In vitro transdermal diffusion of zileuton from a topical gel

Zileuton, a leukotriene inhibitor used to treat asthma, is usually administered via the oral route. A transdermal drug delivery system for zileuton was developed for this study. A vertical diffusion cell and freshly harvested human skin were used to test the system. Thirteen percent (3.3mg) of the drug was delivered into the dermis within 24 hours, and 13.6% (3.3 mg) of the drug was delivered through the epidermis into the receiving chamber of the diffusion cell within 24 hours. A specially constructed transdermal zileuton gel delivered 13.1% (3.3 mg) of the drug through the epidermis into the receiving chamber within 24 hours. These results are predictive of the successful use of zileuton as a transdermal gel in human subjects.