Poloxamer Hydrogels for Biomedical Applications

Advances in Hydrogels for Periodontitis Treatment

Periodontitis is a common condition characterized by a bacterial infection and the disruption of the body's immune-inflammatory response, which causes damage to the teeth and supporting tissues and eventually results in tooth loss. Current therapy involves the systemic and local administration of antibiotics. However, the existing treatments cannot exert effective, sustained release and maintain an effective therapeutic concentration of the drug at the lesion site. Hydrogels are used to treat periodontitis due to their low cytotoxicity, exceptional water retention capability, and controlled drug release profile. Hydrogels can imitate the extracellular matrix of periodontal cells while offering suitable sites to load antibiotics. This article reviews the utilization of hydrogels for periodontitis therapy based on the pathogenesis and clinical manifestations of the disease. Additionally, the latest therapeutic strategies for smart hydrogels and the main techniques for hydrogel preparation have been discussed. The information will aid in designing and preparing future hydrogels for periodontitis treatment.

Development and Characterization of Gelatin-Based Hydrogels Containing Triblock Copolymer and Phytic Acid

In recent research, significant interest has been directed towards gelatin-based hydrogels due to their affordable price, extensive availability, and biocompatibility, making them promising candidates for various biomedical applications. The development and characterization of novel hydrogels formed from varying ratios of gelatin, triblock copolymer Pluronic F-127, and phytic acid have been presented. Swelling properties were examined at different pH levels. The morphology of hydrogels and their thermal properties were analyzed using scanning electron microscopy (SEM), thermogravimetric analysis (TG), and differential scanning calorimetry (DSC). Fourier-transform infrared (FTIR) analysis of the hydrogels was also performed. The introduction of phytic acid in the hydrogel plays a crucial role in enhancing the intermolecular interactions within gelatin-based hydrogels, contributing to a more stable, elastic, and robust network structure.

Phase transforming in situ gels for sustained and controlled transmucosal drug delivery via the intravaginal route

Direct, reliable, controlled, and sustained drug delivery to female reproductive tract (FRT) remains elusive, with conventional dosage forms falling way short of the mark, leading to premature leakage, erratic drug delivery, and loss of compliance. Historically, the intravaginal route remains underserved by the pharmaceutical sector. To comprehensively address this, we turned our focus to phase-transforming sol-gels, using poloxamers, a thermosensitive polymer and, doxycycline (as hyclate salt, DOXH) as our model agent given its potential use in sexually transmitted infections (STIs). We further enhanced mucoadhesiveness through screening of differing viscosity grade hydroxypropyl methyl celluloses (HPMCs). The optimised sol-gels remained gelled at body temperature (<37 °C) and were prepared in buffer aligned to vaginal cavity pH and osmolality. Lead formulations were progressed based on their ability to retain key rheological properties, and acidic pH in the presence of simulated vaginal fluid (SVF). From a shelf-life perspective, DOXH stability, gelation temperature (Tsol-gel), and pH to three months (2-8 °C) was attained. In summary, the meticulously engineered, phase-transforming sol-gels provided sustained mucoretention despite dilution by vaginal fluid, paving the way for localised antimicrobial drug delivery at concentrations that potentially far exceed the minimum inhibitory concentration (MIC) for target STI-causing bacteria of the FRT.

Enhanced efficacy of β-carotene loaded solid lipid nanoparticles optimized and developed via central composite design on breast cancer cell lines

β-carotene is obtained from both plants and animals and has been the subject of intense research because of its provitamin-A, antioxidant, and anticancer effects. Its limited absorption and oxidative degradation significantly reduce its antitumor efficacy when taken orally. In our study, we utilize a central composite design to develop "bio-safe and highly bio-compatible" solid lipid nanoparticles (SLNs) by using only the combination of palmitic acid and poloxamer-407, a block co-polymer as a surfactant. The current research aim to develop and characterize SLNs loaded with β-carotene to improve their bioavailability and therapeutic efficacy. In addition, the improved cytotoxicity of solid lipid nanoparticles loaded with β-carotene was screened in-vitro in human breast cancer cell lines (MCF-7). The nanoparticles exhibits good stability, as indicated by their mean zeta potential of -26.3 ± 1.3 mV. The particles demonstrated high drug loading and entrapment capabilities. The fabricated nanoparticle's prolonged release potential was shown by the in-vitro release kinetics, which showed a first-order release pattern that adhered to the Higuchi model and showed a slow, linear, and steady release over 48 h. Moreover, a diffusion-type release mechanism was used to liberate β-carotene from the nanoparticles. For six months, the nanoparticles also showed a notable degree of physical stability. Lastly, using the MTT assay, the anti-cancer properties of β-carotene-loaded solid lipid nanoparticles were compared with intact β-carotene on MCF-7 cell lines. The cytotoxicity tests have shown that the encapsulation of β-carotene in the lipid bilayers of the optimized formulation does not interfere with the anti-cancer activity of the drug. When compared to standard β-carotene, β-carotene loaded SLNs showed enhanced anticancer efficacy and it is a plausible therapeutic candidate for enhancing the solubility of water-insoluble and degradation-sensitive biotherapeutics like β-carotene.

Novel Drug Delivery Systems for the Management of Fungal Keratitis

Fungal keratitis (FK) is a dangerous corneal infection that is common in tropical and subtropical areas. Its incidence is extremely high, and ocular trauma and contact lenses can lead to FK, but its common treatment such as using topical antifungal eye drop instillation is often less effective because of several drawbacks of the drugs typically used, including limited ocular penetration, high frequency of dosing, poor biocompatibility, and the potential for severe drug reactions. Therefore, the development of novel drug delivery devices for the treatment of FK is urgent. The urgent need for novel drug delivery devices to treat FK has led to the development of several techniques, including nanoparticles (NPs), in situ forming hydrogels, contact lenses, and microneedles (MNs). However, it is important to note that the main mechanisms differ between these techniques. NPs can transport large amounts of drugs and be taken up by cells owing to their large surface area and small size. In situ forming hydrogels can significantly extend the residence time of drugs because of their strong adhesive properties. Contact lenses, with their comfortable shape and drug-carrying capacity, can also act as drug delivery devices. MNs can create channels in the cornea, bypassing its barrier and enhancing drug bioavailability. This article will go over novel medication delivery techniques for treating FK and make a conclusion about their advantages and limitations in anticipation to serve the best option for the individual therapy of FK.

