Development and Validation of the Spectrophotometric Method for the Determination of Menthol

The main objective of the present study is a quantitative determination of menthol using a simple, sensitive, and reproducible method of reacting menthol with an aromatic aldehyde (salicylaldehyde) in an acidic medium. A linear response was observed between the concentration and the absorbance in the range 0.02–3 mg/5 mL possessing a correlation coefficient greater than 0.999 and exhibiting good recovery values (99.54–100.40%). The wavelength of the maximum absorbance (λ<inf>max</inf>) was measured at 498 nm immediately after the reaction and subsequently within 1 h. The proposed method was validated according to the ICH guidelines for parameters including linearity, precision, accuracy, range, stability, and robustness. Hence the developed method can be used in the analysis of menthol in drug formulations.