Influence of lactide vs glycolide composition of poly (lactic-co-glycolic acid) polymers on encapsulation of hydrophobic molecules: molecular dynamics and formulation studies.

The work demonstrates the preparation of PLGA (PLGA 50:50, PLGA 75:25) nanoparticles, to encapsulate a hydrophobic molecule (coumarin-6), using the microreactor-based continuous process. The formulations were characterized using dynamic light scattering and transmission electron microscopy to determine their size, homogeneity, zeta potential, and surface morphology. The resulting nanoparticles were safe to the CHO cells (≈80% cell survival), at the concentration of ≤600 µg/mL and were successfully taken up by the cells, as demonstrated using confocal microscopy. Moreover, imaging flow cytometry confirmed that the nanoparticles were internalized in 73.96% of the cells. Furthermore, molecular dynamics simulation and docking studies were carried out to explore the effect of polymer chain length of PLGA and lactide vs glycolide (LA:GA) ratio on their compatibility with the coumarin-6 molecules and to study the coiling and flexibility of PLGA in the presence of coumarin-6 molecules. Flory-Huggins interaction parameter (χ) was calculated for polymer chains of varying lengths and LA:GA ratio, with respect to coumarin-6. χ parameter increased with increase in polymer chain length, which indicated superior interaction of coumarin-6 with the smaller chains. Amongst all the polymeric systems, PLGA55 exhibited the strongest interaction with coumarin-6, for all the chain lengths, possibly because of their homogeneous spatial arrangements and superior binding energy. PLGA27 showed better compatibility compared to PLGA72 and PGA, whereas PLA-based polymers exhibited the least compatibility. Analysis of the radius of gyration of the polymer chains in the polymer-coumarin-6 complexes, at the end of molecular dynamics run, exhibited that the polymer chains displayed varying coiling behavior and flexibility, depending upon the relative concentrations of the polymer and coumarin-6. Factors like intra-chain interactions, spatial arrangement, inter-chain binding energies, and polymer-coumarin-6 compatibility also influenced the coiling and flexibility of polymer chains.

Preparation of Biodegradable PLGA-Nanoparticles Used for pH-Sensitive Intracellular Delivery of an Anti-inflammatory Bacterial Toxin to Macrophages.

Poly(D,L-lactide-co-glycolic) acid (PLGA) is a synthetic copolymer that has been used to design micro/nanoparticles as a carrier for macromolecules, such as protein and nucleic acids, that can be internalized by the endocytosis pathway. However, it is difficult to control the intracellular delivery to target organelles. Here we report an intracellular delivery system of nanoparticles modified with bacterial cytotoxins to the endoplasmic reticulum (ER) and anti-inflammatory activity of the nanoparticles. Subtilase cytotoxin (SubAB) is a bacterial toxin in certain enterohemorrhagic Escherichia coli (EHEC) strains that cleaves the host ER chaperone BiP and suppresses nuclear factor-kappaB (NF-κB) activation and nitric oxide (NO) generation in macrophages at sub-lethal concentration. PLGA-nanoparticles were modified with oligo histidine-tagged (6 × His-tagged) recombinant SubAB (SubAB-PLGA) through a pH-sensitive linkage, and their translocation to the ER in macrophage cell line J774.1 cells, effects on inducible NO synthase (iNOS), and levels of tumor necrosis factor (TNF)-α cytokine induced by lipopolysaccharide (LPS) were examined. Compared with free SubAB, SubAB-PLGA was significantly effective in BiP cleavage and the induction of the ER stress marker C/EBP homologous protein (CHOP) in J774.1 cells. Furthermore, SubAB-PLGA attenuated LPS-stimulated induction of iNOS and TNF-α. Our findings provide useful information for protein delivery to macrophages and may encourage therapeutic applications of nanoparticles to the treatment of inflammatory diseases.

Slicing parameter optimization for 3D printing of biodegradable drug-eluting tracheal stents.

