Investigation of a novel preparation of @entity71007 in XXXX : pharmacokinetics and spermatogenic suppression with etonogestrel implants.

@entity71007 @entity1 @entity251
We have investigated the pharmacokinetics and effects on the male reproductive axis of a novel preparation of @entity71007 (TD) with a progestogen implant. Twenty healthy Chinese @entity1 were administered TD (400 mg intramuscular 4 weekly) with two subcutaneous (SC) etonogestrel implants. Trough @entity251 concentrations rose with repeated administration. Peak concentrations 1 week after the fourth injection were 31 +/- 2 nmol/liter. Both LH and FSH were rapidly suppressed and continued to fall during treatment. Spermatogenesis was also suppressed, to <or=1 x 10(6)/mL in all @entity1 with 16 (80%) azoospermic at 12 weeks. Treatment was associated with an increase in weight, and also increases in hemoglobin concentration (9%) and hematocrit (15%). No subjects withdrew from the study, although the study was terminated after subjects had completed 12 to 18 weeks as some @entity1 were found to have elevated liver enzyme tests. These data demonstrate that the pharmacokinetics of TD are improved compared to previous injectable @entity251 preparations, although peak @entity251 concentrations rise briefly into the supraphysiological range. The speed and degree of spermatogenic suppression suggest that this combination has promise as an effective male contraceptive.
