Intranasal and intravenous administration of octa-arginine modified poly(lactic-co-glycolic acid) nanoparticles facilitates central nervous system delivery of loperamide

Abstract Objectives The potential of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) surface modified with octa-arginine (R8) for central nervous system (CNS) delivery was investigated. Methods PLGA NPs containing coumarin-6 or loperamide were surface modified using R8 and characterised for size, zeta potential, drug loading and release. We examined the cellular uptake of NPs in Madin-Darby Canine Kidney (MDCK) cells and CNS delivery of loperamide in a mouse model following intranasal (i.n.) and intravenous (i.v.) administration. Key findings NPs were 300–350 nm in diameter and of negative zeta potential which neutralised on R8 conjugation. Cellular uptake of R8-PLGA NPs was rapid compared with PLGA NPs and correlated with a high antinociceptive effect in mice by both the i.n. and i.v. routes. Little antinociceptive effect for PLGA NPs was observed reflecting their slow uptake in the in-vitro cell model. Conclusion This study demonstrates the potential of R8-PLGA NPs as carriers of therapeutic agents to the CNS.