TLC-Densitometric Analysis of Clotrimazole and Metronidazole in Combined Dosage Forms

Normal-phase TLC with densitometric detection at 220 nm has been used for analysis of clotrimazole and metronidazole in combined-dose tablets and cream. The compounds were separated on silica gel plates with toluene-ethyl acetate-methanol-acetic acid 5.5:2:0.6:0.1 (v/v) as mobile phase. Regression analysis showed response was a linear function of the amounts of the drugs in the ranges 0.4-0.8 and 2-4 mu g per band for clotrimazole and metronidazole, respectively. Quantification was achieved by measurement of peak area and comparison with calibration standards. The method was successfully applied to pharmaceutical formulations. There was no chromatographic interference from common excipients present in the tablets and cream. The method was validated for accuracy, precision, and specificity.