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Abstract

The effect of differing densities of poly (ethylene glycol-2000) (PEG2000) at the particle surface of polystyrene-poly (ethylene glycol-2000) (PS-PEG2000) particles was assessed in terms of hydrophobic interaction chromatography (HIC) and the in vitro and in vivo behaviour of the particles. The particles, with different surface densities of PEG, were prepared by varying the copolymerizing reaction of styrene with a PEG macromonomer. There is a clear relationship between the surface density of PEG as determined by X-ray photoelectron spectroscopy and surface hydrophobicity as assessed by hydrophobic interaction chromatography (HIC). Similarly, the interaction of the particles with non-parenchymal liver cells in in vitro studies was shown to decrease as the surface density of PEG increases. The in vivo study investigating the biodistribution of the PS-PEG particles after intravenous injection into rats reveals that a relationship exists between the surface density of PEG and the extent to which the particles remain in the circulation, avoiding recognition by the reticuloendothelial system. Particles with the higher surface densities show increased circulatory times which compared well with data for particles prepared with the surface adsorbed PEO-PPO block copolymer, Poloxamine 908.

Block Copolymer ‘Stealth’ Nanoparticles for Chemotherapy: Interactions with Blood Cells In Vitro

“…[12][13][14][15][16] Most of the earlier work has been captured in an excellent review by Gref et. al.…”

Testosterone-encapsulated Surfactant-free Nanoparicles of Poly(DL-lactide-co-glycolide): Preparation and Release Behavior

“…1,14,15 The size of the nanoparticles is important for establish drug delivery strategies to specific sites of the body, since particles of several micrometers in diameter are filtered by the lung capillaries 16,17 and submicron particles are rapidly cleared by the reticuloendothelial system (RES). [18][19][20] In particular, nanoparticles below 200 nm have advantages for site-specific drug delivery or long blood circulation by avoiding the RES. 21 Figure 2 shows the nanoparticle morphology observed by FE-SEM.…”

Polímeros sintéticos biodegradáveis: matérias-primas e métodos de produção de micropartículas para uso em drug delivery e liberação controlada

“…As micropartículas de poliestireno podem ser protegidas da captura do fígado e do baço, através da adsorção de diblocos de co-polímeros anfipáticos à sua superfície, prolongando-se desta forma o seu tempo de residência na corrente sanguínea. O aumento da hidrofilicidade da superfície do sistema resulta na redução da fagocitose mediada por macrófagos circulantes [19] . Microesferas de poliestireno contendo albumina sérica bovina (BSA) adsorvida à superfície apresentam maior tempo de residência na corrente sanguínea do que as que contêm fibronectina à superfície.…”