Effect of Drug Carrier Melting Points on Drug Release of Dexamethasone-Loaded Microspheres

3D-printed scaffolds: Incorporating dexamethasone microspheres and BMP2 for enhanced osteogenic differentiation of human mesenchymal stem cells

This study investigates the fabrication and evaluation of 3D-printed scaffolds (G-scaffolds) incorporating dexamethasone-loaded microspheres (Dex-M) and bone morphogenetic protein 2 (BMP2) to enhance osteogenic differentiation of human mesenchymal stem cells (hMSCs). Dex-M was prepared using an ultrasonic atomizer, achieving a high encapsulation efficiency and uniform particle size. The G-scaffolds were precisely printed using photoactive bioprinting, creating Dex-M+BMP2 +G-scaffolds. In vitro release studies demonstrated sustained Dex release over 6 weeks, with the Dex-M+BMP2 +G-scaffold significantly reducing the initial burst release and maintaining stable levels of osteogenic factors. Cytotoxicity assays confirmed the biocompatibility of the scaffolds, showing no adverse effects on hMSC viability. Osteogenic differentiation was assessed via RT-PCR, revealing that the Dex-M+BMP2 +G-scaffold exhibited the highest expression levels of critical osteogenic markers (ON, OP, OC, and COL1A) compared with the other scaffold formulations. Calcium deposition and elemental analysis also demonstrated enhanced mineralization in the Dex-M+BMP2 +G-scaffold group, with calcium and phosphate levels 3.9-1.7 times higher than in the other groups. Overall, the Dex-M+BMP2 +G-scaffold effectively promoted osteogenic differentiation and mineralization of hMSCs, underscoring its potential as a promising biomaterial for bone tissue engineering applications.

Targeted drug-loaded PLGA-PCL microspheres for specific and localized treatment of triple negative breast cancer

The paper presents the results of the experimental and analytical study of targeted drug-loaded polymer-based microspheres made from blend polymer of polylactic-co-glycolic acid and polycaprolactone (PLGA-PCL) for targeted and localized cancer drug delivery. In vitro sustained release with detailed thermodynamically driven drug release kinetics, over a period of three months using encapsulated targeted drugs (prodigiosin-EphA2 or paclitaxel-EphA2) and control drugs [Prodigiosin (PGS), and paclitaxel (PTX)] were studied. Results from in vitro study showed a sustained and localized drug release that is well-characterized by non-Fickian Korsmeyer-Peppas kinetics model over the range of temperatures of 37 °C (body temperature), 41 °C, and 44 °C (hyperthermic temperatures). The in vitro alamar blue, and flow cytometry assays in the presence of the different drug-loaded polymer formulations resulted to cell death and cytotoxicity that was evidence through cell inhibition and late apoptosis on triple negative breast cancer (TNBC) cells (MDA-MB 231). In vivo studies carried out on groups of 4-week-old athymic nude mice that were induced with subcutaneous TNBC, showed that the localized release of the EphA2-conjugated drugs was effective in complete elimination of residual tumor after local surgical resection. Finally, ex vivo histopathological analysis carried out on the euthanized mice revealed no cytotoxicity and absence of breast cancer metastases in the liver, kidney, and lungs 12 weeks after treatment. The implications of the results are then discussed for the development of encapsulated EphA2-conjugated drugs formulation in the specific targeting, localized, and sustain drug release for the elimination of local recurred TNBC tumors after surgical resection.

Fat Graft with Allograft Adipose Matrix and Magnesium Hydroxide-Incorporated PLGA Microspheres for Effective Soft Tissue Reconstruction

BACKGROUND

Autologous fat grafting is one of the most common procedures used in plastic surgery to correct soft tissue deficiency or depression deformity. However, its clinical outcomes are often suboptimal, and lack of metabolic and architectural support at recipient sites affect fat survival leading to complications such as cyst formation, calcification. Extracellular matrix-based scaffolds, such as allograft adipose matrix (AAM) and poly(lactic-co-glycolic) acid (PLGA), have shown exceptional clinical promise as regenerative scaffolds. Magnesium hydroxide (MH), an alkaline ceramic, has attracted attention as a potential additive to improve biocompatibility. We attempted to combine fat graft with regenerative scaffolds and analyzed the changes and viability of injected fat graft in relation to the effects of injectable natural, and synthetic (PLGA/MH microsphere) biomaterials.

