Isoniazid loaded core shell nanoparticles derived from PLGA–PEG–PLGA tri-block copolymers: In vitro and in vivo drug release

Tumour-specific hybrid nanoparticles in therapy of breast cancer

In this study, salicylic acid (SA) dopped into poly(3-hydroxybutyrate) (PHB) and prepared nanoparticles (NPs) to increase encapsulation efficiency, anti-cancer activity of caffeic acid (Caff), and folic acid (FA) for breast cancer treatment. NPs were prepared by solvent evaporation method and characterised by FTIR, DSC, SEM, and entrapment-loading efficiencies. The mean diameter, polydispersity index (PDI), and zeta potential (ZP) were evaluated by dynamic light scattering (DLS). In vitro release and stability studies were done via eppendorf method. The cytotoxicity, cell dead and internalisation of NPs were shown by MTT, fluorescein and confocal microscopy. The diameter and ZP of NPs were 172 ± 7 nm and -29 ± 0.38 mV. The entrapment efficiencies of 5 and 10 Caff NPs were 79 ± 0.23% and 70 ± 0.42%. NPs showed good stability within 30 d and sustained release over 25 d. FA-5Caff NPs showed 37 ± 0.3% viability on MCF-7. FA-Caff NPs were identified as promising carrier system for breast cancer therapy.

Micro-nanoemulsion and nanoparticle-assisted drug delivery against drug-resistant tuberculosis: recent developments

Tuberculosis (TB) is a major global health problem and the second most prevalent infectious killer after COVID-19. It is caused by Mycobacterium tuberculosis (Mtb) and has become increasingly challenging to treat due to drug resistance. The World Health Organization declared TB a global health emergency in 1993. Drug resistance in TB is driven by mutations in the bacterial genome that can be influenced by prolonged drug exposure and poor patient adherence. The development of drug-resistant forms of TB, such as multidrug resistant, extensively drug resistant, and totally drug resistant, poses significant therapeutic challenges. Researchers are exploring new drugs and novel drug delivery systems, such as nanotechnology-based therapies, to combat drug resistance. Nanodrug delivery offers targeted and precise drug delivery, improves treatment efficacy, and reduces adverse effects. Along with nanoscale drug delivery, a new generation of antibiotics with potent therapeutic efficacy, drug repurposing, and new treatment regimens (combinations) that can tackle the problem of drug resistance in a shorter duration could be promising therapies in clinical settings. However, the clinical translation of nanomedicines faces challenges such as safety, large-scale production, regulatory frameworks, and intellectual property issues. In this review, we present the current status, most recent findings, challenges, and limiting barriers to the use of emulsions and nanoparticles against drug-resistant TB.

Nanocarriers in Tuberculosis Treatment: Challenges and Delivery Strategies

The World Health Organization identifies tuberculosis (TB), caused by Mycobacterium tuberculosis, as a leading infectious killer. Although conventional treatments for TB exist, they come with challenges such as a heavy pill regimen, prolonged treatment duration, and a strict schedule, leading to multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. The rise of MDR strains endangers future TB control. Despite these concerns, the hunt for an efficient treatment continues. One breakthrough has been the use of nanotechnology in medicines, presenting a novel approach for TB treatment. Nanocarriers, such as lipid nanoparticles, nanosuspensions, liposomes, and polymeric micelles, facilitate targeted delivery of anti-TB drugs. The benefits of nanocarriers include reduced drug doses, fewer side effects, improved drug solubility, better bioavailability, and improved patient compliance, speeding up recovery. Additionally, nanocarriers can be made even more targeted by linking them with ligands such as mannose or hyaluronic acid. This review explores these innovative TB treatments, including studies on nanocarriers containing anti-TB drugs and related patents.