Fabrication of carboxymethyl cellulose-based thermo-sensitive hydrogels and inhibition of corneal neovascularization

Corneal neovascularization (CNV) is a common multifactorial sequela of anterior corneal segment inflammation, which could lead to visual impairment and even blindness. The main treatments available are surgical sutures and invasive drug injections, which could cause serious ocular complications. To solve this problem, a thermo-sensitive drug-loaded hydrogel with high transparency was prepared in this study, which could achieve the sustained-release of drugs without affecting normal vision. In briefly, the thermo-sensitive hydrogel (PFNOCMC) was prepared from oxidized carboxymethyl cellulose (OCMC) and aminated poloxamer 407 (PF127-NH2). The results proved the PFNOCMC hydrogels possess high transparency, suitable gel temperature and time. In the CNV model, the PFNOCMC hydrogel loading bone morphogenetic protein 4 (BMP4) showed significant inhibition of CNV, this is due to the hydrogel allowed the drug to stay longer in the target area. The animal experiments on the ocular surface were carried out, which proved the hydrogel had excellent biocompatibility, and could realize the sustained-release of loaded drugs, and had a significant inhibitory effect on the neovascularization after ocular surface surgery. In conclusion, PFNOCMC hydrogels have great potential as sustained-release drug carriers in the biomedical field and provide a new minimally invasive option for the treatment of neovascular ocular diseases.

Structural and therapeutic properties of salicylic acid-solubilized Pluronic solutions and hydrogels

Salicylic acid (SA) finds extensive applications in the treatment of rheumatic and skin diseases because of its analgesic, anti-inflammatory and exfoliating properties. As it is lipophilic in nature, there is a need for appropriate delivery systems to harness these properties for different applications. Herein, we examined the suitability of Pluronic P123/F127 micellar systems as delivery media by investigating the structural, flow and antimicrobial properties of P123/F127-SA solutions and hydrogels using DLS, SANS, rheological and zone inhibition measurement techniques. SA modulates the aggregation characteristics of these surfactant systems and brings about spherical-to-worm-like micelle-to-vesicular structural transitions in the hydrophobic Pluronic P123 system, a spherical-to-worm-like micellar transition in the mixed P123/F127 system and an onset of inter-micellar attraction in the hydrophilic Pluronic F127 system. SA-solubilized systems of both hydrophobic and hydrophilic Pluronics inhibit the growth of Gram-positive and Gram-negative bacteria with comparable MIC values. This suggests that the interaction of SA molecules with the bacterial cell membrane remains unobstructed upon encapsulation in Pluronic micelles. F127 hydrogel-based SA formulations with rheological properties suitable for topical applications and up to 15% SA loading were prepared. These will be useful SA ointments as F127 is an FDA-approved excipient for topical drug delivery applications. The results indicate that Pluronics remain effective as delivery agents for SA and exhibit interesting structural polymorphism upon its solubilization.

Hydrogel-Based Therapy for Age-Related Macular Degeneration: Current Innovations, Impediments, and Future Perspectives

Age-related macular degeneration (AMD) is an ocular disease that leads to progressive photoreceptor death and visual impairment. Currently, the most common therapeutic strategy is to deliver anti-vascular endothelial growth factor (anti-VEGF) agents into the eyes of patients with wet AMD. However, this treatment method requires repeated injections, which potentially results in surgical complications and unwanted side effects for patients. An effective therapeutic approach for dry AMD also remains elusive. Therefore, there is a surge of enthusiasm for the developing the biodegradable drug delivery systems with sustained release capability and develop a promising therapeutic strategy. Notably, the strides made in hydrogels which possess intricate three-dimensional polymer networks have profoundly facilitated the treatments of AMD. Researchers have established diverse hydrogel-based delivery systems with marvelous biocompatibility and efficacy. Advantageously, these hydrogel-based transplantation therapies provide promising opportunities for vision restoration. Herein, we provide an overview of the properties and potential of hydrogels for ocular delivery. We introduce recent advances in the utilization of hydrogels for the delivery of anti-VEGF and in cell implantation. Further refinements of these findings would lay the basis for developing more rational and curative therapies for AMD.

Temperature-sensitive hydrogel releasing pectolinarin facilitate scarless wound healing

The dressing that promotes scarless healing is essential for both normal function and aesthetics after a wound. With a deeper understanding of the mechanisms involved in scar formation during the wound healing process, the ideal dressing becomes clearer and more promising. For instance, the yes-associated transcriptional regulator (YAP) has been extensively studied as a key gene involved in regulating scar formation. However, there has been limited attention given to pectolinarin, a natural flavonoid that may exhibit strong binding affinity to YAP, in the context of scarless healing. In this study, we successfully developed a temperature-sensitive Pluronic@F-127 hydrogel as a platform for delivering pectolinarin to promote scarless wound healing. The bioactive pectolinarin was released from the hydrogel, effectively enhancing endothelial cell migration, proliferation and the expression of angiogenesis-related genes. Additionally, a concentration of 20 μg/mL of pectolinarin demonstrated remarkable antioxidant ability, capable of counteracting the detrimental effects of reactive oxygen species (ROS). Our results from rat wound healing models demonstrated that the hydrogel accelerated wound healing, promoting re-epithelialization and facilitating skin appendage regeneration. Furthermore, we discovered that a concentration of 50 μg/mL of pectolinarin incorporated to the hydrogel exhibited the most favourable outcomes in terms of promoting wound healing and minimizing scar formation. Overall, our study highlights that the significant potential of locally released pectolinarin might substantially inhibit YAP and promoting scarless wound healing.

Formulation of Budesonide-Loaded Polymeric Nanoparticles into Hydrogels for Local Therapy of Atopic Dermatitis

Budesonide is a mineral corticoid applied in the local therapy of pediatric atopic dermatitis. Unfortunately, its dermal administration is hindered by the concomitant adverse effects and its physicochemical properties. The characteristic pH change in the atopic lesions can be utilized for the preparation of a pH-sensitive nanocarrier. In this view, the formulation of Eudragit L 100 nanoparticles as a budesonide delivery platform could provide more efficient release to the desired site, improve its penetration, and subsequently lower the undesired effects. In this study, budesonide-loaded Eudragit L100 nanoparticles were prepared via the nanoprecipitation method (mean diameter 57 nm, -31.2 mV, and approx. 90% encapsulation efficiency). Their safety was proven by cytotoxicity assays on the HaCaT keratinocyte cell line. Further, the drug-loaded nanoparticles were incorporated into two types of hydrogels based on methylcellulose or Pluronic F127. The formulated hydrogels were characterized with respect to their pH, occlusion, rheology, penetration, spreadability, and drug release. In conclusion, the developed hydrogels containing budesonide-loaded nanoparticles showed promising potential for the pediatric treatment of atopic dermatitis.