METHODS

In vitro cell cytotoxicity, angiogenesis of the scaffolds, and wound healing were evaluated using human dermal fibroblast cells. Subcutaneous soft-tissue integration of harvested fat tissue was investigated in vivo in nude mouse with random fat transfer protocol Fat integrity and angiogenesis were identified by qRT-PCR and immunohistochemistry.

RESULTS

In vitro cell cytotoxicity was not observed both in AAM and PLGA/MH with human dermal fibroblast. PLGA/MH and AAM showed excellent wound healing effect. In vivo, the AAM and PLGA/MH retained volume compared to that in the only fat group. And the PLGA/MH showed the highest angiogenesis and anti-inflammation.

CONCLUSION

In this study, a comparison of the volume retention effect and angiogenic ability between autologous fat grafting, injectable natural, and synthetic biomaterials will provide a reasonable basis for fat grafting.

Dexamethasone: Insights into Pharmacological Aspects, Therapeutic Mechanisms, and Delivery Systems

Dexamethasone (DEX) has been widely used to treat a variety of diseases, including autoimmune diseases, allergies, ocular disorders, cancer, and, more recently, COVID-19. However, DEX usage is often restricted in the clinic due to its poor water solubility. When administered through a systemic route, it can elicit severe side effects, such as hypertension, peptic ulcers, hyperglycemia, and hydro-electrolytic disorders. There is currently much interest in developing efficient DEX-loaded nanoformulations that ameliorate adverse disease effects inhibiting advancements in scientific research. Various nanoparticles have been developed to selectively deliver drugs without destroying healthy cells or organs in recent years. In the present review, we have summarized some of the most attractive applications of DEX-loaded delivery systems, including liposomes, polymers, hydrogels, nanofibers, silica, calcium phosphate, and hydroxyapatite. This review provides our readers with a broad spectrum of nanomedicine approaches to deliver DEX safely.

Topical ocular delivery of vancomycin loaded cationic lipid nanocarriers as a promising and non-invasive alternative approach to intravitreal injection for enhanced bacterial endophthalmitis management

Vancomycin (VCM) is a drug of choice for treating infections caused by Staphylococcus species, reported being the most causative agent of bacterial endophthalmitis. However, the ocular bioavailability of topically applied VCM is low due to its high molecular weight and hydrophilicity. The current study sought to explore whether the nanostructured lipid carriers (NLCs) fabricated via cold homogenization technique could improve ocular penetration and prolong the ophthalmic residence of VCM. A 2³ full factorial design was adopted to evaluate the influence of different process and formulation variables on VCM-loaded NLC formulae. The optimized formula with the particle size of 96.4 ± 0.71 nm and narrow size distribution showed spherical morphology obtained by AFM and represented sustained drug release up to 67% in 48 h fitted to the Korsmeyer-Peppas model with probably non-Fickian diffusion kinetic. FTIR studies visualized the drug-carrier interactions in great detail. High encapsulation of VCM (74.8 ± 4.3% w/w) in NLC has been established in DSC and PXRD analysis. The optimal positively charged (+ 29.7 ± 0.47 mV) colloidal dispersion was also stable for 12 weeks at both 4 °C and 25 °C. According to in vivo studies, incorporation of VCM in NLC resulted in a nearly 3-fold increase in the intravitreal concentration of VCM after eye-drop instillation over control groups. Besides, microbiological evaluation admitted its therapeutic effect within five days is comparable to intravitreal injection of VCM. Further, the optimized formula was found to be nonirritant and safe for ophthalmic administration in RBC hemolytic assay. Also, fluorescent tracking of NLCs on rabbit's cornea showed an increase in corneal penetration of nanoparticles. Thus, it is possible to infer that the evolved NLCs are promising drug delivery systems with superior attainments for enhanced Vancomycin ophthalmic delivery to the eye's posterior segment and improved bacterial endophthalmitis management.

