James G. Allen

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A high proportion of an oral dose of 14C-debrisoquine sulfate is excreted in the urine by rat and man. The urinary radioactivity consists of a mixture of unchanged drug and polar, water-soluble metabolites which cannot be extracted into organic solvents. Treatment of methanolic extracts of the freeze dried urine with acetylacetone incorporates the amidino(More)
1. The metabolism of debrisoquine sulphate in the dog has been studied and is similar to that in rat and man. 2. Two acidic urinary metabolites, shown to be present in rat, dog and man, have been isolated from rat urine. After derivatization they were characterized by n.m.r. and mass spectroscopy as methyl(More)
In view of the paucity of information on the synovial-fluid pharmacokinetics of nonsteroidal anti-inflammatory drugs with a long half-life, we have compared the pharmacokinetics of tenoxicam (Tilcotil, Mobiflex) in plasma and synovial fluid in six patients with polyarthritis causing knee effusion. Plasma and synovial-fluid concentrations of tenoxicam were(More)
We have studied the clinical effects and pharmacokinetics of levodopa infusions and oral therapy in seven patients with Parkinson's disease. They all showed on-off fluctuations whilst receiving long-term treatment with levodopa in combination with a peripheral decarboxylase inhibitor. Intravenous infusion at a constant rate for up to 16 h resulted in a(More)
Tenoxicam is a new non-steroidal anti-inflammatory drug with a long half-life. Since such drugs may be particularly prone to accumulate in elderly patients, a group of the population in which anti-inflammatory agents are most commonly prescribed, we have studied the pharmacokinetics of tenoxicam in 18 patients (age range 62-87 years) with osteoarthrosis or(More)
Pharmacokinetic studies in parkinsonian patients and healthy volunteers have shown that Madopar HBS behaves as a slow-release formulation of L-dopa and benserazide. In comparison with standard Madopar the rate of absorption is reduced, providing lower peak concentrations of L-dopa. The drug is released and absorbed over a period of 4-5 h, thus maintaining(More)