COMPARISON OF ARTIFICIAL HYDROPHILIC AND LIPOPHILIC MEMBRANES AND HUMAN SKIN TO EVALUATE NIACINAMIDE PENETRATION IN VITRO

The evaluation of skin penetration of active substances from topical preparations is a pre-clinical requirement in the pharmaceutical industry. While in vitro preparations of human or animal skin are frequently used the development of artificial lipophilic and hydrophilic membranes with similar properties to human or animal skin need to be developed. This preliminary study compared the in vitro permeation of niacinamide (vitamin B3), which is used as a model drug, across artificial hydrophilic and lipophilic membranes with iv vitro penetration across human skin. The experiments were carried out in Franz diffusion cells. Artificial membranes were filter paper impregnated with either collodium (hydrophilic), stearic acid, cetyl alcohol or cetyl alcohol + cholesterol (lipophilic). Acidic and neutral hydrogel and emulsion (pH 5.4 and 7.4) containing 0.5% of niacinamide were applied to membranes for up to 4 hours. Niacinamide permeated hydrophilic better than lipophilic membranes. There were no significant differences between the cumulated amounts of niacinamide that penetrated artificial lipophilic membranes consisting of, stearic acid, cetyl alcohol and cholesterol as compared with human skin in vitro. Also, hydrogel and emulsion solvents gave similar results. In conclusion, these artificial membranes seem to be a promising alternative to human or animal skin.