PLGA Microspheres Containing Hydrophobically Modified Magnesium Hydroxide Particles for Acid Neutralization-Mediated Anti-Inflammation

BACKGROUND

Poly(lactic-co-glycolic acid) (PLGA) microspheres have been actively used in various pharmaceutical formulations because they can sustain active pharmaceutical ingredient release and are easy to administer into the body using a syringe. However, the acidic byproducts produced by the decomposition of PLGA cause inflammatory reactions in surrounding tissues, limiting biocompatibility. Magnesium hydroxide (MH), an alkaline ceramic, has attracted attention as a potential additive because it has an acid-neutralizing effect.

METHODS

To improve the encapsulation efficiency of hydrophilic MH, the MH particles were capped with hydrophobic ricinoleic acid (RA-MH). PLGA microspheres encapsulated with RA-MH particles were manufactured by the O/W method. To assess the in vitro cytotoxicity of the degradation products of PLGA, MH/PLGA, and RA-MH/PLGA microspheres, CCK-8 and Live/Dead assays were performed with NIH-3T3 cells treated with different concentrations of their degradation products. In vitro anti-inflammatory effect of RA-MH/PLGA microspheres was evaluated with quantitative measurement of pro-inflammatory cytokines.

RESULTS

The synthesized RA-MH was encapsulated in PLGA microspheres and displayed more than four times higher loading content than pristine MH. The PLGA microspheres encapsulated with RA-MH had an acid-neutralizing effect better than that of the control group. In an in vitro cell experiment, the degradation products obtained from RA-MH/PLGA microspheres exhibited higher biocompatibility than the degradation products obtained from PLGA microspheres. Additionally, the RA-MH/PLGA microsphere group showed an excellent anti-inflammatory effect.

CONCLUSION

Our results proved that RA-MH-encapsulated PLGA microspheres showed excellent biocompatibility with an anti-inflammatory effect. This technology can be applied to drug delivery and tissue engineering to treat various incurable diseases in the future.

Metformin loaded cholesterol-lysine conjugate nanoparticles: A novel approach for protecting HDFs against UVB-induced senescence

Cellular senescence is one of the hallmarks of aging. Since senescence of dermal fibroblasts has been reported in vivo, reduction of the deleterious effects of these cells, has been considered an important intervention to counteract skin aging. Promising anti-aging effect of metformin has been reported. However, permeation of metformin due to its high hydrophilicity through skin epidermal barriers is limited. In this study, solid lipid nanoparticles (SLNs) of metformin were designed with the newly synthesized cholesterol-lysine conjugate as lipid for topical delivery of metformin. Characterization of SLNs strongly confirmed the effect of cholesterol-lysine conjugate on increasing entrapment of metformin. The designed SLNs with particle size of 283 nm and spherical morphology represented controlled drug release up to 18 days. Fluorescent tracking of SLNs on mice skin samples showed an increase in epidermal penetration. SLNs containing metformin showed anti-senescence effects on UVB-induced senescence of human dermal fibroblasts, this effect was confirmed by senescence-associated β-galactosidase staining, RT q-PCR and cell cycle analyses. Furthermore, our drug-free SLNs showed anti-senescence effects, suggesting that they can be a suitable carrier for phytochemicals with anti-aging effect or other hydrophilic compounds which have constraints permeating skin.

Development of a heat labile antibiotic eluting 3D printed scaffold for the treatment of osteomyelitis

In general, osteomyelitis is treated with antibiotics, and in severe cases, the inflammatory bone tissue is removed and substituted with poly (methyl methacrylate) (PMMA) beads containing antibiotics. However, this treatment necessitates re-surgery to remove the inserted PMMA beads. Moreover, rifampicin, a primary heat-sensitive antibiotic used for osteomyelitis, is deemed unsuitable in this strategy. Three-dimensional (3D) printing technology has gained popularity, as it facilitates the production of a patient-customized implantable structure using various biodegradable biomaterials as well as controlling printing temperature. Therefore, in this study, we developed a rifampicin-loaded 3D scaffold for the treatment of osteomyelitis using 3D printing and polycaprolactone (PCL), a biodegradable polymer that can be printed at low temperatures. We successfully fabricated rifampicin-loaded PCL 3D scaffolds connected with all pores using computer-aided design and manufacturing (CAD/CAM) and printed them at a temperature of 60 °C to prevent the loss of the antibacterial activity of rifampicin. The growth inhibitory activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the representative causative organisms of osteomyelitis, was confirmed. In addition, we optimized the rifampicin-loading capacity that causes no damage to the normal bone tissues in 3D scaffold with toxicity evaluation using human osteoblasts. The rifampicin-releasing 3D scaffold developed herein opens new possibilities of the patient-customized treatment of osteomyelitis.

