Effects of poly(lactic-co-glycolic acid) on preparation and characteristics of plasmid DNA-loaded solid lipid nanoparticles

Poly(lactic-co-glycolic acid) (PLGA) was used as a polymeric emulsifier to encapsulate plasmid DNA into hydrogenated castor oil (HCO)-solid lipid nanoparticles (SLN) by w/o/w double emulsion and solvent evaporation techniques. The effects of PLGA on the preparation, characteristics and transfection efficiency of DNA-loaded SLN were studied. The results showed that PLGA was essential to form the primary w/o emulsion and the stability of the emulsion was enhanced with the increase of PLGA content. DNA-loaded SLN were spherical with smooth surfaces. The SLN had a negative charge in weak acid and alkaline environment but acquired a positive charge in acidic pH and the cationisation capacity of the SLN increased with the increase of PLGA/HCO ratio. Agarose gel electrophoresis demonstrated that the majority of the DNA maintained its structural integrity after preparation and being extracted or released from DNA-loaded SLN. When PLGA/HCO ratio increased from 5 to 15%, the encapsulation efficiency, loading capacity and transfection efficiency of the nanoparticles increased significantly, whereas the changes of particle size and polydispersity index were insignificant. Cytotoxicity study in cell culture demonstrated that the SLN was not toxic.     

Nanoparticles obtained by confined impinging jet mixer: poly(lactide-co-glycolide) vs. Poly-ε-caprolactone

This paper is focused on the production and characterization of polymeric nanoparticles obtained by nanoprecipitation. The method consisted of using a confined impinging jet mixer (CIJM), circumventing high-energy equipment. Differences between the use of poly-ε-caprolactone (PCL) and poly(lactide-co-glycolide) (PLGA) as concerns particle mean size, zeta potential, and broad-spectrum antibiotic florfenicol entrapment were investigated. Other analyzed variables were polymer concentration, solvent, and anti-solvent flow rates, and antibiotic initial concentration. To our knowledge, no data were found related to PLGA and PCL nanoparticles comparison using CIJM. Also, florfenicol encapsulation within PCL or PLGA nanoparticles by nanoprecipitation has not been reported yet. The complexity of the nanoprecipitation phenomena has been confirmed, with many relevant variables involved in particles formation. PLGA resulted in smaller and more stable nanoparticles with higher entrapping of florfenicol than PCL.     

Preparation and Optimization of Dry PLGA Nanoparticles by Spray Drying Technique

The aim of this article was to evaluate the potential of poly lactide-coglycolide (PLGA) nanoparticles (NPs) as carriers for controlling release of doxorubicin (DOX) via a spray drying technique. The challenge was to entrap a hydrophilic molecule into a lipophilic core molecule of PLGA. To achieve this objective, we modified conventional approach of drug loading to spray drying technique. The eight formulations of nanoparticles were prepared by modified double emulsion and solvent evaporation technique followed by spray drying using 2³ factorial designs. PLGA (A) and PVA (B) and stirring speed (C) were used as independent variables where particle size (Y₁), entrapment efficiency (Y₂) and percentage of drug release at the 32 hour (Y₃) were taken as dependant variables. The results showed that the method is easy and efficient for the entrapment of the drug as well as the formation of spherical nanoparticles. This modification improved DOX entrapment efficiency relative to controls real loadings up to 40%. The in vitro release studies indicated the DOX loaded PLGA nanoparticles provide controlled drug release over a period of 32 h. Hence, this investigation demonstrated the potential of the experimental design in understanding the effect of the formulation variables on the quality of DOX-PLGA nanoparticles.     

去甲斑蝥素PLA-PEG纳米微球的制备研究

采用复乳法和相分离法两种方法制备去甲斑蝥素的聚乳酸-聚乙二醇嵌段共聚物(PLA-PEG)纳米微球.对比了两种不同方法对制得的含药微球在粒径、包封率以及缓释性能方面的差异.用激光粒度分析仪表征了微球的粒径及其分布,并用透射电镜观察了微球的形貌,其结果表明:复乳法与相分离法制备的微球粒径均在100nm左右,并且成球性好;相对于复乳法,相分离法制备的微球分布较宽,包封率较高,可达到50%左右;体外释放实验表明两种方法制备的微球都具有缓释作用.     

