Comparative Evaluation of in Vitro Diclofenac Sodium Permeability across Excised Mouse Skin from Different Common Pharmaceutical Vehicles

The comparative in vitro skin permeability of diclofenac sodium through excised mouse skin from different common pharmaceutical vehicles like castor oil, olive oil, arachis oil, liquid paraffin, white soft paraffin melt, 3% sodium carboxymethyl cellulose (CMC) aqueous gel and isopropyl myristate (IPM), excluding other excipients was evaluated. Significantly (p < 0.05) higher flux of diclofenac sodium (0.26 ± 0.01 mg/cm/hr) was provided by isopropyl myristate as vehicle than other vehicles used. Maximum permeability coefficient and diffusion coefficient were also observed for isopropyl myristate and minimum in case of white soft paraffin melt. But, isopropyl myristate had minimal lag time (0.60 ± 0.05 hr); while, maximum lag time (0.86 ± 0.05 hr) was observed for white soft paraffin melt. We have also investigated the in-vitro skin permeability of diclofenac sodium through excised mouse skin from liquid paraffin and olive oil with addition of 0.1 % menthol and dried Aloe vera juice as permeation enhancers. Flux, permeability coefficient, diffusion coefficient and enhancement ratio were better in the case of liquid paraffin with 0.1 % menthol as permeation enhancer than others. We believe this investigation is considered to be useful in preformulation step to predict the best vehicle in further experiment and also provides valuable data that can be utilized for designing and development of various topical formulations of diclofenac sodium.