator ani is considered to indicate anabolic activity
 Immature male Sprague-Dawley rats weighing about 55 g are orchidectomized
 Test compound is administered in various doses administered orally or s.c for 10 days

21. Weight of ventral prostate, seminal vesicles
and musculus levator ani
 Standard- Testosterone (0.02, 0.1, and 0.5 mg) s.c or methyltestosterone (0.25, 1.5, and
5 mg)
 Ten animals are used for each group.
 On the 11th day, the animals are sacrificed and the seminal vesicles, the ventral
prostate, and the musculus levator ani are dissected and weighed
 Dose-response curves are constructed for each organ comparing the test compound
with the standard in order to calculate potency ratios

22. Conclusion
 An ideal contraceptive agent must possess 100% efficacy, Reversibility of action and free
from adverse events and easy to use
 Newer methods are needed to support the reproductive health needs of both women and
men, recognizing that these needs may change over their reproductive life-course.
 Methods under development aim to reduce potential side effects, improve access and
ease of use, ensure safety, increase secondary benefit associated with method use.

23. References
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2016.
 Gupta SK. Drug screening methods. 3rd ed. New Delhi: Jaypee; 2016
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anti-fertility agents. Asian Pac J Reprod. 2016;5:175–8
 Gnanasegaran, S., Adhimoolam, M. (2022). Screening Methods for the Evaluation of Antifertility
Drugs. In: Lakshmanan, M., Shewade, D.G., Raj, G.M. (eds) Introduction to Basics of Pharmacology
and Toxicology. Springer, Singapore.
 Haddad LB, Townsend JW, Sitruk-Ware R. Contraceptive Technologies: Looking Ahead to New
Approaches to Increase Options for Family Planning. Clin Obstet Gynecol. 2021 Sep 1;64(3):435-
448.