• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3225-3232
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• 2012

The purposes of this research were to synthesize amoxicillin-carrying magnetic nanoparticles. Magnetic nanoparticles were prepared by a chemical precipitation of ferric and ferrous chloride salts in the presence of a strong basic solution. PLGA and PLGA-PEG copolymers were prepared by ring opening polymerization of lactide (LA) and glycolide (GA) (mole ratio of LA: GA 3:1) with or without polyethylene glycol (PEG). Amoxicillin loaded magnetic PLGA and PLGA-PEG nanoparticles were prepared by an emulsion-evaporation process (o/w). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) photomicrographs showed that the magnetic nanoparticles have the mean diameter within the range of 65-260 nm also they were almost spherical in shape. Magnetic nanoparticles prepared with PLGA showed more efficient entrapment (90%) as compared with PLGA-PEG (48-52%) nanoparticles. In-vitro release of amoxicillin from magnetic PLGA nanoparticles showed that 78% of drug was released over 24 hours. The amount of amoxicillin released from PLGA-PEG s was higher than PLGA.

• Journal of Pharmaceutical Investigation
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• v.37 no.1
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• pp.39-43
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• 2007

Previously, we have reported that PLGA nanoparticles were prepared for sustained release of water-soluble blue dextran and the particle size, in vitro release pattern and encapsulation were modulated by varying polymers. This study was designed to encapsulate plasmid DNA in PLGA nanoparticles and to investigate the effect of Polymers and temperatures. PLGA nanoparticles were fabricated with poloxamer 188 (P188) or poloxamer 407 (P407) by using spontaneous emulsification solvent diffusion method. As a model plasmid DNA, pCMV-Taq2B/1L-18 was encapsulated in PLGA nanoparticles. Then, the particle size, zeta potential and encapsulation efficiency of nanoparticles containing plasmid DNA were investigated. Particle sizes of PLGA nanoparticles prepared with P188 and P407 were in the range of 200-330 nm and 250-290 nm, respectively. Zeta potentials of nanoparticles were negative regardless of nanoparticle compositions. Encapsulation efficiency of P407 nanoparticles prepared at $30^{\circ}C$ was higher than those at other preparation condition. From the results, the PLGA nanoparticles prepared with poloxamers at different temperature, could modulate the particles size of nanoparticles, and encapsulation efficiency of plasmid DNA.

• Journal of Pharmaceutical Investigation
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• v.36 no.2
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• pp.109-114
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• 2006

Biodegradable poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles were developed for sustained delivery of water-soluble macromolecules. PLGA nanoparticles were fabricated by spontaneous emulsification solvent diffusion method generating negatively charged particles and heterogeneous size distribution. As a model drug, blue dextran was encapsulated in PLGA nanoparticles. In addition, nanoparticles were also prepared with varying ratio of poloxamer 188 (P188) and poloxamer 407 (P407), and coating with poly(vinyl alcohol) (PVA). Then, the particle size, zeta potential and encapsulation efficiency of nanoparticles containing blue dextran were studied. In vitro release of blue dextran from nanoparticles was also investigated. The surface and morphology of nanoparticles were characterized by scanning electron microscopy (SEM). In case of nanoparticles prepared with PLGA, P407, and different organic solvents, particle size was in the range of $230{\sim}320\;nm$ and zeta potentials of nanoparticles were negative. The SEM images showed that ethyl acetate is suitable for the formulation of PLGA nanoparticles with good appearance. Moreover, ethyl acetate showed higher encapsulation efficiency than other solvents. The addition of P188 to formulation did not affect the particle size of PLGA nanoparticles but altered the release patterns of blue dextran from nanoparticles. However, PVA, as a coating material, altered the particle size with increasing the PVA concentration. The nanoparticles were physically stable in the change of particle size during long-term storage. From the results, the PLGA nanoparticles prepared with various contents of poloxamers and PVA, could modulate the particles size of nanoparticles, in vitro release pattern, and encapsulation of water-soluble macromolecules.

• Journal of Pharmaceutical Investigation
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• v.34 no.2
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• pp.101-106
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• 2004

This work aims at examining the cellular uptake behavior of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles derivatized with a protein transduction domain (PTD) using HeLa cells. For this purpose, $Tat_{49-57}$ peptide derived from transcriptional activation (Tat) protein of HIV type-1 was covalently conjugated to the terminal end of PLGA. Nanoparticles were ten prepared with the $Tat_{49-57}-PLGA$ conjugates by a spontaneous phase inversion method. The prepared particles had a mean diameter of ca. 84 nm, as measured by dynamic light scattering. The interaction of the Tat-PLGA nanoparticles with cells was examined by using confocal laser scanning microscopy. It was found tat Tat-PLGA nanoparticles incubated with HeLa cells could efficiently translocate into cytoplasm, while plain PLGA nanoparticles showed negligible cellular uptake. In addition, even at $4^{\circ}C$ or in the presence of sodium azide significant cellular internalization of Tat-PLGA nanoparticles was still observed. These results indicate that a non-endocytotic translocation mechanism might be involved in the cellular uptake of Tat-PLGA nanoparticles.

