Effect of polydimethylsiloxane and ethylcellulose on in vitro permeation of centchroman from its transdermal patches.

This research aims at the development of controlled release contraceptive transdermal patches of centchroman using ethylcellulose (EC) as film-forming polymer, polydimethylsiloxane (PDMS) as pressure sensitive adhesive with propylene glycol and Di-n-butyl-phthalate for their penetration enhancer and plasticizing properties, respectively. The physicochemical compatibility of the drug and the polymers was performed by differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopic technique. Effects of EC and PDMS ratios on moisture uptake, moisture content, tensile strength (TS), Young's modulus, adhesive strength, water vapor transmission rate (WVTR) and in vitro permeation of centchroman through Sprague-Dawley rats abdominal skin using Franz's diffusion cell were evaluated. A 3(2) full factorial design was employed to observe the effect of independent variables; concentration of ethyl cellulose and PDMS on drug permeated after 32 h, which was selected as dependent variable. Compatibility studies suggested that there were no significant interaction between the drug and polymers used. It was found that incorporation of only EC resulted in too hard patches and addition of PDMS produced patches with lower TS, increased percentage elongation, WVTR and Young's modulus. Statistical analyses suggested that independent variables have a significant effect on the dependent variable. All formulation follows zero-order release kinetics with r(2) > 0.990. In conclusion, drug in adhesive transdermal patches can be successfully fabricated for non-steroidal contraceptive centchroman to obtain a zero-order release systems.