Percutaneous permeation of basic compounds through shed snake skin as a model membrane

Relationships between the in-vitro permeability of basic compounds through shed snake skin as a suitable model membrane for human stratum corneum and their physiochemical properties were investigated. Compounds with low pKa values were selected to compare the permeabilities of non-ionized forms of the compounds. Steady-state penetration was achieved immediately without a lag time for all compounds. Flux rate and permeability coefficient were calculated from the steady-state penetration data and relationships between these parameters and the physicochemical properties were investigated. The results showed that permeability may be controlled by the lipophilicity and the molecular size of the compounds. Equations were developed to predict the permeability from the molecular weights and the partition coefficients of basic compounds.