Development and validation of quantitative procedure of clotrimazole and eugenol in gel product using high-performance liquid chromatography

Vulvovaginitis is a prevalent gynaecological ailment worldwide, often attributed to bacteria, Candida fungi, or Trichomonas. The synergistic action of antifungal agents and essential oils can enhance the efficacy against pathogenic microorganisms. In this study, a simultaneous quantitative method for determining clotrimazole and eugenol in a laboratory-compounded gel product was developed using high-performance liquid chromatography with a photodiode array detector (HPLC-PDA). The HPLC-PDA system utilised in this study was the Shimadzu LC-20AD, with a HiQ Sil RP C18 HS column (250 x 4.6 mm, 5 μm), and a mobile phase consisting of methanol-water in an 80:20 (v/v) ratio, employing isocratic elution at a flow rate of 1.0 ml/min. The injection volume was set at 20 μl, and detection was performed at a wavelength of 229.0 nm. The analytical procedure was validated in accordance with ASEAN guidelines for the validation of analytical procedures, successfully meeting the criteria for specificity, accuracy, system suitability, repeatability, intermediate precision, and linearity within the concentration range of 2.25 to 36.00 ppm for eugenol and 12.00 to 200.00 ppm for clotrimazole. Subsequently, this validated procedure was applied to quantify the clotrimazole and eugenol content in bulk materials and three different lots of gel products. The results for clotrimazole and eugenol content in both the raw materials and the gel product lots fell within an acceptable range, with deviations of less than ±10% compared to the labelled content.