CONCEPTUAL AND COMMERCIALLY AVAILABLE INTRAVAGINAL VETERINARY DRUG-DELIVERY SYSTEMS

In the veterinary area the utilization of the vagina as a route for dr ug delivery has focused on the systemic delivery of hormonal steroids to control synchrony, ovulation and fertility in a variety of livestoc k. There are several reasons for administering drugs to modify the men strual cycle in humans and the estrous cycle in animals and this paper provides a comparison of the objectives of drug Intervention to contr ol reproduction in humans and livestock. In addition, the types of hor mones and their concentrations found during the menstrual cycle in hum ans and during the estrous cycle in animals are compared. The paper al so reviews the intravaginal drug delivery systems developed for the co ntrol of the estrous cycle in livestock and both conceptual and commer cially available intravaginal drug delivery systems that have been des cribed in the literature are described. The history of some of the del ivery systems is included and the future directions of this area of re search are discussed. (C) 1997 Elsevier Science B.V.