PLGA Based Drug Carrier and Pharmaceutical Applications: The Most Recent Advances

Bone Tissue Engineering and Nanotechnology: A Promising Combination for Bone Regeneration

Large bone defects are the leading contributor to disability worldwide, affecting approximately 1.71 billion people. Conventional bone graft treatments show several disadvantages that negatively impact their therapeutic outcomes and limit their clinical practice. Therefore, much effort has been made to devise new and more effective approaches. In this context, bone tissue engineering (BTE), involving the use of biomaterials which are able to mimic the natural architecture of bone, has emerged as a key strategy for the regeneration of large defects. However, although different types of biomaterials for bone regeneration have been developed and investigated, to date, none of them has been able to completely fulfill the requirements of an ideal implantable material. In this context, in recent years, the field of nanotechnology and the application of nanomaterials to regenerative medicine have gained significant attention from researchers. Nanotechnology has revolutionized the BTE field due to the possibility of generating nanoengineered particles that are able to overcome the current limitations in regenerative strategies, including reduced cell proliferation and differentiation, the inadequate mechanical strength of biomaterials, and poor production of extrinsic factors which are necessary for efficient osteogenesis. In this review, we report on the latest in vitro and in vivo studies on the impact of nanotechnology in the field of BTE, focusing on the effects of nanoparticles on the properties of cells and the use of biomaterials for bone regeneration.

Harnessing the Potential of PLGA Nanoparticles for Enhanced Bone Regeneration

Recently, nanotechnologies have become increasingly prominent in the field of bone tissue engineering (BTE), offering substantial potential to advance the field forward. These advancements manifest in two primary ways: the localized application of nanoengineered materials to enhance bone regeneration and their use as nanovehicles for delivering bioactive compounds. Despite significant progress in the development of bone substitutes over the past few decades, it is worth noting that the quest to identify the optimal biomaterial for bone regeneration remains a subject of intense debate. Ever since its initial discovery, poly(lactic-co-glycolic acid) (PLGA) has found widespread use in BTE due to its favorable biocompatibility and customizable biodegradability. This review provides an overview of contemporary advancements in the development of bone regeneration materials using PLGA polymers. The review covers some of the properties of PLGA, with a special focus on modifications of these properties towards bone regeneration. Furthermore, we delve into the techniques for synthesizing PLGA nanoparticles (NPs), the diverse forms in which these NPs can be fabricated, and the bioactive molecules that exhibit therapeutic potential for promoting bone regeneration. Additionally, we addressed some of the current concerns regarding the safety of PLGA NPs and PLGA-based products available on the market. Finally, we briefly discussed some of the current challenges and proposed some strategies to functionally enhance the fabrication of PLGA NPs towards BTE. We envisage that the utilization of PLGA NP holds significant potential as a potent tool in advancing therapies for intractable bone diseases.

Novel 40 µm spot size 3050/3200 nm DFG laser versus CO2 laser for laser-assisted drug delivery

BACKGROUND AND OBJECTIVES

The use of ablative fractional lasers to enhance the delivery of topical drugs through the skin is known as laser-assisted drug delivery. Here, we compare a novel 3050/3200 nm difference frequency generation (DFG) fiber laser (spot size: 40 µm) to a commercially used CO2 laser (spot size: 120 µm). The objective is to determine whether differences in spot size and coagulation zone (CZ) thickness influence drug uptake.

MATERIALS AND METHODS

Fractional ablation was performed on ex-vivo human abdominal skin with the DFG (5 mJ) and CO2 (12 mJ) lasers to generate 680 µm deep lesions. To evaluate drug delivery, 30 kDa encapsulated fluorescent dye was topically applied to the skin and histologically analyzed at skin depths of 100, 140, 200, 400, and 600 µm. Additionally, transcutaneous permeation of encapsulated and 350 Da nonencapsulated dye was assessed using Franz Cells.

