Sustained release compositions

A process for providing sustained release solid tablets of a therapeutically active composition, the process comprising

• (a) comminuting a substantially water-soluble hydroxypropyl methylcellulose ether, having a hydroxypropoxyl substitution of from about 7 to about 12 weight percent, a methoxyl substitution of from about 28 to about 30 weight percent, and a number average molecular weight of at least 50,000, to a relatively fine particle sized cellulose ether composition, having a 2% aqueous solution viscosity of at least 800 cps and wherein at least 90% by weight of the cellulose ether particles can pass through a 100 mesh screen;
• and
• (b) intimately mixing an amount of the active composition in the form of a powder with a functionally effective amount of the fine particle sized cellulose ether composition;
• and
• (c) subjecting the mixture of active composition and fine particle sized cellulose ether composition to compression conditions to form a solid tablet.