Stimuli-responsive Biomaterials for Tissue Engineering Applications

The use of ''smart materials,'' or ''stimulus responsive'' materials, has proven useful in a variety of fields, including tissue engineering and medication delivery. Many factors, including temperature, pH, redox state, light, and magnetic fields, are being studied for their potential to affect a material's properties, interactions, structure, and/or dimensions. New tissue engineering and drug delivery methods are made possible by the ability of living systems to respond to both external stimuli and their own internal signals) for example, materials composed of stimuliresponsive polymers that self assemble or undergo phase transitions or morphology transformation. The researcher examines the potential of smart materials as controlled drug release vehicles in tissue engineering, aiming to enable the localized regeneration of injured tissue by delivering precisely dosed drugs at precisely timed intervals.

Interpenetrating alginate network as drug delivery matrix: Effects on protein stability and release

The study investigates the rheological properties and protein release capacity of a uniform hydrogel composed of sodium alginate (SA) and poloxamer (P407). The hydrogel is prepared through the sustained release of calcium ions, resulting in a reinforced and homogeneous interpenetrating networks (IPNs) of SA and P407 polymeric chains. By adjusting the amount of crosslink agent, the hydrogel exhibites an adjustable dissolution ratio and adaptable gelling time. Moreover, the composite showed a well-structured network and superior mechanical strength, enabling the sustained release of both calcium ions and Soybean Trypsin Inhibitor (STI) protein, a model of Bone Morphogenic Protein (BMP). Importantly, the protein release kinetic can be tuned based on the SA content in the polymeric blend, highlighting the versatile nature of this hydrogel for drug delivery purposes.

Mucin-mediated mucosal retention via end-terminal modified Pluronic F127-based hydrogel to increase drug accumulation in the lungs

Noninvasive lung drug delivery is critical for treating respiratory diseases. Pluronic-based copolymers have been used as multifunctional materials for medical and biological applications. However, the Pluronic F127-based hydrogel is rapidly degraded, adversely affecting the mechanical stability for prolonged drug release. Therefore, this study designed two thermosensitive copolymers by modifying the Pluronic F127 terminal groups with carboxyl (ADF127) or amine groups (EDF127) to improve the viscosity and storage modulus of drug formulations. β-alanine and ethylenediamine were conjugated at the terminal of Pluronic F127 using a two-step acetylation process, and the final copolymers were characterized using 1H nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectra. According to the 1H NMR spectra, Pluronic F127 was functionalized to form ADF127 and EDF127 with 85 % and 71 % functionalization degrees, respectively. Rheological studies revealed that the ADF127 (15 wt%) and EDF127 (15 wt%) viscosities increased from 1480 Pa.s (Pluronic F127) to 1700 Pa.s and 1800 Pa.s, respectively. Furthermore, the elastic modulus of ADF127 and EDF127 increased, compared with that of native Pluronic F127 with the addition of 5 % mucin, particularly for ADF127, thereby signifying the stronger adhesive nature of ADF127 and EDF127 with mucin. Additionally, ADF127 and EDF127 exhibited a decreased gelation temperature, decreasing from 33 °C (Pluronic F127 at 15 wt%) to 24 °C. Notably, the in vitro ADF127 and EDF127 drug release was prolonged (95 %; 48 h) by the hydrogel encapsulation of the liposome-Bdph combined with mucin, and the intermolecular hydrogen bonding between the mucin and the hydrogel increased the retention time and stiffness of the hydrogels. Furthermore, ADF127 and EDF127 incubated with NIH-3T3 cells exhibited biocompatibility within 2 mg/mL, compared with Pluronic F127. The nasal administration method was used to examine the biodistribution of the modified hydrogel carrying liposomes or exosomes with fluorescence using the IVIS system. Drug accumulation in the lungs decreased in the following order: ADF127 > EDF127 > liposomes or exosomes alone. These results indicated that the carboxyl group-modified Pluronic F127 enabled well-distributed drug accumulation in the lungs, which is beneficial for intranasal administration routes in treating diseases such as lung fibrosis.

CO2 electrocatalytic reduction to ethylene and its application outlook in food science

The efficient conversion of CO2 is considered to be an important step toward carbon emissions peak and carbon neutrality. Presently, great efforts have been devoted to the study of efficient nanocatalysts, electrolytic cell, and electrolytes to achieve high reactivity and selectivity in the electrochemical reduction of CO2 to mono- and multi-carbon (C2+) compounds. However, there are very few reviews focusing on highly reactive and selective ethylene production and application in the field of electrochemical carbon dioxide reduction reaction (CO2RR). Ethylene is a class of multi-carbon compounds that are widely applied in industrial, ecological, and agricultural fields. This review focuses especially on the convertibility of CO2 reduction to generate ethylene technology in practical applications and provides a detailed summary of the latest technologies for the efficient production of ethylene by CO2RR and suggests the potential application of CO2RR systems in food science to further expand the application market of CO2RR for ethylene production.