RESULTS

The DFG laser generated smaller channels (diameter: 56.5 µm) with thinner CZs (thickness: 22.4 µm) than the CO2 laser (diameter: 75.9 µm, thickness: 66.8 µm). The DFG laser treated group exhibited significantly higher encapsulated dye total fluorescence intensities after 3 h compared to the CO2 laser treated group across all skin depths (p < 0.001). Permeation of nonencapsulated dye was also higher in the DFG laser treated group vs the CO2 laser treated group after 48 h (p < 0.0001), while encapsulated dye was not detected in any group.

CONCLUSION

The DFG laser treated skin exhibited significantly higher total fluorescence uptake compared to the CO2 laser. Additionally, the smaller spot size and thinner CZ of the DFG laser could result in faster wound healing and reduced adverse effects while delivering similar or greater amount of topically applied drugs.

Polymeric Particle BAM15 Targeting Macrophages Attenuates the Severity of LPS-Induced Sepsis: A Proof of Concept for Specific Immune Cell-Targeted Therapy

Macrophage polarization requires different energy sources and metabolic processes. Therefore, cell energy interference to alter macrophage functions has been proposed as a treatment for severe inflammatory diseases, including sepsis. In this study, targeting cell energy using BAM15 (a mitochondrial uncoupling agent) in human THP-1 and mouse RAW264.7 macrophages prominently interfered with M1 but not M2 polarization. Free BAM15 (BAM15) and BAM15-loaded PLGA particles (BAM15 particles) reduced the inflammatory response of M1 macrophages and enhanced the expression of M2 signature genes with the restoration of mitochondrial activity (extracellular flux analysis) in RAW264.7 cells. Furthermore, BAM15 particles but not BAM15 showed specific effects on the inflammatory response of macrophages but not neutrophils, and the particles were actively captured by splenic and liver macrophages in vivo. Administration of BAM15 and BAM15 particles attenuated the severity of sepsis in LPS-induced sepsis mice. Interestingly, BAM15 particles but not BAM15 alleviated LPS-induced liver injury by reducing hepatic inflammation. Our findings substantiate the superior efficacy of macrophage-targeted therapy using a BAM15 particle-delivery system and provide further support for clinical development as a potential therapy for severe inflammatory diseases.

Synthesis and characterization of chemical engineered PLGA nanosphere: Triggering mechanism of Catechol-O-methyltransferase inhibition on in vivo neurodegeneration

Chemically engineered PLGA nanospheres are one of the emerging technologies for treating neurodegenerative disorders by inhibiting Catechol-O-methyltransferase (COMT). PLGA-MATPM nanospheres were chemically synthesized using PLGA and MATPM (N-allyl-N-(3-(m-tolyloxy)propyl) methioninate). The tailored PLGA nanospheres induce dose-dependent COMT inhibition in competitive kinetic mode. The interactions between COMT and PLGA nanosphere are explained by spectroscopic and molecular dynamics analysis. PLGA-MATPM NPs suppressed the growth of neuroblastoma cells due to the neurodegenerative toxicity of MPTP induction, demonstrating its potency as a cure for neurological disorders. PLGA-MATPM NPs cross the blood-brain barrier more effectively than those in the blood. Furthermore, PLGA nanospheres showed the most neurodegenerative recovery against MPTP-induced C57BL/6 mice. Using magnetic resonance imaging (MRI), it was validated for quality images of cerebral blood flow (CBF).

Polymer-Based Nanoparticles as Drug Delivery Systems for Purines of Established Importance in Medicine

