PLGA Research Articles

Structure-based drug design of pre-clinical candidate nanopiperine: a direct target for CYP1A1 protein to mitigate hyperglycaemia and associated microbes

ABSTRACT Diabetes is attributed to an increased vulnerability to bacterial infection linked to unregulated hyperglycaemia. The present study highlights the formulation of nanoparticles with phyto-compound piperine (PIP) encapsulated within non-toxic biodegradable polymer poly-lactide co-glycolide (PLGA) which showed a variety in surface functionality, biocompatibility, and the ability to tailor an optimized release rate from its polymeric enclosure. The observations revealed that nanopiperine (NPIP) pre-treatment in mice inhibited alteration in hepatic tissue architecture and hepato-biochemical parameters in diabetes and its associated bacterial infections. NPIP also decreased the propensity of lipids to undergo an oxidation process and stabilized the membrane lipids in vivo, thereby lowering oxidative stress and preventing enzymatic activation of CYP1A1. This result is corroborated with the in silico molecular docking study where PIP binding with CYP1A1 gave −11.32 Kcal/mol dock score value. The antibacterial activity of PIP was further demonstrated by the in silico PIP and Ef-Tu protein-binding efficacy revealing −6.48 Kcal/mol score value which was coupled with the results of in vitro studies where the zone of inhibition assay with NPIP against Staphylococcus aureus and Escherichia coli. Thus, NPIP could serve as a potential drug candidate in modulating targeted proteins to inhibit the progression of hyperglycaemia and its associated microbes.

Chitooligosaccharide-modified PLGA-loaded PPD nanoparticles ameliorated sepsis-associated acute kidney injury via the NF-κB signaling pathway

Objectives Sepsis-associated acute kidney injury (SA-AKI) is a significant clinical challenge with high morbidity and mortality. Low bioavailability of protopanaxadiol (PPD) limits its clinical application. In this study, PPD was encapsulated with chitooligosaccharide (COS) modified polylactic-co-glycolic acid (PLGA) to develop novel nanomedicines for the treatment of SA-AKI. Methods COS-PLGA-PPD nanoparticles were prepared by emulsified solvent evaporation method, and their properties were evaluated. In vitro, the anti-inflammatory and protective effects of COS-PLGA-PPD NPs were investigated in a cellular model of LPS-induced NRK-52E cells and their uptake in Caco-2 cells. Indicators of renal injury, inflammation, and NF-κB signaling pathway were evaluated by injecting LPS into SD rats and inducing SA-AKI model in vivo. The oral bioavailability of nanoparticles was evaluated by pharmacokinetics. Results Compared with PPD and unmodified nanoparticles, COS-PLGA-PPD NPs were more stable, with a particle size of 139.69 nm, which enhanced the viability of NRK-52E cells, increased the uptake of Caco-2 cells, alleviated the symptoms of SA-AKI in rats, inhibited the NF-κB signaling pathway, reduced the expression of inflammatory factors, and had a bioavailability 1.7-fold that of PPD. Conclusion COS-PLGA-PPD NPs ameliorate LPS-induced SA-AKI in rats by inhibiting the NF-κB signaling pathway, providing a basis for the treatment of SA-AKI.

Effectiveness of amine plasma-functionalized 3D PLGA scaffolds immobilized with Fibroblast Growth Factor in periodontal tissue regeneration

Polylactic-co-glycolic acid (PLGA) has widely been used as a biodegradable material for three-dimensional (3D) printed scaffolds. However, the lack of surface chemicals and poor wettability limit the application of the polymer. Therefore, we modified the 3D scaffold surface using plasma surface modifications and evaluated its biocompatibility. To introduce amine functional groups on the 3D PLGA scaffold surface, amine plasma-polymerization was performed using 1, 2-diaminocyclohexane (DACH) monomers. Then, Fibroblast Growth Factor (FGF) was immobilized on the amine-functionalized 3D PLGA scaffold surface using a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide. Human Gingival Fibroblast (HGF-1) cell behaviors were evaluated through cell adhesion, migration, proliferation, and western blot. The results showed that DACH plasma-polymerization provided the amine-functionalized surface which is capable of immobilizing FGF bioactive molecules on the 3D PLGA scaffold. Cell adhesion, proliferation, and migration on plasma surface-modified scaffolds have greatly improved compared to pristine 3D PLGA scaffolds. Notably, FGF-immobilized groups demonstrated the highest proliferation. These results suggest that the FGF-immobilized scaffold surface had a significant effect on accelerating oral gingival cell proliferation. In the future, 3D PLGA scaffolds with surface functionalized by plasma-polymerization and biomolecule immobilization can be used as a good alternative to autogenous soft tissue grafts for damaged soft tissue restoration.

