PLGA Research Articles

Exploiting immunostimulatory mechanisms of immunogenic cell death to develop membrane-encapsulated nanoparticles as a potent tumor vaccine

Vaccine is one of the most promising strategies for cancer immunotherapy; however, there are no therapeutic cancer vaccine achieving significant clinical efficacy till now. The main limiting factors include the immune suppression and escape mechanisms developed by tumor and not enough capacity of vaccines to induce a vigorous anti-tumor immunity. This study aimed to develop a strategy of membrane-based biomimetic nanovaccine and investigate the immunological outcomes of utilizing the unique immunostimulatory mechanisms derived of immunogenic cell death (ICD) and of fulfilling a simultaneous nanoscale delivery of a highlighted tumor antigen and broad membrane-associated tumor antigens in the vaccine design. TC-1 tumor cells were treated in vitro with a mixture of mitoxantrone and curcumin for ICD induction, and then chitosan (CS)-coated polylactic co-glycolic acid (PLGA) nanoparticles loaded with HPV16 E744-62 peptides were decorated with the prepared ICD tumor cell membrane (IM); further, the IM-decorated nanoparticles along with adenosine triphosphate (ATP) were embedded with sodium alginate (ALG) hydrogel, And then, the immunological features and therapeutic potency were evaluated in vitro and in vivo. The nanovaccine significantly stimulated the migration, antigen uptake, and maturation of DCs in vitro, improved antigen lysosome escape, and promoted the retention at injection site and accumulation in LNs of the tumor antigen in vivo. In a subcutaneously grafted TC-1 tumor model, the therapeutic immunization of nanovaccine elicited a dramatical antitumor immunity. This study provides a strategy for the development of tumor vaccines.Graphical

PLGA nanoparticle loaded with antioxidants and photosensitizer for ROS shock mediated phototherapy of triple negative breast cancer

The potential use of antioxidants for photodynamic therapy (PDT) is investigated in this study. PDT causes reactive oxygen species (ROS)-mediated cell death; on the contrary, antioxidants scavenge ROS. The use of a photosensitizer along with an antioxidant photosensitizer compensates for the loss of ROS due to the use of antioxidant, eventually leading to cell death. In this work, for PDT and photothermal therapy (PTT), we have combined the photosensitizer IR 792 perchlorate dye with the antioxidants alpha-tocopherol (A) and p-coumaric acid (C) encapsulated in a polymeric nanocarrier (AC IR NPs). We have reported the synthesis of AC IR NPs using poly lactic-co-glycolic acid (PLGA) by nanoprecipitation method. The size of the polymeric nanoparticles was found to be 80.4 ± 15.6 nm, with a spherical morphology observed by scanning electron microscopy and transmission electron microscopy. The synthesized AC IR NPs demonstrated good biocompatibility in fibroblast cell lines (L929). Furthermore, the efficacy assessment of the as prepared nanosystem in vitro on breast cancer cell lines (4T1) revealed a significant cell death of nearly 80%. This could be attributed to the ROS generation leading to oxidative stress and inhibition of metastasis. This study provides evidence that the combination of antioxidant drugs along with photosensitizers have the potential to be an effective therapy for treating triple negative breast cancer.

Bio-evaluation of poly(lactic-co-glycolic) acid nanoparticles loaded with radiolabelled rifampicin.

The poly(lactic-co-glycolic) acid (PLGA) nanoparticles of tubercular drugs have been demonstrated to have a sustained release profile over 7 days. There is no information on the location or mode of release of these nanoparticles in living systems. Therefore, we have planned the study to explore the pharmacokinetics and biodistribution of PLGA rifampicin nanoparticles in healthy human volunteers. We aim to study the distribution pattern of PLGA-loaded nano-formulation of radiolabelled rifampicin in humans. Rifampicin was labelled with 99m Tc by indirect method and nanoparticles were prepared by a single emulsion evaporation method. To investigate the pharmacokinetics and biodistribution of nanoparticles, a single dose of 450 mg of rifampicin was administered orally to healthy human volunteers divided into two different groups. Following a single oral dosage of the rifampicin nanoformulation, the pharmacokinetic (PK) parameters were significantly different between the nanoparticle and conventional groups: area under the concentration-time curve (AUC = 113.8 vs. 58.6; P < .001), mean residence time (MRT = 16.2 vs. 5.8; P < .01) and elimination rate constant (Ke = 0.04 vs. 0.10; P < .05). Also, Single-photon emission computed tomography/computed tomography (SPECT/CT) images revealed biodistribution of nanoparticles in the distal portions of the intestine, which is consistent with our dosimetry analysis. Significant difference in PK parameters and biodistribution of nanoparticles in spleen and lymph nodes with maximum deposition were observed in the large intestine. The nanoparticle distribution pattern may be advantageous for the treatment of intestinal or lymph node tuberculosis (TB) and has the potential to result in a lower dose of rifampicin nanoformulation for the treatment of pulmonary TB.

