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ABSTRACT: Methoxy poly(ethylene oxide)-b-poly(ethyl cyanoacrylate) (mPEG-b-PECA), amphiphilic block copolymer, was synthesized via oxyanion-initiated
polymerization with a sodium alcoholate-terminated monomethoxy poly(ethylene glycol) as the macroinitiator. mPEG-b-PECA was
characterized by GPC, 1H-NMR and FTIR. The results indicate that the structure of mPEG-b-PECA is well controlled with narrow molecular weight distribution.
The dexamethasone (DXM)-loaded mPEG-b-PECA nanoparticles (NPs) were prepared by the nanoprecipitation technique and characterized
by LPSA, 1H-NMR and TEM. The DXM-loaded mPEG-b-PECA NPs are of spherical shape with the size of less than 100 nm. The drug-loaded amount
(DL) and encapsulation efficiency (EE) of DXM-loaded NPs were investigated by HPLC. The results show that DXM can be effectively
incorporated into mPEG-b-PECA NPs, which provides a potential delivery system for DXM and other hydrophobic drugs.
Chinese Science Bulletin 04/2012; 54(17):2918-2924. · 1.32 Impact Factor
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ABSTRACT: This work focused on the preparation and characterization of a novel amphiphilic block co-polymer and paclitaxel-loaded co-polymer nanoparticles (NPs) and in vitro evaluation of the release of paclitaxel and cytotoxicity of NPs. mPEG-b-P(OA-DLLA)-b-mPEG was prepared via melt polycondensation of methoxy poly(ethylene glycol) (mPEG), octadecanedioic acid (OA) and D,L-lactic acid (DLLA) and characterized by FT-IR, (1)H-NMR, (13)C-NMR, GPC, DSC and XRD. The paclitaxel-loaded mPEG-b-P(OA-DLLA)-b-mPEG NPs were prepared by nanoprecipitation and then characterized by LPSA, TEM and (1)H-NMR. In vitro release behaviors of the paclitaxel-loaded NPs were investigated by HPLC. In vitro cytotoxicity of NPs was evaluated by MTT assay with normal mouse lung fibroblast cells (L929) as model cells. The composition of mPEG-b-P(OA-DLLA)-b-mPEG is consistent with that of the designed co-polymer. The paclitaxel-loaded NPs are of spherical shape with core/shell structure and size smaller than 300 nm. Paclitaxel can be continuously released from the paclitaxel-loaded NPs and the in vitro release rate of paclitaxel decreases with increasing the content of the P(OA-DLLA) segments in the co-polymer. The mPEG-b-P(OA-DLLA)-b-mPEG NPs are non-toxic to L929. The results suggest that mPEG-b-P(OA-DLLA)-b-mPEG NPs are a potential candidate carrier material for the controlled delivery of paclitaxel and other hydrophobic compounds.
Journal of Biomaterials Science Polymer Edition 01/2011; 22(4-6):701-15. · 1.69 Impact Factor
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ABSTRACT: A family of injectable, biodegradable and thermosensitive co-polymer nanoparticle (NP) hydrogels based on mPEG-b-POA-b-mPEG, which was synthesized from mono-methoxy poly(ethylene glycol) (mPEG) and poly(octadecanedioic anhydride) (POA), was investigated in this paper. It was found that the aqueous dispersions of these NPs underwent a reversible gel-sol transition upon temperature change. By using paclitaxel and Bovine serum albumin (BSA) as model drugs, we noticed that the in vitro releases of both in situ gel-forming formulations were sustained and no initial burst releases were observed for 7 days. In vitro cytotoxicity tests via MTT assay indicate that mPEG-b-POA-b-mPEG NPs are non-toxic to normal mouse lung fibroblast cells (L929). The in vivo hydrogel formation and in vivo biocompatibility of co-polymer NP hydrogel were also investigated and the results further validate the biocompatible nature of co-polymer NP hydrogel. In conclusion, our mPEG-b-POA-b-mPEG NP hydrogel is able to control the release of incorporated drug for longer duration.
