A Sustainable Gas Chromatography–Flame Ionization Detection Method for Simultaneous Quantification of Key Terpenoids in a <i>Novel</i> Herbal Anti‐Scabies Serum

ABSTRACT A novel herbal formulation, containing Tea tree oil and Rose oil, was developed as an alternative to conventional chemical therapies for the treatment of scabies. An analytical method is developed and validated for the simultaneous estimation of terpinen‐4‐ol and citronellol as bioactive markers in this anti‐scabies serum. Scabies, caused by the mite Sarcoptes scabiei , is recognized as a widespread parasitic skin disease, often treated with chemical scabicides that are associated with adverse effects and the emergence of resistance. Due to their lower toxicity and demonstrated efficacy, herbal formulations have been increasingly explored. In this study, a novel anti‐scabies serum was formulated, and a gas chromatography–flame ionization detection (GC‐FID) method was established for the quantification of its key active markers, terpinen‐4‐ol and citronellol, which are known for their antiparasitic and anti‐inflammatory properties. The GC‐FID conditions were optimized (Shimadzu GC‐2014C, RTX‐5 column, nitrogen as the carrier gas, and temperature program from 80 to 280°C) to achieve effective separation. The method was validated in accordance with ICH guidelines for linearity, precision, accuracy, sensitivity (limits of detection and quantification [LOD and LOQ]), and specificity. Linearity was demonstrated ( r 2 ≈ 0.99), and high precision (percent relative standard deviation &lt; 2%) and accuracy (recoveries between 97% and 101%) were achieved. The LOD and LOQ for Terpinen‐4‐ol were found to be 26 and 78 µg/mL, respectively, while those for Citronellol were 3 and 10 µg/mL, respectively. Greenness of the analytical procedure was evaluated using multiple assessment tools: an Eco‐Scale score of 91, an Analytical GREEnness Metric score of 0.78, a predominantly green Green Analytical Procedure Index profile, and a Blue Applicability Grade Index score of 80/100. Based on these findings, the method was found to be reliable, reproducible, environmentally sustainable, and suitable for routine quality control of the herbal anti‐scabies formulation.