Imiquimod-Loaded Chitosan-Decorated Di-Block and Tri-Block Polymeric Nanoparticles Loaded In Situ Gel for the Management of Cervical Cancer.

Cervical intraepithelial neoplasia, the predisposing factor for cervical cancer (CC), is caused by human papillomavirus (HPV) infection and can be treated with imiquimod (IMQ). However, poor water solubility and side effects such as local inflammation can render IMQ ineffective. The aim of this study is to design a prolonged release nano system in combination with mucoadhesive-thermosensitive properties for an effective vaginal drug delivery. Polylactic-co-glycolic acid (PLGA), polycaprolactone (PCL), poly lactide-co-caprolactone (PLA-PCL), and poly L-lactide-co-caprolactone-co-glycolide (PLGA-PCL) were used to create IMQ nanoparticles. Chitosan (CS) was then added to the surfaces of the IMQ NPs for its mucoadhesive properties. The NPs were then incorporated into poloxamer hydrogels. The NPs' size and morphology, encapsulation efficiency (EE), in vitro drug release, gel characterization, ex vivo drug permeation, and in vitro safety and efficacy were characterized. Two batches of NPs were prepared, IMQ NPs and CS-coated NPs (CS-IMQ NPs). In general, both types of NPs were uniformly spherical in shape with average particle sizes of 237.3 ± 4.7 and 278.2 ± 5.4 nm and EE% of 61.48 ± 5.19% and 37.73 ± 2.88 for IMQ NPs and CS-IMQ NPs, respectively. Both systems showed prolonged drug release of about 80 and 70% for IMQ NPs and CS-IMQ NPs, respectively, within 48 h. The gelation temperatures for the IMQ NPs and CS-IMQ NPs were 30 and 32 °C, respectively; thus, suitable for vaginal application. Although ex vivo permeability showed that CS-IMQ NPs showed superior penetration compared to IMQ NPs, both systems enhanced drug penetration (283 and 462 µg/cm2 for IMQ NPs and CS-IMQ NPs, respectively) relative to the control (60 µg/cm2). Both systems reduced the viability of cervical cancer cells, with a minimal effect of the normal vaginal epithelium. However, IMQ NPs exhibited a more pronounced cytotoxic effect. Both systems were able to reduce the production of inflammatory cytokines by at least 25% in comparison to free IMQ. IMQ and CS-IMQ NP in situ gels enhanced stability and drug release, and improved IMQ penetration through the vaginal tissues. Additionally, the new systems were able to increase the cytotoxic effect of IMQ against CC cells with a reduction in inflammatory responses. Thus, we believe that these systems could be a good alternative to commercial IMQ systems for the management of CC.

Hot deformation and fatigue behaviour of a zinc base doped biocompatible material: characterization of plasma spray coating on surface

Composite materials are natural or man-made substances put into the body to turn a living cell into a working organ. Bone tissue and biocompatibility are emerging as an alternative approach to regenerating bone due to some distinct advantages over autografting. This research aimed to fabricate a novel porous scaffold that can be utilized as a bone substitute. Zn-nHApx-Srx (x = 0, 3, 6, 9) was selected by different weight ratios and synthesized using the powder metallurgy method. The utilization of nanohydroxyapatite (Ca10(PO4)6(OH)2) is due to its excellent biocompatibility with the human body. Polylactic-co-glycolic acid (PLGA) is incorporated to get enhanced biological performance. Plasma spray coating was performed on a zinc substrate using pure and doped biocomposites calcined at 800 °C. The biocomposites tensile strength increased between 0.4 and 19.8 MPa by increasing Zn and Sr weight ratios. In addition, 3% Sr/2.5% Zn with 2% of nHAp-PLGA composite showed improved hardness, which is beneficial for resembling bone tissue and die-casting fittings in automobile manufacturing applications. Mechanical properties, FT-IR, hot deformation behaviour, and SEM techniques help us understand the behaviour of Zn-Sr-nHAp in a vial containing PLGA. The highest ultimate tensile strength of 182 MPa and improved flow softening behaviour are achieved in a coated Zn/6% (nHAp-Sr) mixture suitable for biodegradable implant applications.