Development of Carvedilol Nanoformulation-Loaded Poloxamer-Based In Situ Gel for the Management of Glaucoma

The objective of the current study was to fabricate a thermosensitive in situ gelling system for the ocular delivery of carvedilol-loaded spanlastics (CRV-SPLs). In situ gel formulations were prepared using poloxamer analogs by a cold method and was further laden with carvedilol-loaded spanlastics to boost the precorneal retention of the drug. The gelation capacity, rheological characteristics, muco-adhesion force and in vitro release of various in situ gel formulations (CS-ISGs) were studied. The optimized formula (F2) obtained at 22% w/v poloxamer 407 and 5% w/v poloxamer 188 was found to have good gelation capacity at body temperature with acceptable muco-adhesion properties, appropriate viscosity at 25 °C that would ease its ocular application, and relatively higher viscosity at 37 °C that promoted prolonged ocular residence of the formulation post eye instillation and displayed a sustained in vitro drug release pattern. Ex vivo transcorneal penetration studies through excised rabbit cornea revealed that F2 elicited a remarkable (p ˂ 0.05) improvement in CRV apparent permeation coefficient (Papp = 6.39 × 10-6 cm/s) compared to plain carvedilol-loaded in situ gel (CRV-ISG; Papp = 2.67 × 10-6 cm/s). Most importantly, in normal rabbits, the optimized formula (F2) resulted in a sustained intraocular pressure reduction and a significant enhancement in the ocular bioavailability of carvedilol, as manifested by a 2-fold increase in the AUC0-6h of CRV in the aqueous humor, compared to plain CRV-ISG formulation. To sum up, the developed thermosensitive in situ gelling system might represent a plausible carrier for ophthalmic drug delivery for better management of glaucoma.

An injectable photopolymerizable chitosan hydrogel doped anti-inflammatory peptide for long-lasting periodontal pocket delivery and periodontitis therapy

Periodontitis is a common chronic inflammatory disease caused by plaque that leads to alveolar bone resorption and tooth loss. Inflammation control and achieving better tissue repair are the key to periodontitis treatment. In this study, human β-Defensin 1 short motif Pep-B with inflammation inhibition and differentiation regulation properties, is firstly used in the treatment of periodontitis, and an injectable photopolymerizable Pep-B/chitosan methacryloyl composite hydrogel (CMSA/Pep-B) is constructed. We confirm that Pep-B improves inflammation, and restores osteogenic behavior and function of injured stem cells. CMSA/Pep-B has good injectability, fluidity and photopolymerizability, and can sustainably release Pep-B to maintain drug concentration in periodontal pockets. Furthermore, animal experiments showed that CMSA/Pep-B significantly ameliorated the inflammation of the periodontium and reduced the alveolar bone loss by decreasing inflammatory infiltration, osteoclast formation and collagen destruction. In conclusion, CMSA/Pep-B is envisaged to be a novel bioactive material or therapeutic drug for treating periodontitis.

Poloxamer sols endowed with in-situ gelability and mucoadhesion by adding hypromellose and hyaluronan for prolonging corneal retention and drug delivery

The purpose of this study was to develop poloxamer (P407)-based in-situ thermogellable hydrogels with reducing concentration of P407 by adding hypromellose (HPMC) and with enhancing mucoadhesion of resulting hydrogels by adding hyaluronic acid (HA) for prolonging ocular delivery of hydroxypropyl-β-cyclodextrin (HPβCD)-solubilized testosterone (TES). Results demonstrated that 0.5% TES solution was successfully solubilized with adding 10% HPβCD. Non-gellable 13% P407 sol became in-situ gellable with adding 2.0-2.5% HPMC and mucoadhesibility was further imporved with adding 0.3% HA-L (low MW) or HA-H (high MW). Optimized 0.5% HPβCD-solubilized TES P407-based thermogellable hydrogels with enhancement of mucoadhesion for prolonging ocular delivery comprised 13% P407, 2.5% HPMC, and 0.3% HA-L or HA-H. Furthermore, rheological measurements under simulated eye blinking confirmed that non-thixotropic properties of optimized hydrogels could be spreaded evenly and retain a greater amount of drug-loaded hydrogels on the ocular surface for a longer period to prolong drug delivery. Compared with conventional eye drops, the prolonged residence time of optimized hydrogels from ex vivo and in vivo studies were observed, indicating relationships between rheological properties and in vivo performances. It was concluded that P407-based thermosensitive hydrogels with reducing concentration of P407 and enhancing mucoadhesion was successfully formulated by adding 2.5% HPMC and 0.3% HA in 13% P407 for potentially accomplishing effective clinical treatment of DED.

Sustained delivery of triamcinolone acetonide from a thermosensitive microemulsion gel system for the treatment of sensorineural hearing loss

Intratympanic administration for the delivery of steroids has been extensively studied but limited because of low permeability of the drug through the row window membrane. Here, to effectively deliver poorly soluble triamcinolone acetonide (TA), microemulsions (ME) were prepared from Capmul MCM (oil), Cremophor RH40 (surfactant), and tetraglycol (cosurfactant) based on solubility studies, emulsifying ability test, and pseudoternary phase diagrams. Microemulsion gel (MEG) was prepared by mixing TA-ME with a poloxamer hydrogel base. The physicochemical properties of ME and MEG formulations were characterized, and the toxicity and oto-protective effectiveness were evaluated in vitro and in vivo. The ME-3 formulation showed a small droplet size (16.5 ± 0.2 nm), narrow PDI (0.067 ± 0.041), and enhanced TA solubility (2619.7 ± 57.6 μg/g). The optimized MEG demonstrated temperature-dependent gelation with a gelation time of 208 ± 10 sec at 37 °C. Slow degradation of the gel matrix sustained release of TA from MEG compared to the ME formulation. Both TA-ME and TA-MEG were found to be nontoxic to NIH3T3 cells at the test concentrations (0 to 5 µg/mL), and biocompatible after intratympanic administration to mice. The incorporation of ME into thermosensitive hydrogels prolonged retention of TA at the site of administration until 6 days. As a consequence, the enhanced drug absorption into the cochlea in TA-MEG group (approximately 2 times higher than other groups) protected hair cells, spiral ganglion neurons, and stria vascular cells from cisplatin-induced damage. Therefore, this injectable TA-loaded MEG is an effective and safe vehicle for the sustained delivery of triamcinolone acetonide into the inner ear.