Optimization of PLGA nanoparticles formulation containing L-DOPA by applying the central composite design

The aim of this work was to prepare L-DOPA loaded poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles by a modified water-in-oil-in-water (W₁/O/W₂) emulsification solvent evaporation method. A central composite design was applied for optimization of the formulation parameters and for studying the effects of three independent variables: PLGA concentration, polyvinyl alcohol (PVA) concentration and organic solvent removal rate on the particle size and the entrapment efficiency (response variables). Second-order models were obtained to adequately describe the influence of the independent variables on the selected responses. The analysis of variance showed that the three independent variables had significant effects (p < 0.05) on the responses. The experimental results were in perfect accordance with the predictions estimated by the models. Using the desirability approach and overlay contour plots, the optimal preparation area can be highlighted. It was found that the optimum values of the responses could be obtained at higher concentration of PLGA (5%, w/v) and PVA (6%, w/v); and faster organic solvent removal rate (700 rpm). The corresponding particle size was 256.2 nm and the entrapment efficiency was 62.19%. FTIR investigation confirmed that the L-DOPA and PLGA polymer maintained its backbone structure in the fabrication of nanoparticles. The scanning electron microscopic images of nanoparticles showed that all particles had spherical shape with porous outer skin. The results suggested that PLGA nanoparticles might represent a promising formulation for brain delivery of L-DOPA. The preparation of L-DOPA loaded PLGA nanoparticles can be optimized by the central composite design.     

Co-delivery of gemcitabine and simvastatin through PLGA polymeric nanoparticles for the treatment of pancreatic cancer: in-vitro characterization,cellular uptake,and pharmacokinetic studies

Despite the ongoing extensive research, cancer therapeutics still remains an area with unmet needs which is hampered by shortfall in the development of newer medicines. The present study discusses a nano-based combinational approach for treating solid tumor. Dual-loaded nanoparticles encapsulating gemcitabine HCl (GM) and simvastatin (SV) were fabricated by double emulsion solvent evaporation method and optimized. Optimized nanoparticles showed a particle size of 258?±?2.4?nm, polydispersity index of 0.32?±?0.052, and zeta potential of ?12.5?mV. The size and the morphology of the particles wee further confirmed by transmission electron microscopy (TEM) and scanning electron microscopy, respectively of the particles. The entrapment efficiency of GM and SV in the nanoparticles was 38.5?±?4.5% and 72.2?±?5.6%, respectively. The in vitro release profile was studied for 60?h and showed Higuchi release pattern. The cell toxicity was done using MTT assay and lower IC₅₀ was obtained with the nanoparticles as compared to the pure drug. The bioavailability of GM and SV in PLGA nanoparticles was enhanced by 1.4-fold and 1.3-fold respectively, compared to drug solution. The results revealed that co-delivery of GM and SV could be used for its oral delivery for the effective treatment of pancreatic cancer.     

载紫杉醇聚乳酸-羟基乙酸纳米粒的体外释药研究

以生物可降解材料聚乳酸-羟基乙酸(PLGA)为载体制备了载紫杉醇纳米粒,重点考察了纳米粒的体外释放特性.采用乳化-溶剂挥发法制备了载紫杉醇PLGA纳米粒,其平均粒径为200nm,载药量为21%,包封率为89.44%;体外释药符合Higuchi方程:Q=3.8796t1/2+30.4649(r=0.9397),同时载紫杉醇纳米粒具有一定的缓释作用.     

Development and In Vitro Evaluation of Surface Modified Poly(lactide-co-glycolide) Nanoparticles with Chitosan-4-Thiobutylamidine

ABSTRACT

The objective of this study was to develop a nanoparticulate drug delivery system based on the surface modification of poly(lactide-co-glycolide) (PLGA) nanoparticles with a thiolated chitosan. PLGA nanoparticles were prepared by the emulsification-solvent evaporation method. Immobilization of chitosan to the surface of PLGA nanoparticles via amide bonds was mediated by a carbodiimide. Thiol groups were covalently bound to the chitosan surface of particles by reaction with 2-iminothiolane. Obtained nanoparticles were characterized in vitro regarding size, zeta potential, thiol group content, stability at different pH values, mucoadhesion, and drug release. Results demonstrated that the surface modification of PLGA nanoparticles with thiolated chitosan (chitosan-TBA) leads to nanoparticles of a mean diameter of 889.5 ± 72 nm and positive zeta potential of + 24.74 mV. The modified nanoparticles contained 7.32 ± 0.24 μmol thiol groups per gram nanoparticles. The size of nanoparticles was strongly influenced by the pH of the surrounding medium, being 925.0 ± 76.3 nm at pH 2 and 577.8 ± 66.7 nm at pH 7.4. Thiolated nanoparticles showed a 3.3-fold prolonged residence time on the mucosa and an unchanged release profile in comparison to unmodified PLGA nanoparticles. These data suggest that surface modified chitosan-TBA conjugate PLGA nanoparticles have the potential to be used as mucoadhesive drug delivery system.     

