Influence of dimethylsulphoxide on the in vitro permeation and retention of 5-aminolevulinic acid: optimization of vehicle for topical photodynamic therapy - De Rosa, F S; Steluti, R; Hernandes, Juliana Maldonado Marchetti; Tedesco, Antônio Cláudio; Bentley, Maria Vitória Lopes Badra (Pharmatech, 1998)