The effect of crystal size on the bioavailability of benoxaprofen: studies utilizing deuterium labeled drug

Biomedical Mass Spectrometry
R L WolenE A Ziege


A study of the effect of crystal size on the bioavailability of benoxaprofen, 2-[4-chlorophenyl]-alpha-methyl-5-benzoxazoleacetic acid, in man is reported. The technique utilized comparison of either the plasma concentrations or urine levels, resulting from administration of deuterium labeled (2H7) drug in solution coadministered with a test capsule formulation. Drug concentrations were determined by gas chromatography, and the ratio of labeled to unlabeled drug was obtained by gas chromatography mass spectrometry. Measurements following coadministration of labeled and unlabeled drug in solution established the absence of an isotope effect due to the presence of deuterium. The dry formulations consisted of either a 3.17--100 micron fraction (mean = 18.5 microns) or a 32--1000 micron fraction (mean = 610 microns) formulated with starch powder. The results in three subjects indicate an almost complete availability (0.95--0.98) of the small crystals as measured by comparison of either area under the plasma level curves or urine excretion (0.94--0.97) of labeled versus unlabeled drug measured to 168 hours. The larger crystals exhibited a lower availability as shown by plasma levels (0.41--0.46) or urine recovery (0.39--0.43). A hig...Continue Reading


Oct 1, 1977·British Journal of Clinical Pharmacology·D H ChatfieldC F Speirs
Oct 1, 1977·British Journal of Clinical Pharmacology·G L SmithD H Chatfield
Nov 11, 1975·Clinical Pharmacology and Therapeutics·J M StrongA J Atkinson
Nov 1, 1972·Journal of Pharmaceutical Sciences·S I Naito, K Fukui

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Apr 22, 2009·The AAPS Journal·Masoud JameiGeoffrey Tucker
Feb 1, 1989·Journal of Clinical Pharmacology·Y BenchekrounJ L Brazier
Jul 1, 1982·Chemico-biological Interactions·C M IrelandG M Holder

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