Accelerated blood clearance of PEGylated nanoparticles induced by PEG-based pharmaceutical excipients

PEGylated nanomedicines have been extensively developed and applied to cancer therapy. However, the antitumor efficacy of these nanoparticles is hampered by the accelerated blood clearance (ABC) effect caused by anti-PEG antibodies in vivo. There is still limited understanding about the cause of pre-existing anti-PEG antibodies in the human body. Herein, we discovered that PEG-based pharmaceutical excipients, commonly used in clinical and daily settings, could induce anti-PEG antibodies in vivo and lead to considerable potential clinical impacts on pharmacokinetics and pharmacodynamics of PEGylated nanoparticles. Specifically, we investigated the ability of poloxamer 188 (F68) and poloxamer 407 (F127), the two most frequently used PEG-based pharmaceutical excipients, to elicit the production of anti-PEG antibodies and influence the pharmacokinetics of PEGylated nanoparticles, with PEGylated liposome nanoparticles (L-NPs) as a model. Anti-PEG IgG and IgM levels were significantly boosted 3.8- and 32.2-fold, respectively, after pre-injection with F68, leading to rapid clearance of subsequently injected L-NPs from circulation due to the capture by neutrophils and monocytes. However, pre-injection of F127 did not induce the production of anti-PEG IgG, although there was a 7.7-fold increase in IgM level, which resulted in minimal effect on circulation time of L-NPs. Furthermore, the potential clinical impacts of F68 and F127 were further inspected for PEGylated liposomal doxorubicin (PLD). It was found that administering F68 prior to treatment led to over a one-third decrease in the antitumor effectiveness of PLD, while F127 had a negligible impact. Our study elucidates the mechanism by which PEG-based pharmaceutical excipients influence the effectiveness of PEGylated nanomedicines. It also highlights the significance of considering the potential for an ABC effect induced by PEG-based pharmaceutical excipients in patients.

Evaluation of the in vitro performance of generic and original adapalene gel

OBJECTIVE

The aim was to evaluate the difference of the in vitro behavior between the commercially available generic adapalene gel and original product with Topical Classification System (TCS), and to analyze the effect of changes of excipients on the release behavior.

SIGNIFICANCE

Establishing in vitro performance assays to understand the impact of formulation variables on the critical quality attributes (CQA) is critical for the quality assessment of semi-solid generic drug.

METHODS

In vitro release (IVR), in vitro permeation (IVP), viscosity, and pH measurement methods for adapalene gels were established and validated. The differences between generic adapalene gel from 7 companies and original products were evaluated by correlation analysis (CA) and principal component analysis (PCA), and the relationship among 4 parameters was elucidated. The effect of excipients on the above variables was examined by univariate tests.

RESULTS

There were some differences between the gels of 5 of the 7 imitation enterprises and reference listed drug (RLD). There were varying degrees of correlation between viscosity, pH, the adapalene amount retained in skin and release rate. The result validated the key role of IVR, and identified that pH value, type of suspending agent, the amount of carbomer, etc. had certain effects on the release rate.

CONCLUSIONS

The factors mentioned above should be considered when developing and manufacturing generic adapalene gels, and the application of TCS in the evaluation of generic topical drugs was advanced. Additionally, our research revealed some discrepancies from USP<1724>, which could be valuable information for the revision.

Development of Innovative Electrospun Nepafenac-Loaded Nanofibers-based Ophthalmic Inserts

Electrospun nanofibers can be utilized to develop patient-centric ophthalmic formulations with reasonable bioavailability at the targeted site. The current study aimed to develop 0.1% w/w of nepafenac-loaded electrospun nanofibrous webs as potential candidates for ocular delivery of nepafenac with improved solubility and stability. Nine different formulations were prepared by electrospinning and investigated for morphology, physicochemical properties, drug release, cytocompatibility, and in vitro and ex vivo permeability. The scanning electron microscopy images showed fibrous samples. Fourier transform infrared spectroscopy and X-ray diffraction confirmed the polymer cross-linking and the formation of amorphous solid dispersion. All formulations showed complete and fast release of nepafenac (≤ 60 minutes), and the release followed first-order kinetics (β values for all formulations were <1). The formulations (F3, F6, and F9) showed considerable in vitro and ex vivo permeability. The Raman studies revealed comparable corneal distributions of F3 and the commercial Nevanac® suspension at 60 min (p value = 0.6433). The fibrous composition remains stable under stress conditions (40 ± 2 °C, 75 ± 5% relative humidity). The formulation composition showed good cytocompatibility with hen eggs tested on the chorioallantoic membrane of chick embryos. The developed nanofiber webs could be a promising candidate for nepafenac-loaded ophthalmic inserts. Chemical compounds studied in this article Nepafenac (PubChem CID151075); Polyvinyl alcohol (PubChem CID 11199); Poloxamer 407 (PubChem CID 24751); Chloroform (PubChem CID 6212); Methanol (PubChem CID 887); L-α-phosphatidylcholine (PubChem CID 10425706); Ethylenediaminetetraacetic acid (PubChem CID 6049).

Tailoring Risperidone-Loaded Glycethosomal In Situ Gels Using Box-Behnken Design for Treatment of Schizophrenia-Induced Rats via Intranasal Route

Schizophrenic patients often face challenges with adherence to oral regimens. The study aimed to highlight the potentiality of intranasal ethanol/glycerin-containing lipid-nanovesicles (glycethosomes) incorporated into in situ gels for sustaining anti-psychotic risperidone (RS) release. The Box-Behnken Design (BBD) was followed for in vitro characterization. Glycethosomal-based in situ gels were examined by physical, ex vivo, and in vivo investigations. The ethanol impact on minimizing the vesicle size (VS) and enhancing the zeta potential (ZP) and entrapment efficiency (EE%) of nanovesicles was observed. Glycerin displayed positive action on increasing VS and ZP of nanovesicles, but reduced their EE%. After incorporation into various mucoadhesive agent-enriched poloxamer 407 (P407) in situ gels, the optimized gel containing 20% P407 and 1% hydroxypropyl methyl cellulose-K4M (HPMC-K4M) at a 4:1 gel/glycethosomes ratio showed low viscosity and high spreadability with acceptable pH, gel strength, and mucoadhesive strength ranges. The ethanol/glycerin mixture demonstrated a desirable ex vivo skin permeability of RS through the nasal mucosa. By pharmacokinetic analysis, the optimized gel showed eight-fold and three-fold greater increases in RS bioavailability than the control gel and marketed tablet, respectively. Following biochemical assessments of schizophrenia-induced rats, the optimized gel boosted the neuroprotective, anti-oxidant, and anti-inflammatory action of RS in comparison to other tested preparations. Collectively, the intranasal RS-loaded glycethosomal gel offered a potential substitute to oral therapy for schizophrenic patients.