Elongated Particles Show a Preferential Uptake in Invasive Cancer Cells

Mechanically driven cellular preference for drug carriers can enhance selectivity in cancer therapy, underscoring the importance of understanding the physical aspects of particle uptake. In this study, it was hypothesized that elongated particles might be preferentially taken up by deformable, aggressive cancer cells compared to normal cells. Two film-stretching methods were tested for 0.8–2.4 μm polystyrene (PS) particles: one based on solubility in organic solvents and the other on heat-induced softening. The heat-induced method produced more homogenous particle batches, with a standard deviation in the particle aspect ratio of 0.42 compared to 0.91 in the solvent-based method. The ability of cells to engulf elongated PS particles versus spherical particles was assessed in two subsets of human melanoma A375 cells. In the more aggressive cancer cell subset (A375+), uptake of elongated PS particles increased by 10% compared to spherical particles. In contrast, the less aggressive subset (A375−) showed a 25% decrease in uptake of elongated particles. This resulted in an uptake ratio between A375+ and A375− that was 1.5 times higher for elongated PS particles than for spherical ones. To further demonstrate relevance to drug delivery, elongated paclitaxel-loaded biodegradable, slow-releasing poly(lactic-co-glycolic) acid (PLGA) particles were synthesized. No significant difference in cytotoxic effect was observed between A375+ and A375− cells treated with spherical drug-loaded particles. However, treatment with ellipsoidal particles led to a significantly enhanced cytotoxic effect in aggressive cells compared to less aggressive cells. These findings present promising directions for tailored cancer drug delivery and demonstrate the importance of particle physical properties in cellular uptake and drug delivery mechanisms.

Nanotechnology in Pain Management.

Chronic pain is a debilitating condition that affects millions of patients worldwide, contributing to a high disease burden and millions of dollars in lost wages, missed workdays, and healthcare costs. Opioids, NSAIDs, acetaminophen, gabapentinoids, muscle relaxants, anticonvulsants, and antidepressants are the most used medications for chronic pain and carry significant side effects, including gastric bleeding, hepatotoxicity, stroke, kidney damage, constipation, dizziness, and arrhythmias. Opioids in particular carry the risk of long-term dependence, drug tolerance, and overdose. In 2022, 81,806 people died from opioid overdose in the United States alone. Alternative treatments for chronic pain are critically needed, and nanotechnology has emerged as a promising means of achieving effective long-term analgesia while avoiding the adverse side effects associated with conventional pharmacological agents. Nanotechnology-based treatments include liposomes, Poly Lactic-co-Glycolic Acid (PLGA) and other polymeric nanoparticles, and carbon-based polymers, which can help mitigate those adverse side effects. These nanomaterials can serve as drug delivery systems that facilitate controlled release and drug stability via the encapsulation of free molecules and protein-based drugs, leading to longer-lasting analgesia and minimizing side effects. In this review, we examine the role of nanotechnology in addressing concerns associated with conventional chronic pain treatments and discuss the ongoing efforts to develop novel, nanotechnology-based treatments for chronic pain such as nanocapacitor patches, gene therapy, the use of both viral and non-viral vectors, CRISPR, and scavengers.

Development and characterization of solriamfetol-loaded PVA/PLGA electrospun nanofiber membranes: A promising approach for sustained narcolepsy treatment

