Enhancement of the topical tolnaftate delivery for the treatment of tinea pedis via provesicular gel systems

Abstract

Tolnaftate is a thiocarbamate antifungal drug which is therapeutically active against dermatophytes that cause various forms of tinea. Due to the small amount of tolnaftate released from ordinary ointment bases and insufficient penetration through the infected skin layers the need to incorporate the drug in a more suitable pharmaceutical form has evolved. A provesicular system is one such form that can solve these problems. Once in contact with the skin, dilution with moisture occurs and the provesicular system rapidly transforms into a vesicular one. Provesicular systems were prepared according to full-factorial experimental design. Plain provesicular systems were compared with systems containing Phospholipon 80 H and Lipoid S45 as penetration enhancers. Design expert software was used to analyze the effect of formulation variables (type of Span used as well as the presence or the absence of the penetration enhancer and its type) on the dependent variables: percent encapsulation efficiency (EE%), vesicle size and percent in vitro drug released). Three formulations were chosen; a plain provesicular system (PV-2), one containing Phospholipon 80H (PV-6) and another containing Lipoid S45 (PV-10) with the goal to reveal the effect of penetration enhancer on morphology, rheological properties and ex vivo permeation using confocal laser scanning microscopy (CLSM). Analysis of CLSM results showed that the penetration enhancing effect for the tested formulations followed the order PV-10 > PV-6 > PV-2. Promising clinically active treatment for tinea patients could be expected as shown by the in vivo permeation results for the provesicular systems as suggested by the CLSM results.