Coamorphization combined with complexation enhances dissolution of lurasidone hydrochloride and puerarin with synchronized release.

Coamorphous systems have gained increasing interests due to their ability to enhance solubility and dissolution of poorly soluble drugs. In the current study, coamorphous system of lurasidone hydrochloride (LH), a BCS class II drug, with puerarin (PUE) was prepared by the solvent-evaporation method. The observation of a single Tg at 65.8 °C in differential scanning calorimetry thermogram and the absence of crystalline diffraction peaks in powder X-ray diffraction pattern indicated the formation of coamorphous LH-PUE. Compared to physical mixture of amorphous LH and amorphous PUE, peak shifts in FTIR with principal component analysis indicated potential intermolecular hydrogen bonding formed between the carbonyl group of LH and the hydroxyl group of PUE in the coamorphous system. In comparison to crystalline/amorphous LH and PUE, the coamorphous system exhibited significantly enhanced dissolution with synchronized release behavior of LH and PUE, which was mainly due to the complexation formation between LH and PUE in solution proved by fluorescence quenching test and phase-solubility diagram. In addition, coamorphous LH-PUE showed superior physical stability over pure amorphous LH and PUE under both long-term and accelerated storage conditions.