PLGA

In vivo biocompatibility was assessed through subcutaneous implantation in Sprague-Dawley rats. PLGA was used as a control polymer. PGS and PLGA implants with the same surface area/volume ratio were implanted in dorsal subcutaneous pockets. A fibrous capsule around PGS (45 pm thick after 35 days implantation) appeared later than that around PLGA (140 pm thick after 14 days implantation). After 60 days of implantation, the implant was completely absorbed with no signs of granulation or scar formation. ... 

PEG/PBT copolymers are also very good matrix materials for the release of growth factors in tissue engineering. Proteins have been delivered from PEG/PBT microspheres with preservation of protein delivery of complete activity. In the case of protein delivery from PLGA and poly(ortho ester) microspheres, the protein activity was significantly reduced. " ... 

A similar technique, the so-called spontaneous emulsification solvent diffusion method, is derived from the solvent injection method to prepare liposomes [161]. Kawashima et al. [162] used a mixed-solvent system of methylene chloride and acetone to prepare PLGA nanoparticles. The addition of the water-miscible solvent acetone results in nanoparticles in the submicrometer range this is not possible with only the water-immiscible organic solvent. The addition of acetone decreases the interfacial tension between the organic and the aqueous phase and, in addition, results in the perturbation of the droplet interface because of the rapid diffusion of acetone into the aqueous phase. 

HS Yoo, JE Oh, KH Lee, TG Park. Biodegradable nanoparticles containing doxorubicin-PLGA conjugate for sustained release. Pharm Res 16(7) 1114-1118, 1999. 

Song, X., Zhao, Y., Hou, S., Xu, F., Zhao, R., He, J., Cai, Z., Li, Y. and Chen, Q. (2008) Dual agents loaded PLGA nanopartides systematic study of particle size and drug entrapment efficiency. European Journal of Pharmaceutics and Biopharmaceutics, 69, 445-453. 

Vaccination Using Antigen-Loaded PLGA Nanoparticles. 54... 

Preparation of Biodegradable Polymeric Nanoparticles 2.1 PLGA Nanoparticles... 

In vitro studies have shown that y-PGA-Phe or PLGA nanoparticle-pulsed DCs result in DC maturation by upregulation of co-stimulatory molecule expression and cytokine production (Fig. 14). To determine whether the uptake of y-PGA-Phe... 

It has also been reported that antigen delivery to DCs via PLGA particles increased the amount of protein that escaped from endosomes into the cytoplasm. How proteins or peptides encapsulated within PLGA particles become accessible to the cytoplasm is still not clear. It is suggested that the gradual acidification of endosomes leads to protonation of the PLGA polymer, resulting in enhanced hydrophobicity and attachment and rupture of the endosomal membrane [147]. 

Lii JM, Wang X, Marin-Muller C et al (2009) Current advances in research and clinical applications of PLGA-based nanotechnology. Expert Rev Mol Diagn 9 325-341... 

Nayak B, Panda AK, Ray P et al (2009) Formulation, characterization and evaluation of rotavirus encapsulated PLA and PLGA particles for oral vaccination. J Microencapsul 26 154-165... 

Hamdy S, Molavi O, Ma Z et al (2008) Co-delivery of cancer-associated antigen and Toll-like receptor 4 ligand in PLGA nanoparticles induces potent CD8+ T cell-mediated anti-tumor immunity. Vaccine 26 5046-5057... 

Chong CS, Cao M, Wong WW et al (2005) Enhancement of T helper type 1 immune responses against hepatitis B virus core antigen by PLGA nanoparticle vaccine delivery. J Control Release 102 85-99... 

These representative aliphatic polyesters are often used in copolymerized form in various combinations, for example, poly(lactide-co-glycolide) (PLGA) [66-68] and poly(lactide-co-caprolactone) [69-73], to improve degradation rates, mechanical properties, processability, and solubility by reducing crystallinity. Other monomers such as 1,4-dioxepan-5-one (DXO) [74—76], 1,4-dioxane-2-one [77], and trimethylene carbonate (TMC) [28] (Fig. 2) have also been used as comonomers to improve the hydrophobicity of the aliphatic polyesters as well as their degradability and mechanical properties. 

Fig. 10 Multifunctional solid biodegradable PLGA nanoparticles attached to several moieties such as T-cell antibodies, magnetic resonance contrast agent (biotin-BSA-Gd-DTPA) and encapsulated immunosuppressive drug (doxorubicin). (Adapted from [48])...

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