Development, characterization, comparative pharmacokinetic and pharmacodynamic studies of iloperidone solid SMEDDS and liquisolid compact

Iloperidone (ILO) is an anti-psychotic, used in schizophrenia. It has low bioavailability (36%) due to low solubility and first pass effect. Oral solid self microemulsifying drug delivery system (SMEDDS) and liquisolid compact (LSC) of ILO were developed. The hypothesis is to test in vivo performance (PK and PD effects) of these delivery systems, as both systems improve dissolution. Based on solubility Capmul MCM, Labrafac WL 1349 were selected as oils, Lauroglycol 90 and PEG 600 were selected as surfactant and cosurfactant. Syloid XDP was optimized for adsorption of liquid SMEDDS. Syloid XDP and Aerosil 200 were optimized as carrier and coating material in the ratio of 15:1 w/w for liquisolid formulation. SEM and PXRD studies indicated no specific crystallinity due to bulkiness in both formulations, which showed similar flow and release behavior. Pharmacokinetic studies were performed for ILO Coarse suspension (CS), Tablet suspension (TS), optimized solid SMEDDS (A1X) and liquisolid compact (S3) in wistar rats. About 3.80 and 2.19-fold improvements in relative bioavailabilty were found for A1X and S3, respectively, when compared to CS. In comparison to TS, 2.61 and 1.51 fold improvements in bioavailability were found for A1X and S3, respectively. Further, Pharmacodynamic activity was studied by reversal of MK-801 induced hyperlocomotion in rats. A1X and S3 formulations showed maximum reversal after 15 min when compared to CS and found to have similar performance. Thus, in comparison to S3, A1X showed significant difference in pharmacokinetic effects but similar pharmacodynamic effects.