Narcolepsy presents challenges in medication adherence and delivery, with traditional oral medications not always suitable for patients experiencing unexpected sleep episodes or difficulty in swallowing pills. This study focused on developing a solriamfetol (SF) loaded nanofiber membrane using a polymer blend of polyvinyl alcohol (PVA) and polylactic-co-glycolic acid (PLGA) for the management of narcoleptic patients with non-oral dosage options. The design required synthesis, optimization, characterization, and evaluation of these nanofibers for transdermal drug delivery. Using a Box-Behnken design, the nanofibers were produced via the electrospinning technique, achieving a high drug content of 96.31 ± 1.21 % and entrapment efficiency of 96.18 ± 1.42 %. The in vitro drug release studies demonstrated a prolonged release profile of SF over 24 h, with 97 % ± 2 % of the drug released. The SEM analysis revealed that the surface morphology of the nanofibers was smooth and homogenous, and the average diameter of the SF/PVA/PLGA nanofibers was found to be 150.23 ± 2.50 nm. X-ray diffraction results confirmed the amorphous structure of the nanofibers. The zebrafish embryonic toxicological study did not reveal any signs of toxicity or morphological abnormalities in the developing embryos, indicating that the nanofibers are safe. The results point to the applicability of SF nanofiber membranes in personalized narcolepsy therapy, which improves patients’ quality of life and the efficacy of their treatment. These nanofibers can be given in the form of a transdermal patch to patients for sustained drug delivery, even when they fall asleep or when they cannot take medicines orally.

Rapid DNA Repair in Mesenchymal Stem Cells and Bone Regeneration by Nanoparticle-Based Codelivery of Nrf2-mRNA and Dexamethasone.

Directional differentiation is a key factor determining the result of stem cell therapy. Herein, we developed a polyethylenimine (PEI)-coated poly(lactic-co-glycolic) acid (PLGA) nanoparticle (mPDN) carrying both nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA and dexamethasone (Dex) to human mesenchymal stem cells (hMSCs). The combination of Dex and Nrf2-mRNA delivered by mPDN promoted the osteogenic differentiation of hMSCs. In particular, Nrf2-mRNA rapidly reduced the DNA damage caused by ROS due to early and efficient gene expression at 3 h after treatment, which was not achieved in traditional pDNA systems. High and rapid transfection, effective ROS-scavenging effect, and protection of mitochondrial dynamics were observed in hMSCs after treatment with the resulting Nrf2-mPDN. Osteogenic differentiation was also observed in 3D pellets for up to 5 weeks. Finally, the effects of rapid DNA repair in hMSCs by Nrf2-mPDN and on in vivo bone regeneration were evaluated in a rat femoral bone defect model using CT. This study demonstrated the potential of an NP-based codelivery system and efficient transfection of mRNA at early stages in hMSCs for bone regeneration and stem cell therapy.

Unveiling the potential of pulmonary surfactant-based nanocarriers for protein inhalation therapy

The study investigates the effect of pulmonary surfactant (PS) coating on the performance of lysozyme-loaded poly(lactic-co-glycolic) acid (PLGA) nanoparticles (NPs). The NPs were fabricated using a double emulsification technique and optimized using the Box-Behnken experimental design (BBED). The NPs were assessed for size, polydispersity index (PDI), zeta potential, drug loading (DL%), and encapsulation efficiency (EE%). In addition, the optimized PLGA NPs were modified with either a neutral dipalmitoylphosphatidylcholine DPPC or an anionic dipalmitoyl phosphatidylglycerol (DPPG) with different molar ratios of PS to PLGA (PS: PLGA = 1:2, 1:1 and 2:1). These NPs were assessed for biological activity, drug release, mucus adhesion, mucus penetration, cellular uptake, toxicity, and in vivo destiny after intratracheal (IT) instillation to mice. Results showed a bi-phasic drug release, with no significant effect of PS on the release and biological activities of PLGA NPs. The PS@PLGA NPs improved mucus adhesion, decreased mucus penetration, and increased cellular internalization of PLGA NPs. In addition, ex vivo experiments demonstrated that DPPC@PLGA NPs and DPPG@PLGA NPs could adhere to mucus. These NPs created a thicker layer at the interface of the airway compared to unmodified PLGA NPs. Moreover, interaction of PS@PLGA NPs with BALF suggested improved mucoadhesive characteristics. Finally, the in vivo studies confirmed the precise distribution of all NPs in the lungs after IT administration. The study presents empirical evidence and scientific guidance for developing a lung surfactant-modified nanocarrier system for lung drug delivery.