Nanosized Drug Delivery Systems to Fight Tuberculosis

Tuberculosis (TB) is currently the second deadliest infectious disease. Existing antitubercular therapies are long, complex, and have severe side effects that result in low patient compliance. In this context, nanosized drug delivery systems (DDSs) have the potential to optimize the treatment's efficiency while reducing its toxicity. Hundreds of publications illustrate the growing interest in this field. In this review, the main challenges related to the use of drug nanocarriers to fight TB are overviewed. Relevant publications regarding DDSs for the treatment of TB are classified according to the encapsulated drugs, from first-line to second-line drugs. The physicochemical and biological properties of the investigated formulations are listed. DDSs could simultaneously (i) optimize the therapy's antibacterial effects; (ii) reduce the doses; (iii) reduce the posology; (iv) diminish the toxicity; and as a global result, (v) mitigate the emergence of resistant strains. Moreover, we highlight that host-directed therapy using nanoparticles (NPs) is a recent promising trend. Although the research on nanosized DDSs for TB treatment is expanding, clinical applications have yet to be developed. Most studies are only dedicated to the development of new formulations, without the in vivo proof of concept. In the near future, it is expected that NPs prepared by "green" scalable methods, with intrinsic antibacterial properties and capable of co-encapsulating synergistic drugs, may find applications to fight TB.

Effective uptake of folate-functionalized ethionamide-loaded hybrid system: targeting alveolar macrophages

Aim: To assess the targeting ability of hybrid nanosystems functionalized with folate. It also aimed to reduce stomach intolerance by substituting the oral route for parenteral delivery. Method: The nanosystems, prepared by nanoprecipitation technique, utilized a one-step method to prepare nanoparticles followed by surface functionalization through adsorption. The prepared nanosystems underwent physical characterization, in vitro and in vivo evaluations. Result: The nanosystems were effective in targeting the alveolar macrophages. Ethionamide was released from the formulation over 5 days. Fourier-transform infrared results proved the structural characteristics, and the positive charge further improved the targeting efficacy on the functionalized system. Conclusion: The hybrid formulation improved the release characteristics. Reduction in dosing frequency due to prolonged release improves compliance with the dosage regimen.

High-Efficient Vacuum Ultraviolet-Ozone Assist-Deposited Polydopamine for Poly(lactic-co-glycolic acid)-Coated Pure Zn toward Biodegradable Cardiovascular Stent Applications

Zinc is a prospective metal for biodegradable cardiovascular stent applications, but the excessively released Zn²⁺ during degradation remains a huge challenge in biocompatibility. Considerable efforts have been made to develop a high-efficient surface modification method, while maintaining adhesion strength, mechanical support, and vascular compatibility. Biomimetic polydopamine (PDA) can adhere to Zn tightly, subsequently achieving robust chemical bonds with poly(lactic-co-glycolic acid) (PLGA) coating. However, the deposition of PDA on Zn depends on the controlled conditions such as a sensitive pH and a long period of time. Herein, we introduce vacuum ultraviolet-ozone (VUV/O₃) assist-deposition technology to accelerate the polymerization of PDA on pure Zn, which shortens the process to 40 min at a moderate pH of 8.5 and improves the deposition rate by 1-2 orders of magnitude under sufficient active oxygen species (ROS). Additionally, PLGA/PDA coating enhances the corrosion resistance, and their effective protection maintains the mechanical properties after long-term corrosion. Moreover, the controlled Zn²⁺ release contributes to the superior in vitro biocompatibility, which inhibits the hemolysis rate and smooth muscle cell (SMC) proliferation. The enhanced endothelial cell (EC) proliferation is promising to promote the re-endothelialization, avoiding in-stent restenosis and neointimal hyperplasia. Such modified Zn might be a viable candidate for the treatment of cardiovascular diseases.