Artificial neural networks for the prediction of mechanical properties of CGNP/PLGA nanocomposites

The mechanical properties of composite-based components have an impact on both their quality and efficacy. As a result, a scientific framework is needed to discover the practical set of progression constraints that will result in exceptional mechanical qualities. The possibilities of an artificial neural network (ANN) for predicting mechanical properties—specifically, the density and hardness of a carboxyl decorated graphene Nanocomposites (CGNP)/Poly Lactic-co-Glycolic Acid (PLGA) nanocomposite created under various spark plasma sintering (SPS) operating conditions—are explored in this work. A back-propagation with a 2–10-2 structural design and Levenberg-Marquardt algorithm was advanced to anticipate the automated performance of CGNP/PLGA nanocomposites in expressions of density and hardness parameters. The hypothesized outcomes of the models were compared to the actual experimental value. Density (0.9842) and hardness (0.9737) were found to be near to one; the archetypal accomplished well, with a good correlation coefficient (R) for both outputs and a low root-mean-squared error. The anticipated data findings were found to be quite compatible with the values acquired from the investigational assessment results. Our findings demonstrate the utility of a well-trained ANN method in assessing the density and hardness properties of SPSed CGNP/PLGA nanocomposites. As a result, the ANN system provides an unswerving tool for making decisions that can reduce the high costs involved with the experimental characterization of newly manufactured polymer composites.

A composite membrane with microtopographical morphology to regulate cellular behavior for improved tissue regeneration.

Tissue engineering scaffolds with specific surface topographical morphologies can regulate cellular behaviors and promote tissue repair. In this study, poly lactic(co-glycolic acid) (PLGA)/wool keratin composite guided tissue regeneration (GTR) membranes with three types of microtopographies (three groups each of pits, grooves and columns, thus nine groups in total) were prepared. Then, the effects of the nine groups of membranes on cell adhesion, proliferation and osteogenic differentiation were examined. The nine different membranes had clear, regular and uniform surface topographical morphologies. The 2 µm pit-structured membrane had the best effect on promoting the proliferation of bone marrow mesenchymal stem cells(BMSCs) and periodontal ligament stem cells (PDLSCs), while the 10 µm groove-structured membrane was the best for inducing osteogenic differentiation of BMSCs and PDLSCs. Then, we investigated the ectopic osteogenic, guided bone tissue regeneration and guided periodontal tissue regeneration effects of the 10 µm groove-structured membrane combined with cells or cell sheets. The 10 µm groove-structured membrane/cell complex had good compatibility and certain ectopic osteogenic effects, and the 10 µm groove-structured membrane/cell sheet complex promoted better bone repair and regeneration and periodontal tissue regeneration. Thus, the 10 µm groove-structured membrane shows potential to treat bone defects and periodontal disease. STATEMENT OF SIGNIFICANCE: PLGA/wool keratin composite GTR membranes with microcolumn, micropit and microgroove topographical morphologies were prepared by dry etching technology and the solvent casting method. The composite GTR membranes had different effects on cell behavior. The 2 µm pit-structured membrane had the best effect on promoting the proliferation of rabbit BMSCs and PDLSCs and the 10 µm groove-structured membrane was the best for inducing the osteogenic differentiation of BMSCs and PDLSCs. The combined application ofa 10 µm groove-structured membrane and PDLSC sheet can promote better bone repair and regeneration as well as periodontal tissue regeneration. Our findings may have significant potential for guiding the design of future GTR membranes with topographical morphologies and clinical applications of the groove-structured membrane/cell sheet complex.

Sphingosine-1-Phosphate Receptor Targeted PLGA Nanobubbles for Inflammatory Vascular Endothelial Cell Catching.

Vascular inflammation is an early manifestation and common pathophysiological basis of numerous cardiovascular and cerebrovascular diseases. However, effective surveillance methods are lacking. In this study, sulfur hexafluoride (SF6 )-loaded polylactic acid-co-glycolic acid (PLGA) nanobubbles (NBs) with a surface assembly of cyclodextrin (CD) and sphingosine-1-phosphate (S1P) (S1P@CD-PLGA NBs) are designed. The characterization results show that S1P@CD-PLGA NBs with diameters of ≈200nm have good stability, biosafety, and ultrasound imaging-enhancement effects. When interacting with inflammatory vascular endothelial cells, S1P molecules encapsulated in cyclodextrin cavities exhibit a rapid, excellent, and stable targeting effect owing to their specific interaction with the highly expressed S1P receptor 1 (S1PR1) on the inflammatory vascular endothelial cells. Particularly, the S1P-S1PR1 interaction further activates the downstream signaling pathway of S1PR1 to reduce the expression of tumor necrosis factor-α (TNF-α) to protect endothelial cells. Furthermore, mouse models of carotid endothelial injuries and mesenteric thrombosis demonstrate that S1P@CD-PLGA NBs have excellent capabilities for in vivo targeting imaging. In summary, this study proposes a new strategy of using S1P to target inflammatory vascular endothelial cells while reducing the expression of TNF-α, which has the potential to be utilized in the targeted surveillance and treatment of vascular inflammatory diseases.