Dual drug delivery systems based on natural and synthetic polymer particles for isoniazid and rifampicin vehiculization

AbstractThe purpose of this work is the design and characterization of novel systems based on micro and nanoparticles prepared from poly(lactic‐co‐glycolic) acid (PLGA), chitosan (CHT) and gelatin (GEL) for compartmentalization and dual release of rifampicin and isoniazid. The emulsion/evaporation method is employed for the preparation of PLGA based microparticles and nanoparticles. CHT and GEL are used for the preparation of microparticles by spray‐drying. Entrapment efficiencies are in the range of 35%–73% and 5%–29% for rifampicin and isoniazid in PLGA microparticles, respectively. For isoniazid GEL:CHT particles the entrapment efficiencies are within 82%–100%. Isoniazid shows a complete release at acid condition from GEL:CHT particles, while rifampicin release is maintained from GEL:CHT particles or displays an slightly increase from PLGA particles during buffer conditions. Antimycobacterial activity experiments show that the formulations present the ability to inhibit the bacterial growth in comparison with a control culture without treatment. Rifampicin PLGA and isoniazid GEL:CHT microparticles could be used for the preparation of a dual drug delivery system with each antibiotic in a single particulate compartment. GEL:CHT microparticles containing free isoniazid and rifampicin PLGA nanoparticles are a novel two compartment delivery system.

An Adaptive Approach in Polymer-Drug Nanoparticle Engineering using Slanted Electrohydrodynamic Needles and Horizontal Spraying Planes.

The present study focuses on the adaptive development of a key peripheral component of conventional electrohydrodynamic atomisation (EHDA) systems, namely spraying needles (also referred to as nozzles or spinnerets). Needle geometry and planar alignment are often overlooked. To explore potential impact, curcumin-loaded polylactic-co-glycolic acid (PLGA) and methoxypolyethylene glycol amine (PEG)-based nanoparticles were fabricated. To elucidate these technological aspects, a horizontal electrospraying needle regime was adapted, and three formulations containing different polymeric ratios of PLGA: PEG (50:50, 75:25, and 25:75) were prepared and utilised. Furthermore, processing head tip geometries e.g.blunt (a flat needle exit) or slanted (a 45° inclination angle), were subjected to various flow rates (5 µL-100 µL). Successful engineering of curcumin-loaded polymeric nanoparticles (< 150nm) was observed. In-silico analysis demonstrated stable properties of curcumin, PEG and PLGA (molecular docking studies) and fluid flow direction towardsthe Taylor-Cone (also known as the stable jet mode), was shownby the assessment of fluid dynamics simulations in various needle outlets. Curcumin-loaded nanoparticles were characterised using an array of methods including Scanning electron microscopy, Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, as well as their contact angles, encapsulation efficiencies and finally release patterns. The discrepancy when spraying with blunt and angled needles was evidenced by electron micrographs and deposition patterns. Spraying plumes utilising slanted needles enhanced particle collection efficiency and distribution of resultant atomised structures. In addition to needle design, fine-tuning the applied voltage and flow rate impacted the electrospraying process. The coefficient of variation was calculated as 30.5% and 25.6% for blunt and angled needle outlets, respectively, presenting improved particle uniformity with the employment of angled needle tips (8-G needle at 25 µL). The interplay of processing parameters with the utilisation of a slanted exit at a capillary optimised the spray pattern and formation of desired nanoparticulates. These demonstrate great applicability for controlled deposition and up-scaling processes in the pharmaceutical industry. These advances elaborate on EHDA processes, indicating a more cost-effective and scalable approach for industrial applications, facilitating the generation of a diverse range of particle systems in a controlled and more uniform fashion.

Enhanced Mandibular Bone Repair Using Poly Lactic-co-glycolic Acid Combined with Nanohydroxyapatite Scaffold Loaded by Mesenchymal Stromal/Stem Cells and Curcumin in Male Rats.

This study aimed to investigate the healing effect of a polylactic-co-glycolic acid (PLGA) scaffold containing nanohydroxyapatite (NHA) along with curcumin (CCM), loaded with adipose-derived mesenchymal stem cells (AD-MSCs), on mandibular bone defects. The designed PLGA scaffolds containing NHA were evaluated for their mechanical and structural properties. Forty rats were divided into five groups (n = 8) based on the treatment: Sham, PLGA scaffolds containing NHA, PLGA scaffolds containing NHA + CCM, PLGA scaffolds containing NHA + AD-MSCs, and PLGA scaffolds containing NHA + CCM + AD-MSCs. After 8 weeks' follow-up, mandible bones were isolated for histomorphometry evaluation. Data were analyzed using SPSS version 21, with p-values <0.05 considered statistically significant. SEM evaluation showed that the designed nanocomposite scaffold had 80% porosity. Histomorphometry results indicated a significant difference in osteocyte, osteoblast, bone area, and vascular area parameters in the group treated with scaffolds loaded with AD-MSCs + CCM compared to the other groups (p < 0.05). The PLGA-containing NHA-CCM nanocomposite scaffold demonstrated good porosity and dispersion, suitable for treating bone defects. Rats treated with scaffolds containing AD-MSCs and CCM showed better therapeutic results than the other groups. Further research is needed to evaluate its anti-inflammatory, antioxidant properties, osteogenesis, and therapeutic effects in larger animal models.

