Content versus label claims in ephedra-containing dietary supplements.
The content of ephedra alkaloids in herbal dietary supplements containing ephedra (ma huang) was studied. The ephedra alkaloid content of 20 ephedra-containing supplements was determined by high-performance liquid chromatography. Contents of (-)-ephedrine, (+)-pseudoephedrine, (-)-methylephedrine, (-)-norephedrine, and (+)-norpseudoephedrine were measured. Ephedra alkaloid content varied considerably among products. Total alkaloid content ranged from 0.0 to 18.5 mg per dosage unit. Ranges for (-)-ephedrine and (+)-pseudoephedrine were 1.1-15.3 mg and 0.2-9.5 mg, respectively. (+)-Norpseudoephedrine, a Schedule IV controlled substance, was often present. Significant lot-to-lot variations in alkaloid content were observed for four products. For one product, lot-to-lot variations in the content of (-)-ephedrine, (+)-pseudoephedrine, and (-)-methylephedrine exceeded 180%, 250%, and 1000%, respectively. Half of the products exhibited discrepancies between the label claim for ephedra alkaloid content and actual alkaloid content in excess of 20%. One product was devoid of ephedra alkaloids. Assay of 20 ephedra-containing dietary supplements showed that alkaloid content often differed markedly from label claims and was inconsistent between two lots of some products.
Gurley
B J
BJ
Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock 72205, USA. gurleybillyj@exchange.uams.edu
Gardner
S F
SF
Hubbard
M A
MA
D000470:Alkaloids / Q000032:analysis*; D019587:Dietary Supplements; D004348:Drug Labeling; D004335:Drug and Narcotic Control; D004809:Ephedrine / Q000032:analysis; D006801:Humans; D010946:Plants, Medicinal / Q000737:chemistry*
D000470:Alkaloids; D004809:Ephedrine