Abstract

A series of 1- and 7-substituted xanthines was studied in vitro for dilator activity in preventing bronchospasm from histamine or acetylcholine.

Two of the most effective, 7-chloroethyl and 7-isoamyl theophylline, were compared to aminophylline in intact guinea pigs exposed to histamine or metacholine aerosols. The effectiveness of the compounds was very similar toward both the spasmogens. 7-Chloroethyl theophylline was the most potent compound tested, by both in vitro and in vivo tests.