The present experiments were carried out to elucidate the chemical structure and the pharmacological activity of the main metabolites of picumast (3,4-dimethyl-7-[4-(4-chlorobenzyl)piperazine-1-yl]propoxycoumarin ). The metabolic pathways were identical in animals and man, but there were major quantitative differences. The fraction of the radioactivity in the plasma attributable to the parent compound 0.5 to 3 h after oral administration of picumast dihydrochloride was less than 15% in animals but 95% to 57% in man. Inhibition of the C3-zymosan-induced chemilumiescence of human leucocytes was taken as an indicator of the diminished liberation of mediators and inhibition of the histamine-induced contraction of isolated guinea-pig lung strips as an example for the antagonism of picumast dihydrochloride to mediators of allergic reactions. Stepwise oxidation of the 3-methyl substituent of the coumarin ring to the alcohol and the carbonic acid increased the histaminolytic potency, but decreased the inhibition of chemiluminescence. Another metabolite formed by cleavage of the piperazine-containing side chain was inactive in both tests.
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Picumast dihydrochloride (Auteral), a new anti-allergic inhibitor of mediator release and action.
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August 1991
Department of Experimental Ophthalmology, University of Bonn, F.R.G.
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October 1989
Department of Product Development, Boehringer Mannheim GmbH, Fed Rep. of Germany.
104 adult patients with predominantly extrinsic perennial asthma who were maintained on bronchodilator or glucocorticoid therapy, were entered into a one-year open study designed to evaluate the efficacy, safety and acceptability of picumast dihydrochloride (3,4-dimethyl-7-[4-(4-chlorobenzyl)piperazine-1-yl]propoxycoumarin dihydrochloride) (2 mg twice daily). 74 patients completed the 12-month treatment period and a further 18 (total 92) were followed up for at least 2 months. Adverse drug reactions were reported in 14 patients and 5 of them were withdrawn from the trial for only non serious reactions.
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The efficacy and tolerability of picumast dihydrochloride (3,4-dimethyl-7-[4-(4-chlorobenzyl)piperazine-1-yl]propoxycoumarin dihydrochloride) (2 mg twice daily orally) in comparison with ketotifen (1 mg twice daily orally) was investigated in 400 patients with bronchial asthma (picumast dihydrochloride n = 202, ketotifen n = 198) in a double-blind, controlled, parallel group study. Assessment of therapeutic and preventative efficacy was by means of symptom scores, quantitative measurements (accumulatory threshold dose) of the bronchial hyperreactivity by means of inhalatory acetylcholine provocation, measurements of peak expiratory flow, vital capacity (VC) and 1-s capacity (FEV1) as well as global assessment of efficacy by the doctor and patient. Tolerability was assessed by recording side effects and global assessment of tolerance on a rank scale at the end of the treatment as well as by means of clinico-chemical parameters.
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October 1989
Department of Product Development, Boehringer Mannheim GmbH, Fed. Rep. of Germany.
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