The present study was designed to develop a suitable matrix type transdermal drug delivery system (TDDS) of olanzapine using blends of two different polymeric combinations, polyvinylpyrrolidone (PVP) and ethylcellulose (EC). A total of fourteen matrix patches were prepared by using these polymers, dibutylthalate as plasticizer and vegetable oils (soyabean oil, olive oil, eucalyptus oil) as permeation enhancers in dichloromethane and chloroform (1:1) as a solvent system. The formulations were characterized including uniformity of weight, drug content, moisture content, moisture uptake, flatness, folding endurance and thickness to study the stability of the formulations and in vitro dissolution of the experimental formulations were performed to determine the amount of olanzapine present in the patches and scanning electron microscopy (SEM) of the prepared TDDS were taken to see the drug distribution pattern. Drug–excipient interaction studies were carried out using Fourier transform infrared (FTIR) spectroscopic technique. In vitro dissolution studies showed that the drug distribution in the matrix was homogeneous and it was found that the maximum drug release in 24 hrs was 89.5% with formulation C3 (containing olive oil). In vitro skin permeation study was also conducted in a modified Franz's diffusion cell which shows that the maximum permeation was with the formulation C3 and it was 768.64μg/cm2 after 48 hrs. Optimized formulations were found to be suitable for formulating in terms of physicochemical characteristics and there was no significant interaction noticed between the drug and polymers used.
