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 Vogel HG. Drug discovery and evaluation: pharmacological assays. 4th ed. New York: Springer; 2016. Gupta SK. Drug screening methods. 3rd ed. New Delhi: Jaypee; 2016 Shah M, Singh R, Shah R, Kakar S. An overview of the current methodologies used for evaluation of 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.