Formulation optimization and Evaluation of Transdermal patch of losartan potassium containing DMSO as permeation enhancer

The present investigation focused on the formulation optimization and evaluation of transdermal patch of losartan potassium containing DMSO as permeation enhancer. Transdermal patches were prepared by solvent evaporation method by taking different ratios of polymers such as HPMC K100M and Eudragit RS 100, along with the DMSO as permeation enhancer and PEG-400 as plasticizer. Two factor three levels central composite design applied to optimize the formulation variables. In this study, amount of HPMC K100 M (X1) and amount of Eudragit RS 100 (X2) were selected as independent variables. The percentage losartan potassium permeated at 3 hrs (Y1), percentage losartan potassium permeated at 6 hrs (Y2) and permeation flux (Y3) were selected as dependent variables. The FTIR studies confirmed that there is no interaction between losartan potassium and the polymers. Nine formulations were formulated according to design. The prepared formulations were evaluated for various physical and chemical parameters. In-vitro drug permeation study was carried out for 6 hrs. The formulation OLP-4 was given as best batch by the design expert software. The formulation OLP-4 showed the 34.47% permeation in 6 hrs and permeation flux435.74 μg/cm2/hr. The best fit model for optimized batch OLP4 is zero order model with highest r2 value of (r2 = 0.9641) and the mechanism of release was fickian diffusion mediated. Statistical optimization proved to be very useful in the subsequent formulation development work following preliminary evaluations. Thus, the design of experiment with response surface method is an efficient tool to determine and optimize formulation conditions within experimental conditions.