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Am J Health Syst Pharm. 2000 May 15;57(10):963-9.

Content versus label claims in ephedra-containing dietary supplements.

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Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock 72205, USA.


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.

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