Basic fibroblast growth factor loaded biodegradable PCL-PEG-PCL copolymeric nanoparticles: preparation, in vitro release and immunogenicity study

In this article, human basic fibroblast growth factor (bFGF) loaded PCL-PEG-PCL (PCEC) nanoparticles were prepared by modified W1/O/W2 double emulsion solvent evaporation method. The bFGF encapsulated in PCEC nanoparticles could be released in sustained release behavior in vitro. After subcutaneous single-dose injection of bFGF loaded PCEC nanoparticles at 20 microg of bFGF per dose in mice, the anti-bFGF special autoantibody IgG continued to grow until 8 weeks after the immunization and was still kept at high level at week 11. At the same time, HK293 cell viability assay in vitro indicated that the cytotoxicity of blank PCEC nanoparticles was low but dose dependent. For some success in controlling tumor growth had been met by neutralizing bFGF reported previously, the bFGF loaded PCEC nanoparticles prepared in this paper might have potential application as anti-tumor vaccine.     

Fabrication and characterization of porous poly(lactic-<Emphasis Type="Italic">co</Emphasis>-glycolic acid) (PLGA) microspheres for use as a drug delivery system

In this work, Simvastatin (SIM) loaded porous poly(lactic-co-glycolic acid) (PLGA) microspheres were fabricated using the W/O/W1/W2 double emulsion and solvent evaporation method. The optimal conditions for fabricating porous PLGA microspheres were determined to be 20% distilled water (v/v), 10% PLGA (m/v), and a 4:1 ratio of internal polyvinyl alcohol (PVA) to dichloromethane (DCM). The pores size distribution of porous PLGA microspheres was varied from 0.01 to 40 μm, while their particle displayed a bimodal size distribution that had two diameter peaks at around 100 μm and 500 μm. The SIM encapsulation efficacy was found to be very high with a yield near 80% and the porous PLGA microspheres showed the excellent biocompatibility. In addition, the drug release profile was found to be significantly different from a temporal basis. Base on the combined results of this study, SIM loaded PLGA microspheres holds great promise for use in biomedical applications, especially in drug delivery system or tissue regeneration.     

Development and in vitro evaluation of surface modified poly(lactide-co-glycolide) nanoparticles with chitosan-4-thiobutylamidine

The objective of this study was to develop a nanoparticulate drug delivery system based on the surface modification of poly(lactide-co-glycolide) (PLGA) nanoparticles with a thiolated chitosan. PLGA nanoparticles were prepared by the emulsification-solvent evaporation method. Immobilization of chitosan to the surface of PLGA nanoparticles via amide bonds was mediated by a carbodiimide. Thiol groups were covalently bound to the chitosan surface of particles by reaction with 2-iminothiolane. Obtained nanoparticles were characterized in vitro regarding size, zeta potential, thiol group content, stability at different pH values, mucoadhesion, and drug release. Results demonstrated that the surface modification of PLGA nanoparticles with thiolated chitosan (chitosan-TBA) leads to nanoparticles of a mean diameter of 889.5 ± 72 nm and positive zeta potential of + 24.74 mV. The modified nanoparticles contained 7.32 ± 0.24 μmol thiol groups per gram nanoparticles. The size of nanoparticles was strongly influenced by the pH of the surrounding medium, being 925.0 ± 76.3 nm at pH 2 and 577.8 ± 66.7 nm at pH 7.4. Thiolated nanoparticles showed a 3.3-fold prolonged residence time on the mucosa and an unchanged release profile in comparison to unmodified PLGA nanoparticles. These data suggest that surface modified chitosan-TBA conjugate PLGA nanoparticles have the potential to be used as mucoadhesive drug delivery system.     

