The sustained release tablet of (R)-5,6-dihydro-5-(methylamino)-4H-imidazo[4,5-ij]-quinolin-2(1H)-one (Z)-2-butenedioate (1:1) which is disclosed permits twice daily administration of (R)-5,6-dihydro-5-(methylamino)-4H-imidazo[4,5-ij]-quinolin-2(1H)-one (Z)-2-butenedioate (1:1) to treat humans with Parkinson's disease.

A pharmaceutical tablet containing diltiazem hydrochloride suitable for once daily oral administration comprising by weight not less than 30 percent diltiazem hydrochloride and from 30 percent to 70 percent hydroxypropyl methylcellulose having a number average molecular weight of at least 50,000. A two piece hard gelatin capsule containing a plurality of such tablets.

A unit dosage form of capsule, tablet or the like is composed of a large number of pellets made up of two or more populations of pellets or particles. Each pellet contains a core containing the therapeutic drug and a water soluble osmotic agent. A water-permeable, water-insoluble polymer film encloses each core. In corporated into the polymer film is a hydrophobic, water insoluble agent which alters the permeability of the polymer film. The film coating of each population of pellets differs from the coating of every other population of pellets in the dosage form in the rate at which water passes through to the core and the rate at which drug diffuses out of the core. The osmotic agent dissolves in the water, causing the pellet to swell and regulating the rate of diffusion of drug into the environment of use. As each population of pellets releases its drug into the environment sequentially, the effect is to provide a series of pulsatile administrations of the drug from a single dosage form.

A pharmaceutical composition in the form of a tablet or a capsule for the controlled release of diltiazem, comprises about 30 to about 97% by weight of a hydrophilic polymer, about 0.5 to about 30% by weight of an enteric (pH-dependent) polymer, and about 2.5 to about 60% by weight of diltiazem or a pharmaceutically acceptable salt or ester thereof. The ratio of hydrophilic polymer to enteric polymer is in the range of about 1:1 to about 15:1. Such a pharmaceutical composition releases diltiazem at a rate that allows effective plasma levels of diltiazem to be maintained over a period of twenty-four hours after administration to human adult subjects.

A controlled absorption diltiazem pellet formulation for oral administration comprises a core having diltiazem or a pharmaceutically acceptable salt thereof as the active ingredient. The core is surrounded by a coating which has only a single layer which is comprised of a relatively major proportion of talc and relatively minor proportion of sodium lauryl sulfate admixed with a minor proportion of a pharmaceutically acceptable film-forming, first polymer permeable to water and diltiazem, and a major proportion of a pharmaceutically acceptable film-forming, second polymer that is less permeable to water and diltiazem than the first polymer. The core and the coating layer both exclude organic acids. The composition of the coating layer as well as the proportion of core to coating layer are effective to permit release of the diltiazem allowing controlled absorption following oral administration. By combining short lag and long lag pellets into a single formulation, the release of diltiazem is controlled over a twenty four hour period.