The Solid State Amorphization Of Poorly Water Soluble Drugs
This review addresses the issue of amorphization of poorly water soluble drugs in the solid state. Amorphous phase formation of the drugs is desirable for enhancement of dissolution rate, which can lead to a significant improvement of bioavailability. Grinding, a regularly used process in the pharmaceutical industry can bring about changes in molecular mobility and consequently induce amorphous phase formation. Sorbed water into the amorphous regions increases molecular mobility and subsequently affects physical and chemical stability. Adsorption and entrapment of drug molecules or amorphous molecular dispersion of drug into microporous carrier granules lead to an enhancement of physicochemical stability of the drug. Enthalpy relaxation experiments could be used to indicate relative molecular mobility and relative likelihood of reversion from amorphous to lower energy crystalline state.