These delivery systems use skin as either a rate controlling barrier to drug absorption or as a reservoir for drug.2 This technology was successfully utilised for developing various drugs like, nitroglycerine, oestradiol, clonidine, nicotine

and testosterone patches. This route maximises bio-availability, thereby optimising the therapeutic efficacy and minimises the side effects.3 Present work was aimed at developing a matrix drug delivery system using a model anti hypertensive agent, losartan potassium (LP), an angiotensin II receptor (type AT1) antagonist. Rationality of selecting losartan learn more was based on various physicochemical, pharmacokinetic and pharmacodynamic parameters.4 Physicochemical parameters include molecular weight (461.0), pka (4.9) and melting point – 183.5 °C to 184.5 °C Pharmacokinetic and pharmacodynamic parameters include plasma elimination half life 1.5–2.5 h, bioavailability 33%. Usage of polymethylmethacrylate is widely seen as a component in eudragit mixtures.5 Ethyl cellulose, a hydrophobic polymer finds its usage in TD delivery.6 In the present study hydrophobic polymers were selected to prepare patches of losartan potassium which is a hydrophilic drug. Release profile was observed by altering the concentrations of these two polymers. DMSO, sulfoxides

class of enhancers, was used.3, 7, 8 and 9 and PEG-400, as plasticizer were used.10 The prepared patches were tested for various physicochemical Sirolimus supplier parameters and in vitro drug release using dialysis membrane. 11 Losartan was purchased from SL Drugs, Hyderabad. PMMA was purchased from Himedia laboratories, Mumbai. All other chemicals of pharmaceutical grade, are purchased from SD Fine Chemicals, Mumbai. The films were prepared as given in the Table 1 and solvent casting technique was used to prepare the films. A dispersion of polymers was prepared by dissolving PMMA and then EC to form a matrix in chloroform. Then losartan was separately dissolved in chloroform, containing 5% v/v methanol and was added to the polymer dispersion and mixed thoroughly to facilitate distribution of drug in the polymer matrix. To the formed dispersion

required amount of PEG-400 and DMSO were added one after the other and mixed. Resultant dispersion was checked for any air entrapment and was poured in a glass petri plate of known area 70 cm2 and allowed to dry overnight whatever at room temperature by inverting a funnel to ensure uniform evaporation of the solvent. Dried patches were removed from petri plate and stored in a dessicator with aluminium foil wrapping for further evaluation. UV spectrophotometric method based on the measurement of absorbance at 254 nm in phosphate buffer of pH 7.4 was used to estimate the drug content in the prepared transdermal patches. The method obeyed Beer’s law in the concentration range of 5–40 μg/ml and was validated for linearity, accuracy and precision. No interference with excipients was observed.