Cross-linked sodium carboxymethylcellulose as a carrier for dissolution rate improvement of drugs.

The dissolution rate is often the limiting step in gastrointestinal absorption of water insoluble drugs from solid oral dosage forms. The aim of this work was to use a swellable polymer chosen among superdisintegrants, for improving the dissolution rate of a sparingly soluble drug, loaded on its surface. Nifedipine, which has a very low water solubility, was chosen as a model drug, while cross-linked sodium carboxymethylcellulose (Ac-Di-Sol) was chosen as the swellable polymer. The Nifedipine/Ac-Di-Sol systems were prepared using two different techniques: evaporation and spraying; in some preparations polyethylene glycol (PEG 1500), or sucrose palmitate (Sucrodet), or dioctyl sodium sulfosuccinate (Aerosol OT) were added. The results of the dissolution tests showed that the dissolution rate of Nifedipine from the systems prepared increases, particularly in the case of the preparation composed of Ac-Di-Sol plus surfactant agents.