Quantification of Residual Organic Solvents in Clobetasol Propionate using Headspace Capillary Gas Chromatography

In this study, we aimed to develop a headspace capillary gas chromatography method to quantify residual methanol, acetone, methylene chloride, diisopropyl ether, ethyl acetate, and n,n-dimethylformamide (DMF), in raw clobetasol propionate.

The headspace gas chromatography method employs a chromatographic column packed with 6% cyanopropylphenyl-94% dimethylpolysiloxane as the stationary phase. The column temperature program initiated at 40 °C, was held for 10 min, then ramped up at 10 °C per minute to 220 °C, and maintained for 1 min. Nitrogen served as the carrier gas at a flow rate of 4.84 ml/min. The injection port temperature was set at 140 °C; the flame ionization detector (FID) operated at 250 °C, and the headspace equilibrium temperature was maintained at 105 °C with a 30 min equilibration time.

All six residual solvents exhibited complete separation, displaying strong linearity and achieving high recovery rates. Furthermore, the residual solvent levels in the six samples tested remained comfortably below the permissible limit.

Our method is accurate, reliable, rapid, and sensitive, making it well-suited for the detection of organic residual solvents in raw clobetasol propionate.