ANALYTICAL METHOD DEVELOPMENT FOR SIMULTANEOUS ESTIMATION OF METHYL SALICYLATE, MENTHOL, THYMOL AND CAMPHOR IN AN OINTMENT AND ITS VALIDATION BY GAS CHROMATOGRAPHY

A simple, precise and fast Gas Chromatographic method has been developed first time for the simultaneous determination of Methyl Salicylate, Menthol, Thymol and Camphor in an ointment formulation. Chromatographic separations of the four drugs were performed on fused silica column of length 30meters, diameter 0.53mmwith ethylene glycol film thickness 1µm as stationary phase.  Nitrogen was flown through the column as carrier gas at a flow rate of 5.0mL/min. The initial oven temperature was 120°C (5 min) and raised at the rate of 15°C per minute to final temperature 200°C(3min.). Detector and injection temperatures were fixed at 270°C and 230°C respectively. The injection volume was 1 µl with run time 20 minutes .The linearity of Methyl Salicylate, Menthol, Thymol and Camphor were in the range of 0.1-0.15 mg/ml,0.1-0.15 mg/ml, 0.02-0.03 mg/ml and 0.2-0.3 mg/ml respectively. The recovery was calculated by standard addition method and the   average recovery was found to be 100.629%, 100.417%, 100.086% and 100.045% for Methyl Salicylate, Menthol, Thymol and Camphor respectively . The proposed method is simple, accurate, precise and rapid for the simultaneous estimation of these four actives.