Epidermal penetration and protoporphyrin IX formation of two different 5-aminolevulinic acid formulations in ex vivo human skin.

Background: Photosensitizer formation and epidermal penetration depth represent basic predictors of drug efficacy in dermatological Photodynamic Therapy (PDT). Different drug formulations and application standards are used to perform PDT in clinical practice.

Methods: Thus, we developed a human ex vivo model suitable to explore drug permeation in human skin and compared in 10 patients the penetration of nanoemulsion formulation (BF-200 ALA) with that of a 20% ALA cream formulation frequently used in clinical practice.