Abstract
The pharmacokinetics of 3H-metoprolol, a new selective β 1-receptor antagonist, have been studied in healthy volunteers by following the plasma concentrations and the urinary excretion of the unchanged compound and its total radioactive metabolites after oral and intravenous administration. The compound was rapidly and completely absorbed after oral administration, and about 40% of the dose reached the systemic circulation. The estimated half-life of the absorption process was 10 min. Metoprolol was extensively distributed to extravascular tissues, with the half-life of the distribution phase close to 12 min. About 95% of the dose was excreted in the urine within 72 hr, mainly in metabolized form. The elimination halflife of the compound was close to 3 hr as was also the half-life of the total metabolites after oral administration. After intravenous administration, the elimination half-life of the metabolites was raised to 5 hr, indicating that the route of administra tion might influence the metabolic pathways of the parent compound.
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Regårdh, C.G., Borg, K.O., Johansson, R. et al. Pharmacokinetic studies on the selectiveβ 1-receptor antagonist metoprolol in man. Journal of Pharmacokinetics and Biopharmaceutics 2, 347–364 (1974). https://doi.org/10.1007/BF01061407
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DOI: https://doi.org/10.1007/BF01061407