Multitarget, multiagent PLGA nanoparticles for simultaneous tumor eradication and TME remodeling in a melanoma mouse model

Despite the fact that chemoimmunotherapy has emerged as a key component in the era of cancer immunotherapy, it is challenged by the complex tumor microenvironment (TME) that is jam-packed with cellular and non-cellular immunosuppressive components. The aim of this study was to design a nanoparticulate system capable of sufficiently accumulating in the tumor and spleen to mediate local and systemic immune responses, respectively. The study also aimed to remodel the immunosuppressive TME. For such reasons, multi-functional polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) were engineered to simultaneously eradicate the cancer cells, silence the tumor-associated fibroblasts (TAFs), and re-educate the tumor-associated macrophages (TAMs) using doxorubicin, losartan, and metformin, respectively. These agents were also selected for their ability to tip the balance of the splenic immune cells towards immunostimulatory phenotypes. To establish TAM and TAF cultures, normal macrophages and fibroblasts were incubated with B16F10 melanoma cell (Mel)-derived secretome. Drug-loaded PLGA NPs were prepared, characterized, and tested in the target cell types. Organ distribution of fluorescein-loaded PLGA NPs was evaluated in a mouse model of melanoma. Finally, the local and systemic effects of different combination therapy programs were portrayed. The in vitro studies showed that the drug-loaded PLGA NPs could significantly ablate the immunosuppressive nature of Mel and skew TAMs and TAFs towards more favorable phenotypes. While in vivo, PLGA NPs were proven to exhibit long blood circulation time and to localize preferentially in the tumor and the spleen. The combination of either metformin or losartan with doxorubicin was superior to the monotherapy, both locally and systemically. However, the three-agent combo produced detrimental effects in the form of compromised well-being, immune depletion, and metastasis. These findings indicate the potential of TME remodeling as means to prime the tumors for successful chemoimmunotherapy. In addition, they shed light on the importance of the careful use of combination therapies and the necessity of employing dose-reduction strategies.Graphical D-NPs doxorubicin-loaded NPs, M-NPs metformin-loaded NPs, L-NPs losartan-loaded NPs, TAMs tumor-associated macrophages, TAFs tumor-associated fibroblasts, PD-L1 programmed death ligand 1, TNF-α tumor necrosis factor alpha, TGF-β transforming growth factor beta, CD206/40/86 cluster of differentiation 206/40/86, α-SMA alpha-smooth muscle actin, MMPs matrix metalloproteases

The Cooperation of IL-29 and PLGA Nanoparticles Improves the Protective Immunity of the gD-1 DNA Vaccine Against Herpes Simplex Virus Type 1 in Mice

ABSTRACT In clinical practice, the low immunogenicity and low stability of the DNA plasmid vaccine candidates are two significant shortcomings in their application against infectious diseases. To overcome these two disadvantages, the plasmid expressing IL-29 (pIL-29) as a genetic adjuvant and polylactic-co-glycolic acid (PLGA) as a non-viral delivery system were used, respectively. In this study, the pIL-29 encapsulated in PLGA nanoparticles (nanoIL-29) and the pgD1 encapsulated in PLGA nanoparticles (nanoVac) were simultaneously applied to boost immunologic responses against HSV-1. We generated spherical nanoparticles with encapsulation efficiency of 75 ± 5% and sustained the release of plasmids from them. Then, Balb/c mice were subcutaneously immunized twice with nanoVac+nanoIL-29, Vac+IL-29, nanoVac, Vac, nanoIL-29, and/or IL-29 in addition to negative and positive control groups. Cellular immunity was evaluated via lymphocyte proliferation assay, cytotoxicity test, and IFN-γ, IL-4, and IL-2 measurements. Mice were also challenged with 50X LD50 of HSV-1. The nanoVac+nanoIL-29 candidate vaccine efficiently enhances CTL and Th1-immune responses and increases the survival rates by 100% in mice vaccinated by co-administration of nanoVac and nanoIL-29 against the HSV-1 challenge. The newly proposed vaccine is worth studying in further clinical trials, because it could effectively improve cellular immune responses and protected mice against HSV-1.