Many purine derivatives are active pharmaceutical ingredients of significant importance in the therapy of autoimmune diseases, cancers, and viral infections. In many cases, their medical use is limited due to unfavorable physicochemical and pharmacokinetic properties. These problems can be overcome by the preparation of the prodrugs of purines or by combining these compounds with nanoparticles. Herein, we aim to review the scientific progress and perspectives for polymer-based nanoparticles as drug delivery systems for purines. Polymeric nanoparticles turned out to have the potential to augment antiviral and antiproliferative effects of purine derivatives by specific binding to receptors (ASGR1-liver, macrophage mannose receptor), increase in drug retention (in eye, intestines, and vagina), and permeation (intranasal to brain delivery, PEPT1 transport of acyclovir). The most significant achievements of polymer-based nanoparticles as drug delivery systems for purines were found for tenofovir disoproxil in protection against HIV, for acyclovir against HSV, for 6-mercaptopurine in prolongation of mice ALL model life, as well as for 6-thioguanine for increased efficacy of adoptively transferred T cells. Moreover, nanocarriers were able to diminish the toxic effects of acyclovir, didanosine, cladribine, tenofovir, 6-mercaptopurine, and 6-thioguanine.

NLRP3 Inflammasome-Targeting Nanomicelles for Preventing Ischemia-Reperfusion-Induced Inflammatory Injury

Ischemia-reperfusion (I/R) injury is a disease process that affects several vital organs. There is widespread agreement that the NLRP3 inflammasome pathway plays a crucial role in the development of I/R injury. We have developed transferrin-conjugated, pH-responsive nanomicelles for the entrapment of MCC950 drug. These nanomicelles specifically bind to the transferrin receptor 1 (TFR1) expressed on the cells of the blood-brain barrier (BBB) and thus help the cargo to cross the BBB. Furthermore, the therapeutic potential of nanomicelles was assessed using in vitro, in ovo, and in vivo models of I/R injury. Nanomicelles were injected into the common carotid artery (CCA) of a middle cerebral artery occlusion (MCAO) rat model to achieve maximum accretion of nanomicelles into the brain as blood flows toward the brain in the CCA. The current study reveals that the treatment with nanomicelles significantly alleviates the levels of NLRP3 inflammasome biomarkers which were found to be increased in oxygen-glucose deprivation (OGD)-treated SH-SY5Y cells, the I/R-damaged right vitelline artery (RVA) of chick embryos, and the MCAO rat model. The supplementation with nanomicelles significantly enhanced the overall survival of MCAO rats. Overall, nanomicelles exerted therapeutic effects against I/R injury, which might be due to the suppression of the activation of the NLRP3 inflammasome.

Box-Behnken assisted development and validation of high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles

While histone deacetylase inhibitors, such as vorinostat, demonstrate a significant effect against hematological cancers, their application for solid tumor treatment is limited. However, there is strong evidence that combinatorial administration of vorinostat and genotoxic agents (e.g., doxorubicin) enhances the antitumoral action of both drugs against tumors. We developed a high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles designed to provide the parenteral administration of both drugs and increase their safety profile. We performed separation on Nucleodur C-18 Gravity column with a mixture of 10 mM potassium dihydrogen phosphate buffer pH 3.9:ACN (90:10 v/v) as mobile phase at 240 nm. The method was linear within the concentration range of 4.2-52.0 μg/ml for both drugs with limits of detection and quantification of 3.5 and 10.7 μg/ml for doxorubicin and 2.5 and 7.7 μg/ml for vorinostat, respectively. The method was precise and accurate over the concentration range of analysis. Drug loading was 5.4% for doxorubicin and 0.8% for vorinostat. Degradation of doxorubicin after irradiation was less than 5%, while the amount of vorinostat decreased at 88% under the same conditions. Thus, the validated method could be adopted for routine simultaneous analysis of doxorubicin and vorinostat in polymeric nanoparticles.

PLGA-PVA-PEG Single Emulsion Method as a Candidate for Aminolevulinic Acid (5-ALA) Encapsulation: Laboratory Scaling up and Stability Evaluation