Development of Stable and Intensified Mixing Processes for the Precise and Scalable Production of Uniform Drug Delivery Nanocarriers.

Nanocarriers show great promise in drug delivery but face challenges in stability, uniformity, and morphology control. This work introduces an enhanced mixing process to overcome these obstacles, specifically aiming to produce consistently sized poly(lactic-co-glycolic) acid (PLGA) nanoparticles loaded with anti-tumor drugs. By innovatively integrating a pulsation dampener into the microfluidic channels of a continuous flow preparation system, the flow stability of piston pumps is improved nearly tenfold. Consequently, large-scale production of uniformly sized nanoparticles with customizable dimensions is achieved through nanoprecipitation. Furthermore, incorporating terminal double-bond-functionalized poly(lactic-co-glycolic acid)-b-poly(ethylene glycol)-maleimide (PLGA-PEG-Mal) enables these nanoparticles to act as nano-crosslinkers. This facilitates in situ crosslinking with thiolated hyaluronic acid via a spontaneous thiol-ene coupling reaction under physiological conditions, allowing for minimally invasive drug administration and significantly enhancing localized drug retention. The material's degradability in the presence of endogenous enzymes ensures controlled drug release, as demonstrated with the anti-tumor drug doxorubicin (DOX). Validation in a murine breast cancer model shows reduced toxicity and a substantial reduction in tumor weight compared to the free DOX group. These findings confirm the approach's effectiveness for breast cancer treatment and pave the way for innovative solutions in nanomedicine, providing a practical microfluidic mixing system for the design and large-scale production of nanomedicines.

Rifampicin-Loaded PLGA/Alginate-Grafted pNVCL-Based Nanoparticles for Wound Healing

The topical therapy with rifampicin (RF)-based formulations is beneficial for treating postoperative wound infections and to accelerate healing. Despite recent research highlighting the antibiotic’s significant anti-inflammatory properties, limited topical wound healing products are currently available. The present study aimed to prove that the newly synthesized nanoparticles based on grafted alginate and poly(N-vinylcaprolactam) (pNVCL) and poly-lactic-co-glycolic acid (PLGA) contribute to the healing process of a wound. The methods used were at first the synthesis of the copolymer of alginate and pNVCL via grafting from technique and radical polymerization followed by water-in-oil-in water (W/O/W) emulsification; as oil phase PLGA dissolved in dichloromethane (DCM) was used. The formed nanoparticles were than characterized. The loaded RF was determined to be 160 µg/mL for a 20 mg formulation and within a four-hour time frame approximately 10% of the total loaded amount was released. The inhibitory concentrations (IC50) were 192.1 µg/mL for the nanoparticle, 208.8 µg/mL for pure rifampicin, and 718.1 µg/mL for the rifampicin-loaded nanoparticles. Considering the double role rifampicin was used for, the result was considered satisfactory in the way that these formulations could be used predominantly for postoperative wound irrigation in order to avoid infections and to improve healing.

High quality factor, monodisperse micron-sized random lasers based on porous PLGA spheres.

Miniature random lasers with high quality factor are crucial for applications in barcoding, bioimaging, and on-chip technologies. However, achieving monodisperse and size-tunable biocompatible random lasers has been a significant challenge. In this study, we employed poly(lactic-co-glycolic) acid (PLGA), a biocompatible material approved for medical use, as the base material for random lasers. By integrating a dye-doped PLGA solution with a microfluidic system, we successfully fabricated monodisperse and miniature dye-doped PLGA spheres with tunable sizes ranging from 25 to 52 µm. Upon optical pulse excitation, these spheres exhibited strong random lasing emission at 610-640 nm with a threshold of approximately 22 µJ·mm-2. The lasing modes demonstrated a spectral linewidth of 0.2 nm, corresponding to a quality factor of 3100. Fourier transform analysis of the lasing emission revealed fundamental cavity lengths, providing insights into the properties of the random lasers.

Magnesium-Titanium Alloys: A Promising Solution for Biodegradable Biomedical Implants.

