Monitoring of thermal and oxidation stability of sodium picosulfate by modified RP-HPLC method

Abstract

A selective, precise and stability-indicating, modified high performance liquid chromatographic method for the analysis of sodium picosulfate both as a bulk drug and in formulations was developed and validated. As the method could effectively separate the drug from its degradation product, it can be employed as a stability-indicating one. The chromatographic separation was achieved on a ZORBAX Eclipse XDB C-18 analytical column. The mobile phase consisted of phosphate buffer (pH 7):acetonitrile (85:15 v/v). The absorbance was monitored with a DAD detector at 263 nm. The flow rate was 1.5 mL min-1. Statistical analysis proved the method is repeatable, selective, and accurate for estimation of sodium picosulfate in the presence its degradation product. Forced degradation studies were performed on bulk sample of sodium picosulfate using heat (25, 40, 60 and 80 ?C) and oxidation (0.1, 0.5 and 1% v/v hydrogen peroxide). The proposed method was successfully applied, with excellent recovery, to the analysis of a pharmaceutical formulation (Sodium picosulfate, Zdravlje-Actavis, Serbia).