In 3D printing, the schematic representation of an object must be converted into machine commands. This process is called slicing. Depending on the slicing parameters, products with different properties are obtained. In this work, biodegradable drug-eluting tracheal stents consisting of a medical grade poly(lactic-co-glycolic acid) and a drug were printed by fused deposition modeling. A slicing parameter optimization method was proposed with the aim of obtaining a particularly low stent porosity and high mechanical strength while maintaining the stent dimensions, which is essential regarding patient-tailored implants. Depending on the three slicing parameters printing pattern, lateral strand distance and spatial fill, porosities of approximately 2-5% were obtained. The tensile strength was used as a measure for the mechanical strength of the implants and was found to be dependent on the porosity as well as the strand orientation relative to the load direction. Strand orientations in load direction yielded the highest tensile strengths of 40-46 MPa and the bonding between individual layers yielded the lowest tensile strengths of 20-24 MPa. In vitro dissolution tests of successfully printed stents were used to predict sustained release of the drug over several months.

Synthesis of Poly(acyclic orthoester)s: Acid-Sensitive Biomaterials for Enhancing Immune Responses of Protein Vaccine.

While poly(acyclic orthoester)s (PAOEs) have many appealing features for drug delivery, their application is significantly hindered by a lack of facile synthetic methods. Reported here is a simple method for synthesizing acyclic diketene acetal monomers from diols and vinyl ether, and their polymerization with a diol to first synthesize PAOEs. The PAOEs rapidly hydrolyze at lysosomal pH. With the help of a cationic lipid, ovalbumin, a model vaccine antigen was efficiently loaded into PAOEs nanoparticles using a double emulsion method. These nanoparticles efficiently delivered ovalbumin into the cytosol of dendritic cells and demonstrated enhanced antigen presentation over poly(lactic-co-glycolic acid) (PLGA) nanoparticles. PAOEs are promising vehicles for intracellular delivery of biopharmaceuticals and could increase the utility of poly(orthoesters) in biomedical research.

Mesenchymal Stem Cell Capping on ECM-Anchored Caspase Inhibitor-Loaded PLGA Microspheres for Intraperitoneal Injection in DSS-Induced Murine Colitis.

Mesenchymal stem cells (MSCs) are considered as a promising alternative for the treatment of various inflammatory disorders. However, poor viability and engraftment of MSCs after transplantation are major hurdles in mesenchymal stem cell therapy. Extracellular matrix (ECM)-coated scaffolds provide better cell attachment and mechanical support for MSCs after transplantation. A single-step method for ECM functionalization on poly(lactic-co-glycolic acid) (PLGA) microspheres using a novel compound, dopamine-conjugated poly(ethylene-alt-maleic acid), as a stabilizer during the preparation of microspheres is reported. The dopamine molecules on the surface of microspheres provide active sites for the conjugation of ECM in an aqueous solution. The results reveal that the viability of MSCs improves when they are coated over the ECM-functionalized PLGA microspheres (eMs). In addition, the incorporation of a broad-spectrum caspase inhibitor (IDN6556) into the eMs synergistically increases the viability of MSCs under in vitro conditions. Intraperitoneal injection of the MSC-microsphere hybrid alleviates experimental colitis in a murine model via inhibiting Th1 and Th17 differentiation of CD4+ T cells in colon-draining mesenteric lymph nodes. Therefore, drug-loaded ECM-coated surfaces may be considered as attractive tools for improving viability, proliferation, and functionality of MSCs following transplantation.

Fabrication of rosuvastatin-loaded polymeric nanocapsules: a promising modality for treating hepatic cancer delineated by apoptotic and cell cycle arrest assessment.

Nanotechnology has provided several advantages for the treatment of cancer. Polymeric nanocapsules (PNCs) were proven promising in the treatment of different cancer types, such as hepatic cancer. Meanwhile, the exploration of novel indications of old molecules with the purpose of cancer treatment has been widely reported. Among the promising therapeutic moieties, rosuvastatin (RV) was delineated as a potential anticancer drug. Hence, the target of the presented manuscript was to develop PNCs loaded with RV to overcome its delivery challenges and augment its anticancer activity. RV PNCs were fabricated by the nanoprecipitation method using poly-lactide-co-glycolide (PLGA) polymer, and were characterized for the size, polydispersity index (PDI), charge, entrapment efficiency EE%, in vitro release, stability, and morphology. Furthermore, their anticancer activity was tested on HepG2 cells using MTT assay, followed by elucidating the cytotoxic activity using flow cytometry. Results showed that RV PNCs displayed particle size ranging from 186 to 239 nm, average PDI, and negative zeta potential with sufficient stability for 3 months. PNCs were able to load RV at high EE% reaching 82.6% and sustain its release for eight hours. RV PNCs were superior in their anticancer activity on HepG2 cells, as delineated from the viability study and further elucidated by enhanced apoptosis in addition to cell cycle arrest at G2/M phase, suggesting their promise in treatment of hepatic cancer.

