Pharmaceutical compositions of xanthine derivatives tolerated by the stomach and process for their preparation

#Xanthine derivatives are in general characterized by a very disagreeable lasting bitter taste and by a bad compatibility with the stomach. The therapy of diseases, especially of children, requires pharmaceutical forms that permit an individual dosage, because of the greatly varying body weight. Generally drops or syrup are being used for said purpose. Said administration forms are excluded, however, because of the above properties of a great number of xanthine derivatives, since their bad taste cannot be masked and since the bad compatibility with the stomach is partially caused by reflexes.

#Solid pharmaceutical forms have therefore been coated with films that are insoluble in gastric juice (cf. laid-open Japanese patent application No. 101417/1979; O. Christ et al., Arzneimittelforschung 22 (1972), number 11, page 1933 and follow). Said publications describe pharmaceutical forms that are coated with lacquer films insoluble in the stomach, while using organic solvents. The solvents to be evaporated represent a considerable environmental pollution problem.

#The above Japanese patent application describes a process for preparing gastric juice-resistant (or enteric) pharmaceutical pellets (granules) containing the xanthine derivative pentoxyfilline. Said process has two disadvantages:

#1. 100 g of sugar pellets are humidified in an operating coating vessel with a 70% sugar syrup containing additionally gum arabic and talc. Onto the humid pellets there is strewed portionwise a powder mixture consisting of

#100 g of 1-(5-oxohexyl)-3,7-dimethylxanthine,

#25 g of talc and