One of the most widely used molecules used for photodynamic therapy (PDT) is 5-aminolevulinic acid (5-ALA), a precursor in the synthesis of tetrapyrroles such as chlorophyll and heme. The 5-ALA skin permeation is considerably reduced due to its hydrophilic characteristics, decreasing its local bioavailability and therapeutic effect. For this reason, five different systems containing polymeric particles of poly [D, L–lactic–co–glycolic acid (PLGA)] were developed to encapsulate 5-ALA based on single and double emulsions methodology. All systems were standardized (according to the volume of reagents and mass of pharmaceutical ingredients) and compared in terms of laboratory scaling up, particle formation and stability over time. UV-VIS spectroscopy revealed that particle absorption/adsorption of 5-ALA was dependent on the method of synthesis. Different size distribution was observed by DLS and NTA techniques, revealing that 5-ALA increased the particle size. The contact angle evaluation showed that the system hydrophobicity was dependent on the surfactant and the 5-ALA contribution. The FTIR results indicated that the type of emulsion influenced the particle formation, as well as allowing PEG functionalization and interaction with 5-ALA. According to the ¹H-NMR results, the 5-ALA reduced the T1 values of polyvinyl alcohol (PVA) and PLGA in the double emulsion systems due to the decrease in molecular packing in the hydrophobic region. The results indicated that the system formed by single emulsion containing the combination PVA–PEG presented greater stability with less influence from 5-ALA. This system is a promising candidate to successfully encapsulate 5-ALA and achieve good performance and specificity for in vitro skin cancer treatment.

Pharmaceutical-eluting hybrid degradable hydrogel/microparticle loaded sacs for finger joint interpositional arthroplasty

Despite recent advances in medical technology, treatment of chronic osteomyelitis in the small joint of the hand remains challenging. Here, we exploited hybrid biodegradable hydrogel/microparticle/polycaprolactone (PCL) sacs for finger joint interpositional arthroplasty via electrospraying and rotational molding techniques. Degradable Pluronic F127, poly(lactic-co-glycolic acid) (PLGA), and PCL were starting materials for the hydrogels, microparticles, and sac, respectively. Vancomycin, ceftazidime, and lidocaine were the embedded pharmaceuticals. The in vitro and in vivo drug release behaviors of hybrid drug-eluting sacs were assessed. The empirical outcomes show that the size distribution of the electrosprayed vancomycin/ceftazidime/lidocaine PLGA microparticles was 8.25 ± 3.35 μm. Biodegradable PCL sacs offered sustainable and effective release of vancomycin, ceftazidime, and lidocaine, respectively, after 30, 16, and 11 days in vitro. The sacs also discharged high levels of anti-microbial agents for 56 days and analgesics for 14 days in a rabbit knee joint model. The blood urea nitrogen (creatinine) levels remained normal at various time points: 16.5 ± 2.5 mg/dL (0.85 ± 0.24 mg/dL), 20.0 ± 1.4 mg/dL (1.0 ± 0.16 mg/dL), 19.3 ± 2.4 mg/dL (1.13 ± 0.15 mg/dL), and 20.0 ± 2.16 mg/dL (1.0 ± 0.16 mg/dL) at days 7, 14, 21, and 35, respectively. The empirical outcomes of this study suggested that the hybrid biodegradable drug-eluting sacs with extended liberation of pharmaceuticals may find applications in the small joints for post-operative pain relief and infection control.

Biomimetic Gradient Scaffolds Containing Hyaluronic Acid and Sr/Zn Folates for Osteochondral Tissue Engineering

Regenerative therapies based on tissue engineering are becoming the most promising alternative for the treatment of osteoarthritis and rheumatoid arthritis. However, regeneration of full-thickness articular osteochondral defects that reproduces the complexity of native cartilage and osteochondral interface still remains challenging. Hence, in this work, we present the fabrication, physic-chemical characterization, and in vitro and in vivo evaluation of biomimetic hierarchical scaffolds that mimic both the spatial organization and composition of cartilage and the osteochondral interface. The scaffold is composed of a composite porous support obtained by cryopolymerization of poly(ethylene glycol) dimethacrylate (PEGDMA) in the presence of biodegradable poly(D,L-lactide-co-glycolide) (PLGA), bioactive tricalcium phosphate β-TCP and the bone promoting strontium folate (SrFO), with a gradient biomimetic photo-polymerized methacrylated hyaluronic acid (HAMA) based hydrogel containing the bioactive zinc folic acid derivative (ZnFO). Microscopical analysis of hierarchical scaffolds showed an open interconnected porous open microstructure and the in vitro behaviour results indicated high swelling capacity with a sustained degradation rate. In vitro release studies during 3 weeks indicated the sustained leaching of bioactive compounds, i.e., Sr2+, Zn2+ and folic acid, within a biologically active range without negative effects on human osteoblast cells (hOBs) and human articular cartilage cells (hACs) cultures. In vitro co-cultures of hOBs and hACs revealed guided cell colonization and proliferation according to the matrix microstructure and composition. In vivo rabbit-condyle experiments in a critical-sized defect model showed the ability of the biomimetic scaffold to promote the regeneration of cartilage-like tissue over the scaffold and neoformation of osteochondral tissue.

