Doramectin percutaneous absorption in dogs: in vivo and in vitro characterization

Abstract

Endectocides (avermectins and milbemycins) are important antiparasitic drugs owing to their wide spectrum of activity, high potency, safety margin and unique mode of action. They are mainly licensed for use in large animals and only few formulations have been approved to control endoparasites in companion animals. Due to its ease and practical administration, topical formulations have received great acceptance by pet owners. However, limited information is available on dermal absorption and disposition of endectocides, particularly doramectin (DRM), in dogs. Time saving in vitro methods that allow characterising topical drug absorption and influence of different excipients are also lacking. The objectives of the present work were to characterize doramectin percutaneous permeation both in vivo and in vitro and to correlate in vivo absorption with in vitro permeation parameters.