Figure 3From: Stratum corneum lipids liposomes for the topical delivery of 5-aminolevulinic acid in photodynamic therapy of skin cancer: preparation and in vitro permeation studyAmount of 5-ALA (μg) permeated and retained in the SC and epidermis without SC + dermis after 36 hours of in vitro permeation study. Errors bars indicate standard deviation of the mean. Statistical significance indicated by one-tailed Student's t test: (*) P < 0.05) and (**) P < 0.001.Back to article page