Journal of Biomaterials Science Polymer Edition 01/2011; 23(1-4):465-82. · 1.69 Impact Factor
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ABSTRACT: The poly(ethylene glycol)/poly(2-(N,N-dimethylamino)ethyl methacrylate) (PEG/PDMAEMA) double hydrophilic block copolymers were synthesized by atom transfer radical polymerization using mPEG-Br or Br-PEG-Br as macroinitiators. The narrow molecular weight distribution of PEG/PDMAEMA block copolymers was identified by gel permeation chromatography results. The thermosensitivity of PEG/PDMAEMA block copolymers in aqueous solution was revealed to depend significantly on pH, ionic strength, chain structure, and concentration of the block copolymers. By optimizing these factors, the cloud point temperature of PEG/PDMAEMA block copolymers can be limited within body temperature range (30–37 °C), which suggests that PEG/PDMAEMA block copolymers could be a good candidate for drug delivery systems. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 503–508, 2010
Journal of Polymer Science Part B Polymer Physics 01/2010; 48(5):503 - 508. · 1.53 Impact Factor
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ABSTRACT: A series of amphiphilic triblock copolymers, methoxy poly(ethylene glycol)-b-poly(octadecanoic anhydride)-b-methoxy poly(ethylene glycol) (mPEG-b-POA-b-mPEG), were prepared via melt polycondensation of methoxy poly(ethylene glycol) (mPEG) and poly(octadecanoic anhydride) (POA). mPEG-b-POA-b-mPEG were characterized by FTIR, 1H-NMR, GPC, DSC, and XRD. Drug-loaded mPEG-b-POA-b-mPEG nanoparticles (NPs) with spherical morphology and narrow size polydispersity index were prepared by nanoprecipitation technique with paclitaxel as the model drug. In vitro release behaviors of drug-loaded NPs present that the biphasic process and the release mechanism of each phase are zero order drug releases. According to this study, mPEG-b-POA-b-mPEG NPs could serve as suitable delivery agents for paclitaxel and other hydrophobic drugs. Copyright © 2009 John Wiley & Sons, Ltd.
Polymers for Advanced Technologies 10/2009; 22(5):669 - 674. · 2.01 Impact Factor
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ABSTRACT: A novel injectable thermogelling poly(ester-anhydride) co-polymer, methoxy poly(ethylene glycol)-poly(sebacic acid-D,L-lactic acid)-methoxy poly(ethylene glycol) (mPEG-poly(SA-LA)-mPEG) triblock co-polymer, was prepared by melt-condensation polymerization. The synthesized triblock co-polymer was characterized by FT-IR and (1)H-NMR. The aqueous solutions of mPEG-poly(SA-LA)-mPEG underwent sol-gel precipitation transition when the temperature was increased from 20 to 70 degrees C, depending on the concentration of the polymer. 5-FU, as the model drug, was mixed into the gel in a low-viscous sol state at room temperature. About 63 wt% of the loaded 5-FU could be released in vitro from the gel over 72 h at 37 degrees C. Subcutaneous injection of 25 wt% mPEG-poly(SA-LA)-mPEG aqueous solution resulted in the formation of a in situ gel depot in a rat model, which sustained for longer time than that of Pluronic F-127 aqueous solution. The biodegradable thermogelling mPEG-poly(SA-LA)-mPEG triblock co-polymer is believed to be a promising candidate for drug-delivery applications.
Journal of Biomaterials Science Polymer Edition 02/2009; 20(7-8):923-34. · 1.69 Impact Factor
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ABSTRACT: P((MAA-co-DMAEMA)-g-EG) polyampholyte nanogels (PANGs) were prepared by distillation-dispersion copolymerization of poly(ethylene
glycol) methyl ether methacrylate (MPEGMA), N,N-dimethylaminoethyl methacrylate (DMAEMA), and methacrylic acid (MAA) using acetonitrile (AN) as dispersion medium. The results
of FTIR spectra indicate that the composition of P((MAA-co-DMAEMA)-g-EG) PANGs is consistent with the designed structure.
The results of TEM and laser particle size analyzer (LPSA) show that P((MAA-co-DMAEMA)-g-EG) PANGs present spherical morphology
and a bimodal size distribution after and before swelling. P((MAA-co-DMAEMA)-g-EG) PANGs have typically amphoteric characters
responding to pH, whose isoelectric point (IEP) increases with decreasing the ratio of MAA/DMAEMA and equilibrium swelling
degree (ESD) is greater than that at IEP when the pH value is distant from IEP. P((MAA-co-DMAEMA)-g-EG) PANGs also represent
ionic strength sensitivity. Using the water-soluble chitosan (CS, Mn=5kDa) as model drug, invitro release indicates that
CS can be effectively incorporated into PANGs and the release rate of CS at pH 1.89 is an order of magnitude greater than
that at pH 8.36. P((MAA-co-DMAEMA)-g-EG) PANGs may be useful in biomedicine, especially in oral drug delivery of biomacromolecule.