Preparation and in vivo pharmacokinetics of rhGH-loaded PLGA microspheres.

Recombinant human growth hormone (rhGH) therapy must be administered as a daily injection due to its short half-life. To achieve sustained release of rhGH, the preparation of rhGH-loaded PLGA microspheres was investigated, and the influence of various factors on encapsulation efficiency was tested, including rhGH concentration, the ratio of internal phase to organic phase, stirring speed, PVA concentration, surrounding pH value, and the type of emulsifier and organic solvent. A pharmacokinetic study was performed by subcutaneous administration to explore the sustained release effect. It was found that rhGH-loaded PLGA microspheres were prepared with a narrow size distribution, and optimization of the formulation could enhance encapsulation efficiency. FTIR analysis indicated that the activity of rhGH was maintained after encapsulation. The pharmacokinetic behavior of rhGH solutions was consistent with a two-compartment model, which showed fast absorption and distribution. RhGH-loaded PLGA microspheres achieved a higher bioavailability and a long-term effective concentration by controlling the release, and PLGA 50/50 demonstrated favorable AUC compared with PLGA 75/25. Nevertheless, the higher bioavailability of rhGH-loaded PLGA microspheres lacking Span 80 did not predicate better sustained release behavior, indicating that further investigation is needed to explore the use of bioavailability as the standard in evaluating the sustained release characteristics and in vivo behavior of microspheres.

Formation Mechanism, In vitro and In vivo Evaluation of Dimpled Exenatide Loaded PLGA Microparticles Prepared by Ultra-Fine Particle Processing System.

Spherical poly (D, L-lactic-co-glycolic acid) microparticles (PLGA-MPs) have long been investigated in order to achieve sustained delivery of proteins/peptides. However, the formation mechanism and release characteristics of the specific shape MPs were still unknown. This study aimed to develop a novel-dimpled exenatide-loaded PLGA-MPs (Exe-PLGA-MPs) using an ultra-fine particle processing system (UPPS) and investigate the formation mechanism and release characteristics. Exe-PLGA-MPs were prepared by UPPS and optimized based on their initial burst within the first 24 h and drug release profiles. Physicochemical properties of Exe-PLGA-MPs, including morphology, particle size, and structural integrity of Exe extracted from Exe-PLGA-MPs, were evaluated. Furthermore, pharmacokinetic studies of the optimal formulation were conducted in Sprague-Dawley (SD) rats to establish in vitro-in vivo correlations (IVIVC) of drug release. Exe-PLGA-MPs with dimpled shapes and uniform particle sizes achieved a high encapsulation efficiency (EE%, 91.50 ± 2.65%) and sustained drug release for 2 months in vitro with reduced initial burst (20.42 ± 1.64%). Moreover, the pharmacokinetic studies revealed that effective drug concentration could be maintained for 3 weeks following a single injection of dimpled Exe-PLGA-MPs with high IVIVC. Dimpled PLGA-MPs prepared using the UPPS technique could thus have great potential for sustained delivery of macromolecular proteins/peptides.

Preparation and Evaluation of Irinotecan Poly(Lactic-co-Glycolic Acid) Nanoparticles for Enhanced Anti-tumor Therapy.

