Development of simultaneous analysis method for 11 respiratory drug substances including theobromine and analysis of commercial products using UPLC-PDA

Abstract

Abstract Recently, the number of people suffering from respiratory symptoms has continued to increase owing to the effects of COVID-19 and particulate matter, and accordingly, the demand for respiratory-related dietary supplements is increasing. Over the past few years, dietary supplements adulterated with pharmaceutical drug substances have been appearing continuously; thus, preventive measures are needed. In this study, we developed a simultaneous analysis method for 11 respiratory-related pharmaceutical compounds using ultra-performance liquid chromatography with photodiode array (UPLC-PDA). The sample preparation method was optimized by comparing three clean-up methods including the QuEChERS for hard capsule, tablet, powder, and liquid formulations, and the analysis conditions were established by comparing various analysis parameters. In method validation, the limit of detection, limit of quantitation, specificity, linearity, recovery, precision, accuracy, matrix effect, and stability all met the standards of the ICH guidelines. Subsequently, 52 types of dietary supplements promoting relief of respiratory-related symptoms were purchased online and analyzed using UPLC-PDA. Theobromine was detected in one product, and the content was calculated to be 247.7 mg/g (117.1 mg/capsule). This study can contribute to preventively blocking dietary supplements adulterated with respiratory-related substances and can be used as a reference for future research.