Failure Mode Critical Effect Analysis and Design of Experiment-Based Robust Chromatographic Method for Simultaneous Estimation Lornoxicam and Eperisone Hydrochloride

Failure mode critical effect analysis and design of experiment-based high performance thin layer chromatography (HPTLC) method has been developed for simultaneous estimation of lornoxicam (LOC) and eperisone hydrochloride (EPR). Failure modes were identified on the basis of prior knowledge and experimental data with the help of Ishikawa diagram for the development of method. The criticality of failure mode was assessed by giving risk priority number and criticality rank on the basis of preliminary experimental trials. The identified critical failure modes were analyzed for their effect by design of experiment (DoE)-based Plackett-Burman screening design. From 11 critical factors, the volume of methanol and modifier in mobile phase composition were found as critical failure modes. Critical failure mode was further analyzed by DoE based on central composite design for study of their relationship with resolution of both drugs. Quadratic model suggested by design was further used for failure mode risk control and navigation of design space for a resolution of both drugs more than 1.5. Failure mode risk control strategy was set for robust HPTLC method for simultaneous estimation of both drugs in laboratory mixture. Developed and validated HPTLC method was applied for assay of LOC and EPR in their laboratory mixture and assay values were found in good agreement with a spiked amount of drugs.