Controlled release theophyllin tablets and process for producing them

摘要

1. Pharmaceutical tablet constituted by a hydrophilic polymeric matrix permitting controlled and constant release of a unitary therapeutic dose of theophyllin during a period of approximately 12 hours, of the type comprising at least one polymer derived from cellulose and a lubricating agent, characterised in that it contains : . an effective therapeutic quantity of theophyllin ; . from 18% to 35% by weight as a ratio of the total weight of the tablet of at least one hydroxypropylmethylcellulose by way of hydrophyllic polymer, the hydroxypropylmethylcellulose(s) having a viscosity of 2% weight for weight at 20 degrees C between 10**-1 Pa s and 15 Pa .s ; . from 7.5% to 22.5% by weight as a ratio of the total weight of the tablet of lactose favouring hydration of the polymer, and . 0.5% to 1% by weight as a ratio of the total weight of the tablet of an internal hydrophobic lubricating agent, and in that the weight ratio of the theophyllin expressed in anhydrous weight as a ratio to the polymer is between 1 and 3.