Journal of Nanoparticle Research 01/2009; 11(2):365-374. · 3.29 Impact Factor
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ABSTRACT: D,L-tetrahydropalmatine (THP)-loaded poly{[α-maleic anhydride-ω-methoxy-poly(ethylene glycol)]-co-(ethy cyanoacrylate)} (PEGECA) amphiphilic graft copolymer nanoparticles (PEGECAT NPs) were prepared by the nanoprecipitation technique. The effects of solvent property, temperature, copolymer composition, and drug feeding on the drug-loaded amount and size of PEGECAT NPs were investigated. The morphological structure of PEGECAT NPs was characterized by transmission electron microscopy (TEM), proton nuclear magnetic resonance (1H NMR), and the size was measured by laser particle size analyzer (LPSA). In vitro release behaviors of drug from PEGECAT NPs were examined by high-pressure liquid chromatography (HPLC). The results demonstrate that PEGECAT NPs take on a spherical morphology with an inner core and outer shell before and after in vitro release. THP can be incorporated into the hydrophobic core of PEGECAT NPs and the drug-loaded amount is higher than 5%. The release of THP from PEGECAT NPs is initially fast and then slows down. The accumulated release is lower than 40% after 48 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Journal of Applied Polymer Science 09/2008; 110(6):3525 - 3531. · 1.29 Impact Factor
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ABSTRACT: Keywords: Polyanhydrides Poly(octadecanoic anhydride) Poly(sebacic acid-octadecanoic diacid) Biodegradable polymers Poly(sebacic anhydride) a b s t r a c t Poly(sebacic acid-octadecanoic diacid) copolyanhydrides (PSAOAs) were prepared by melt polycondensation of sebacic acid (SA) and octadecanoic diacid (OA). PSAOAs were charac-terized by Fourier-transform infrared spectroscopy (FTIR), differential scanning calorime-try (DSC) and wide angle X-ray diffraction (XRD). In vitro degradation experiments and SEM micrographs show that the degradation rate of PSAOAs decrease with increasing the content of POA in copolyanhydrides and the erosion process of PSAOAs is neither bulk nor perfect surface erosion but rather has elements of both in phosphate buffer at 37 °C. In vitro release experiments and SEM micrographs indicate that the release rate of drug from the drug-loaded PSAOAs discs decreases with increasing the content of POA in copolyanhy-drides and the release rate of the hydrophilic drug is greater than that of the hydrophobic one. The results of the investigation suggest that POA can improve the properties of PSA and promote the applications of PSA in biomedicine.
07/2008;
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ABSTRACT: This work evaluates the transdermal drug delivery properties of amphiphilic copolymer self-assembled nanoparticles by skin penetration experiments in vitro. Paclitaxel-loaded methoxy poly(ethylene glycol)-block-poly(D,L-lactic acid) diblock copolymer nanoparticles (PNPs) were prepared by a solid dispersion technique and were applied to the surface of excised full-thickness rat skin in Franz diffusion cells. HPLC, transmission electron microscopy, Fourier transform infrared spectroscopy and 1H NMR were used to assay the receptor fluid. The results show that the amphiphilic copolymer nanoparticles with the entrapped paclitaxel are able to penetrate rat skin. Ethanol can improve the delivery of PNPs and increase the cumulative amount of paclitaxel in the receptor fluid by 3 times. Fluorescence microscopy measurements indicate that the PNPs can penetrate the skin not only via appendage routes including sweat ducts and hair follicles but also via epidermal routes. Copyright © 2007 Society of Chemical Industry
Polymer International 08/2007; 57(2):268 - 274. · 1.90 Impact Factor
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ABSTRACT: P(DMAEMA-g-EG) cationic hydrogel nanoparticles (CHNPs) were prepared by distillation–dispersion copolymerization of poly(ethylene glycol) methyl ether methacrylate (MPEGMA) and N,N-dimethylaminoethyl methacrylate (DMAEMA) using acetonitrile (AN) as dispersion medium. The results of FTIR spectra indicate that the composition of P(DMAEMA-g-EG) CHNPs is consistent with the designed structure. The TEM image shows that P(DMAEMA-g-EG) CHNPs are of spherical morphology before and after swelling. The investigations on the properties of P(DMAEMA-g-EG) CHNPs indicate that P(DMAEMA-g-EG) CHNPs have pH-, ionic strength- and thermo-sensitive characters. This type of P(DMAEMA-g-EG) CHNP is very promising as environment-sensitive drug carriers.
European Polymer Journal.
