| Popis: |
The first synthesis of an active ingredient of the pill was performed on October 15, 1951, at Syntex in Mexico City. These preliminary results, obtained in late 1951, encouraged the submission of a synthetic progestin, norethindrone (19-nor-17alpha-ethynyltestosterone), to a number of outside investigators for more extensive biological scrutiny. Norethynodrel, together with many other steroids synthesized in the Searle laboratories, as well as Syntex's norethindrone, were examined by Pincus and collaborators for ovulation inhibition in animals and humans. Contrary to predictions, orally effective steroid ovulation inhibitors became the most widely used method of reversible birth control in most parts of the world some 40 years after their first synthesis. Toward the end of the 1960s, at least 13 international pharmaceutical companies (9 of them US) had active research and development programs dedicated to new advances in the field of contraception. Every drug to which a woman or man is exposed to for long periods of time (e.g., vaccines, systemic contraceptives, cholesterol-lowering agents, antihypertensives) in the end has to pass through large-scale postmarketing experiments. The most damaging was the requirement for 6-year toxicology in beagle dogs, which resulted in enormous development costs. Another setback was a 1986 judgment in Georgia against Ortho Pharmaceutical Company for the amount of $5,151,030 for alleged birth defects caused by the use of its spermicide Ortho-Gynol in spite of overwhelming epidemiological evidence against such a cause-effect relationship. Mifepristone (RU-486) is clearly the most significant new development in birth control as an important alternative to conventional abortion. A priority list of six new contraceptive methods for future development includes a spermicide with antiviral properties, a once-a-month menses inducer, a reliable ovulation predictor, easily reversible male sterilization, a male contraceptive pill, and an antifertility vaccine. |