Enhanced antitumor activity in A431 cells via encapsulation of 20(R)-ginsenoside Rg3 in PLGA nanoparticles

Objective: The objective of this study is to investigate the encapsulation of 20(R)-ginsenoside Rg3 (20(R)-Rg3) using polylactic-co-glycolic acid (PLGA) and promotion for its antitumor activity.

Significance: Preparation and evaluation of the antitumor efficacy of 20(R)-Rg3-loaded PLGA nanoparticles were the first reported. The data will be helpful to apply 20(R)-Rg3 efficiently and broadly in new drug form development and clinical cancer treatment.

Methods: The nanoparticles were prepared using emulsion and solvent evaporation methods. The uniform particle size and good dispersion were further confirmed by scanning electron microscopy. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was applied to detect cell proliferation after 20(R)-Rg3-loaded PLGA nanoparticles treatment. Western blotting and immunofluorescent staining were used for observation of key proteins related with proliferation and apoptosis. Cell cycle and apoptosis were analyzed by flow cytometer technology.

Results and discussion: The results showed that the size of 20(R)-Rg3-loaded PLGA was 97.5?nm in diameter, and zeta potential was ?28?mV detected by Malvern particle size analyzer. The encapsulation efficiency was 97.5%, and drug loading was 70.2% measured by high-performance liquid chromatography. The in vitro study showed that the encapsulated 20(R)-Rg3 was consecutively released and the release ratio reached to the highest value (19.36%) at the time point of 96?h. The encapsulated 20(R)-Rg3 significantly inhibited the proliferation and induced apoptosis in A431 cancer cells compared with the unencapsulated 20(R)-Rg3, control and PLGA alone.

Conclusion: 20(R)-Rg3-loaded PLGA nanoparticles was well prepared and characterized. The antitumor activity was increased after PLGA encapsulation. The data will be beneficial to the development of new dosage forms of 20(R)-Rg3 and extensive application.     

Developing combination of artesunate with paclitaxel loaded into poly-d,l-lactic-co-glycolic acid nanoparticle for systemic delivery to exhibit synergic chemotherapeutic response

Objectives: Paclitaxel (PTX) has been indicated for the treatment of a variety of solid tumors, whereas artesunate (ART) has been reported to have the potential for use in combination chemotherapy. In this study, the combination of ART and PTX was prepared in nanoparticle to induce the synergic effect and improve therapeutic efficiency in treatment of breast cancer.

Methods: Dual anticancer agents (PTX and ART) were loaded into Poly-D,L-lactic-co-glycolic acid (PLGA) nanoparticle (NP) by solvent evaporation technique from oil-in-water emulsion, stabilized with Tween 80. Physicochemical properties of obtained nanoparticles (PTX-ART-NPs) were characterized including particle size (Z), polydispersity index (PDI), zeta potentials (ZP), encapsulation efficiency (EE), and in-vitro drug release. Combination index (CI) was calculated to determine the synergic effect of the combination and select the best ratio of ART and PTX. The final NPs analyzed intracellular uptake, cytotoxicity assay, and apoptosis study.

Results: The final NP had a small size (around 120?nm) with a narrow size distribution (PDI <0.3). EE values for each drug were 87.8?±?1.1% and 99.5?±?0.1% for ART and PTX, respectively, and drugs were released from NPs in a controlled release pattern. All combinations of PTX and ART had CI values under 1, which confirmed the synergic effects. Meanwhile, NP preparation increased cytotoxicity on three breast cancer cell-lines comparable to free drugs.

Conclusions: Combination of ART- and PTX-loaded PLGA NP showed promising results for anticancer therapy, especially for breast cancer treatment.     

Targeted hepatocellular carcinoma therapy: transferrin modified,self-assembled polymeric nanomedicine for co-delivery of cisplatin and doxorubicin

Background: Targeted hepatocellular carcinoma (HCC) therapy was carried out to improve the efficacy of liver cancers. The aim of this study was to develop transferrin (Tf) modified, self-assembled polymeric nanoparticles for co-delivery doxorubicin (DOX) and cisplatin (DDP), to achieve combination tumor therapy.