Intramuscularly Administered PLGA Microparticles for Sustained Release of Rivastigmine: In Vitro, In Vivo and Histological Evaluation

Rivastigmine is an acetylcholinesterase (AchE) and butyrylcholinesterase (BchE) inhibitor drug approved by the US Food and Drug Administration (FDA) for the treatment of mild to moderate dementia of Alzheimer's type. However, its first-pass metabolism and gastrointestinal side effects negatively affect the tolerability and efficacy of oral therapy. These adverse effects could be avoided with the use of a sustained -release formulation as an intramuscular (IM) administration system. The objective of this work was to develop polylactic co-glycolic acid (PLGA) microparticles for the sustained release of rivastigmine and to evaluate its stability during storage, tissue tolerance, in vitro release, and in vivo pharmacokinetics after its IM administration. The microparticles were made by the solvent evaporation emulsion method. A series of formulation parameters (the type of polymer used, the amount of polymer used, the initial amount of rivastigmine, and the volume of PVA 0.1% w/v) were studied to achieve an encapsulation efficiency (EE) and a rivastigmine load of 54.8 ± 0.9% and 3.3 ± 0.1%, respectively. The microparticles, whose size was 56.1 ± 2.8 μm, had a spherical shape and a smooth surface. FT-IR analysis showed that there is no chemical interaction between rivastigmine and the polymer. PLGA microparticles maintain rivastigmine retained and stable under normal (5 ± 3 °C) and accelerated storage (25 ± 2 °C and 60 ± 5 % RH) conditions for at least 6 months. The microparticles behaved as a sustained release system both in vitro and in vivo compared to non-encapsulated rivastigmine. The IM administration of the formulation in rats did not produce significant tissue damage. However, it is necessary to reproduce the experiments with multiple doses to rule out a negative effect in terms of tolerability in chronic treatment. To the best of our knowledge, this study is the only one that has obtained the sustained release of rivastigmine from PLGA microparticles after IM administration in an in vivo model.

Efficacy and Safety of Beta-Tricalcium Phosphate/Polylactic-Co-Glycolic Acid for Implantation of Bone Defects.

Bone defects are often observed after surgery for fractures and bone tumors. Their treatment is technically difficult and sometimes results in negative clinical and economic outcomes. To repair bone defects, a bone graft is implanted by selecting a transplant material from an autologous or artificial bone. Each method has its advantages and disadvantages. Compared to the gold standard of autologous bone graft, bone graft substitutes are not limited by the amount of harvested graft and avoid complications at the donor site. ORB-03 is a new cotton-like bone graft substitute composed of beta-tricalcium phosphate (β-TCP) and a bioabsorbable polymer, polylactic-co-glycolic acid (PLGA). ORB-03 is easy to mold and can fill various bone defect shapes, and its three-dimensional microfiber scaffold can enhance the differentiation of osteoblasts and promote osteogenesis. We investigated the efficacy, ease of handling, and safety of ORB-03 as a bone graft substitute. A multicenter, open-label, single-group study was conducted at six institutions. Between July 2018 and August 2019, 60 patients with bone defects caused by fracture, benign tumors, or an iliac donor site from bone harvesting were enrolled in this study; 54 patients were finally included for the safety analysis and 48 patients for the image analysis. During surgery, ORB-03 was mixed with the patient's blood and molded into a bone defect. To evaluate the efficacy of ORB-03, radiography and computed tomography (CT) were performed at intervals until 24 weeks after surgery. The effective rate and its accurate bilateral 95% confidence interval (CI) were calculated based on the efficacy criteria at 24 weeks postoperatively. The ease with which ORB-03 could be handled in surgery was evaluated. Adverse events that occurred after surgery were evaluated, and those associated with ORB-03 were examined. Bone fusion was good in all cases, and the radiography and CT effective rates were 100.0% and 91.5%, respectively. Handling was easy in all cases. There were four adverse events, none of which were clinically problematic. ORB-03 was found to be easy to handle, safe, and effective as a bone graft substitute for bone defects.

Fabrication of PLGA Nanoparticles Using Combination of PCL-PVA-PEG Copolymer as Surfactant: In-Vitro Characterization and Cytotoxicity Study

