Comparative bioavailabilities from truncated blood level curves

Authors

  • E. G. Lovering,

    Corresponding author
    1. Drug Research Laboratories and Drug Statistical Services, Health Protection Branch, Health and Welfare Canada, Tunney's Pasture, Ottawa, Ontario, Canada, K1A OL2
    • Drug Research Laboratories and Drug Statistical Services, Health Protection Branch, Health and Welfare Canada, Tunney's Pasture, Ottawa, Ontario, Canada, K1A OL2
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  • I. J. McGilveray,

    1. Drug Research Laboratories and Drug Statistical Services, Health Protection Branch, Health and Welfare Canada, Tunney's Pasture, Ottawa, Ontario, Canada, K1A OL2
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  • I. McMillan,

    1. Drug Research Laboratories and Drug Statistical Services, Health Protection Branch, Health and Welfare Canada, Tunney's Pasture, Ottawa, Ontario, Canada, K1A OL2
    Current affiliation:
    1. Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada
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  • W. Tostowaryk

    1. Drug Research Laboratories and Drug Statistical Services, Health Protection Branch, Health and Welfare Canada, Tunney's Pasture, Ottawa, Ontario, Canada, K1A OL2
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Abstract

The period of time after administration over which blood level measurements are required to obtain a reliable bioavailability comparison of two or more formulations of the same drug was considered by the analysis of bioavailability data taken from the literature. The drugs examined, selected to represent a range of absorption and elimination half-lives, were acetaminophen, aminosalicylic acid, chloramphenicol, chlordiazepoxide, digoxin, isoniazid, phenylbutazone, sulfamethizole, tetracycline, and warfarin. For most drugs, ratios of areas under the curve changed little between the end of the absorption period and the time when blood sampling was terminated. Reliable bioavailability comparisons among different brands of the drugs apparently could have been made by blood sampling over 24 hr or less.

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