Magnesium (Mg) has attracted considerable attention as a biodegradable material for medical implants owing to its excellent biocompatibility, mitigating long-term toxicity and stress shielding. Nevertheless, challenges arise from its rapid degradation and low corrosion resistance under physiological conditions. To overcome these challenges, titanium (biocompatibility and corrosion resistance) has been integrated into Mg. The incorporation of titanium significantly improves mechanical and corrosion resistance properties, thereby enhancing performance in biological settings. Mg-Ti alloys are produced through mechanical alloying and spark plasma sintering (SPS). The SPS technique transforms powder mixtures into bulk materials while preserving structural integrity, resulting in enhanced corrosion resistance, particularly Mg80-Ti20 alloy in simulated body fluids. Moreover, Mg-Ti alloy revealed no more toxicity when assessed on pre-osteoblastic cells. Furthermore, the ability of Mg-Ti-based alloy to create composites with polymers such as PLGA (polylactic-co-glycolic acid) widen their biomedical applications by regulating degradation and ensuring pH stability. These alloys promote temporary orthopaedic implants, offering initial load-bearing capacity during the healing process of fractures without requiring a second surgery for removal. To address scalability constraints, further research is necessary to investigate additional consolidation methods beyond SPS. It is essential to evaluate the relationship between corrosion and mechanical loading to confirm their adequacy in physiological environments. This review article highlights the importance of mechanical characterization and corrosion evaluation of Mg-Ti alloys, reinforcing their applicability in fracture fixation and various biomedical implants.

Partial Protection of Goats against Haemonchus contortus Achieved with ADP-Ribosylation Factor 1 Encapsulated in PLGA Nanoparticles.

Haemonchus contortus (H. contortus), a nematode with global prevalence, poses a major threat to the gastrointestinal health of sheep and goats. In an effort to combat this parasite, a nanovaccine was created using a recombinant ADP-ribosylation factor 1 (ARF1) antigen encapsulated within poly lactic-co-glycolic acid (PLGA). This study aimed to assess the effectiveness of this nanovaccine in providing protection against H. contortus infection. Fifteen goats were randomly divided into three groups. The experimental group received two doses of the PLGA encapsulated rHcARF1 (rHcARF1-PLGA) nanovaccine on days 0 and 14. Fourteen days after the second immunization, both the experimental and positive control groups were challenged with 8000 infective larvae (L3) of H. contortus, while the negative control group remained unvaccinated and unchallenged. At the end of the experiment on the 63rd day, all animals were humanly euthanized. The results showed that the experimental group had significantly higher levels of sera IgG, IgA, and IgE antibodies, as well as increased concentrations of cytokines, such as IL-4, IL-9, IL-17, and TGF-β, compared to the negative control group after immunization. Following the L3 challenge, the experimental group exhibited a 47.5% reduction in mean eggs per gram of feces (EPG) and a 55.7% reduction in worm burden as compared to the positive control group. These findings indicate that the nanovaccine expressing rHcARF1 offers significant protective efficacy against H. contortus infection in goats. The results also suggest the need for more precise optimization of the antigen dose or a reassessment of the vaccination regimen. Additionally, the small sample size limits the statistical rigor and the broader applicability of the findings.

Mechanistic Model for Drug Release from PLGA-Based Biodegradable Implants for In Vitro Release Testing: Development and Validation.

Several factors can affect drug release from polylactide coglycolide (PLGA)-based formulations, including polymer and drug properties, formulation components, manufacturing processes, and environmental in vitro or in vivo conditions. To achieve optimal release profiles for specific drug delivery applications, it is crucial to understand the mechanistic processes that determine drug release from PLGA-based formulations. In the current study, we developed a mechanistic model for the in vitro drug release of PLGA-based solid implants. The model accounts for all known critical quality attributes (CQAs) and considers the most important release rate processes, including water or dissolution medium influx into the porous structure of the implant, initial noncatalytic hydrolysis of PLGA, autocatalytic hydrolysis, dissolution of oligomers and monomers into the aqueous medium, the liberation of the trapped solid drug from the polymer matrix, dissolution of the solid drug into the wetted pore network, diffusion of the dissolved drug out of the implant, and distribution of the dissolved drug into the dissolution medium. The model has been validated using in vitro release data obtained from implants of four drugs (buserelin, afamelanotide, brimonidine, and nafarelin). The model presented in this manuscript provides valuable insights into the kinetics and mechanism of drug release from PLGA-based solid implants and has demonstrated the potential for optimizing formulation design. The in vitro release model, coupled with physiologically based pharmacokinetic (PBPK) modeling, can predict the in vivo performance of implants and can be used to support bioequivalence studies in a drug development program.