Augmented re-endothelialization and anti-inflammation of coronary drug-eluting stent by abluminal coating with magnesium hydroxide

Drug-eluting stents (DESs) have been widely used as a treatment approach for coronary artery diseases. Generally, conventional DESs were fully covered with drugs and biodegradable polymers on both abluminal and luminal layers (i.e., conformal coating). However, uncontrolled drug release from the luminal drug-coating layer of the stent is known to inhibit re-endothelialization. Furthermore, the acidification of the surrounding tissue by the decomposed coating polymer causes inflammation, resulting in restenosis and late thrombosis. To overcome these limitations, here we demonstrated a functional DES coated with poly(lactic-co-glycolic acid) (PLGA), sirolimus (SRL), and magnesium hydroxide (Mg(OH)2, MH) precisely only on the abluminal layer. The acidic neutralization effect of MH was elucidated by measuring the pH change of the fabricated film in PBS solution. In an in vitro cell study, the stent coated with MH exhibited higher compatibility with human coronary artery endothelial cells (ECs) and a lower inflammation score as compared to the control stent. Finally, in an in vivo large porcine model, the abluminal coated DES with SRL and MH showed excellent re-endothelialization and anti-inflammatory and anti-thrombotic effects. In conclusion, it is believed that this approach has great potential for the development of functional DES for the treatment of cardiovascular diseases.

An Injectable Click-Crosslinked Hydrogel that Prolongs Dexamethasone Release from Dexamethasone-Loaded Microspheres

Our purpose was to test whether a preparation of injectable formulations of dexamethasone (Dex)-loaded microspheres (Dex-Ms) mixed with click-crosslinked hyaluronic acid (Cx-HA) (or Pluronic (PH) for comparison) prolongs therapeutic levels of released Dex. Dex-Ms were prepared using a monoaxial-nozzle ultrasonic atomizer with an 85% yield of the Dex-Ms preparation, encapsulation efficiency of 80%, and average particle size of 57 μm. Cx-HA was prepared via a click reaction between transcyclooctene (TCO)-modified HA (TCO-HA) and tetrazine (TET)-modified HA (TET-HA). The injectable formulations (Dex-Ms/PH and Dex-Ms/Cx-HA) were fabricated as suspensions and became a Dex-Ms-loaded hydrogel drug depot after injection into the subcutaneous tissue of Sprague Dawley rats. Dex-Ms alone also formed a drug depot after injection. The Cx-HA hydrogel persisted in vivo for 28 days, but the PH hydrogel disappeared within six days, as evidenced by in vivo near-infrared fluorescence imaging. The in vitro and in vivo cumulative release of Dex by Dex-Ms/Cx-HA was much slower in the early days, followed by sustained release for 28 days, compared with Dex-Ms alone and Dex-Ms/PH. The reason was that the Cx-HA hydrogel acted as an external gel matrix for Dex-Ms, resulting in the retarded release of Dex from Dex-Ms. Therefore, we achieved significantly extended duration of a Dex release from an in vivo Dex-Ms-loaded hydrogel drug depot formed by Dex-Ms wrapped in an injectable click-crosslinked HA hydrogel in a minimally invasive manner. In conclusion, the Dex-Ms/Cx-HA drug depot described in this work showed excellent performance on extended in vivo delivery of Dex.

Sustained drug release using cobalt oxide nanowires for the preparation of polymer-free drug-eluting stents