Preparation and Primary Bioactivity Evaluation of Novel Water-Soluble Curcumin-Loaded Polymeric Micelles Fabricated with Chitooligosaccharides and Pluronic F-68

Curcumin (CU) is a bioactive compound extracted from turmeric and has various advantages. However, the benefit of CU is limited by its low water solubility (11 ng/mL). This research aimed to fabricate a water-soluble CU nano-formulation with chitooligosaccharides (COS) and pluronic F-68 (PF) utilizing the polymeric micelle method. The optimized curcumin-loaded chitooligosaccharides/pluronic F-68 micelles (COSPFCU) exhibited high encapsulation efficiency and loading capacity (75.57 ± 2.35% and 10.32 ± 0.59%, respectively). The hydrodynamic diameter of lyophilized COSPFCU was 73.89 ± 11.69 nm with a polydispersity index below 0.3. The COSPFCU could be completely redispersed in water and showed high DPPH scavenging ability. Meanwhile, COSPFCU could significantly reduce the cytotoxicity of the RAW 264.7 cells compared to native CU. Furthermore, COSPFCU improved the inhibition of NO release activity at 72.83 ± 2.37% but 33.20 ± 3.41% for the CU, with a low cytotoxicity concentration in the RAW 264.7 cells.

Advanced biomaterial agent from chitosan/poloxamer 407-based thermosensitive hydrogen containing biosynthesized silver nanoparticles using Eucalyptus camaldulensis leaf extract

CONTEXT

The emergence of multidrug-resistant (MDR) pathogens poses a significant challenge for global public health systems, increasing hospital morbidity and mortality and prolonged hospitalization.

OBJECTIVE

We evaluated the antimicrobial activity of a thermosensitive hydrogel containing bio-synthesized silver nanoparticles (bio-AgNPs) based on chitosan/poloxamer 407 using a leaf extract of Eucalyptus calmadulensis.

RESULTS

The thermosensitive hydrogel was prepared by a cold method after mixing the ingredients and left at 4°C overnight to ensure the complete solubilization of poloxamer 407. The stability of the hydrogel formulation was evaluated at room temperature for 3 months, and the absorption peak (420 nm) of the NPs remained unchanged. The hydrogel formulation demonstrated rapid gelation under physiological conditions, excellent water retention (85%), and broad-spectrum antimicrobial activity against MDR clinical isolates and ATCC strains. In this regard, minimum inhibitory concentration and minimum microbial concentration values of the bio-AgNPs ranged from 2-8 μg/mL to 8-128 μg/mL, respectively. Formulation at concentrations <64 μg/mL showed no cytotoxic effect on human-derived macrophages (THP-1 cells) with no induction of inflammation.

CONCLUSIONS

The formulated hydrogel could be used in biomedical applications as it possesses a broad antimicrobial spectrum and anti-inflammatory properties without toxic effects on human cells.

MOF-Thermogel Composites for Differentiated and Sustained Dual Drug Delivery

In recent years, multidrug therapy has gained increasing popularity due to the possibility of achieving synergistic drug action and sequential delivery of different medical payloads for enhanced treatment efficacy. While a number of composite material release platforms have been developed, few combine the bottom-up design versatility of metal-organic frameworks (MOFs) to tailor drug release behavior, with the convenience of temperature-responsive hydrogels (or thermogels) in their unique ease of administration and formulation. Yet, despite their potential, MOF-thermogel composites have been largely overlooked for simultaneous multidrug delivery. Herein, we report the first systematic study of common MOFs (UiO-66, MIL-53(Al), MIL-100(Fe), and MOF-808) with different pore sizes, geometries, and hydrophobicities for their ability to achieve simultaneous dual drug release when embedded within PEG-containing thermogel matrices. After establishing that MOFs exert small influences on the rheological properties of the thermogels despite the penetration of polymers into the MOF pores in solution, the release profiles of ibuprofen and caffeine as model hydrophobic and hydrophilic drugs, respectively, from MOF-thermogel composites were investigated. Through these studies, we elucidated the important role of hydrophobic matching between MOF pores and loaded drugs in order for the MOF component to distinctly influence drug release kinetics. These findings enabled us to identify a viable MOF-thermogel composite containing UiO-66 that showed vastly different release kinetics between ibuprofen and caffeine, enabling temporally differentiated yet sustained simultaneous drug release to be achieved. Finally, the MOF-thermogel composites were shown to be noncytotoxic in vitro, paving the way for these underexploited composite materials to find possible clinical applications for multidrug therapy.

Antimicrobial polymer-loaded hydrogels for the topical treatment of multidrug-resistant wound biofilm infections

Integration of antimicrobial polymeric nanoparticles into hydrogel materials presents a promising strategy to address multidrug-resistant biofilm infections. Here we report an injectable hydrogel loaded with engineered cationic antimicrobial polymeric nanoparticles (PNPs) for the effective topical treatment of severe wound biofilm infections. The PNPs demonstrated biofilm penetration and disruption, resulting in the eradication of resistant and persister cells that reside within the biofilm. Significantly, PNPs did not elicit resistance development even after multiple exposures to sub-therapeutic doses. In vitro studies showed PNPs significantly reduced prolonged inflammation due to infection and promoted fibroblast migration. These PNPs were then incorporated into Poloxamer 407 (P407) hydrogels and utilized as an inert carrier for PNPs to provide a controlled and sustained topical release of the antimicrobial nanoparticles at the wound area. In vivo studies using a mature (4-day) wound biofilm infection in a murine model mimicking severe human wound infections demonstrated provided 99% bacterial biofilm clearance and significantly enhanced wound healing. Overall, this work demonstrated the efficacy and selectivity of the antimicrobial polymer-loaded hydrogel platform as a topical treatment for difficult-to-treat wound biofilm infections.

