Facilitated delivery of ALA to inaccessible regions via bioadhesive patch systems.

5-Aminolevulinic acid (ALA) is now being increasingly used in photodynamic therapy (PDT) and photodiagnosis (PDD) of lesions of the oral cavity, esophagus, and female genital tract. Clearly, topically applied creams and solutions are not the most suitable drug delivery systems for such moist and irregularly shaped areas, where shear forces may be high. As a result, such areas of the body are currently relatively inaccessible to efficient topical delivery of ALA. The use of a bioadhesive patch for topical delivery of ALA to the lower female genital tract and now, for the first time, to the human lip, is described. Use of the patch, containing 38 mg ALA cm-2, allowed successful PDT of vulval intraepithelial neoplasia lesions and induced protoporphyrin IX production in Herpes simplex lesions of the lip.