3D-printed magnesium-doped micro-nano bioactive glass composite scaffolds repair critical bone defects by promoting osteogenesis, angiogenesis, and immunomodulation

Magnesium ions play an important immune-regulatory role during bone repair. For this study, we prepared micro-nano bioactive glass (MNBG) containing magnesium, which can release magnesium, silicon, and calcium ions and has a positive impact on osteogenic differentiation and vascular regeneration. In this study, MgMNBG was compounded and combined with poly(lactic-co-glycolic acid (PLGA) and polycaprolactone (PCL) for 3D printing. Afterwards, the physicochemical properties and bone repair performance of the scaffolds were evaluated throughin vitroandin vivoexperiments. We also investigated the effects of MgMNBG on osteogenic differentiation, immune regulation, and vascular regeneration. The results showed that MgMNBG can inhibit inflammation and promote osteogenesis and angiogenesis by regulating macrophages. PLGA/PCL/MgMNBG scaffolds have good osteogenic and angiogenic effects, and the composite scaffolds have excellent bone repair performance and potential application value.

Macrophage Membrane-Biomimetic Multi-Layered Nanoparticles Targeting Synovial Angiogenesis for Osteoarthritis Therapy.

Osteoarthritis (OA) is an inflammatory and progressive joint disease characterized by angiogenesis-mediated sustained, chronic, and low-grade synovitis. Anti-angiogenesis is emerging as a strategy for attenuating OA progression, but is often compromised by poor targeted drug delivery and immune clearance. Recent studies have identified macrophages formed a "protective barrier" in the lining layer (LL) of synovium, which blocked the communication of joint cavity and sublining layer (SL) of synovium. Inspired by natural mimicry, macrophage membrane-camouflaged drug delivery is explored to avoid immune clearance. Based on the single cell RNA sequencing, the CD34+ synovial cells are identified as "sentinel cells" for synovium angiogenesis. Consequently, CD34 antibody-modified macrophage membraneis constructed to target new angiogenesis. Hence, a biomimetic multi-layered nanoparticle (NP) is developed that incorporates axitinib-loaded poly(lactic-co-glycolic) acid (PLGA) with CD34 antibody modified macrophage membrane (Atb@NP@Raw@CD34) to specifically deliver axitinib (Atb) to the SL and sustain inhibiting angiogenesis without immune elimination. It is found that the Atb@NP@Raw@CD34 can pass through macrophage "barrier", specifically targeting CD34+ cells, continuously releasing Atb and anti-angiogenesis in OA synovitis. Furthermore, in vivo data demonstrated that Atb@NP@Raw@CD34 can attenuate joint degeneration by inhibiting synovium angiogenesis-mediated synovitis. In conclusion, local injection of Atb@NP@Raw@CD34 presents a promising approach for clinically impeding OA progression.

Silver Nanoparticles and Simvastatin-Loaded PLGA-Coated Hydroxyapatite/Calcium Carbonate Scaffolds.

The need to develop synthetic bone substitutes with structures, properties, and functions similar to bone and capable of preventing microbial infections is still an ongoing challenge. This research is focused on the preparation and characterization of three-dimensional porous scaffolds based on hydroxyapatite (HA)-functionalized calcium carbonate loaded with silver nanoparticles and simvastatin (SIMV). The scaffolds were prepared using the foam replica method, with a polyurethane (PU) sponge as a template, followed by successive polymer removal and sintering. The scaffolds were then coated with poly(lactic-co-glycolic) acid (PLGA) to improve mechanical properties and structural integrity, and loaded with silver nanoparticles and SIMV. The scaffolds were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), ATR FT-IR, and silver and SIMV loading. Moreover, the samples were analyzed by Brillouin and Raman microscopy. Finally, in vitro bioactivity, SIMV and silver release, and antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis were evaluated. From the Brillouin spectra, samples showed characteristics analogous to those of bone tissue. They exhibited new hydroxyapatite growth, as evidenced by SEM, and good antimicrobial activity against the tested bacteria. In conclusion, the obtained results demonstrate the potential of the scaffolds for application in bone repair.