G. Krishna Mohan

A new simple, precise, accurate and reproducible RP-HPLC method for simultaneous estimation of gentamicin and clobetasol in bulk and pharmaceutical formulations. Separation of gentamicin and clobetasol was successfully achieved on a Zorbax C18 (150 mm x 4.6mm x 5µ ) in an isocratic mode utilizing disodium hydrogen phosphate buffer and methanol (60:40 v/v) at a flow rate of 1.0 mL/min. The method was validated according to ICH guidelines for linearity, sensitivity, accuracy, precision, specificity and robustness. The response was found to be linear in the drug concentration range of 0.1-0.30 mg/mL for gentamicin and 0.05–0.15 mg/mL for clobetasol. The correlation coefficient was found to be 0.9997 for both the drugs. The LOD and LOQ for gentamicin were found to be 0.3525 µg/mL and 1.1751 µg/mL respectively. The LOD and LOQ for clobetasol were found to be 0.1938 µg/mL and 0.6460 µg/mL respectively.  The proposed method was found to be good percentage recovery for gentamicin and clobetasol, which indicates that the proposed method is highly accurate. The specificity of the method shows good correlation between retention times of standard solution with the sample solution. Therefore, the proposed method specifically determines the analyte in the sample without interference from excipients of pharmaceutical dosage forms.