Irinotecan (IRT), the pro-drug of SN-38, has exhibited potent cytotoxicity against various tumors. In order to enhance the anti-tumor effect of IRT, we prepared IRT-loaded PLGA nanoparticles (IRT-PLGA-NPs) by emulsion-solvent evaporation method. Firstly, IRT-PLGA-NPs were characterized through drug loading (DL), entrapment efficiency (EE), particle size, zeta potential, transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). We next studied the in vitro release characteristics of IRT-PLGA-NPs. Finally, the pharmacokinetics and pharmacodynamics profiles of IRT-PLGA-NPs were investigated. The results revealed that IRT-PLGA-NPs were spherical with an average size of (169.97 ± 6.29) nm and its EE and DL were (52.22 ± 2.41)% and (4.75 ± 0.22)%, respectively. IRT-PLGA-NPs could continuously release drug for 14 days in vitro. In pharmacokinetics studies, for pro-drug IRT, the t1/2ß of IRT-PLGA-NPs was extended from 0.483 to 3.327 h compared with irinotecan solution (IRT-Sol), and for its active metabolite SN-38, the t1/2ß was extended from 1.889 to 4.811 h, which indicated that IRT-PLGA-NPs could prolong the retention times of both IRT and SN-38. The pharmacodynamics results revealed that the tumor doubling time, growth inhibition rate, and specific growth rate of IRT-PLGA-NPs were 2.13-, 1.30-, and 0.47-fold those of IRT-Sol, respectively, which demonstrated that IRT-PLGA-NPs could significantly inhibit the growth of tumor. In summary, IRT-PLGA-NPs, which exhibited excellent therapeutic effect against tumors, might be used as a potential carrier for tumor treatment in clinic.

Surface Layer Modification of Poly(d,l-lactic- co-glycolic acid) Nanoparticles with Targeting Peptide: A Convenient Synthetic Route for Pluronic F127-Tuftsin Conjugate.

Nanoparticles consisting of biodegradable poly(d,l-lactic- co-glycolic acid) (PLGA) are promising carriers for drug molecules to improve the treatment of tuberculosis. Surface modifiers, such as Pluronic F127, are essential for biocompatibility and for the protection against particle aggregation. This study demonstrates a successful approach to conjugate Pluronic F127 coated PLGA nanoparticles with Tuftsin, which has been reported as a macrophage-targeting peptide. Transformation of Pluronic F127 hydroxyl groups-which have limited reactivity-into aldehyde groups provide a convenient way to bind aminooxy-peptide derivatives in a one-step reaction. We have also investigated that this change has no effect on the physicochemical properties of the nanoparticles. Our data showed that coating nanoparticles with Pluronic-Tuftsin conjugate markedly increased the internalization rate and the intracellular activity of the encapsulated drug candidate against Mycobacterium tuberculosis. By employing this approach, a large variety of peptide targeted PLGA nanoparticles can be designed for drug delivery.

Lipoyl Ester Terminated Star PLGA as a Simple and Smart Material for Controlled Drug Delivery Application.

PLGA, a copolymer of lactide and glycolide, is one of the most used biodegradable polymers that find a wide range of biomedical applications including drug delivery and tissue engineering. However, in spite of remarkable advancement, nanotherapeutics based on PLGA might have drawbacks of inadequate stability, drug leakage, and slow drug release at the tumor site, which reduces its targeting ability and therapeutic efficacy. Here, we report that direct modification of star PLGA ends with lipoic acid, a natural antioxidant present in our human body, affords a smart material (sPLGA-LA) that forms reversibly crosslinked and bioresponsive multifunctional nanoparticles (sPLGA XNPs). Interestingly, sPLGA XNPs obtained in the presence of 23.0 wt % PEG-PDLLA displayed a small hydrodynamic size of 73 ± 1.2 nm, high stability against dilution and 10% serum, while fast destabilization under a reductive environment. Moreover, sPLGA XNPs achieved efficient loading of lipophilic anticancer drug model, doxorubicin (DOX), at a theoretical drug loading content of 13.3 wt %, giving DOX-loaded sPLGA XNPs with reduced drug leakage under physiological conditions as well as significantly accelerated drug release under 10 mM glutathione condition compared with both linear and star PLGA controls (denoted as lPLGA NPs and sPLGA NPs, respectively). Confocal microscopy and flow cytometry displayed obviously stronger DOX fluorescence in B16F10 melanoma cells treated with DOX-loaded sPLGA XNPs than with lPLGA and sPLGA counterparts. MTT assays revealed that DOX-sPLGA XNPs caused 2.4- and 4.2-fold higher antitumor activity toward B16F10 cells than DOX-sPLGA NPs and DOX-lPLGA NPs, respectively. Notably, in vivo pharmacokinetics studies showed prolonged circulation time and significantly improved AUC for DOX-sPLGA XNPs over lPLGA NPs control. Hence, lipoyl ester terminated star PLGA emerges as a simple and smart material for better-controlled anticancer drug delivery.

