Usha Y Nayak
Manipal University,India
Title: Formulation and In vitro-In vivo evaluationof Risperidone liposomes for brain targeting
Biography
Biography: Usha Y Nayak
Abstract
Risperidone is widely used as an anti-psychotic drug to treat schizophrenia and bipolar disorder.It has significant first-pass metabolism with an oral bioavailability of 70% and a half-life of 3 hours. It produces extrapyramidal side effects dependent on dose. Hence in the present study surface modified liposomes of risperidone were prepared for brain targeting through nasal administration. Nasal administration will avoid the first pass metabolism also provides targeting to the receptor site and bypasses the blood–brain barrier thereby enhancing bioavailability. Liposomes were prepared by lipid film hydration followed by sonication using soyaphosphatidylcholine and cholesterol (molar ratio 8:1). The lipid/drug ratio was10:1. The formulation was modified in its composition by addition of a lipid DSPE-mPEG (2000) (0.05 to 0.2 molar ratio) for long time circulation. Liposomes were evaluated for Mean vesicle size, Poly dispersibility index (PDI), Zeta potential, Encapsulation Efficiency, in vitro release and plasma-brain pharmacokinetic studies. The average particle size and PDIwas found to be 98 to 115 nm and 0.17 to 0.19 respectively. The zeta potential was –28 to -36 indicating stable formulation.DSPE-mPEG (2000) containing liposomes showed higher entrapment (54%) compared to conventional liposomes (49.6%). Also DSPE-mPEG batch released maximum amount of drug 57.12 % at the end of 4 hrs following Korsmeyer-Peppas model and shows diffusion controlled release. The lower Tmax values for brain (0.25 h) when compared to blood (0.5 h) also may be due to nose to brain transport by passing the blood brain barrier. Cmax and AUC0-twere found to be significantly higher compared to pure drug, in particular DSPE-mPEG showed better performance compared to conventional liposomes.