PLGA nanospheres

Figure 8. Preparation mechanisms of PLGA nanospheres by the emulsion-phase separation method in an oil system.

Weissenboeck, A., Bogner, E., Wirth, M., Gabor, F., Binding and uptake of wheat germ agglutinin-decorated PLGA-nanospheres by Caco-2 monolayers. Pharm Res 21, 1919-1925 (2004). 

Kawashima, Y., Yamamoto, H., Takeuchi, H., Fujioka, S., and Hino, T. (1999). Pulmonary delivery of insulin with nebulized DL-lactide/glycolide copolymer (PLGA) nanospheres to prolong hypoglycemic effect. J. Controlled Release, 62, 279-287. 

Fig. 9.2 Blood calcium level after intragastric administration of unmodified calcitonin-loaded PLGA nanospheres (white squares), chitosan-modified calcitonin-loaded PLGA nanospheres (white triangles), and calcitonin solution (white circles). Adapted from Takeuchi et al. (2001)...

Calcitonin is another compound that was often incorporated into nanoparticles to enhance its oral absorption. Takeuchi et al. (2001) developed Elcato-nin-loaded PLGA nanospheres coated with chitosan, observing a reduction of blood calcium level. Sakuma et al. (2002) hypothesizes that both mucoadhesion of nanoparticles incorporating salmon calcitonin into the GI mucosa (Sakuma et al. 1999,2002) and increase in the stability of salmon calcitonin in the GI tract (Sakuma et al. 1997) result in the improvement of salmon calcitonin absorption. Moreover, chitosan-PEG nanocapsules increased the absorption of salmon calcitonin (Prego et al. 2006). 

De, S., and Robinson, D. H. (2004), Particle size and temperature effect on the physical stability of PLGA nanospheres and microspheres containing Bodipy, AAPS Pharm. Sci. Tech., 5(4), e53. 

Kawashima, Y. (1995). Aerosolization oflactide/glycolide copolymer (PLGA) nanospheres for pulmonary delivery of peptide-drugs. Yakugaku Zasshi 115, 732-741. 

Ravi Kumar M N V, Bakowsky U, Lehr C M (2004). Preparation and characterization of cationic PLGA nanospheres as DNA carriers. Biomaterials. 25 1771-1777. 

Yamamoto H, Kuno Y, Sugimoto S, et al. (2005). Surface-modified PLGA nanosphere with chitosan improved pulmonary delivery of calcitonin by mucoadhesion and opening of the intercellular tight junctions. J. Control. Rel. 102 373-381. 

Mukerjee A, Vishwanatha JK. Formulation, characterization and evaluation of curcumin-loaded PLGA nanospheres for cancer therapy. Anticancer Res. 2009 29(10) 3867-3875. 

T Niwa. H Takeuchi. T Hino. N Kunon, Y Kawashima. In-vitro drug release behaviour of D.L-laciide/glycolide copolymer (Plga) nanospheres with nafarelin acetate prepared by a novel spontaneous emulsification, solvent diffusion method. J. Pharm. Sci. 83 727-732. 1994. 

Figure 73 Representative 3-D nanostructured scaffolds for bone-specific drug delivery systems, (a) Electrospun sitk scaffold with BMP-2 loaded, scale bar=5 pm (reprinted from Ref. [86] with permission) (b) Self-assembled peptide-amphiphile (PA) nanofibers network, scale bar= 1 mi (reprinted from Ref. [87] with permission) (c) Nanocrystalline apatite modified poly(lactide-co-glycolide) (PLAGA) microsphere scaffolds, scale bar=2pm (reprinted from Ref. [88] with permission) and (d) poly(L-lactic acid) (PLLA) nanofibrous scaffolds incorporated with poly(lactic-co-glycolic acid) (PLGA) nanospheres, scale bar=2 pm (reprinted from Ref. [89] with permission).

Tahara, K., Sakai, T., Yamamoto, H., Takeuchi, H., and Kawashima, Y. 2008. Establishing chitosan coated PLGA nanosphere platform loaded with wide variety of nucleic acid by complexation with cationic compound for gene delivery. International Journal of Pharmaceutics 354 210-216. 

Teixeira M, Alonso MJ, Pinto MM et al (2005) Development and characterization of PLGA nanospheres and nanocapsules containing xanthone and 3-methoxyxanthone. Fur J Pharm Biopharm 59 491-500... 

Vega, E., Gamisans, F., Garcia, M.L., Chauvet, A., Lacoulonche, F., Egea, M.A., 2008. Plga nanospheres for the ocular delivery of flurbiprofen drug release and interactions. Journal of Pharmaceutical Sciences 97 (12), 5306—5317. 

Water-soluble PLA-PEG copolymers with PLAiPEG ratios of 2 5 and 3 4 (PEG chains of 5 and 2kDa, respectively) were used to coat PLGA nanospheres and thus prepare sterically stabilized particles (Stolnik et al,... 

For this, the PLGA nanospheres were either prepared in the presence of PEG-PLA copolymers by the precipitation-solvent evaporation method or were prepared without any stabilizing agent and subsequently coated by incubation in aqueous solutions of PEG-PLA. 

PLGA nanospheres were prepared by the precipitation-solvent evaporation method in the presence of PEG PLA polymers (Stolnik et al, 1995). The resulting PEG-coated particles had an average particle size between 120 and 140nm and a polydispersity index between 0.08 and 0.13, indicative of a relatively narrow size distribution. 

Effect of the Adsorption of PEG-PLACopolymers and of Poloxamine 908 on Polystyrene and PLGA Nanospheres on the Particle Size and Zeta Potential"... 

Verrecchia et al (1993, 1995) entrapped another water-insoluble drug, [ CJibuprofen ([ C]-IBP), in PEG2K-PLA30K nanospheres. The in vivo data after i.v. administration of the particles in rats showed an increase of IBP plasma half-life, firom a few minutes when encapsulated in non-stealth PLGA nanospheres up to two and a half hours in the case of stealth ... 

Tissue distribution studies 6 hr after injection of PEG-PLA nanospheres revealed that 53% of the injected dose was in the intestines, 11.3% in the liver, and 9.1% in plasma in the case of PLGA nanospheres, 52.2% of the dose was in the intestines, 20% in the liver, and 0.39% in plasma (Verrecchia et al, 1995). IBP is a drug with a fast hepatic metabolism and an intestinal and fecal elimination, and the tissue distribution of the drug is not modified in both cases (PEG-PLA and PLGA nanoparticles), except for the plasma residence time. 

PLGA coated with PEG-PLA, labeled with " In or [ CJ-PLA) have shown that PEG R copolymers can be successMly used to produce or coat biodegradable nanospheres and thus obtain sterically stabilized particles with dramatically increased blood half-lives and decreased hepatic uptake as compared to naked PLA or PLGA nanospheres. 

Although it appears that the majority of work with PLGA microspheres for oral delivery is directed toward vaccine administration, PLGA nanospheres have also been investigated as a potential alternate oral delivery system for cyclosporin (Sanchez et al, 1993). 

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