Sabidal ,S.R. Zyma, UK ,1983
Oxytrimethylline is used in the treatment for chronic asthma.
18 parts by weight of theophylline are added to 37.8 parts by weight of
aqueous choline bicarbonate (47% assay) and the mixture stirred and heated
at 80°C to 90°C until the evolution of carbon dioxide has ceased and complete
solution effected. Water is separated from the reaction mixture by distillation
under a vacuum sufficient to keep the still temperature between 50°C and 55
C. After about 95 parts by weight of water have been separated, about 80
parts by weight of isopropyl alcohol are added and the mixture subjected to
further distillation under a vacuum sufficient to keep the mixture boiling at
about 40°C. The distillation removes some of the water as an azeotrope with
the isopropyl alcohol. During the removal of the water-isopropyl alcohol
azeotrope a crystalline precipitate forms. The mixture is further cooled slowly
to 5°C and the crystalline precipitate filtered off. The choline theophyllinate
crystals are then washed with isopropyl alcohol and dried under vacuum at
about 70°C. A second crop of the product may be obtained from the mother
liquor by further reduction in volume and cooling. A yield of 90.5% of theory
of choline theophyllinate is obtained completely free of inorganic salts.