PLGA Core-Shell Nano/Microparticle Delivery System for Biomedical Application

Core-shell particles are very well known for their unique features. Their distinctive inner core and outer shell structure allowed promising biomedical applications at both nanometer and micrometer scales. The primary role of core-shell particles is to deliver the loaded drugs as they are capable of sequence-controlled release and provide protection of drugs. Among other biomedical polymers, poly (lactic-co-glycolic acid) (PLGA), a food and drug administration (FDA)-approved polymer, has been recognized for the vehicle material. This review introduces PLGA core-shell nano/microparticles and summarizes various drug-delivery systems based on these particles for cancer therapy and tissue regeneration. Tissue regeneration mainly includes bone, cartilage, and periodontal regeneration.

Distinct endocytosis and immune activation of poly(lactic-co-glycolic) acid nanoparticles prepared by single- and double-emulsion evaporation

Background: Poly(lactic-co-glycolic) acid (PLGA) nanoparticles can be prepared by emulsion-solvent-evaporation from o/w and w₁/o/w₂ emulsions. Aims: To elaborate similarities and differences regarding mechanical, morphological and physicochemical properties, as well as endocytosis and dose-dependent immune responses by primary human leukocytes between nanoparticles prepared by these two methods. Methods: Fluorescently labeled as well as TLR agonist (R848)-loaded PLGA nanoparticles were prepared via both single- and double-emulsion solvent evaporation. Results: Particles prepared by both methods were similar in chemical composition and surface charge but exhibited slight differences in size and morphology. Pronounced differences were found for loading, dissolution and mechanical properties. The particles were differently endocytosed by monocytes and induced qualitatively and quantitatively different immune responses. Conclusions: Variations in nanoparticle preparation can affect particle-derived immunological characteristics.

Challenges and Opportunities of Nanotechnological based Approach for the Treatment of Tuberculosis

Mycobacterium tuberculosis, because of its unique biochemical behavior and a complex host relationship, successfully evades the host immune system. Therefore, chemotherapy appears to be the first-line option for patients with tuberculosis. However, poor patient compliance with anti-tubercular treatment and variability in anti-tubercular drug pharmacokinetics are among the major driving factors for the emergence of drug resistance. The rising cases of extrapulmonary TB, cross-resistance patterns, high prevalence of tuberculosis and HIV co-infections make tuberculosis treatment more complicated than conventional multidrug therapy. Due to their distinct advantages like higher solubility, increased payload, controlled release profiles, tissue-specific accumulation, and lack of toxicity, nanoscale materials have immense potential for drug delivery applications. An appropriate selection of polymer and careful particle engineering further improves therapeutic outcomes with opportunities to overcome conventional anti-tubercular drugs' challenges. The present review introduces the prospect of using nanotechnology in tuberculosis (TB) chemotherapy and provides a comprehensive overview of recent advances in nanocarriers implied for delivering anti-tubercular drugs.

Microfluidic-assisted nanoprecipitation of biodegradable nanoparticles composed of PTMC/PCL (co)polymers, tannic acid and doxorubicin for cancer treatment

This study was aimed towards the development of a novel microfluidic approach for the preparation of (co)polymeric and hybrid nanoparticles (NPs) composed of (co)polymers/tannic acid (TA) in the microfluidic flow-focusing glass-capillary device. The MiliQ water was used as water phase, whereas the organic phase was composed of poly(ε-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC) homopolymers and (co)polymers with different proportion of comonomers which were prepared via enzymatic polymerization that allows avoiding the usage of potentially toxic catalyst. To prepare hybrid NPs, TA was additionally added to the organic phase. Subsequently, as a result of mixing between these distinct phases in microfluidic channels, the nanoprecipitation in the form of spherical NPs occurs. The size of NPs was tuned over the range of 140-230 nm by controlling phase flow rates and the composition of NPs. Moreover, the release studies of the encapsulated anticancer drug doxorubicin (DOX) demonstrated that the drug release is greatly influenced by the (co)polymers composition, their molecular weight, NPs size, and the presence of TA. The antitumor activities of the (co)polymeric and hybrid NPs toward breast cancer cells (MCF-7) were tested in vitro. Among all tested formulation, the NPs composed of PCL/TA most efficiently inhibit the cell proliferation of MCF-7 cells, most importantly, their efficiency was higher than free DOX. The proposed strategy may provide an efficient alternative for the construction of nanocarriers with great potential in anticancer therapy.

