The guest polymer effect on the dissolution of drug–polymer crystalline inclusion complexes
Lu Chen, Yanbin Huang
Abstract
A drug-polymer crystalline inclusion complex (IC) is a novel solid form of drug, in which drug molecules form parallel channels, and linear polymer chains reside in these channels. In this study, we used carbamazepine (CBZ) as a model drug, and directly studied the effect of different types of guest polymers on the dissolution properties of drug-polymer ICs. We successfully prepared ICs formed from CBZ with hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(ε-caprolactone) (PCL), respectively, and confirmed that these two drug-polymer ICs both had the same channel-type crystal structure as CBZ form II. During the dissolution test, CBZ-PEG IC showed a faster dissolution rate compared to CBZ form II under both sink and non-sink conditions. CBZ-PCL IC was confirmed to be more stable in aqueous medium, as the guest polymer PCL delayed its transformation to less-soluble crystals during dissolution.