Latest Innovations and Nanotechnologies with Curcumin as a Nature-Inspired Photosensitizer Applied in the Photodynamic Therapy of Cancer

In the context of the high incidence of cancer worldwide, state-of-the-art photodynamic therapy (PDT) has entered as a usual protocol of attempting to eradicate cancer as a minimally invasive procedure, along with pharmacological resources and radiation therapy. The photosensitizer (PS) excited at certain wavelengths of the applied light source, in the presence of oxygen releases several free radicals and various oxidation products with high cytotoxic potential, which will lead to cell death in irradiated cancerous tissues. Current research focuses on the potential of natural products as a superior generation of photosensitizers, which through the latest nanotechnologies target tumors better, are less toxic to neighboring tissues, but at the same time, have improved light absorption for the more aggressive and widespread forms of cancer. Curcumin incorporated into nanotechnologies has a higher intracellular absorption, a higher targeting rate, increased toxicity to tumor cells, accelerates the activity of caspases and DNA cleavage, decreases the mitochondrial activity of cancer cells, decreases their viability and proliferation, decreases angiogenesis, and finally induces apoptosis. It reduces the size of the primary tumor, reverses multidrug resistance in chemotherapy and decreases resistance to radiation therapy in neoplasms. Current research has shown that the use of PDT and nanoformulations of curcumin has a modulating effect on ROS generation, so light or laser irradiation will lead to excessive ROS growth, while nanocurcumin will reduce the activation of ROS-producing enzymes or will determine the quick removal of ROS, seemingly opposite but synergistic phenomena by inducing neoplasm apoptosis, but at the same time, accelerating the repair of nearby tissue. The latest curcumin nanoformulations have a huge potential to optimize PDT, to overcome major side effects, resistance to chemotherapy, relapses and metastases. All the studies reviewed and presented revealed great potential for the applicability of nanoformulations of curcumin and PDT in cancer therapy.

Poly Lactic-Co-Glycolic Acid- (PLGA-) Loaded Nanoformulation of Cisplatin as a Therapeutic Approach for Breast Cancers

Despite recent advancements in cisplatin (cis-diamminedichloroplatinum II) and other platinum-based chemotherapeutic drugs for treating solid tumors, their uses are limited by either in terms of toxicity and/or acquired drug resistance. These side effects have a dangerous problem with higher dose for severe patients. To overcome the low therapeutic ratio of the free drug, a polymeric nanoparticle drug delivery system has been explored promoting delivery of cisplatin to tumors. Recently, the applications of nanoparticles (NPs) have been underlined for encouraging the effects of chemotherapeutic drugs in cancerous cells. The intention of this project is to assess the potential of poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) for enhancing the effects of anticancer drug cisplatin. For the purpose, we have synthesized PLGA-cisplatin nanoparticles for increasing its bioavailability and studied the comparative cytotoxicity of free cisplatin and PLGA-cisplatin against MCF-7 cancer cell lines and HEK-293 normal cell lines. We have also analyzed the hallmarks of PLGA-cisplatin-induced apoptosis. The outcomes of this study may provide the possibility of delivery of anticancer drug to their specific site, which could minimize toxicity and optimize the drug efficacy.