title: Long-acting contraceptive agents: design of the WHO Chemical Synthesis Programme.
abstract: The great demand for improved long-acting injectable steroid contraceptives, particularly in developing countries, and the relative lack of interest from the pharmaceutical industry to develop such products stimulated WHO to launch a synthetic and screening programme to find improved, safe and acceptable injectable preparations. More than 210 esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) and levonorgestrel (D-(-)-13 beta-ethyl-17 alpha-ethynyl-17 beta-hydroxygon-4-en-3-one) have been prepared in university-based research laboratories situated mainly in developing countries, and then screened by NICHHD in animal models. The following three compounds, levonorgestrel butanoate, cyclopropylcarboxylate and cyclobutylcarboxylate, proved to be particularly long-acting when administered as microcrystalline suspensions. The overall strategy of this research and development programme is described.
mesh_terms: D000818:Animals; D003276:Contraceptives, Oral / Q000008:administration & dosage / Q000138:chemical synthesis*; D003277:Contraceptives, Oral, Combined / Q000138:chemical synthesis; D003692:Delayed-Action Preparations; D005260:Female; D006801:Humans; D007267:Injections; D012996:Solutions; D013535:Suspensions; D014944:World Health Organization
chemical_list: D003276:Contraceptives, Oral; D003277:Contraceptives, Oral, Combined; D003692:Delayed-Action Preparations; D012996:Solutions; D013535:Suspensions