Development and Validation of a Stability-Indicating Liquid Chromatographic Method for Determination of Valsartan and Hydrochlorthiazide Using Quality by Design

The present paper involves the analytical quality by design (AQbD)-based development of a simple, rapid, accurate and precise stability-indicating method for the estimation of valsartan and hydrochlorothiazide. Optimized mobile phase (v/v/v) was water (containing 0.25 ml/L triethylamine), methanol and acetonitrile (50:38:37, pH adjusted to 3.0 +/- 0.1). Chromatographic separation was achieved on Hypersil (R)-Gold C-18 (150 x 4.6 mm, 5 mu m, Thermo Fisher Scientific, USA), column at 25 +/- 2 degrees C. The method was validated as per the "International Conference on Harmonisation" (ICH) guidelines. Chromatographic run time was 10.0 minutes. The linearity range for valsartan and hydrochlorothiazide were 1.25-64.00 mu g/ml and 0.195-10.00 mu g/ml respectively. The limits of detection (LOD) for valsartan and hydrochlorothiazide were 0.253 and 0.0226 mu g/ml while the limits of quantitations (LOQ) were 0.767 and 0.068 mu g/ml respectively, using 10 mu l sample. Stability studies indicate that the degradation of valsartan was higher during oxidative stress than other stress conditions.