Pharmaceutical and clinical development of a novel progesterone formulation.

Progesterone plays an essential role in reproductive events. Its use for luteal support in patients undergoing infertility treatment is an established practice. The different routes used to administer progesterone impact on its efficacy in luteal support: oral administration has been shown to be ineffective due to an extensive first-pass metabolism in the liver; vaginal application has a good efficacy but has drawbacks such as vaginal leakage, irritation, discomfort and uncertainty about the real dose adsorbed; finally, intramuscular administration ensures a precise dosage but can be extremely painful with, in some cases, formation of sterile abscesses. A new progesterone preparation is now available in several European and extra-European countries that combines the precise dosage of the injectable formulation with the comfort of a well-tolerated subcutaneous self-administration. The pharmacokinetic and pharmacodynamic properties of this new product are reviewed here, together with the clinical evidence obtained in two multicenter randomized clinical trials.