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The excretion and metabolism of oral 14 C‐pyridostigmine in the rat
Author(s) -
HUSAIN M. A.,
ROBERTS J. B.,
THOMAS B. H.,
WILSON A.
Publication year - 1968
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1968.tb07064.x
Subject(s) - pyridostigmine , urine , excretion , neostigmine , oral administration , metabolism , endocrinology , chemistry , medicine , metabolite , absorption (acoustics) , pharmacology , myasthenia gravis , physics , acoustics
1 Pyridostigmine labelled with carbon‐14 in the methyl group of the quaternary nitrogen has been used to investigate the excretion and metabolism of the drug after administration of single doses (500 μg) to the rat by stomach tube. 2 Pyridostigmine is slowly excreted in the urine; the maximum excretion occurs between 1–3 hr after administration. In 24 hr 42% of the dose is excreted in urine and 38.4% is present in faeces and intestinal contents. 3 The peak concentration of radioactivity in liver and blood occurs about 2 hr after administration. 4 About 75% of the radioactivity in urine is present as unchanged pyridostigmine, the remainder as metabolite. 5 The results are compared with those previously obtained after oral administration of neostigmine. 6 It is concluded that after oral administration the absorption of pyridostigmine is greater and the metabolism substantially less than that of neostigmine.