Methods: Tf modified polyethylene glycol (PEG) containing DOX prodrug (Tf-PEG-DOX) was synthesized. DDP containing poly(lactic-co-glycolic) acid (PLGA) materials (PLGA-DDP) were prepared. Tf modified DOX and DDP loaded PLGA nanoparticles (Tf-DOX/DDP NPs) were prepared by using nanoprecipitation method. The particles sizes, zeta potentials, drug loading effects were characterized. The cytotoxicity of the NPs was evaluated in human hepatoma carcinoma cell lines (HepG2 cells), and in vivo anti-tumor was observed in mice bearing human HepG2 cells model.

Results: Tf-DOX/DDP NPs displayed higher cytotoxicity and enhanced antitumor activity both in vitro and in vivo over their non-modified and single drug loaded counterparts.

Conclusion: Tf-DOX/DDP NPs can achieve outstanding anti-tumor activity due to the combination effect of two drugs and the active targeting ability of Tf ligands. The self-assembled polymeric nanomedicine could act as an efficient therapy method for HCC treatment.     

Preparation and characterization of honokiol nanoparticles

In this paper, honokiol nanoparticles were prepared by emulsion solvent evaporation method. The prepared honokiol nanoparticles were characterized by particle size distribution, morphology, zeta potential and crystallography. Results showed that the obtained honokiol nanoparticles at size of 33 nm might be amorphous, and could be well dispersed in water. Due to the great dispersibility in water, the obtained honokiol nanoparticles might have great potential in medical field.     

PLGA 50:50 nanoparticles of paclitaxel: Development, in vitro anti-tumor activity in BT-549 cells and in vivo evaluation

Clinical administration of paclitaxel is hindered due to its poor solubility, which necessitates the formulation of novel drug delivery systems to deliver such extreme hydrophobic drug. To formulate nanoparticles which makes suitable to deliver hydrophobic drugs effectively (intravenous) with desired pharmacokinetic profile for breast cancer treatment; in this context in vitro cytotoxic activity was evaluated using BT-549 cell line. PLGA nanoparticles were prepared by emulsion solvent evaporation technique and evaluated for physicochemical parameters, in vitro anti-tumor activity and in vivo pharmacokinetic studies in rats. Particle size obtained in optimized formulation was <200?nm. Encapsulation efficiency was higher at polymer-to-drug ratio of 20:1. In vitro drug release exhibited biphasic pattern with initial burst release followed by slow and continuous release (15?days). In vitro anti-tumor activity of optimized formulation inhibited cell growth for a period of 168?h against BT-549 cells. AUC_(0???) and t _1/2 were found to be higher for nanoparticles with low clearance rate.     

Preparation and evaluation of paclitaxel-loaded nanoparticle incorporated with galactose-carrying polymer for hepatocyte targeted delivery

Objective: Paclitaxel-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles incorporated with galactose-carrying polymer poly(vinyl benzyllactonamide) (PVLA) were prepared to facilitate the hepatocyte cell targeted delivery of paclitaxel via ligand-receptor mediated endocytosis. The factors impacting nanoparticle properties, drug release and cellular uptake efficiency were evaluated in vitro.

Method: Paclitaxel-loaded nanoparticles incorporated with PVLA were prepared by emulsion solvent evaporation method with polyvinyl alcohol (PVA) as co-emulsifier. The presence of PVLA on the particle surface was investigated through the change of ζ potential and surface hydrophobicity. Cellular uptake and cytotoxic activity, involving factors concerned with them, were evaluated by HepG2 cells in vitro.

Results: The presence of PVLA led to the increase of ζ potential, reduction of the particle surface hydrophobicity, slight promotion of paclitaxel encapsulation efficiency and more homogeneous particle size, but excessive PVLA accelerated the burst release. With enhanced attachment and cellular uptake efficiency, the PVLA incorporated nanoparticles exhibited significant cytotoxicity to HepG2 cells, and particles with higher PVLA-to-PLGA ratio, although had larger size and almost the same cellular uptake efficiency, performed much higher cytotoxic activity due to the larger drug capacity and faster release rate.     

