Abstract
Several analgesic pharmaceutical formulations dispensed for external use contain menthol and eucalyptol. Simultaneous determination of the two monoterpenes was achieved utilizing high-performance thin layer chromatography (HPTLC) densitometric analysis. The stationary phase composed of silica gel 60 F254 (E-Merck, Germany) glass-backed plates coated with 0.2 mm layers. The used mobile phase hexane : ethyl acetate 8 : 2 (%, v/v) resulted in sharp, symmetrical and well-resolved peak at an Rf value of 0.34 ± 0.04 and 0.56 ± 0.04 for menthol and eucalyptol, respectively. Linearly range for menthol was 100-800 ng/spot (r(2) = 0.9979), whereas that for eucalyptol was 52.25-1107 ng/spot (r(2) = 0.9937). The developed method was validated following the International Conference on Harmonization guidelines. The method was found to be simple, accurate, time saving and enable analyses of many samples simultaneously.