Analytical Method Development and Validation of a Novel RP-HPLC Method for Simultaneous Quantification of Xanomeline and Trospium Chloride in Pharmaceutical Dosage Form

This study aimed to develop and validate a novel RP-HPLC method for the simultaneous estimation of Xanomeline and Trospium Chloride in combination dosage forms, addressing the lack of existing methods for their concurrent analysis. Xanomeline, a muscarinic receptor agonist for schizophrenia, and Trospium Chloride, an anticholinergic for mitigating adverse peripheral effects, are combined for therapeutic synergy. The method utilized a Kromasil C18 column with a mobile phase of acetonitrile and 0.1% formic acid (40:60), a flow rate of 1 mL/min, and a detection wavelength of 231 nm. Validation parameters followed ICH guidelines, demonstrating specificity, linearity (R² = 0.99979 for Xanomeline and 0.99988 for Trospium Chloride), precision (%RSD < 0.8), and robustness under varied chromatographic conditions. Forced degradation studies confirmed the method's stability-indicating capability, with Xanomeline showing maximum degradation under peroxide (14.1%) and alkali (12.2%) stress, while Trospium Chloride exhibited significant degradation under peroxide (14%) and acid (11.2%). Accuracy studies revealed mean recoveries of 99.7%–100.0% for Xanomeline and 99.4%–100.0% for Trospium Chloride. The method is suitable for routine analysis, ensuring quality control for combination therapies.