Capsaicin determination from pain patch for the calculation of Scoville heat units by gas chromatography-mass spectrometry

Abstract

Background and Aims: A sensitive, accurate and precise method has been developed for the determination of Capsaicin from pain patches by Gas chromatography Mass Spectrometry (GC-MS). Capsaicin has irritant effects in high concentrations, so these effects can be minimized by knowing the amount present in pain patches for the efficacy and safety of patches. Methods: Capsaicin was extracted by using liquid-liquid extraction from patches. The Gas Chromatographic separation was performed by using 5% diphenyl 95% dimethylpolysiloxane column with high a purity 2 mL/min flow rate helium gas. The separation was made with a gradient oven temperature program. The oven temperature started at 250°C and was increased to 275°C at 10°C.min-1 ramp rate and held at 275°C for 2.5 min. The injection port was adjusted at 300°C and a split injection mode was used. The analysis was carried out in a split mode of 5:1. MS ionization potential was determined at 70 eV. Results: The calibration curve was found to be linear in the range 5 - 50 μg/mL. The limits of detection and quantification for capsaicin was found to be 3.46 μg/mL and 5 μg/mL, respectively. The method developed was validated and successfully applied to the patch analysis. Conclusion: This method is simple, reproducible, and can be used safely for the routine analysis of Capsaicin without derivatization. This study has the potential how to calculate the Scoville Heat Units (SHU) of pain patches that contain Capsaicin. The amount of Capsaicin in the pain patch, its irritant effects, and its efficacy and safety appear to be low when evaluated by the SHU.