Preparation and characterization of bee venom-loaded PLGA particles for sustained release.

Bee venom-loaded poly(lactic-co-glycolic acid) (PLGA) particles were prepared by double emulsion-solvent evaporation, and characterized for a sustained-release system. Factors such as the type of organic solvent, the amount of bee venom and PLGA, the type of PLGA, the type of polyvinyl alcohol, and the emulsification method were considered. Physicochemical properties, including the encapsulation efficiency, drug loading, particle size, zeta-potential and surface morphology were examined by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The size of the bee venom-loaded PLGA particles was 500 nm (measured using sonication). Zeta-potentials of the bee venom-loaded PLGA particles were negative owing to the PLGA. FT-IR results demonstrated that the bee venom was completely encapsulated in the PLGA particles, indicated by the disappearance of the amine and amide peaks. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that the bee venom in the bee venom-loaded PLGA particles was intact. In vitro release of the bee venom from the bee venom-loaded PLGA particles showed a sustained-release profile over 1 month. Bee venom-loaded PLGA particles can help improve patients' quality of life by reducing the number of injections required.

Development and Characterization of PLGA-Based Multistage Delivery System for Enhanced Payload Delivery to Targeted Vascular Endothelium.

Vascular-targeted drug delivery remains an attractive platform for therapeutic and diagnostic interventions in human diseases. This work focuses on the development of a poly-lactic-co-glycolic-acid (PLGA)-based multistage delivery system (MDS). MDS consists of two stages: a micron-sized PLGA outer shell and encapsulated drug-loaded PLGA nanoparticles. Nanoparticles with average diameters of 76, 119, and 193 nm are successfully encapsulated into 3-6 µm MDS. Sustained in vitro release of nanoparticles from MDS is observed for up to 7 days. Both MDS and nanoparticles arebiocompatible with human endothelial cells. Sialyl-Lewis-A (sLeA ) is successfully immobilized on the MDS and nanoparticle surfaces to enable specific targeting of inflamed endothelium. Functionalized MDS demonstrates a 2.7-fold improvement in endothelial binding compared to PLGA nanoparticles from human blood laminar flow. Overall, the presented results demonstrate successful development and characterization of MDS and suggest that MDS can serve as an effective drug carrier, which can enhance the margination of nanoparticles to the targeted vascular wall.

The composite microbeads of alginate, carrageenan, gelatin, and poly(lactic-co-glycolic acid): Synthesis, characterization and Density Functional Theory calculations.

Binary (AC, AG), ternary (ACG, ACP, AGP), quaternary (ACGP) composite beads of alginate (A), carrageenan (C), gelatin (G), and poly (lactic-co-glycolic acid) (P) were prepared. The dried beads had a 700 µm average diameter. The microspheres with and without P were characterized by FT-IR, TGA/DTA, SEM, and PZC analysis. The results proved that the features of the composites were completely different from their bare components. Density Functional Theory (DFT) calculations were performed at the B3LYP/6-311++G** level to enlighten the elementary physical and chemical properties of A, C, P, and G compounds. The vibrational modes obtained by calculations were compared with those observed in the FT-IR spectra. The Frontier Molecular Orbital (FMO) analyses showed that the component G was the softer and had smaller energy gap than the other components and vice versa for component P. NBO (Natural Bond Orbital) analyses implied that the n → П* (resonance) interactions for components A, G, and P contributed to the lowering of the molecular stabilization, whereas that the n → σ* (anomeric) interactions were responsible for decreasing of the stabilization of the component. From the obtained results, these kinds of components can be hoped the promising materials for usage in the many scientific fields, especially in medicine and in drug design.

Tumor-Penetrable Nitric Oxide-Releasing Nanoparticles Potentiate Local Antimelanoma Therapy.

