Determination of Anti-Diabetic Drugs in Health Supplements by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) Method

Abstract

The mixing of unpermitted drugs with health supplements to increase effectiveness can cause negative effects to consumers, requiring quality testing of these products. In this study,
an analytical method for simultaneously determination of 5 anti-diabetic drugs (ADDs)
(i.e., metformin, phenformin, buformin, glibenclamide, and gliclazide) in health supplement samples was developed with a combination of ultrasonic extraction, dispersive solid-phase extraction (d-SPE), and liquid chromatography tandem mass spectrometry (LC-MS/MS). Hard capsule, soft capsule, and liquid samples were extracted with methanol twice, followed by activated carbon addition for extract clean-up and LC-MS/MS quantification. The analytical method was validated through various factors such as: specificity, limit of detection, limit of quantification, linearity, repeatability, and recovery. The method had high precision (mean recovery from 88% to 99%, relative standard deviation lower than 10%) and low detection limit of 0.1 mg/kg, meeting the requirements of detection of these substances at trace to ultra-trace levels in complex sample matrices. The validated method was then applied to analyze concentrations of 5 ADDs in 30 health supplement samples. Metformin was detected at a concentration of 2.20 mg/kg in one hard capsule sample, while the remaining samples did not contain ADDs at detectable levels.