Application of Pluronics for Enhancing Aqueous Solubility of Lipophilic Microtubule Destabilizing Compounds on the Sea Urchin Embryo Model

In screening, the dilution of DMSO stock solution of a lipophilic molecule with an assay medium often causes compound precipitation. To overcome the issue, the application of Pluronics as cosolvents was examined using a phenotypic sea urchin embryo assay that allows for the quick and facile evaluation of the antiproliferative effect together with systemic toxicity. Maximum tolerated concentration values for Pluronics L121, P123, and F127 were 1.4 μM, 8.6 μM, and 39.7 μM, respectively, and correlated directly with their hydrophilicity. Pluronics L121 and P123 suppressed cleavage and blastomeres retained the round shape, unlike hydrophilic Pluronic F127, which induced fertilization envelope creasing and embryo deformation that could be associated with the interaction of hydrophilic PEO units with mucopolysaccharides at the surface of sea urchin embryos. The toxicity of P123, but not of L121 and F127, was temperature-dependent and markedly increased at lower temperatures. CMC values obtained at different temperatures confirmed that the toxic effect of P123 was associated with both unimers and micelles, whereas F127 toxicity was related mainly to micelles. Evaluation using phenotypic sea urchin embryo assay revealed that potent microtubule destabilizers, namely albendazole, diarylisoxazole, and two chalcones, retained antimitotic activity after the dilution of their DMSO or 2-pyrrolidone stock solutions with 1.25% w/v Pluronic P123 or 5% w/v Pluronic F127. It was suggested that Pluronic P123 and Pluronic F127 could be used as cosolvents to improve the solubility of lipophilic molecules in aqueous medium.

Effect of chain architecture on the structure, dynamics, and rheology of thermoresponsive poloxamer hydrogels and associated blends

Poloxamers, ABA triblock polymers composed of a poly(propylene oxide) (PPO) midblock (B) and poly(ethylene oxide) (PEO) endblocks (A), are widely studied for biomedical applications. Aqueous poloxamer 407 (P407; also referred to as F127) undergoes a solution-to-gel transition with increasing temperature, driven by the formation and ordering of micelles onto periodic lattices; however, the gel temperature and resulting modulus has limited tunability. Here, reverse P407 (RP407), a BAB polymer of the same composition and molar mass but the inverted architecture, is synthesized via anionic polymerization. The micellization and gelation temperatures of RP407 are higher than that of P407 and the PPO endblocks allow for intermicelle bridging; however, both single-component solutions favor body-centered cubic (BCC) packings. Further, aqueous RP407 displays a "soft gel" region with interesting rheological behavior, including viscoelastic aging and thermal hysteresis. Combining P407 and RP407 yields solutions with intermediate transition temperatures and alters the size and micelle packing. While the single-component solutions produce BCC packings, the blends form close-packed structures and larger micelles of higher aggregation numbers. Blends of P407 with an analogous AB diblock (E111P32) display similar behavior, whereas RP407/diblock blends form intermediate-sized BCC-packed micelles. These differences in packing and aggregation alter the local environments within the gels, which could have implications for applications such as drug delivery and protein stabilization.

Modern Approaches in Wounds Management

Wound management represents a well-known continuous challenge and concern of the global healthcare systems worldwide. The challenge is on the one hand related to the accurate diagnosis, and on the other hand to establishing an effective treatment plan and choosing appropriate wound care products in order to maximize the healing outcome and minimize the financial cost. The market of wound dressings is a dynamic field which grows and evolves continuously as a result of extensive research on developing versatile formulations with innovative properties. Hydrogels are one of the most attractive wound care products which, in many aspects, are considered ideal for wound treatment and are widely exploited for extension of their advantages in healing process. Smart hydrogels (SHs) offer the opportunities of the modulation physico-chemical properties of hydrogels in response to external stimuli (light, pressure, pH variations, magnetic/electric field, etc.) in order to achieve innovative behavior of their three-dimensional matrix (gel-sol transitions, self-healing and self-adapting abilities, controlled release of drugs). The SHs response to different triggers depends on their composition, cross-linking method, and manufacturing process approach. Both native or functionalized natural and synthetic polymers may be used to develop stimuli-responsive matrices, while the mandatory characteristics of hydrogels (biocompatibility, water permeability, bioadhesion) are preserved. In this review, we briefly present the physiopathology and healing mechanisms of chronic wounds, as well as current therapeutic approaches. The rational of using traditional hydrogels and SHs in wound healing, as well as the current research directions for developing SHs with innovative features, are addressed and discussed along with their limitations and perspectives in industrial-scale manufacturing.

The role of lactoferrin in bone remodeling: evaluation of its potential in targeted delivery and treatment of metabolic bone diseases and orthopedic conditions

Lactoferrin (Lf) is a multifunctional protein that is synthesized endogenously and has various biological roles including immunological regulation, antibacterial, antiviral, and anticancer properties. Recently, research has uncovered Lf's critical functions in bone remodeling, where it regulates the function of osteoblasts, chondrocytes, osteoclasts, and mesenchymal stem cells. The signaling pathways involved in Lf's signaling in osteoblasts include (low density lipoprotein receptor-related protein - 1 (LRP-1), transforming growth factor β (TGF-β), and insulin-like growth factor - 1 (IGF-1), which activate downstream pathways such as ERK, PI3K/Akt, and NF-κB. These pathways collectively stimulate osteoblast proliferation, differentiation, and mineralization while inhibiting osteoclast differentiation and activity. Additionally, Lf's inhibitory effect on nuclear factor kappa B (NF-κB) suppresses the formation and activity of osteoclasts directly. Lf also promotes chondroprogenitor proliferation and differentiation to chondrocytes by activating the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) and phosphoinositide 3-kinase/protein kinase B(PI3K/Akt)signaling pathways while inhibiting the expression of matrix-degrading enzymes through the suppression of the NF-κB pathway. Lf's ability to stimulate osteoblast and chondrocyte activity and inhibit osteoclast function accelerates fracture repair, as demonstrated by its effectiveness in animal models of critical-sized long bone defects. Moreover, studies have indicated that Lf can rescue dysregulated bone remodeling in osteoporotic conditions by stimulating bone formation and suppressing bone resorption. These beneficial effects of Lf on bone health have led to its exploration in nutraceutical and pharmaceutical applications. However, due to the large size of Lf, small bioactive peptides are preferred for pharmaceutical applications. These peptides have been shown to promote bone fracture repair and reverse osteoporosis in animal studies, indicating their potential as therapeutic agents for bone-related diseases. Nonetheless, the active concentration of Lf in serum may not be sufficient at the site requiring bone regeneration, necessitating the development of various delivery strategies to enhance Lf's bioavailability and target its active concentration to the site requiring bone regeneration. This review provides a critical discussion of the issues mentioned above, providing insight into the roles of Lf in bone remodeling and the potential use of Lf as a therapeutic target for bone disorders.

