Zayıf asit bir ilacın pH'dan bağımsız salım yapan matriks formülasyonunun geliştirilmesi

The aim of this study is to develop pH -independent controlled release matrix tablet dosage form for a weak acidic drug, valsartan and to study the effect of important formulation parameters on pH independent controlled release behaviour of these systems. pH independent controlled release matrix tablets were prepared by direct compression method using different types of pH modifiers, a solubility enhancer and matrix forming polymers. The weak acid valsartan was incorporated into the formulation as a model drug.Physicochemical characteristics of valsartan were determined by UV and FT-IR spectrums, differential scanning calorimetry and particle size analysis. In vitro dissolution studies were performed using the paddle method in USP 31, Method A, 0.1 N HCl, pH 4.5 phosphate buffer and pH 6.8 phosphate buffer mediums. The pH independent controlled release of the matrix tablets were investigated by in vitro dissolution studies. The effect of the solubility and alcalinity of pH modifiers and the viscosity and epoxy groups of matrix forming polymer on the resulting pH independent release of the investigated tablets was found important in the preformulation studies. Central composite design have been applied to study the effect of the concentration of pH modifier and the solubility enhancer on drug release in acidic and basic medium. The drug release patterns can effectively be adjusted by varying simple formulation parameters, such as the type and concentration of pH modifier and matrix forming polymer.In conclusion the addition of sodium citrate as pH modifier and Lutrol F127 as the solubility enhancer to the controlled release matrix tablet maintained high drug release in acidic medium leading to pH independent drug release.