DEVELOPMENT AND VALIDATION OF STABILITY INDICATING ANALYTICAL METHOD FOR THE ESTIMATION OF PROMETHAZINE HCL IN BULK AND FORMULATION

Abstract

ABSTRACT

Introduction: Promethazine Hydrochloride is a first-generation antihistamine widely used for the treatment of allergic conditions, nausea, vomiting, motion sickness, and as a sedative. Reliable analytical methods are essential to ensure its quality, safety, and stability throughout its shelf life. The present study aimed to develop and validate a simple, accurate, precise, and cost-effective UV spectrophotometric method for the quantitative estimation of Promethazine Hydrochloride in bulk and marketed formulations, along with evaluation of its stability under various stress conditions. Materials and Methods: The analytical method was developed using UV spectrophotometry with methanol as the solvent, and absorbance was measured at 253 nm. The method obeyed Beer–Lambert's law over the concentration range of 2–10 µg/mL. Validation was carried out according to analytical parameters including linearity, accuracy, precision, robustness, limit of detection (LOD), and limit of quantification (LOQ). Forced degradation studies were performed under acidic, basic, oxidative, thermal, and photolytic conditions to assess the stability-indicating capability of the method. Results and Discussion: The developed method exhibited excellent linearity with a correlation coefficient (R²) of 0.9998. The assay of the marketed formulation was found to be 98.01%, meeting pharmacopeial acceptance criteria. Recovery values ranged from 99.82% to 100.79%, confirming the accuracy of the method. Intraday and interday precision showed low %RSD values of 0.414% and 0.389%, respectively, indicating high precision. Among all stress conditions, Promethazine Hydrochloride showed maximum degradation under basic hydrolysis, demonstrating its greater susceptibility to alkaline conditions. The proposed method was simple, reliable, reproducible, and suitable for routine quality control and stability studies.