Objective: The present study aimed to fabricate Poly lactic acid co-glycolic acid (PLGA) nanoparticles loaded with resveratrol using a novel graft co-polymer surfactant named Soluplus®. Methods: The PLGA nanoparticles were prepared in the present study using polyvinyl caprolactam polyvinyl acetate polyethylene glycol amphiphilic graft copolymer named Soluplus® as surfactant through double emulsification and single emulsification-solvent evaporation method. The formulations were prepared successfully to encapsulate the drug resveratrol, and then evaluated for their particle size, polydispersity index, zeta potential, drug loading and the degree of entrapment of the drug. A scanning electron microscope was used to examine the morphology of the nanoparticles. In vitro drug release was assessed and, mathematical pharmacokinetic modelling was done to assess the release pattern. A comparative cytotoxicity study between free drug and prepared nanoparticles using MTT assay was carried out for cell viability evaluation. Uptake and internalization of nanoparticles were also studied using confocal fluorescence microscopy. Results: The results demonstrated successful fabrication of the PLGA nanoparticles using the Soluplus as polymer surfactant. The drug, polymer and the all the excipients were found to be compatible and did not indicate any interaction. The results also indicated the prepared nanoparticles (SF2) as suitable resveratrol delivery vehicle in terms of the compliant particle size (344.6 ±6.63 nm), polydispersity index (0.962), zeta potential (- 18.5±1.21), drug loading (18.94± 0.27%), the entrapment efficiency (39.62±0.17%) and drug release (75.13±0.17%). The shape and surface morphology of the formulated nanoparticles were found to be spherical and smooth. Cytotoxicity study also demonstrated significant reduction of cell viability by the nanoparticle compared to free resveratrol. The highest cytotoxicity of SF2 against MCF7 cell was found in 2000 nM concentration with 3.03±0.05 percent of cell viability. It was found that the percentage of growth inhibition was increasing with increasing concentration of SF2 and IC50 value of this assay was 108.94 μg/ml. Conclusion: It has been found that the Resveratrol loaded PLGA nanoparticles were successfully formulated and found to perform better in terms of efficacy and cytotoxicity.

An in-depth investigation of the C2 polymer as a next-generation transdermal drug delivery platform

Dermal administration of medications offers high accessibility and convenience for users. Transdermal drug delivery systems (TDDS) have emerged as a promising approach for various applications, including cosmetics, medical purposes, disease treatment, and prevention. While some materials such as hyaluronic acid (HA) and poly(lactic-co-glycolic) acid (PLGA) have been previously investigated for TDDS, our research recently discovered a next-generation material known as the poly(dimethylsilylethylene-dimethylsiloxane) (PDDS) series. Among the PDDS series, the C2 polymer showed high biocompatibility and superior transdermal drug delivery efficacy. In this study, we systematically investigated the C2 polymer and discovered several remarkable attributes. One of the key findings is its high potential for large-scale synthesis. We have demonstrated the biodegradability of the C2 polymer and confirmed that the degradation products derived from the C2 polymer showed negligible toxicity. The C2 polymer also displayed superior skin penetration abilities, allowing for the efficient delivery of hydrophobic and hydrophilic compounds. Our study positions the C2 polymer as a promising next-generation polymeric material for TDDS.

Evaluation of Drug Release Profiles of Titanium Plates Coated with PLGA or Chitosan with Meropenem Using UPLC: An In Vitro Study

In some cases, titanium plates could be a reservoir for harboring bacteria resulting in challenging cases of infection. Current estimates indicate that 10–12% of plates require removal due to infection, exposure, pain, and discomfort. The present investigation was conducted to evaluate the potential sustained meropenem-coated plates amalgamated with “PLGA” polylactic co-glycolic acid and chitosan polymers with the concurrent sterilization effect of gamma irradiation. After coating the plates with either M “meropenem”, MP “meropenem-PLGA, or MC “meropenem-chitosan”, they were divided into two groups of sterile and non-sterile coated plates. The drug release was studied over three-time intervals of 1, 3, and 7 days using ultrahigh-performance liquid chromatography. Overall, the three materials had similar drug release on day one, both in sterile and non-sterile groups, while on days 3 and 7, a noticeable increase in the drug release was perceived in favor of MP. At the same time, no statistically significant difference was observed between sterile and non-sterile groups. A statistically significant increase in drug release was observed between and within the materials over time, with no overall difference between sterile and non-sterile groups.

The Sustained-released Polylactic Co-glycolic Acid Nanoparticles Loaded with Chlorhexidine as Antibacterial Agents Inside the Dental Implant Fixture.

