Optimization of HPLC–MS/MS method for determination of antimalarial adulterants in herbal products
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Date
2023-01-12
Journal Title
Journal ISSN
Volume Title
Publisher
SPRINGER
Abstract
The use of herbal products is booming all over the world because of being believed as safer than conventional drugs and
free of side effects. However, there are untrustworthy manufacturers who adulterate herbal products by adding conventional
drugs which might eventually lead to microbial resistance and herb-to-drug interactions. There is a need to develop methods
for detecting adulterants in herbal products. A high performance liquid chromatography-tandem mass spectrometry (HPLC–
MS/MS) method for simultaneous identification and determination of conventional antimalarials (chloroquine, quinine,
sulfadoxine, pyrimethamine, mefloquine, lumefantrine, amodiaquine, artemisinin, dihydroartemisinin, artesunate and
artemether) in herbal products was developed. Stable isotopically labelled compounds (artemether-d3, quindine-d3, and
sulfadoxine-d3) were used as internal standards (ISs) for quantitative analysis. Extraction of analytes was performed using
methanol: water: formic acid (90:10:0.1, v/v) and chromatographic separation was done in a gradient mode using mobile
phase A: Ultrapure water containing 0.1% formic acid and 1 mM ammonium formate and mobile phase B: Acetonitrile/
methanol (50:50) containing 0.1% formic acid and 1 mM ammonium formate. The calibration curves were linear (r2 ≥ 0.991)
over the range of 0.001–0.3 μg mL−1 for all compounds. The limit of detection (LOD) ranged from 0.002 to 0.02 μg mL−1
while the limit of quantification (LOQ) ranged from 0.006 to 0.08 μg mL−1. Accuracy, expressed as recovery of spiked
herbal products ranged from 52 to 128%. The precision, expressed as percent relative standard deviation (%RSD) at two
concentration levels, ranged from 1.0 to 13.8%. The matrix effect expressed as the matrix factor (MF) ranged from 0.77 to
0.97. The developed method was used to identify and quantify conventional antimalarials in herbal product samples from
Tanzania. Ten out of 50 herbal products were found to contain amodiaquine, sulfadoxine, pyrimethamine, mefloquine,
dihydroartemisinin, artemether and lumefantrine. The developed method is considered a valuable tool for getting a better
understanding of the adulteration of conventional antimalarials in herbal products.
Description
Journal of Analytical Sciences
Keywords
Conventional drugs, Herbal products, Herbal drugs, Adulteration