The effect of liposomal incorporation of topically applied hydrocortisone on its serum concentration and urinary excretion.

We demonstrated previously, that hydrocortisone incorporated in the phospholipid bilayer of liposomes (liposomal hydrocortisone) shows an improved concentration-time profile in the different skin layers after external application when compared with a conventional ointment. In the present work, it was investigated under in vivo conditions, whether or not the liposomal formulation also enhances the percutaneous absorption rate. The results obtained in guinea pigs clearly demonstrate a decrease in serum concentration and urinary excretion. Thus, hydrocortisone-loaded liposomes, when applied topically, act as a selective drug delivery system or "drug localizer" increasing the therapeutic efficacy and, simultaneously, decreasing adverse systemic effects. The significance of liposomal attenuative and potent glucocorticoids in topical treatment is discussed.