The preparation of chitosan membrane improved with nanoparticles based on unsaturated fatty acid for using in cancer-related infections

This study includes the design of a chitosan membrane decorated with unsaturated fatty acid–based carrier system for cancer treatment and antibacterial application. For this, polystyrene-graft-polyoleic acid-graft-polyethylene glycol was prepared by free radical polymerization and characterized. Nanoparticles and caffeic acid–loaded nanoparticles were prepared by solvent evaporation technique and optimized. The short-term stability of nanoparticles was investigated at 4°C. Drug encapsulation and loading efficiency were evaluated. The chitosan membrane and caffeic acid–loaded nanoparticles embedded into chitosan membrane were fabricated. The caffeic acid loaded nanoparticles embedded into chitosan membrane showed controlled release. The mechanical properties of all samples were investigated. The caffeic acid–loaded nanoparticles embedded into chitosan membranes indicated excellent antibacterial properties against the Escherichia coli and Staphylococcus aureus. The anticancer activity of all the samples was evaluated against SaOS-2 human primary osteogenic sarcoma and MC3T3-E1 pre-osteoblast cell lines by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay, the flow cytometry and double staining methods. As a result, the designed carrier system showed great potential to cancer-associated infections treatment in bone cancer cases.

Targeted Theranostics for Tuberculosis: A Rifampicin-Loaded Aggregation-Induced Emission Carrier for Granulomas Tracking and Anti-Infection

Tuberculosis (TB) causes a global burden with its high rates of infection and death, especially the irrepressible threats of latent infection and drug resistance. Therefore, it is important to construct efficient theranostics for the prevention and control of TB. Herein, we created a targeted theranostic strategy for TB with a rifampicin-loaded aggregation-induced emission (AIE) carrier and performed testing in laboratory animals. The AIE carrier was constructed to localize in the granulomas and emit fluorescent signals at the early stage of infection, enabling the early diagnosis of TB. Subsequently, reactive oxygen species (ROS) were generated to eradicate infection, and the loaded rifampicin (RIF) was released for the synergistic treatment of persistent bacteria. Furthermore, targeted TB therapy was performed with the light-controlled release of ROS and accurate delivery of RIF, which realizes an anti-infection effect, providing an especially important treatment for drug-resistant TB. Thus, targeted theranostics for TB in laboratory animals possess the potential to become granulomas-tracking and anti-infection strategies for the diagnosis and treatment of TB.

Development and effects of tacrolimus-loaded nanoparticles on the inhibition of corneal allograft rejection

Tacrolimus has been widely applied to prevent organ rejection after transplantation. However, the conventional pharmaceutical formulation of tacrolimus limits its applications in ocular therapy due to its hydrophobicity and low corneal penetrability. We optimized tacrolimus-loaded methoxy poly (ethylene glycol-block-poly (d, l)-lactic-co-glycolic acid) nanoparticles (TAC-NPs) by simple and effective nanotechnology as a drug delivery system for corneal graft rejection to overcome these drawbacks. The prepared TAC-NPs were 82.9 ± 1.3 nm in size, and the drug loading and encapsulation efficiency were 8.01 ± 0.23% and 80.10 ± 2.33%. Furthermore, New Zealand rabbits were used to analyze the single-dose pharmacokinetics of the TAC-NPs using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). In rats with allogenic penetrating keratoplasty, the administration of TAC-NPs dispersion drops improved the TAC concentrations in the aqueous humor and cornea, consistent with a significantly higher effective inhibition of IL-2, IL-17, and VEGF expression compared with conventional 0.1% tacrolimus drops. Meanwhile, we also compared two different topical administration methods (including eye drop and subconjunctival injection) of TAC-NPs to maximize the sustained release characteristic of NPs. In summary, the small-sized TAC-NPs enhanced transcorneal permeation and absorption of TAC and more effectively inhibited corneal allograft rejection, which indicated that biodegradable polymeric nanomaterials-based drug delivery system had great potential for improving the clinical therapy efficacy of hydrophobic drugs.

