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A new hyperbranched poly (amine-ester)-poly (lactide-co-glycolide) copolymer (HPAE-co-PLGA) was synthesized by ring-opening polymerization of D, L-lactide (DLLA) glycolid and branched poly (amine-ester) (HPAE-OHs) with Sn(Oct)2 as catalyst. The chemical structures of copolymers were determined by FT-IR, 1H-NMR(13C NMR), TGA and their molecular weights were determined by gel permeation chromatography (GPC). Paclitaxel-loaded copolymer nanoparticles were prepared by the nanoprecipitation method. Their physicochemical characteristics, e.g. morphology and nanoparticles size distribution were then evaluated by means of fluorescence spectroscopy, environmental scanning electron microscopy (ESEM), and dynamic light scattering (DLS). Paclitaxel-loaded nanoparticles assumed a spherical shape and have unimodal size distribution. It was found that the chemical composition of the nanoparticles was a key factor in controlling nanoparticles size, drug-loading content, and drug release behavior. As the molar ratio of DL-lactide/glycolide to HPAE increased, the nanoparticles size and drug-loading content increased, and the drug release rate decreased. The antitumor activity of the paclitaxel-loaded HPAE-co-PLGA nanoparticles against human liver cancer H7402 cells was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The paclitaxel-loaded HPAE-co-PLGA nanoparticles showed comparable anticancer efficacy with the free drug. Copyright © 2010 John Wiley & Sons, Ltd.

A new amphiphilic hyperbranched poly (amine-ester)-poly(e-caprolactone) copolymer (HPAE-co-PCL) was synthesized by ring-opening polymerization of e-caprolactone and branched poly (amine-ester) (HPAE-OHs) with Sn(Oct)2 as catalyst. The chemical structures of copolymers were determined by FT-IR, 1H-NMR (13C-NMR), thermo gravimetric analysis apparatus (TGA) and differential scanning calorimetry (DSC). Camptothecin (CPT)-loaded copolymer nanoparticles were prepared by the oil-in water (o/w) emulsion technique method. Their physicochemical characteristics, e.g. morphology and nanoparticles size distribution were then evaluated by means of fluorescence spectroscopy, environmental scanning electron microscopy (ESEM), and dynamic light scattering (DLS). CPT-loaded nanoparticles assumed a spherical shape and have unimodal size distribution. It was found that the chemical composition of the nanoparticles was a key factor in controlling nanoparticles size, drug-loading content, and drug release behavior. As the molar ratio of e-caprolactone to HPAE increased, the nanoparticles size and drug-loading content increased, and the drug release rate decreased. The antitumor activity of the CPT-loaded HPAE-co-PCL nanoparticles against human hepatoma HEPG2 cells was evaluated by 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The CPT-loaded HPAE-co-PCL nanoparticles showed comparable anticancer efficacy with the free drug.

The aim of this study was to generate a new type of nanoparticles made of quaternized chitosan (QCS) and poly (aspartic acid) and to evaluate their potential for the association and delivery of protein drugs. QCS and poly (aspartic acid) were processed to nanoparticles via the ionotropic gelation technique. The size, polydispersity, zeta potential, and morphology of the nanoparticles were characterized. Entrapment studies of the nanoparticles were conducted using bovine serum albumin (BSA) as a model protein. The effects of the pH value of nanoparticles with different QCS/poly (aspartic acid) ratios, QCS molecular weight (MW), poly (aspartic acid) concentration, and BSA concentration on the nanoparticle size, the nanoparticle yield, and BSA encapsulation were studied in detail. Suitably pH value of nanoparticles with different QCS/poly (aspartic acid) ratios, moderate QCS MW, optimal concentration ratio of poly (aspartic acid), and QCS favored more nanoparticles formed and higher BSA encapsulation efficiency. The release of BSA from nanoparticles was pH-dependent. Fast release occurred in 0.1 M phosphate buffer solution (PBS, pH 7.4), while the release was slow in 0.1 M HCl (pH 1.2). The results showed that the new QCS/poly (aspartic acid) nanoparticles have a promising potential in protein delivery system.