SPECTROPHOTOMETRIC DETERMINATION OF BENZALKONIUM CHLORIDE IN PHARMACEUTICAL PREPARATIONS

Benzalkonium chloride is a quaternary ammonium compound widely used in the manufacture of pharmaceuticals. Revised quality requirements and an expanding range of benzalkonium chloride products lead to a review of existing analysis methods and the development of optimal ones for each manufacturer.The aim of the study is to optimize and validate a spectrophotometric method for the quantitative determination of benzalkonium chloride in pharmaceutical preparations such as suppositories, nasal sprays and extemporaneously prepared gels.Materials and methods. Benzalkonium chloride was determined in samples using UV spectrophotometry on a SHIMADZU-2600 spectrophotometer (Shimadzu, Japan) with UV-Probe 2.33 software. For method development, a 10% benzalkonium chloride solution was used, with testing samples prepared in water acidified to pH 4.0 with 0.1 M hydrochloric acid. The validation of the method was performed according to ICH Q2R guidelines and the State Pharmacopoeia of Ukraine. The method was tested on “PHARMATEX” vaginal suppositories, “Zinc Oxide Gel 10%”, and “Aqua Di Mare Sea Water” nasal spray.Results The absorption spectra of benzalkonium chloride water acidified with 0.1M hydrochloric acid solution to pH 4.0 displayed characteristic peaks at 257 nm, 263 nm, and 268 nm. The most linear and reproducible results were observed at 263 nm. The validated method demonstrated high correlation coefficients (r > 0.9995) across a concentration range of 1.6–2.4 µg/ml of benzalkonium chloride. Analytical performance met all acceptance criteria for accuracy and precision. The method proved effective for determining benzalkonium chloride concentrations in pharmaceutical formulations with minimal sample preparation.The developed spectrophotometric method is simple, cost-effective, and reliable for routine benzalkonium chloride determination in pharmaceutical products. It ensures compliance with regulatory standards and safeguards patient safety.