Nanomedicines as Drug Delivery Carriers of Anti-Tubercular Drugs: From Pathogenesis to Infection Control

In spite of advances in tuberculosis (TB) chemotherapy, TB is still airborne deadly disorder as a major issue of health concern worldwide today. Extensive researches have been focused to develop novel drug delivery systems to shorten the lengthy therapy approaches, prevention of relapses, reducing dose-related toxicities and to rectify technologically related drawbacks of anti-tubercular drugs. Moreover, the rapid emergence of drug resistance, poor patient compliance due to negative therapeutic outcomes and intracellular survival of Mycobacterium highlighted to develop carrier with optimum effectiveness of the anti-tubercular drugs. This could be achieved by targeting and concentrating the drug on the infection reservoir of Mycobacterium. In this article, we briefly compiled the general aspects of Mycobacterium pathogenesis, disease treatment along with progressive updates in novel drug delivery carrier system to enhance therapeutic effects of drug and the high level of patient compliance. Recently developed several vaccines might be shortly available as reported by WHO.

Graphene oxide encapsulated by mesoporous silica for intelligent anticorrosive coating: studies on release models and self-healing ability

The efficient release of benzotriazole from an insulating graphene/mesoporous silica nanoreservoir inspired us to fabricate a bi-layered anticorrosive coating with self-healing ability at the functional level.

Multimetallic Microparticles Increase the Potency of Rifampicin against Intracellular Mycobacterium tuberculosis

Mycobacterium tuberculosis ( M.tb) has the extraordinary ability to adapt to the administration of antibiotics through the development of resistance mechanisms. By rapidly exporting drugs from within the cytosol, these pathogenic bacteria diminish antibiotic potency and drive the presentation of drug-tolerant tuberculosis (TB). The membrane integrity of M.tb is pivotal in retaining these drug-resistant traits. Silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs) are established antimicrobial agents that effectively compromise membrane stability, giving rise to increased bacterial permeability to antibiotics. In this work, biodegradable multimetallic microparticles (MMPs), containing Ag NPs and ZnO NPs, were developed for use in pulmonary delivery of antituberculous drugs to the endosomal system of M.tb-infected macrophages. Efficient uptake of MMPs by M.tb-infected THP1 cells was demonstrated using an in vitro macrophage infection model, with direct interaction between MMPs and M.tb visualized with the use of electron FIB-SEM tomography. The release of Ag NPs and ZnO NPs within the macrophage endosomal system increased the potency of the model antibiotic rifampicin by as much as 76%, realized through an increase in membrane disorder of intracellular M.tb. MMPs were effective at independently driving membrane destruction of extracellular bacilli located at the exterior face of THP1 macrophages. This MMP system presents as an effective drug delivery vehicle that could be used for the transport of antituberculous drugs such as rifampicin to infected alveolar macrophages, while increasing drug potency. By increasing M.tb membrane permeability, such a system may prove effectual in improving treatment of drug-susceptible TB in addition to M.tb strains considered drug-resistant.

Memantine loaded PLGA PEGylated nanoparticles for Alzheimer's disease: in vitro and in vivo characterization

Background

Memantine, drug approved for moderate to severe Alzheimer’s disease, has not shown to be fully effective. In order to solve this issue, polylactic-co-glycolic (PLGA) nanoparticles could be a suitable solution to increase drug’s action on the target site as well as decrease adverse effects. For these reason, Memantine was loaded in biodegradable PLGA nanoparticles, produced by double emulsion method and surface-coated with polyethylene glycol. MEM–PEG–PLGA nanoparticles (NPs) were aimed to target the blood–brain barrier (BBB) upon oral administration for the treatment of Alzheimer’s disease.

