Development and Validation of Stability Indicating HPLC Method for Benzalkonium Chloride in Betaxolol (0.5%) Opthalmic Solution

Background: Preservative assay in eye drops require the development of a suitable validated method for the assay. Objective: This study was conducted to develop and validate stability indicating High Performance Liquid Chromatography (HPLC) method for assay of benzalonium chloride in betaxolol 0.5% ophthalmic solution. Method: Method was developed validated according to International conference on harmonization (ICH) guideline. Chromatographic condition used was: L10 CN column (250 cm × 4.6 mm × 10 μm); flow rate 2.0 ml per minute; detection wavelength 245 nm; column oven 30°C; mobile phase: (0.1M sodium acetate, acetonitrile) (55:45 v/v) and injection volume 100 μL. Results: The method was found fulfilling the ICH requirement with R2 of 0.9995 for drug, Limit of detection (LOD) of 4.53 μg/ml, and Limit of quantification (LOQ) of 13.75 for benzalkonium chloride. The mean of overall recovery % was found to be 99.96% and the repeatability results was found to be: 99.95% for benzalkonium chloride. The overall intermediate precision results were found to be 100.77%. The method proved to be accurate, precise and specific. Conclusion: The developed method was found to be simple, sensitive and can be used for routine quality control analysis of benzalkonium chloride in betaxolol (0.5%) ophthalmic solutions.