Preparation and characterization of taste masked valsartan by ion-exchange resin approach

Abstract

The bitter taste is one of the most important drug formulation problems. The unpleasant taste leads to noncompliance, which consequently decreases the therapeutic efficacy of the drug. Therefore, masking of bitter taste is very important in drug formulation. In this study an antihypertensive drug, valsartan, which is a weak acid with bitter taste, was used as a model drug to mask its taste with dowex2 (weak base anion exchange resin). The taste masking of a drug using ion exchange resin basically depends on the complex formation between the drug and a specific type of resin. Complex formation under various preparation conditions including; the ratio of drug to resin, mixing time, the pH of the processing medium and the concentration of valsartan was investigated in this study. Optimum conditions for complex formation and maximum drug load were obtained at a drug-resin ratio 1:8, mixing time 4 hours, pH 6.8, temperature 50º C and drug concentration 0.02% w/v. The drug resinate complex was evaluated for the drug content, taste, drug release and molecular properties. The resinate formation was confirmed using different analytical techniques like thermal analysis using differential scanning calorimetry (DSC), spectroscopic method like Fourier transform infrared spectroscopy (FTIR) and by X-ray powder diffraction analysis (XRPD).