Results

The production parameters were optimized by design of experiments. MEM–PEG–PLGA NPs showed a mean particle size below 200 nm (152.6 ± 0.5 nm), monomodal size distribution (polydispersity index, PI < 0.1) and negative surface charge (− 22.4 mV). Physicochemical characterization of NPs confirmed that the crystalline drug was dispersed inside the PLGA matrix. MEM–PEG–PLGA NPs were found to be non-cytotoxic on brain cell lines (bEnd.3 and astrocytes). Memantine followed a slower release profile from the NPs against the free drug solution, allowing to reduce drug administration frequency in vivo. Nanoparticles were able to cross BBB both in vitro and in vivo. Behavioral tests carried out on transgenic APPswe/PS1dE9 mice demonstrated to enhance the benefit of decreasing memory impairment when using MEM–PEG–PLGA NPs in comparison to the free drug solution. Histological studies confirmed that MEM–PEG–PLGA NPs reduced β-amyloid plaques and the associated inflammation characteristic of Alzheimer’s disease.

Conclusions

Memantine NPs were suitable for Alzheimer’s disease and more effective than the free drug.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0356-z) contains supplementary material, which is available to authorized users.

Dopamine-assisted fixation of drug-loaded polymeric multilayers to osteoarticular implants for tuberculosis therapy

Currently, the major issues in the treatment of osteoarticular tuberculosis (TB) after implant placement are low drug concentration at the infected focus and drug resistance resulting from the long-term chemotherapy. The application of drug-loaded polymeric multilayers on implantable devices offers a promising solution to the problems. Herein, a poly(ethylene glycol)-based hydrogel film embedded with isoniazid (INH)-loaded alginate microparticles was fixed to Ti implants via adhesive polydopamine, subsequently capped by poly(lactic-co-glycolic acid) membranes for the sustained and localized delivery of the anti-TB drug. The antibacterial efficacy of the released INH was confirmed by a 4.5 ± 0.8 cm inhibition zone formed in the fourth week after inoculation of Mycobacterium tuberculosis. The INH-loaded Ti implants showed no toxicity to the osteoblast cell and provided a consistent drug release for nearly one week in vitro. The release profile in vivo showed a high local concentration and low systemic exposure. The local INH concentration could be kept higher than its minimum inhibitory concentration over a period of 8 weeks, which proves that it is a promising strategy to improve the severe osteoarticular TB treatment.

Building the design, translation and development principles of polymeric nanomedicines using the case of clinically advanced poly(lactide(glycolide))-poly(ethylene glycol) nanotechnology as a model: An industrial viewpoint

The design of the first polymeric nanoparticles could be traced back to the 1970s, and has thereafter received considerable attention, as evidenced by the significant increase of the number of articles and patents in this area. This review article is an attempt to take advantage of the existing literature on the clinically tested and commercialized biodegradable PLA(G)A-PEG nanotechnology as a model to propose quality building and outline translation and development principles for polymeric nano-medicines. We built such an approach from various building blocks including material design, nano-assembly - i.e. physicochemistry of drug/nano-object association in the pharmaceutical process, and release in relevant biological environment - characterization and identification of the quality attributes related to the biopharmaceutical properties. More specifically, as envisaged in a translational approach, the reported data on PLA(G)A-PEG nanotechnology have been structured into packages to evidence the links between the structure, physicochemical properties, and the in vitro and in vivo performances of the nanoparticles. The integration of these bodies of knowledge to build the CMC (Chemistry Manufacturing and Controls) quality management strategy and finally support the translation to proof of concept in human, and anticipation of the industrialization takes into account the specific requirements and biopharmaceutical features attached to the administration route. From this approach, some gaps are identified for the industrial development of such nanotechnology-based products, and the expected improvements are discussed. The viewpoint provided in this article is expected to shed light on design, translation and pharmaceutical development to realize their full potential for future clinical applications.