Nanoparticle formulation for controlled release of capsaicin

Capsaicin might be an effective pharmacological agent for the treatment of discogenic back pain due to its effect on pain control neuronal degeneration. Therefore, capsaicin-loaded nano- and micro-particles for sustained release were formulated by nano-precipitation or oil-in-water single emulsion solvent evaporation/extraction method. First, the capsaicin-loaded PLGA nanoparticles were prepared by nano-precipitation method. By increasing the volume of oil-water ratio from 1:2 to 1:5, slight changes in size from 162 +/- 3 nm to 153 +/- 3 nm and in drug loading efficiency from 25% to 20% were observed, whereas the drug release period was significantly changed from 11 days for 1:2 to 5 days for 1:5 ratio. To get a more sustained release, a modified single emulsion method was applied with three kinds of biocompatible polymers (PLLA, PLGA, and PCL). Among them, PLLA particles showed a much sustained release profile than PLGA or PCL ones with the similar size. For PLLA particles, particles size and drug encapsulation efficiency increased as the oil/water ratio decreased, and the bigger particles showed the slower release profiles as well as the higher drug-loading efficiency, thus about 1 month release was obtained with 800 nm particles. In conclusion, formulation for the controlled release of capsaicin from 1 week to 1 month was prepared by using biocompatible nanoparticles.     

Surface functionalization of PLGA nanoparticles by non-covalent insertion of a homo-bifunctional spacer for active targeting in cancer therapy

This work reports the surface functionalization of polymeric PLGA nanoparticles by non-covalent insertion of a homo-bifunctional chemical crosslinker, bis(sulfosuccinimidyl) suberate (BS3) for targeted cancer therapy. We dissolved BS3 in aqueous solution of PVA during formulation of nanoparticles by a modified solid/oil/water emulsion solvent evaporation method. The non-covalent insertion of BS3 was confirmed by Fourier transform infrared (FTIR) spectroscopy. Curcumin and annexin A2 were used as a model drug and a cell specific target, respectively. Nanoparticles were characterized for particle size, zeta potential and surface morphology. The qualitative assessment of antibody attachment was performed by transmission electron microscopy (TEM) as well as confocal microscopy. The optimized formulation showed antibody attachment of 86%. However, antibody attachment was abolished upon blocking the functional groups of BS3. The availability of functional antibodies was evaluated by the presence of a light chain fraction after gel electrophoresis. We further evaluated the in vitro release kinetics of curcumin from antibody coated and uncoated nanoparticles. The release of curcumin is enhanced upon antibody attachment and followed an anomalous release pattern. We also observed that the cellular uptake of nanoparticles was significantly higher in annexin A2 positive cells than in negative cells. Therefore, these results demonstrate the potential use of this method for functionalization as well as to deliver chemotherapeutic agents for treating cancer.     

Nanoparticles made of fluorescence-labelled Poly(L-lactide-co-glycolide): preparation, stability, and biocompatibility

Nanoparticles have recently been demonstrated in a rat model to be a promising tool for targeting inflamed areas of the intestinal mucosa in inflammatory bowel diseases whilst concentrating anti-inflammatory drugs at their site of action. Still, however, this novel concept has to be proven in vivo in humans. As a first step biodegradable and biocompatible fluorescent nanoparticles were prepared and characterized to serve as markers for successful inflammation targeting in future clinical trials. To achieve stable fluorescence labelling, fluoresceinamine was covalently bound to poly(L-lactide-co-glycolide) (PLGA) as described by Horisawa et al. The modification rate of carboxyl-end groups of the PLGA chains determined by 1H NMR was 65%. From this modified polymer, nanoparticles (FA-PLGA nanoparticles) of approximately 270 nm size were prepared via nanoprecipitation. Apart from an initial burst effect, most of the label (> 88%) appeared to be strongly bound and was leaked only slowly from the particles. In contrast, we found an immediate leakage of encapsulated sodium fluorescein with nanoparticles prepared by a double emulsion method. In degradation experiments we studied and visualized the changes in morphology and elastic properties of the FA-PLGA nanoparticles within 15 weeks using atomic force microscopy. When FA-PLGA nanoparticles were applied on an in vitro model of the intestinal mucosa (Caco-2 cell culture), only minor amounts of their fluorescent degradation products (approximately 0.02% after 6 h) were transported. In a cytotoxicity study with Caco-2 cells, FA-PLGA nanoparticles yielded an IC50 value as for plain PLGA nanoparticles. In conclusion, the polymer modification method allows to prepare fluorescently labelled nanoparticles from a well-known biodegradable pharmaceutical polymer with sufficient stability to be monitored over a period of several days. Some initial leakage of fluorescence label appears to be unavoidable but negligible with respect to potential absorption and cytotoxicity when applied in vivo.