Although nitric oxide (NO) has been emerging as a novel local anticancer agent because of its potent cytotoxic effects and lack of off-target side effects, its clinical applications remain a challenge because of the short effective diffusion distance of NO that limits its anticancer activity. In this study, we synthesized albumin-coated poly(lactic-co-glycolic acid) (PLGA)-conjugated linear polyethylenimine diazeniumdiolate (LP/NO) nanoparticles (Alb-PLP/NO NPs) that possess tumor-penetrating and NO-releasing properties for an effective local treatment of melanoma. Sufficient NO-loading and prolonged NO-releasing characteristics of Alb-PLP/NO NPs were acquired through PLGA-conjugated LP/NO copolymer (PLP/NO) synthesis, followed by nanoparticle fabrication. In addition, tumor penetration ability was rendered by the electrostatic adsorption of the albumin on the surface of the nanoparticles. The Alb-PLP/NO NPs showed enhanced intracellular NO delivery efficiency and cytotoxicity to B16F10 murine melanoma cells. In B16F10-tumor-bearing mice, the Alb-PLP/NO NPs showed improved extracellular matrix penetration and spatial distribution in the tumor tissue after intratumoral injection, resulting in enhanced antitumor activity. Taken together, the results suggest that Alb-PLP/NO NPs represent a promising new modality for the local treatment of melanoma.

Micelle nanovehicles for co-delivery of Lepidium meyenii Walp. (maca) polysaccharide and chloroquine to tumor-associated macrophages for synergistic cancer immunotherapy.

Here, we fabricated amphiphilic polysaccharide micelles for synergistic cancer immunotherapy targeting tumor-associated macrophages (TAMs). Lepidium meyenii Walp. (maca) polysaccharide (MP), a naturally derived macromolecule with a strong TAM-remodeling effect, was grafted on a hydrophobic poly(lactic-co-glycolic acid) (PLGA) segment, with a disulfide bond for redox-sensitive linkage. The amphiphilic polysaccharide derivatives could self-assemble into core (PLGA)-shell (MP)-structured micelles and encapsulate chloroquine (CQ) into the hydrophobic core. By using a 4T1-M2 macrophage co-culture model and a 4T1 tumor xenograft mouse model, we showed that the prepared micelles could co-deliver MP and CQ to the tumor sites and selectively accumulate at TAMs because of the specific properties of MP. Furthermore, the nanoparticles exerted synergistic tumor immunotherapeutic and antimetastatic effects, which might be attributable to the enhanced cell internalization of the micelles and the multiple regulatory mechanisms of MP and CQ. Thus, immunomodulatory MP may be a promising biomaterial for cancer immunotherapy.

N-trimethyl chitosan coated nano-complexes enhance the oral bioavailability and chemotherapeutic effects of gemcitabine.

N-trimethyl chitosan (TMC) is a multifunctional polymer that can be used in various nanoparticle forms in the pharmaceutical, nutraceutical and biomedical fields. In this study, TMC was used as a mucoadhesive adjuvant to enhance the oral bioavailability and hence antitumour effects of gemcitabine formulated into nanocomplexes composed of poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) conjugated with d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS). A central composite design was applied to achieve the optimal formulation. Cellular uptake and drug transportation studies revealed the nanocomplexes permeate over the intestinal cells via adsorptive-mediated and caveolae-mediated endocytosis. Pharmacokinetic studies demonstrated the oral drug bioavailability of the nanocomplexes was increased 5.1-fold compared with drug solution. In pharmacodynamic studies, the formulation reduced tumour size 3.1-fold compared with the drug solution. The data demonstrates that TMC modified nanocomplexes can enhance gemcitabine oral bioavailability and promote the anticancer efficacy.

Engineering large porous microparticles with tailored porosity and sustained drug release behavior for inhalation.

