In vitro release of tranilast from oily gels and penetration of the drug into Yucatan micropig skin.

Abstract

For the transdermal delivery of tranilast (TL), a drug used for the treatment of skin diseases such as keloids and hypertrophic scars, its oily gels were prepared; its in vitro release and penetration into Yucatan micropig skin were evaluated. In the gels that consisted of hydrogenated soybean phospholipids (HSL) and octyl isononanoate (IOIN), a fatty-acid ester, the release of TL from the gels was proportional to the drug content, and the extent of TL released up to 6 h from them was approximately 70% of the amount of applied TL. On the other hand, with the gels consisting of HSL and isocetyl isostearate (ICIS), the release of TL from the gels was about half of that from IOIN gels, even at the same drug concentration. When oily gels were used, the TL skin concentration was rapidly increased compared with the level obtained with suspensions. With 0.1% IOIN gel, a high concentration of TL (ca. 160 microg/g) in the dermis was obtained and continued until at least 48 h. These results suggest that oily gels may be useful for the topical application of TL.