Use of Dicalcium Phosphate Dihydrate for Sustained Release of Highly Water Soluble Drugs

The utilituy of Dicalcium phosphate dihydrate (DCPD), a commonly used water insoluble pharmaceutical excipient, has been investigated for its use in formulating a controlled release matrix type tablet for highly water soluble drugs. Various drugs were formulated into a tablet by direcly compressing mixture of the drug, dicalcium phosphate dihydrate, and magnecium stearate on a single punch tablet machine. Effects of drug concentation and tablet weight on the release profiles were studied using USP II dissolution machine.

The release from these matrices followed first order kinetics rather than square root time rule. The release profile and the first order rate constant seemed to be dependent upon the the size of the tablet. Incorporation of drug in a quantity excess of 5% w/w of the tablet resulted in disintegration of the tablet and subsequent rapid release of the drug.

Dicalcium phosphate may be a simpler, cheaper, and a viable way to formulating directly compressible sustained release formulations.