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January 11, 1971

Biological Availability of Oxytetracycline HCl Capsules: A Comparison of All Manufacturing Sources Supplying the United States Market

Author Affiliations

From the Office of the Assistant to the Director for Drug Availability, Bureau of Medicine, Food and Drug Administration, Washington, DC. Dr. Blair is now with the Department of Internal Medicine, University of Michigan Medical Center, and Dr. Murray is now with the Department of Pharmacology and Anesthesiology, University of Michigan Medical School, Ann Arbor.

JAMA. 1971;215(2):251-254. doi:10.1001/jama.1971.03180150035007

The equivalency of drug products is being questioned with increasing frequency. Oxytetracycline hydrochloride 250-mg capsules produced by the 11 manufacturers supplying the US market were compared in a series of two-way crossover studies with 19 to 22 subjects each. The product (original manufacturer's) associated with the most clinical experience was used as reference product. Serum concentrations of seven comparison products were more variable and markedly lower (P < 0.005) than the reference product two, three, and six hours after ingestion.