Preparation, in vitro and in vivo evaluation of mPEG-PLGA nanoparticles co-loaded with syringopicroside and hydroxytyrosol

This study investigated the therapeutic efficiency of monomethoxy polyethylene glycol-poly(lactic-co-glycolic acid) (mPEG-PLGA) co-loaded with syringopicroside and hydroxytyrosol as a drug with effective targeting and loading capacity as well as persistent circulation in vivo. The nanoparticles were prepared using a nanoprecipitation method with mPEG-PLGA as nano-carrier co-loaded with syringopicroside and hydroxytyrosol (SH-NPs). The parameters like in vivo pharmacokinetics, biodistribution in vivo, fluorescence in vivo endomicroscopy, and cellular uptake of SH-NPs were investigated. Results showed that the total encapsulation efficiency was 32.38 ± 2.76 %. Total drug loading was 12.01 ± 0.42 %, particle size was 91.70 ± 2.11 nm, polydispersity index was 0.22 ± 0.01, and zeta potential was -24.5 ± 1.16 mV for the optimized SH-NPs. The nanoparticle morphology was characterized using transmission electron microscopy, which indicated that the particles of SH-NPs were in uniformity within the nanosize range and of spherical core shell morphology. Drug release followed Higuchi kinetics. Compared with syringopicroside and hydroxytyrosol mixture (SH), SH-NPs produced drug concentrations that persisted for a significantly longer time in plasma following second-order kinetics. The nanoparticles moved gradually into the cell, thereby increasing the quantity. ALT, AST, and MDA levels were significantly lower on exposure to SH-NPs than in controls. SH-NPs could inhibit the proliferation of HepG2.2.15 cells and could be taken up by HepG2.2.15 cells. The results confirmed that syringopicroside and hydroxytyrosol can be loaded simultaneously into mPEG-PLGA nanoparticles. Using mPEG-PLGA as nano-carrier, sustained release, high distribution in the liver, and protective effects against hepatic injury were observed in comparison to SH.

Probing the interaction of nanoparticles with mucin for drug delivery applications using dynamic light scattering

Drug delivery via the eye, nose, gastrointestinal tract and lung is of great interest as they represent patient-compliant and facile methods to administer drugs. However, for a drug to reach the systemic circulation it must penetrate the "mucus barrier". An understanding of the characteristics of the mucus barrier is therefore important in the design of mucus penetrating drug delivery vehicles e.g. nanoparticles. Here, a range of nanoparticles - silica, aluminium coated silica, poly (lactic-co-glycolic acid) (PLGA) and PEGylated PLGA - each with known but different physicochemical characteristics were examined in the presence of mucin to identify those characteristics that engender nanoparticle/mucin interactions and thus, to define "design rules" for mucus penetrating (nano)particles (MPP), at least in terms of the surface characteristics of charge and hydrophilicity. Dynamic light scattering (DLS) and rheology have been used to assess the interaction between such nanoparticles and mucin. It was found that negatively charged and hydrophilic nanoparticles do not exhibit an interaction with mucin whereas positively charged and hydrophobic nanoparticles show a strong interaction. Surface grafted poly (ethylene glycol) (PEG) chains significantly reduced this interaction. This study clearly demonstrates that the established colloid science techniques of DLS and rheology are very powerful screening tools to probe nanoparticle/mucin interactions.

Nanocarriers for antibiotics: a promising solution to treat intracellular bacterial infections

In the field of antibiotherapy, intracellular infections remain difficult to eradicate mainly due to the poor intracellular penetration of most of the commonly used antibiotics. Bacteria have quickly understood that their intracellular localisation allows them to be protected from the host immune system, but also from the action of antimicrobial agents. In addition, in most cases pathogens nestle in professional phagocytic cells, and can even use them as a 'Trojan horse' to induce a secondary site of infection thereby causing persistent or recurrent infections. Thus, new strategies had to be considered in order to counteract these problems. Amongst them, nanocarriers loaded with antibiotics represent a promising approach. Nowadays, it is possible to encapsulate, incorporate or even conjugate biologically active molecules into different families of nanocarriers such as liposomes or nanoparticles in order to deliver antibiotics intracellularly and hence to treat infections. This review gives an overview of the variety of nanocarriers developed to deliver antibiotics directly into infected cells.

