Skin Penetration of Two Topical Formulations of Gossypol, an Ex Vivo Comparative Study

Gossypol is a product known for its several biological activities but not usable in clinic due to its toxicity once administered by oral or parenteral route. Two topical formulations of gossypol (L-ascorbyl palmitate and L-ascorbyl ibuprofenate coagels) have been developed to reduce these side effects. In the present study penetration of gossypol entrapped in these coagels at the amount of 5 % w/w through the stratum corneum was evaluated. Both coagels were applied on porcine ears separately; 20 tape strips were removed from the same treated area and analysed using a colorimetric method (ferric chloride test for phenol). It was found that gossypol remained distributed within the stratum corneum, thus limiting its availability in systemic circulation where it can cause serious side effects. Hence, gossypol coagel 5 % could be used to target the drug to stratum corneum.