• Polymer(Korea)
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• v.26 no.4
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• pp.535-542
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• 2002

We have prepared the surfactant-free nanoparticles of poly(DL-lactide-co-glycolide) (PLGA) by dialysis method and their physicochemical properties such as particle size and drug contents were investigated against various solvent. The size of PLGA nanoparticles prepared by using dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethylsulfoxide (DMSO) was smaller than that from acetone. Also, the order of drug contents was DMAc>DMF>DMSO=acetone. These phenomena could be expected from the fact that solvent affects the size of nanoparticles and drug contents. The PLGA nanoparticles have a good spherical shapes as observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Also, surfactant-free nanoparticles entrapping norfloxacin (NFx) have a good drug loading capacity without free-drug on the surface of nanoparticles confirmed by the analysis of X-ray powder diffraction. Release kinetics of NFx used as a model drug was governed not only by drug contents but also by particle size. Also, the biodegradation rate of PLGA nanoparticles prepared from DMF was faster than that prepared from acetone, indicating that the biodegradation of PLGA nanoparticles is size-dependent.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1579-1584
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• 2002

Since surfactant or emulsifiers remained on the nanoparticle surface significantly affect the physicochemical properties, the biodegradation rate, the biodistribution, and the biocompatibility of nanoparticles, surfactant-free nanoparticles should be good candidate. surfactant-free PLGA nanoparticles were successfully prepared by both the dialysis method and the solvent diffusion method. The PLGA nanoparticles prepared using the solvent diffusion method has a smaller particle size than the dialysis method. The solvent diffusion method was better for a higher loading efficiency than the dialysis method but the nanoparticle yield was lower. Testosterone (TST) release from the PLGA nanoparticles was dependent on the particle size rather than the drug contents. Testosterone release from the PLGA nanoparticles prepared by the solvent diffusion method using acetone was faster than those prepared by the dialysis method. TST release from the PLGA nanoparticles prepared by the solvent diffusion method using acetone and the dialysis method using dimethylformamide (DMF) was completed for 4 days while the PLGA nanoparticles prepared by the dialysis method using acetone showed approximately 80% TST release after 4 days. Since the PLGA nanoparticle degradation ratio was below 20% within 5 days at all samples while TST release completed within 4 days, TST release was dependent on the diffusion mechanism rather than degradation.

• Journal of Life Science
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• v.31 no.9
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• pp.849-855
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• 2021

Recently, as nanotechnology has been introduced and used in various fields, the development of new drugs has been accelerating. Nanoparticles have maintained blood drug concentration for extended periods of time with a single administration of the drug. The drug can then be selectively released only at the pathological site, thereby reducing side effects to other non-pathological sites. In addition, nanoparticles can be modified for selective target sites delivery for other specific diseases, with polymers being widely used in the manufacture of these nanoparticles. Poly (D,L-lactic-co-glycolic acid ) (PLGA) is one of the most extensively developed biodegradable polymers. PLGA is widely used in drug delivery for a variety of applications. It has also been approved by the FDA as a drug delivery system and is widely applied in controlled release formulations, such as in gene therapy treatments. PLGA nanoparticles have been developed as delivery systems with high efficiency to specific cell types by using passive and active targeting methods. After the development of a drug delivery system using PLGA nanoparticles, the drug is selectively delivered to the target site, and the effective blood concentration for extended periods of time is optimized according to the disease. In this review paper, we focus on ways to improve cell-specific treatment outcomes by examining the development of astrocyte selective nanoparticles based on PLGA nanomaterials for gene therapy.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.712-719
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• 2006

In this study, we prepared core-shell type nanoparticles of a poly(DL-lactide-co-glycolide) (PLGA) grafted-dextran (DexLG) copolymer with varying graft ratio of PLGA. The synthesis of the DexLG copolymer was confirmed by $^1H$ nuclear magnetic resonance (NMR) spectroscopy. The DexLG copolymer was able to form nanoparticles in water by self-aggregating process, and their particle size was around $50\;nm{\sim}300\;nm$ according to the graft ratio of PLGA. Morphological observations using a transmission electron microscope (TEM) showed that the nanoparticles of the DexLG copolymer have uniformly spherical shapes. From fluorescence probe study using pyrene as a hydrophobic probe, critical association concentration (CAC) values determined from the fluorescence excitation spectra were increased as increase of DS of PLGA. $^1H-NMR$ spectroscopy using $D_2O$ and DMSO approved that DexLG nanoparticles have core-shell structure, i.e. hydrophobic block PLGA consisted inner-core as a drug-incorporating domain and dextran consisted as a hydrated outershell. Drug release rate from DexLG nano-particles became faster in the presence of dextranase in spite of the release rate not being significantly changed at high graft ratio of PLGA. Core-shell type nanoparticles of DexLG copolymer can be used as a colonic drug carrier. In conclusion, size, morphology, and molecular structure of DexLG nanoparticles are available to consider as an oral drug targeting nanoparticles.

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.418-422
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• 1998

Aim of this work is to prepare poly(DL-lactide-co-glycolide) (PLGA) nanoparticles by dialysis method without surfactant and to investigate drug loading capacity and drug release. The size of PLGA nanoparticles was 269.9 $\pm$118.7 nm in intensity average and the morphology of PLGA nanoparticies was spherical shape from the observation of SEM and TEM. In the effect of drug loading contents on the particle size distribution, PLGA nanoparticles were monomodal pattern with narrow size distribution in the empty and lower drug loading nanoparticles whereas bi- or trimodal pattern was showed in the higher drug loading ones. Release of clonazepam from PLGA nanoparticles with higher drug loading contents was slower than that with lower loading contents.

• KSBB Journal
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• v.23 no.5
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• pp.408-412
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• 2008

The rosiglitazone loaded poly (lactide-co-glycolide) (PLGA) nanoparticles (NPs) were prepared by the emulsion-evaporation method and optimized for particle size and entrapment efficiency. The optimized particles were 140-180 nm in size with narrow size distribution and 80% entrapment efficiency at 1% w/w initial drug loading when prepared with 1-3% w/v of PVA as a surfactant. These particulate carriers exhibited controlled in vitro release of rosiglitazone for 36 hrs at a nearly constant rate after 4 hrs release. In conclusion, these results indicate that PLGA NPs have greater potential for oral delivery of rosiglitazone.