Lynestrenol phenylpropionate explained

Lynestrenol phenylpropionate (LPP), also known as ethynylestrenol phenylpropionate, is a progestin and a progestogen ester which was developed for potential use as a progestogen-only injectable contraceptive by Organon but was never marketed.^{[1] [2] [3] [4] [5] [6] [7]} It was assessed at doses of 25 to 75 mg in an oil solution once a month by intramuscular injection. LPP was associated with high contraceptive failure at the low dose and with poor cycle control.^[8] The medication was found to produce estrogenic effects in the endometrium in women due to transformation into estrogenic metabolites.

A single intramuscular injection of 50 to 100 mg LPP in oil solution has been found to have a duration of action of 14 to 30 days in terms of clinical biological effect in the uterus and on body temperature in women.

LPP has a long biological half-life in rats when given as an intramuscular depot injection; its half-life was similar to that of nandrolone laurate (nandrolone dodecanoate) and was about 2-fold longer than that of nandrolone decanoate, 10-fold longer than that of lynestrenol and nandrolone phenylpropionate, 50-fold longer than that of progesterone, and 430-fold longer than that of nandrolone.

See also

• List of progestogen esters § Esters of 19-nortestosterone derivatives

Notes and References

1. Book: Elsayed Saad Eldin Hafez. Human reproduction: conception and contraception. 1980. Harper and Row. 978-0-06-141066-6. 607,614.
2. Book: Mokhtar K. Toppozada . Monthly Injectable Contraceptives . 93–103 . Alfredo Goldsmith . Mokhtar Toppozada . Long-Acting Contraception . 1983 . 35018604 .
3. Badawy S, Makhlouf A . The contraceptive action of lynestrenol phenylpropionate . Adv Plan Parent . 10 . 3 . 149–53 . 1975 . 789155 .
4. van der Vies J . Implications of basic pharmacology in the therapy with esters of nandrolone . Acta Endocrinol Suppl (Copenh) . 271 . 3_Suppla. 38–44 . 1985 . 3865480 . 10.1530/acta.0.109S0038 .
5. Van der Vies . J . Mechanism of action of long-acting hormone preparations . Organorama . 6 . 5 . 4–8 . 1969 . 0369-7762 . Studies were made with nandrolone phenpropionate (Durabolin), nandrolone decanoate, and 16α-ethylprogesterone in peanut oil injected into the gastrocnemius muscle of rats. The free steroid was much more rapidly resorbed than the esters, explaining the action-prolonging effects obtained with the latter. Generally, resorption rates correlated well with duration of action. Resorption from the muscle was followed by transport to the receptor site in the body, during which time ester hydrolysis may occur, releasing the free steroid. Resorption and hydrolysis take place independently, since plasma with inactivated enzymes (heated to 55°) eluted the compds. from a filter paper strip as rapidly as did normal plasma..
6. van der Vies J . Model studies in vitro with long-acting hormonal preparations . Acta Endocrinol. . 64 . 4 . 656–69 . August 1970 . 5468664 . 10.1530/acta.0.0640656 .
7. Hobbelen PM, Coert A, Geelen JA, van der Vies J . Interactions of steroids with serum lipoproteins . Biochem. Pharmacol. . 24 . 2 . 165–72 . January 1975 . 163092 . 10.1016/0006-2952(75)90273-7 .
8. Toppozada M . The clinical use of monthly injectable contraceptive preparations . Obstet Gynecol Surv . 32 . 6 . 335–47 . June 1977 . 865726 . 10.1097/00006254-197706000-00001 .