Solid dispersions present a useful technique for increasing the dissolution, absorption and therapeutic efficacy of drug dosage forms that have poor solubility. They work by dispersing the poorly-soluble drug within a highly soluble solid hydrophilic matrix. The process can be used to produce either eutectic products that mix at a non-molecular level, or solid solutions where the mix takes place at a molecular level. The second system is the preferred route, as the material produced by converting the drug into an amorphous state dissolves more rapidly than the corresponding crystalline drug substance.
Solid dispersions can be prepared by dissolving both drug and polymer in volatile solvent, and then removing the solvent by spray drying or other method to form an amorphous complex of drug and polymer. We have extensive experience of developing and formulating solid dispersions using processes such as spray drying, spray congealing and melt granulation.