Titanium-based implants are widely used due to their good biocompatibility and high corrosion resistance. Infections after implant placement are the main reason for the failure of implant treatment. Some recent studies have also shown that microbial contamination can occur at the implant-abutment level in implants with healthy or diseased surrounding tissue. The purpose of this study is to investigate the antibacterial effect of slow-release nanoparticles of polylactic co-glycolic acid (PLGA) loaded with chlorhexidine (CHX) inside the implant fixture. Thirty-six implants in three groups were examined in the bacterial culture environment. In the first group, PLGA/CHX nanoparticles; in the second group, the negative control group (distilled water) and in the third group, the positive control groups (chlorhexidine) were used. The bacterial suspensions, including Escherichia coli ATCC: 25922, Staphylococcus aureus ATCC: 6538 and Enterococcus faecalis ATCC: 29212 were used to investigate the antimicrobial effect of the prepared nanoparticles. The results showed that the use of PLGA/CHX nanoparticles significantly inhibited the growth of all three bacteria. Nanoparticles loaded with chlorhexidine had a significant decrease in the growth rate of all three bacteria compared to chlorhexidine and water. The lowest bacterial growth rate was observed in the Enterococcus faecalis/PLGA nanoparticles group, and the highest bacterial growth rate was observed in the Staphylococcus aureus/H2O group. The current study showed that the use of PLGA/CHX nanoparticles could significantly inhibit the growth of all three bacteria. Of course, the current study was conducted in vitro, and to obtain clinical results, we need to conduct a study on human samples. In addition, the results of this study showed that the chemical antimicrobial materials could be used in low concentrations and in a sustained- released manner in cases of dealing with bacterial infections, which can lead to better and targeted performance as well as reduce possible side effects.

Macrophage targeted polymeric curcumin nanoparticles limit intracellular survival of Mycobacterium tuberculosis through induction of autophagy and augment anti-TB activity of isoniazid in RAW 264.7 macrophages.

Rapid emergence of antibiotic resistance in tuberculosis has left us with limited resources to treat and manage multi drug resistant (MDR) cases of tuberculosis, prompting the development of novel therapeutics. Mycobacterium tuberculosis (MTB) perturbs the host protective pathways for its survival, therefore host directed therapeutic (HDT) interventions offer an attractive alternative strategy. Curcumin (CMN), the principle curcuminoid from Curcuma longa is known to have anti-TB activity against MDR strains of MTB in macrophages. We discovered that treatment of CMN induced autophagy in uninfected and MTB infected macrophages which was evident by conversion of LC3-I to LC3-II and degradation of p62. Inhibition of autophagy by a pharmacological inhibitor 3-MA resulted in significant inhibition of intracellular killing activity of CMN, suggesting the involvement of autophagy in intracellular clearance of MTB. Moreover, annexin v-FITC/PI staining data suggested induction of apoptosis in uninfected and MTB infected macrophages post CMN treatment. This finding was further corroborated by up-regulated expression of pro-apoptotic proteins, Bax, cleaved caspase-3 and PARP and diminished expression of anti-apoptotic protein Bcl-2 as evaluated by immunoblotting. Using GFP-MTB H37Rv and Lysotracker Red staining we demonstrated co-localization of GFP-MTB H37Rv containing phagosome to lysosome after CMN treatment, indicating enhanced phagosome lysosome fusion. Due to poor bioavailability of CMN, its clinical use is limited, therefore to overcome this issue, CMN was encapsulated in Poly(lactic-co-glycolic) acid (PLGA) shell, resulting in polymeric CMN nano particles (ISCurNP). Flow cytometric evaluation suggested >99% uptake of ISCurNP after 3h of treatment. In BALB/c mice, oral dose of ISCurNP resulted in 6.7-fold increase in the bioavailability compared to free CMN. Moreover, ISCurNP treatment resulted in significant decrease in the intracellular survival of MTB H37Rv through induction of autophagy. Adjunct action of ISCurNP and CMN in combination with isoniazid (INH) revealed >99% decrease in intracellular survival of MTB in macrophage as compared to ISCurNP, CMN or INH alone. In conclusion, our findings suggest the role of ISCurNP as novel host directed formulation to combat both sensitive and MDR strains of MTB by induction of autophagy.

Formulation and Optimization of Rivastigmine-Loaded PLGA and Chitosan Nanoparticles for Transdermal Delivery

