Development and evaluation of matrix diffusion controlled Transdermal patches of Donepezil

Background study: Transdermal drug delivery systems (TDDS) are a class of novel drug delivery systems, which are gaining worldwide accolade, as evidenced by researchers. Objective: The present work was aimed at developing a matrix dispersion type transdermal drug delivery of donepezil, an alzheimer drug to ensure satisfactory drug release with the use of optimum polymers and thereby to avoid first pass metabolism and prolong duration of action. Methods: Donepezil transdermal patches were prepared by solvent casting method using aluminium foil as the backing membrane with different concentrations of hydrophobic polymeric system (eudragit L 100 & pvp) and 30% w/w of dibutyl phthalate (DBT) as plasticizer. Different concentrations of propylene glycol were used to increase the transdermal permeation of donepezil. The drug and polymers physicochemical compatibility were studied by means of Fourier transform infrared spectroscopy (FTIR) and Differential scanning calorimetry (DSC). Formulated transdermal patches were evaluated for thickness, tensile strength, hardness, weight variation, swellability, flatness, folding endurance & water vapour transmission rate. Results: The physicochemical evaluation study reveals that all formulations measured weight and thickness with low standard deviation values. The results of flatness study showed that none of the formulations had the difference in the strip lengths before and after longitudinal cut, indicating 100% flatness, and thus they could maintain a smooth surface when applied onto the skin. The cumulative percentage drug permeation was higher in case of eudragit containing polymer matrix. Conclusion: From the evaluation studies of the transdermal patches, it may be concluded that transdermal drug delivery system of donepezil can be formulated, which provides better compliance than conventional drug delivery system.