Method development and method validation of guaifenesin and dextromethorphan by RP-HPLC

A new, simple, precise, accurate and reproducible RP-HPLC method for Simultaneous estimation of bulk and pharmaceutical formulations. Separation of Guaifenesin and Dextromethorphan was successfully achieve THERMO, C18, 250X4.6mm, 5µm or equivalent in an isocratic mode utilizing 0.1M KH2PO4: Methanol (60:40) at a flow rate of 1.0ml/min and eluate was monitored at 280nm, with a retention time of 3.259 and 4.164 minutes for Guaifenesin and Dextromethorphan respectively. The method was validated and there response was found to be linear in the drug concentration range of 50µg/ml to150 µg/ml for Guaifenesin and 50µg/ml to150 µg/ml for Dextromethorphan. The values of the correlation coefficient were found to 0.999 for Guaifenesin and 1for Dextromethorphan. respectively. The LOD and LOQ for Guaifenesin were found to be 0.597 and 1.991 respectively. The LOD and LOQ for Dextromethorphan were found to be 0.1072 and 0.3572 respectively. This method was found to be good percentage recovery for were found to be 99 and 100 respectively indicates that the proposed method is highly accurate. The specificity of the method shows good correlation between retention times of standard with the sample so, the method specifically determines the analyte in the sample without interference from excipients of tablet dosage forms. The method was extensively validated according to ICH guidelines for Linearity, Accuracy, Precision, Specificity and Robustness.