PHARMACOKINETIC STUDY OF NORETHINDRONE COPRECIPITATE

Document Type : Original Article

Authors

1 Department of Biochemistry, Faculty of Medicine, Assiut University, Assiut, Egypt

2 Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, Egypt

Abstract

Pharmacokinetic parameters of norethindrone (NE) were studied in 12 adult female guinea pigs following either oral or rectal administration of a single dose of 2.5 mg. The animals were divided into three groups (4 animals each) and each group was given the single dose either in capsule, tablet or suppository form. NE in blood plasma was determined by HPLC at various time intervals (0.5, 1, 2, 4, 6, 8, 12 hour). The results indicate that NE was readily absorbed by, both routes but the maximum plasma concentration (Cmax) and the area under the plasma concentration time curve AUC of NE were significantly high by the rectal route. No significant differences in the plasma half-life (t1/2), absorption (Ka) and elimination (Ke) rate constants and the time to maximum plasma concentration (tmax) were observed between the oral and rectal administrations. These findings suggest that the rectal route offers the possibility of reducing the effective dose of NE, which is widely used for contraception and hormone replacement therapy.