Norgestimate and Ethinyl Estradiol Tablets are dispensed in a blister pack . Norgestimate and Ethinyl Estradiol Tablets USP may be started using either a Day 1 start or a Sunday start. For the first cycle of a Sunday Start regimen, an additional method of contraception should be used until after the first 7 consecutive days of administration.

The relative affinities of the steroids for cytosolic progestin receptors were assessed by their ability to displace 3H-R5020, a highly specific synthetic progestin, from rabbit uterine receptors. Immature female rabbits were primed with 17 beta-estradiol (5 mcg sc) daily for five days and then sacrificed on day six. The excised uteri were washed and homogenized in ice cold Tris-EDTA buffer (1:5 w/v; pH 7.4). The homogenate was centrifuged at 105,000 x g at 4°C for one hour and the supernatant was used as the cytosolic progestin receptor preparation. Aliquots of the cytosol preparation were incubated with 0.4 nM 3H-R5020 (86.2 Ci/mmole; New England Nuclear) and unlabelled test steroids in Tris-EDTA buffer for 5 hours at 4°C. After incubation, free 3H-R5020 was extracted with dextran-coated charcoal from the bound ligand, and the amount of 3H-R5020 bound to the receptor was determined by liquid scintillation spectrometry. The concentration of the test progestin corresponding to 50% inhibition of total 3H-R5020 binding (IC50) was used as the measure of binding affinity for the progestin receptor. For norgestimate IC50 was found to be 3.4 nM.