FTIR assay method for UV inactive drug carisoprodol and identification of degradants by RP-HPLC and ESI-MS

• A FTIR method has been developed and validated for UV inactive drug carisoprodol.
• The method is accurate, precise and reproducible.
• Formation of degradants under stress conditions has been identified by RP-HPLC.
• The degradants produced under alkaline condition have been identified by ESI–MS.
• The plausible alkaline degradation pathway has been described.

A new method of analysis has been developed for UV inactive drug carisoprodol using FTIR spectroscopy. These methods were validated for various parameters according to ICH guidelines. The proposed method has also been successfully applied for the determination of the drug concentration in a tablet formulation. The method proved to be accurate (mean percentage recovery between 95 and 105%), precise and reproducible (relative standard deviation < 2%), while being simple, economical and less time consuming than other methods and can be used for routine estimation of carisoprodol in the pharmaceutical industry. The developed method also implicates its utility for other UV inactive substances. The stability of the drug under various stress conditions was studied and the drug was found to be particularly susceptible to alkaline hydrolysis. Degradation products of the alkaline hydrolysis were detected by RP-HPLC and tentatively identified by ESI–MS.