Biodegradable poly(D,L-lactide-co-glycolide)/poly(L-γ-glutamic acid) nanoparticles conjugated to folic acid for targeted delivery of doxorubicin.

A novel targeted drug delivery nanoparticle system based on poly(D,L-lactide-co-glycolide) acid (PLGA) for delivery of doxorubicin (DOX) was developed. DOX-PLGA NPs were obtained by the emulsification-solvent evaporation technique. Then, their surface was modified with poly(L-γ-glutamic acid) (γ-PGA) and finally conjugated to modified folic acid (FA) as a targeting ligand. The surface modification and FA conjugation were followed by UV-Vis and FT-IR spectroscopies. Morphology was observed by TEM/SEM. Particle size, PDI and zeta potential were measured using DLS studies. Encapsulation and loading efficiencies, and DOX release kinetics were determined. Specific uptake and cell viability of DOX-PLGA/γ-PGA-FA NPs were tested in HeLa cells. Quasi-spherical nanoparticles with a particle size lower than 600nm (DLS) were obtained. Spectroscopic techniques demonstrated the successful surface modification with γ-PGA and FA conjugation. Release profile of DOX-PLGA/γ-PGA-FA NPs showed a release of 55.4±0.6% after seven days, in an acidic environment. HeLa cells exhibited a decrease in viability when treated with DOX-PLGA/γ-PGA-AF NPs, and cellular uptake was attributed to FA receptor-mediated endocytosis. These results suggest that DOX-PLGA/γ-PGA-FA NPs are a potential targeted drug carrier for further applications in cancer therapy.

Multimeric System of RGD-Grafted PMMA-Nanoparticles as a Targeted Drug- Delivery System for Paclitaxel.

BACKGROUND: Polymer-based nanoparticles as drug-delivery systems offer new therapeutic opportunities. Among them, ligand-mediated targeting, which increases selectivity and efficacy, allows controllable drug delivery. The aim of the this research was to prepare and characterize poly(methyl methacrylate) (PMMA) nanoparticles grafted with the -Arginine, Glycine, Aspartic Acid (RGD)- peptide sequence as a promising smart drug delivery system for Paclitaxel (PTX), directed at the sites of integrin receptor overexpression. METHODS: Nanoparticles were characterized by FT-IR and Raman spectroscopy, dynamic light scattering, zeta potential and transmission electron microscopy. RESULTS: RGD-PMMA-PTX size distribution was 17.58 ± 7.45 nm with a zeta potential of -38.73 ± 5.62 mV. According to the boxLucas Model, PTX was incorporated into nanoparticles with an entrapment efficiency of 100% (evaluated by HPLC analysis). In vitro sustained release was determined, with the maximum release of 55% and 40% after 21 days at pH 5.3 and 7.4, respectively. The highest inhibition on cell proliferation was found with RGD-PMMA-PTX nanoparticles (90 %). CONCLUSION: The obtained results showed that RGD-PMMA-PTX represents an attractive and suitable therapeutic approach for targeting overexpressed integrins in the cancer cells.

Polymer-Based Drug Delivery Systems, Development and Pre-Clinical Status.

BACKGROUND: The nanomedicine is considered as the application of nanotechnology in the medical field where nanoparticles are sized in the nanoscale range. Drug delivery technologies are becoming increasingly important as a scientific area of investigation. Controlled-release systems and drug-targeting systems represents an alternative to traditional delivery nanoparticles, and the use of polymers is increasing nowadays. Although polymers could be classified as excipients, they are capable of modifying the biopharmaceutical and biokinetic behaviour of the transported active molecule increasing its efficacy and stability, and reduced cytotoxicity on healthy peripheral tissues. METHODS: The goal of this work is to collect and analyse the most current polymeric nanoparticles development as controlledrelease and drug-targeting systems in cancer, infectious diseases and immunomodulation areas, as alternatives to conventional therapies. RESULTS: This review provides an update on the polymeric nanoparticles development analysing the trend of polymeric-based drug delivery systems, future opportunities and challenges of this fast-growing area. CONCLUSION: With the thorough comprehension of biological effects depending on structure, it is possible to design specific systems for specific diseases, treatments and patients. The ability of polymer- based nanoparticles to modify and improve pharmacokinetics and pharmacodynamics, associated to techniques for enhancement of the therapeutic efficiency with minimal side effects, demonstrate the advantages of these systems.