15 . 0 parts by weight of proxyphylline and 15 . 0 parts by weight of diprophylline were dissolved in 500 parts by weight of distilled water with slight heating ( ph = about 7 . 2 ). then , slowly with continuous stirring , there were added 10 parts by weight of pure , anhydrous theophylline as a very fine powder . the clear solution was filtered and sterilized . there were dissolved in this solution 2 weight % of theophylline as a pure , stable , neutral aqueous composition . a portion of the solution obtained was evaporated to dryness . the residue obtained likewise can be used in solid form as a medicament . 30 parts by weight of proxyphylline were dissolved in 500 parts of distilled water with slight heating ( ph about 7 . 2 ). with continuous stirring , there were slowly added 10 parts by weight of pure anhydrous theophylline as a very fine powder . the clear solution was filtered and sterilized . it contained 2 weight % of pure theophylline as a stable , neutral aqueous solution . again , a portion of the solution obtained was subsequently evaporated to dryness . the residue obtained likewise can be used as a solid material as a medicament . the solution can be used , for example , in the form of a microclysma . the solid can be dispersed as a delay dragee alone or simultaneously with pure solid theophylline in delay form . aqueous solution according to the invention for use in microclysmas were prepared . they contained about 2 weight % of pure theophylline and about 3 weight % of proxyphylline and about 3 weight % of diprophylline , ˜ 2 weight % of pure theophylline and about 6 weight % of proxyphylline or about 2 weight % of pure theophylline and about 6 weight % of diprophylline . to these aqueous solutions were added about 1 weight % of methocell , at least one surfactant and at least one preservation agent .