The effect of proxicromil, a new oral chromone derivative, in antigen challenge tests is asthmatic patients

Proxicromil is a compound shown in biological tests to have anti-allergic properties. It is well absorbed in humans after oral administration. In order to assess its anti-allergic activity in humans, experiments were carried out in asthmatic patients to investigate its inhibitory effects upon the bronchoconstrictor response to antigen challenge. Two controlled experiments were carried out according to randomized double blind crossover designs, in each of which ten selected patients were pretreated orally with proxicromil before being challenged with inhaled doses of antigen. Inhibition of the immediate response to antigen challenge by single and repeated doses was meaured by intermittent recordings of forced expiratory volume in one second (FEV1) for 30 minutes after challenge. The duration of action of proxicromil and studied by varying the time between administration of the last dose given and inhalation of the antigen. The results showed that proxicromil significantly protected patients against the immediate response to challenge, and possessed a long duration of action of at least 12 hours.