Dissolution properties of controlled release capsules containing quetiapine fumarate

Quetiapine fumarate (QF) is a BCS CLASS II with low solubility and high permeability, which has a problem of low bioavailability. It has also been reported that Quetiapine possesses two hydroxyl groups, so it has a higher solubility under acidic conditions. The solubility is low in the range of pH 4 or higher and it is high when pH is 2, and it decreases when the pH is lower than 2 which is due to ion effect. Therefore, capsules were prepared using immediate-release and sustained-release granules to improve the solubility of QF and induce constant release even with a change in pH. XRD and DSC were used to evaluate the crystallinity and inclusion of drugs, SEM was used for morphological analysis, and FTIR was used to analyze chemical changes. In addition, fluidity was evaluated to confirm that it was improved by granulation process. Finally, the solubility patterns of solid dispersions and capsules were analyzed by a solubility test.