Polymer-based drug-eluting stents (DESs) represented attractive application for the treatment of cardiovascular diseases; however, polymer coating has caused serious adverse responses to tissues such as chronic inflammation due to acidic by-products. Therefore, polymer-free DESs have recently emerged as promising candidates for the treatment; however, burst release of drug(s) from the surface limited its applications. In this study, we focused on delivery of therapeutic drug from polymer-free (or -less) DESs through surface modification using cobalt oxide nanowires (Co₃O₄ NWs) to improve and control the drug release. The results demonstrated that Co₃O₄ NWs could be simply fabricated on cobalt-chromium substrate by ammonia-evaporation-induced method. The Co₃O₄ NWs were uniformly arrayed with diameters of 50-100 nm and lengths of 10 µm. It was found that Co₃O₄ NWs were comparatively stable without any delamination or change of the morphology under in vitro long-term stability using circulating system. Sirolimus was used as a model drug for studying in vitro release behavior under physiological conditions. The sirolimus release behavior from flat cobalt-chromium showed an initial burst (over 90%) after one day. On the other hand, Co₃O₄ NWs presented a sustained sirolimus release rate for up to seven days. Similarly, the polymer-less specimens on Co₃O₄ NWs substrates sustained sirolimus release for a longer-period of time when compared to flat Co-Cr substrates. In summary, the current approach of using Co₃O₄ NWs-based substrates might have a great potential to sustain drug release for drug-eluting implants and medical devices including stents.

Synergistically enhanced osteoconductivity and anti-inflammation of PLGA/β-TCP/Mg(OH)2 composite for orthopedic applications

Synthetic biodegradable polymers including poly(lactide-co-glycolide) (PLGA) have been widely used as alternatives to metallic implantable materials in the orthopedic field due to their superior biocompatibility and biodegradability. However, weak mechanical properties of the biodegradable polymers and inflammatory reaction caused by the acidic degradation products have limited their biomedical applications. In this study, we have developed a PLGA composite containing beta-tricalcium phosphate (β-TCP) and magnesium hydroxide (Mg(OH)₂) as additives to improve mechanical, osteoconductivity, and anti-inflammation property of the biopolymer composite simultaneously. The β-TCP has an osteoconductive effect and the Mg(OH)₂ has a pH neutralizing effect. The PLGA/inorganic composites were uniformly blended via a twin extrusion process. The mechanical property of the PLGA/β-TCP/Mg(OH)₂ composite was improved compared to the pure PLGA. In particular, the addition of Mg(OH)₂ suppressed the inflammatory reaction of normal human osteoblast (NHOst) cells and also inhibited the differentiation of pre-osteoclastic cells into osteoclasts. Moreover, synergistically upregulated late osteogenic differentiation of NHOst cells was observed on the PLGA/β-TCP/Mg(OH)₂ composite. Taken all together, we believe that the use of β-TCP and Mg(OH)₂ as additives with synthetic biodegradable polymers has great potential by the synergistic effect in orthopedic applications.

Fabrication of Oxygen Releasing Scaffold by Embedding H2O2-PLGA Microspheres into Alginate-Based Hydrogel Sponge and Its Application for Wound Healing

In the regeneration process for new tissues, oxygen promotes re-epithelialization and healing of infected wounds, increases keratinocyte differentiation, proliferation and migration of fibroblast, and induces angiogenesis, collagen synthesis and wound contraction. Therefore, provision of oxygen to cells and tissues at an optimal level is critical for effective tissue regeneration and wound healing. In this study, we developed sustained oxygen-releasing polymeric microspheres and fabricated a sponge type dressing by embedding the microspheres into alginate-based hydrogel that can supply oxygen to wounds. We further investigated the applicability of the microspheres and hydrogel sponge to wound healing in vitro and in vivo. Oxygen-releasing microspheres (ORM) were made by incorporating hydrogen peroxide (H2O2) into poly(lactic-co-glycolic acid) (PLGA) using double emulsion method. H2O2-PLGA microspheres were embedded into alginate-based hydrogel to form a porous oxygen-releasing hydrogel sponge (ORHS). Biocompatibility was performed using cell counting kit-8. The oxygen release kinetic study was performed using a hydrogen peroxide assay kit and oxygen meter. The wound healing potential of ORHS was evaluated using the wound scratch model. In vivo studies were carried out to investigate the safety and efficacy of the ORHS for wound healing. Experimental results confirmed that oxygen released from ORMand ORHS induced neovascularization and promoted cell proliferation thereby facilitating effective wound healing. It is suggested that the ORM can be used for supplying oxygen to where cells and tissues are deprived of necessary oxygen, and ORHS is an intelligent scaffold to effectively heal wound by enhanced angiogenesis by oxygen. Conclusively, oxygen releasing polymeric microspheres and hydrogel scaffolds have potential for a variety of tissue engineering applications, where require oxygen.