Formulation and in vitro evaluation of carbopol 934-based modified clotrimazole gel for topical application

The aim of present study was to enhance topical permeation of clotrimazole gel preparation by using various permeability enhancers such as coconut oil, pistachio oil and sodium lauryl sulphate (SLS). Clotrimazole gel preparations were prepared and optimized by using three factor, five level central composite design. A second-order polynomial equation was generated in order to estimate the effect of independent variables i.e. coconut oil (X1), pistachio oil (X2) and sodium lauryl sulphate (X3) at various dependent variables i.e. flux (Y1), lag time (Y2), diffusion coefficient (Y3), permeability coefficient (Y4), and input rate (Y5) of clotrimazole gel formulations. Ex vivo skin permeation study was performed through rat skin by using modified Franz diffusion cell system. Optimized formulation F8 exhibited highest flux 2.17 µg/cm2/min, permeability coefficient 0.0019 cm/min and input rate 1.543 µg/cm2/min, along with moderate lag time 77.27 min and diffusion coefficient 0.063 cm2/min, which is further supported by anti-fungal activity that exhibited more prominent zone of inhibition against Candida albicans, Aspergillus niger and Mucor. Thus, it can be concluded that permeation of clotrimazole gel was enhanced by various combination of coconut oil, pistachio oil and sodium lauryl sulphate but optimized formulation F8 containing 0.4 ml pistachio oil, 0.8 ml coconut oil and 0.04 g of SLS exhibited more pronounced and promising effect through rat skin.