Rivastigmine (RVT) is anti-Alzheimer with low bioavailability and with short elimination half-life due to significant first-pass metabolism. RVT is a hydrophilic drug because it has low permeability tothe skin. Therefore, in the present study, RVT-loaded polymeric nanoparticles (NPs) were formulated to improve drug permeation through the transdermal route. A polymeric nanoparticle of RVT was prepared (using the factorial design) and characterized using the biodegradable polymers, Poly (lactic-co-glycolic) acid (PLGA) and Chitosan (CH) as carriers.PLGA NPs were prepared by the nano-precipitation method, while CH NPs were prepared by the ionic gelation method. The effect of formulation variables on particle size (PS), PDI, and percentage entrapment efficiency (%EE) of NPs were studied using factorial design and were optimized based on the responses' desirability, i.e., minimum particle size and PDI and maximum entrapment efficiency. The optimized PLGA NPs showed PS of 291.3nm, PDI of 0.296, and %EE of 75.31%, whereas CH NPS showed PS of 339.3 nm, PDI of 0.264, and %EE of 83.91%. DSC thermograms indicated that RT was dispersed as an amorphous state in both PLGA and CH NPs. TEM and SEM studies indicated that the NPs were spherical and smooth. In vitro release studies showed 52.7±1.07 and 75.02±0.97% release from PLGA NPs and CH NPs in 24 h, respectively, whereas from drug solution 92.21±1.11% with 2h.Optimized NPs were incorporated in the patch, and in vitro permeation studies were performed across the pork ear skin.The steady-state flux of PLGA and CH NPs merged patch, i.e., PPN and PCN, was 223.64 and 265.18µg/cm2.h respectively, whereas for pure RVT containing patch (PD) was shown to be 55.01µg/cm2. h after 24 hrs. Results indicated that the flux of PPN and PCN was 4.06 and 4.82 fold higher than PD. Proposed comparative studies of developed patches with marketed patches showed that the developed patch of drug-loaded in polymeric nanoparticles could be a potential alternative for exiting sold Exelon® patch.

A erythrocyte-platelet hybrid membrane coated biomimetic nanosystem based on ginsenosides and PFH combined with ultrasound for targeted delivery in thrombus therapy

Thrombus is one of the culprits for global health problems. However, most current antithrombotic drugs are limited by restricted targeting ability and a high risk of systemic bleeding. A hybrid cell membrane-coated biomimetic nanosystem (PM/RM@PLGA@P/R) was constructed in this paper to fulfil the targeted delivery of ginsenoside (Rg1) and perfluorohexane (PFH). Poly lactic-co-glycolic acid (PLGA) is used as carriers to coat Rg1 and PFH. Thanks to the camouflage of erythrocyte membrane (RM) and platelet membrane (PM), the nanosystem in question possesses remarkable features including immune escape and self-targeting. Therefore, a compact nano-core with PLGA@P/R was formed, with a hybrid membrane covering the surface of the core, forming a “core-shell” structure. With its “core-shell” structure, this nanoparticle fancifully combines the advantages of both PFH (the low-intensity focused ultrasound (LIFU)-responsive phase-change thrombolysis) and Rg1(the antioxidant, anti-inflammatory and anticoagulant abilities). Meanwhile, PM/RM@PLGA@P/R nanoparticles exhibits superior in-vitro performance in terms of ROS scavenging, anticoagulant activity and immune escape compared with those without cell membranes (PLGA@P/R). Furthermore, in the animal experiment in which the tail vein thrombosis model was established by injecting k-carrageenan, the combined treatment of LIFU and PM/RM@PLGA@P/R showed a satisfactory antithrombotic efficiency (88.20 %) and a relatively higher biological safety level. This strategy provides new insights into the development of more effective and safer targeted biomimetic nanomedicines for antithrombotic treatments, possessing potential application in synergistic therapy field.

Polyoxazoline-Based Nanovaccine Synergizes with Tumor-Associated Macrophage Targeting and Anti-PD-1 Immunotherapy against Solid Tumors.

Immune checkpoint blockade reaches remarkable clinical responses. However, even in the most favorable cases, half of these patients do not benefit from these therapies in the long term. It is hypothesized that the activation of host immunity by co-delivering peptide antigens, adjuvants, and regulators of the transforming growth factor (TGF)-β expression using a polyoxazoline (POx)-poly(lactic-co-glycolic) acid (PLGA) nanovaccine, while modulating the tumor-associated macrophages (TAM) function within the tumor microenvironment (TME) and blocking the anti-programmed cell death protein 1 (PD-1) can constitute an alternative approach for cancer immunotherapy. POx-Mannose (Man) nanovaccines generate antigen-specific T-cell responses that control tumor growth to a higher extent than poly(ethylene glycol) (PEG)-Man nanovaccines. This anti-tumor effect induced by the POx-Man nanovaccines is mediated by a CD8+ -T cell-dependent mechanism, in contrast to the PEG-Man nanovaccines. POx-Man nanovaccine combineswith pexidartinib, a modulator of the TAM function, restricts the MC38tumor growth, and synergizes with PD-1blockade, controlling MC38and CT26tumor growth and survival. This data is further validated in the highly aggressive and poorly immunogenic B16F10melanoma mouse model. Therefore, the synergistic anti-tumor effect induced by the combination of nanovaccines with the inhibition of both TAM- and PD-1-inducing immunosuppression, holds great potential for improving immunotherapy outcomes in solid cancer patients.