Co-encapsulation and sustained-release of four components in ginkgo terpenes from injectable PELGE nanoparticles

It is difficult to develop injectable sustained delivery systems for herbal medicines because of their composition complexity. Encapsulating various compounds with different physiochemical properties and achieving their synchronized and sustained release seem too hard to realize. In this paper, an injectable nanoparticulate system based on an mPEG-PLGA-mPEG (PELGE) platform was prepared for co-encapsulation and sustained release of four active components (ginkgolides A, B, C and bilobalide) in Ginkgo biloba extract. Different carriers were screened by macrophage uptake experiment for their ability to be long-circulation. Drug loaded nanoparticles were prepared with 10% PEG(2000) modified PLGA by a co-precipitation method. The encapsulation efficiency of the total ginkgo terpenes (CT) in the optimal formulation was 78.84 +/- 2.06% with a loading dose of 11.90 +/- 0.31 mg/150 mg PELGE. The particles exhibited a spherical shape with a mean diameter of 123.3 +/- 44.0 nm and zeta potential of -30.86 +/- 2.49 mV. Sustained and synchronized release of the four components from PELGE nanoparticles was observed both in vitro and in vivo, which was mainly contributed to the long circulation of PEGylated nanoparticles and the slow degradation of PLGA. The half-life time of the four terpenoid compounds were also significantly improved by incorporation into PELGE nanoparticles. The results indicate that a PELGE nanoparticle is a promising carrier system for sustained and synchronized release of herbal medicines containing multiple components. (C) 2012 Elsevier B.V. All rights reserved.