Bioavailability of terfenadine in man

✍ Scribed by R. A. Okerholm; D. L. Weiner; R. H. Hook; B. J. Walker; G. A. Leeson; S. A. Biedenbach; M. J. Cawein; T. D. Dusebout; G. J. Wright; Mary Myers; Valerie Schindler; C. E. Cook

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 276 KB
• Volume: 2
• Category: Article
• ISSN: 0142-2782
• DOI: 10.1002/bdd.2510020211

✦ Synopsis

Abstract

Fourteen normal male subjects were given either 60 mg or 180mg of terfenadine suspension in a randomized two‐way crossover study. Peak plasma concentrations of 1.544 ± 0.726 (mean ± S.D.) ng ml^−1^ were obtained in 0.786 ± 0.426 h following the 60 mg dose and displayed an AUC of 11.864 ± 3.369 ng h ml^−1^. Whereas peak plasma concentrations of 4.519.2 ± 002ng ml^−1^in 1.071 ± 0.514h were obtained following the 180mg dose. The AUC following the 180 mg dose was 44.341 ± 22.041 ng h ml^−1^. When 60 mg of ^14^C terfenadine was given to six additional subjects, the peak plasma concentrations of 351.43ng equivalents per ml were obtained in 1.67 ± 0.41 h and the AUC was 2297.71 ± 310.85ng‐equivalentshml^−1^. This indicates that approximately 99.5 per cent of the terfenadine related material that is absorbed undergoes biotransformation. Urinary excretion of ^14^C accounted for 39.89 ± 5.29 per cent of the dose while 60.58 ± 2.44 per cent of the dose was recovered in the feces in twelve days. Thin‐layer chromatographic (TLC) examination of fecal extracts showed only a trace of material chromatographing with terfenadine. This may indicate that the ^14^C present in the feces is not due to lack of absorption.