Gold nanoparticle conjugated PLGA-PEG-SA-PEG-PLGA multiblock copolymer nanoparticles: synthesis, characterization, in vivo release of rifampicin

A series of succinate linearly linked PLGA-PEG-SA-PEG-PLGA multiblock copolymers were synthesized using direct melt polycondensation and characterized using inherent viscosity, gel permeation chromatography (GPC), FTIR and ¹H-NMR spectroscopy techniques. Gold nanoparticles (AuNPs) were synthesized using an as-synthesized citrate-PEG (CPEG) hybrid dendron, which acts as a reducing agent as well as a stabilizing agent. The CPEG capped AuNPs were characterized using UV-visible spectroscopy and TEM analysis. The Au-conjugated PLGA-PEG-SA-PEG-PLGA multiblock copolymer NPs were loaded with the tuberculosis drug rifampicin (RIF) using ultrasonication followed by solvent evaporation and were characterized by TEM, powder XRD and XPS analyses. The RIF loading efficiency and percentage drug content of RIF loaded Au-conjugated multiblock copolymer NPs were evaluated using UV-visible spectroscopy. The RIF loading efficiency and RIF content of the AuNP conjugated multiblock copolymer NPs were 41.8-75.7% and 11.5-17.7% respectively. The in vivo drug release studies in male Wistar rats show that AuNP conjugated multiblock copolymer NPs exhibit drug release up to 240 h. The nanoconjugates exhibit 18.13-29.41 μg mL^-1 of C_max with a delayed T_max of 72 h and the relative bioavailability is increased to 107-190.

Poly(ethylene glycol)-poly(lactic-co-glycolic acid) based thermosensitive injectable hydrogels for biomedical applications

Stimuli triggered polymers provide a variety of applications related with the biomedical fields. Among various stimuli triggered mechanisms, thermoresponsive mechanisms have been extensively investigated, as they are relatively more convenient and effective stimuli for biomedical applications. In a contemporary approach for achieving the sustained action of proteins, peptides and bioactives, injectable depots and implants have always remained the thrust areas of research. In the same series, Poloxamer based thermogelling copolymers have their own limitations regarding biodegradability. Thus, there is a need to have an alternative biomaterial for the formulation of injectable hydrogel, which must remain biocompatible along with safety and efficacy. In the same context, poly(ethylene glycol) (PEG) based copolymers play a crucial role as a biomedical material for biomedical applications, because of their biocompatibility, biodegradability, thermosensitivity and easy controlled characters. This review stresses on the physicochemical property, stability and composition prospects of smart PEG/poly(lactic-co-glycolic acid) (PLGA) based thermoresponsive injectable hydrogels, recently utilized for biomedical applications. The manuscript also highlights the synthesis scheme and stability characteristics of these copolymers, which will surely help the researchers working in the same area. We have also emphasized the applied use of these smart copolymers along with their formulation problems, which could help in understanding the possible modifications related with these, to overcome their inherent associated limitations.

One-pot synthesis of biocompatible superparamagnetic iron oxide nanoparticles/hydrogel based on salep: characterization and drug delivery

This work describes synthesis of biocompatible magnetic iron oxide nanoparticles/hydrogel based on salep (MION-salep hydrogel) by a facile one-pot strategy. The prepared sample was characterized by techniques like scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDAX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The obtained MION had an 8 nm diameter with a narrow size distribution and was superparamagnetic with large saturation magnetization at room temperature. The most attractive feature of the obtained sample was its swelling properties under external magnetic field (EMF), different temperatures, and pHs. Moreover, MION-salep hydrogel showed ability to deferasirox release at pH=7 with non-Fickian diffusion mechanism. An in vitro cytotoxicity study implied that the as-synthesized sample is nontoxic.