Application of Permeation Enhancer in Different Modes and Their Effect on in Vitro Permeation of Ketoprofen across Excised Rat Abdominal Skin

Transdermal route offers inherent advantages over other conventional routes for the delivery of drugs with systemic activity. Transdermal drug delivery provides a continuous mode of administration at rates approaching zero-order similar to that provided by an intravenous infusion.The greatest obstacle is the stratum corneum, the outermost layer of the skin, which is considered to form a primary rate –limiting barrier to the permeation of the drugs across the skin. Permeation enhancers are the substances that facilitate the absorption of penetrant through the skin by temporarily diminishing the impermeability of the skin. In the present study 4% d-limonene was selected as permeation enhancer and incorporated in the transdermal film in three different modes 1) permeation enhancer was incorporated in monolithic system 2) permeation enhancer was incorporated in the rate-controlling membrane 3) permeation enhancer was applied directly onto the skin 10min prior to the study and studied their influence on ketoprofen drug release from the selected transdermal film.The results revealed that highest percentage (92%) of drug release was observed in vitro across rat abdominal skin when we applied permeation enhancer directly on to the skin.