Simultaneous analysis of volatile and semi-volatile components in a topical formulation by gas chromatography using a programmed temperature vaporization inlet and flame ionization detection

Topical formulations are medications applied locally on the skin to treat ailment. They are made up of complex mixtures of active ingredients and excipients. Till date, no analytical method has been found in literature that is able to simultaneously analyze volatile and semi-volatile actives present in topical formulations. In this work, an analytical procedure by gas chromatography equipped with a programmed temperature vaporizing (PTV) inlet and a flame ionization detector was developed and validated for the simultaneous quantitative determination of volatile and semi-volatile actives such as camphor, L-menthol, methyl salicylate, ethyl salicylate, salicylic acid, glycol monosalicylate and capsaicin in a topical formulation. Liquid-liquid extraction was used to isolate the components of interest prior to injection into the gas chromatographic system. All target analytes were completely separated from each other and a linear calibration curve was achieved for all analytes with a determination coefficient >0.995. 2-phenoxyethanol was used as internal standard for quantitation. Good repeatability and recovery values were achieved and reported. This method reports for the first time, the simultaneous quantitative analysis of volatile and semi-volatile active pharmaceutical ingredients in a single measurement. The developed method was successfully applied to the analysis of real pharmaceutical samples and the described analytical protocols can be recommended for routine analysis of both volatile and semi-volatile actives in the topical formulation. (C) 2019 Elsevier B.V. All rights reserved.