Quantitative assay of anti-fertility agents by I.R. spectroscopy.

An infrared spectroscopic method for determining the progestogen content of oral contraceptive (OC) preparations is presented. A linear relationship was established between peak absorption heights and concentrations for ethinyl estradiol mestranol chlormadinone acetate dimethisterone ethynodiol diacetate megestrol acetate norethisterone norethisterone acetate norethynodrel and d-norgestrel. The percent recovery of various progestogens from combined OCs (Enovid Enovid E Norlestrin Ovral Ovulen) and sequential OCs (Oracon Ovex Secrovin) was determined. However some preparations could not be assayed because of excipient interference (C-Quens Ovulen Norinyl Ortho-Novum Ortho-Novum SQ Norquen). In all cases the estrogenic content was too low to permit analysis.