Sustained drug delivery is considered as an effective strategy to improve the treatment of local lung diseases. In this context, inhalation administration of large porous microparticles (LPPs) represents promising prospects. However, one major challenge with said delivery technology is to control the drug release pattern (especially to decrease the burst release) while maintaining a low mass density/high porosity, which is of high significance for the aerodynamic behavior of LPP systems. Here, we show how to engineer drug-loaded, biodegradable LPPs with varying microstructure by means of a premix membrane emulsification-solvent evaporation (PME-SE) method using poly(vinyl pyrrolidone) (PVP) as the pore former. The influence of PVP concentration on the physicochemical properties, in-vitro drug release behavior and in-vitro aerodynamic performance of the drug-loaded microparticles was tested. We demonstrated that the PME-SE technique led to LPPs with favorable pore distribution characteristics (i.e., low external but high internal porosity) as a function of the PVP concentration. In general, more PVP conditioned a larger discrepancy of the internal vs. external porosity. When the external porosity of the LPP formulation (15% of PVP during the manufacturing process) was less than 3%, the burst release of the embedded drug was significantly reduced compared to LPPs prepared by a "conventional" emulsification solvent evaporation method. All the formulations prepared by the PME-SE method had aerodynamic properties suitable for inhalation. This is the first report indicating that the microstructure of LPPs can be tailored using the PME-SE technology with PVP as a suitable pore former. Doing so, we designed LPP formulations having full control over the drug release kinetics and aerodynamic behavior.

Self-organized thermo-responsive poly (lactic-co-glycolic acid)-graft-pullulan nanoparticles for synergistic thermo-chemotherapy of tumor.

Poly (lactic-co-glycolic acid)-graft-pullulan (PPLGA) based self-organized nanoparticles hold immense potential for synergistic thermo-chemotherapy of tumor. Herein, the biocompatible and biodegradable PPLGA were synthesized by a novel microwave-assisted solution polymerization. The polymers showed thermo-responsive properties, which was attributed to the change of polymer-water hydrogen bonding in controlling the macromolecular contraction, chain collapse as a result of changes in micro-rigidity of core. The curcumin loaded PPLGA nanoparticles (CUR-PPLGA-N), with impressively high drug loading (10.85 ± 0.27 %), exhibited temperature dependence in drug release kinetics. The results of both MTT and antitumor efficiency elucidated that the CUR-PPLGA-N under high temperature facilitated on-demand drug release from the nano-assembly and had a synergistic therapeutic effect for cancer. Thus the developed thermo-responsive PPLGA addressed concerns related to the low drug loading and inefficient drug release at target sites, and might be considered as a powerful nanoplatform for synergistic thermo-chemotherapy of tumor.

Functionalized PLGA nanoparticles prepared by nano-emulsion templating interact selectively with proteins involved in the transport through the blood-brain barrier.

During the last few decades, extensive efforts has been made to design nanocarriers to transport drugs into the central nervous system (CNS). However, its efficacy is limited due to the presence of the Blood-Brain Barrier (BBB) which greatly reduces drug penetration making Drug Delivery Systems (DDS) necessary. Polymeric nanoparticles (NPs) have been reported to be appropriate for this purpose and in particular, poly(lactic-co-glycolic acid) (PLGA) has been used for its ability to entrap small molecule drugs with great efficiency and the ease with which it functionalizes NPs. Despite the fact that their synthetic identity has been studied in depth, the biological identity of such manufactured polymers still remains unknown as does their biodistribution and in vivo fate. This biological identity is a result of their interaction with blood proteins, the so-called "protein corona" which tends to alter the behavior of polymeric nanoparticles in the body. The aim of the present research is to identify the proteins bounded to polymeric nanoparticles designed to selectively interact with the BBB. For this purpose, four different PLGA NPs were prepared and analyzed: (i) "PLGA@Drug," in which a model drug was encapsulated in its core; (ii) "8D3-PLGA" NPs where the PLGA surface was functionalized with a monoclonal anti-transferrin receptor antibody (8D3 mAb) in order to specifically target the BBB; (iii) "8D3-PLGA@Drug" in which the PLGA@Drug surface was functionalized using the same antibody described above and (iv) bare PLGA NPs which were used as a control. Once the anticipated protein corona NPs were obtained, proteins decorating both bare and functionalized PLGA NPs were isolated and analyzed. Apart from the indistinct interaction with PLGA NPs with the most abundant serum proteins, specific proteins could also be identified in the case of functionalized PLGA NPs. These findings may provide valuable insight into designing novel vehicles based on PLGA NPs for crossing the BBB.