Long-acting steroidal contraceptive systems.

Abstract

This is a general discussion of the development of long-acting steroidal contraceptive systems. This is believed to be an important solution to the problems of effectiveness, safety, and acceptability of steroidal contraceptives, especially in developing countries. Since side effects from hormones are known to be dose-dependent, the aim is to develop a contraceptive with a great enough amount of hormone to prevent pregnancy but not so great as to cause side effects. There are 2 different approaches to the delivery of fertility control: the pharmacologic and the systems engineering approaches. The pharmacologic approach is typified by an injectable steroid while the systems engineering approach involves inert drug carriers which control the release of the hormone. Delivery of long-acting substances can either be made locally or systemically. The state of the art regarding long-acting contraception is reviewed with a thorough discussion of the process of development, dosage requirements, and method of delivery of the following types of contraceptives: 1) injectable depot formulations; 2) subdermal implants; 3) medical intrauterine systems; 4) medicated intravaginal systems; 5) medicated intracervical systems; and 6) biodegradable systems.