Sustained release tablets on the basis of high molecular weight hydroxypropylmethylcellulose and a process for their manufacture

There are disclosed sustained release tablets. They comprise a therapeutically active hygroscopic or non-hygroscopic therapeutic agent and a carrier base material, comprising hydroxypropylmethylcellulose having a methoxyl content of 28 to 30 weight-%, a hydroxypropoxyl content of 7.5 to 12 weight-% and an average molecular weight of at least 50 000 in a proportion of about 20 to about 40 weight-% of the tablet, optionally up to 10 weight-% of glycerol ditripalmitostearate and from about 10 to about 20 weight-% of microcrystalline cellulose and other conventional pharmaceutically acceptable adjuvants. A process for the manufacture of said tablets is described as well. Said formulation is particularly suitable for the preparation of sustained release systems and in clinical tests it shows a bioavailability which is comparable with or superior to that of known commercial preparations. The prolonged action of said tablets lasts up to 12 hours, which allows the administration of the drug twice a day.