Injectable Poloxamer Hydrogels for Local Cancer Therapy

The widespread push to invest in local cancer therapies comes from the need to overcome the limitations of systemic treatment options. In contrast to intravenous administration, local treatments using intratumoral or peritumoral injections are independent of tumor vasculature and allow high concentrations of therapeutic agents to reach the tumor site with minimal systemic toxicity. Injectable biodegradable hydrogels offer a clear advantage over other delivery systems because the former requires no surgical procedures and promotes drug retention at the tumor site. More precisely, in situ gelling systems based on poloxamers have garnered considerable attention due to their thermoresponsive behavior, biocompatibility, ease of preparation, and possible incorporation of different anticancer agents. Therefore, this review focuses on the use of injectable thermoresponsive hydrogels based on poloxamers and their physicochemical and biological characterization. It also includes a summary of these hydrogel applications in local cancer therapies using chemotherapy, phototherapy, immunotherapy, and gene therapy.

Stability Profile and Clinical Evaluation of an Innovative Hydrogel Containing Polymeric Micelles as Drug Delivery Systems with Oregano Essential Oil against Fibroepithelial Polyps

Skin tags, also known as fibroepithelial polyps (FPs) or acrochordons, are soft, pigmented excrescences, with a prevalence of 50-60% in the population, occurring especially in the fourth decade of life. To date, FPs have been efficiently eliminated using minimum invasive methods such as surgical removal, cauterization, laser irradiation, and cryosurgery. Over-the-counter treatments are also of interest for patients due to their non-invasive character, but their clinical efficiency has not been clearly demonstrated. This study was designed in order to evaluate the efficacy of a modern-pharmaceutical-formulation-type poloxamer-based binary hydrogel, having Origanum vulgare L. essential oil (OEO-PbH) as an active ingredient in the management of FPs. The formulation has been shown to possess good qualities in terms of stability and sterility. Non-invasive measurements revealed changes in some physiological skin parameters. An increase in transepidermal water loss (TEWL) and erythema index was noted, while skin surface water content (SWC) decreased during eight weeks of treatment. The macroscopic evaluation revealed that the FPs dried and shrunk after topical treatment with OEO-PbH. Clinically, patients presented a lowering of the number of lesions on the treated area of 20-30% after one month of treatment and around 50% after the second month. Histopathological examination suggests that topical treatment with OEO-PbH may induce histological changes in the epidermis, dermis, and fibrovascular cores of FPs, including a loss of thickness, reduced size and number of blood vessels, and low cellularity. These changes may contribute to the observed reduction in size of FPs after treatment with OEO-PbH.

Cutaneous Polymeric-Micelles-Based Hydrogel Containing Origanum vulgare L. Essential Oil: In Vitro Release and Permeation, Angiogenesis, and Safety Profile In Ovo

Origanum vulgare var. vulgare essential oil (OEO) is known as a natural product with multiple beneficial effects with application in dermatology. Oregano essential oil represents a potential natural therapeutic alternative for fibroepithelial polyps (FPs), commonly known as skin tags. Innovative formulations have been developed to improve the bioavailability and stability of essential oils. In this study, we aimed to evaluate the morphology of a polymeric-micelles-based hydrogel (OEO-PbH), the release and permeation profile of oregano essential oil, as well as to assess in vivo the potential effects on the degree of biocompatibility and the impact on angiogenesis in ovo, using a chick chorioallantoic membrane (CAM). Scanning electron microscopy (SEM) analysis indicated a regular aspect after the encapsulation process, while in vitro release studies showed a sustained release of the essential oil. None of the tested samples induced any irritation on the CAM and the limitation of the angiogenic process was noted. OEO-PbH, with a sustained release of OEO, potentially enhances the anti-angiogenic effect while being well tolerated and non-irritative by the vascularized CAM, especially on the blood vessels (BVs) in the presence of leptin treatment. This is the first evidence of in vivo antiangiogenic effects of a polymeric-micelle-loaded oregano essential oil, with further mechanistic insights for OEO-PbH formulation, involving leptin as a possible target. The findings suggest that the OEO-containing polymeric micelle hydrogel represents a potential future approach in the pathology of cutaneous FP and other angiogenesis-related conditions.

Advances in Functionalization of Bioresorbable Nanomembranes and Nanoparticles for Their Use in Biomedicine

Bioresorbable nanomembranes (NMs) and nanoparticles (NPs) are powerful polymeric materials playing an important role in biomedicine, as they can effectively reduce infections and inflammatory clinical patient conditions due to their high biocompatibility, ability to physically interact with biomolecules, large surface area, and low toxicity. In this review, the most common bioabsorbable materials such as those belonging to natural polymers and proteins for the manufacture of NMs and NPs are reviewed. In addition to biocompatibility and bioresorption, current methodology on surface functionalization is also revisited and the most recent applications are highlighted. Considering the most recent use in the field of biosensors, tethered lipid bilayers, drug delivery, wound dressing, skin regeneration, targeted chemotherapy and imaging/diagnostics, functionalized NMs and NPs have become one of the main pillars of modern biomedical applications.

Poloxamers Have Vaccine-Adjuvant Properties by Increasing Dissemination of Particulate Antigen at Distant Lymph Nodes

Vaccine technology is still facing challenges regarding some infectious diseases, which can be addressed by innovative drug delivery systems. In particular, nanoparticle-based vaccines combined with new types of adjuvants are actively explored as a platform for improving the efficacy and durability of immune protection. Here, biodegradable nanoparticles carrying an antigenic model of HIV were formulated with two combinations of poloxamers, 188/407, presenting or not presenting gelling properties, respectively. The study aimed to determine the influence of poloxamers (as a thermosensitive hydrogel or a liquid solution) on the adaptive immune response in mice. The results showed that poloxamer-based formulations were physically stable and did not induce any toxicity using a mouse dendritic cell line. Then, whole-body biodistribution studies using a fluorescent formulation highlighted that the presence of poloxamers influenced positively the dissemination profile by dragging nanoparticles through the lymphatic system until the draining and distant lymph nodes. The strong induction of specific IgG and germinal centers in distant lymph nodes in presence of poloxamers suggested that such adjuvants are promising components in vaccine development.

In situ gelling hydrogel loaded with berberine liposome for the treatment of biofilm-infected wounds

Background: In recent years, the impact of bacterial biofilms on traumatic wounds and the means to combat them have become a major research topic in the field of medicine. The eradication of biofilms formed by bacterial infections in wounds has always been a huge challenge. Herein, we developed a hydrogel with the active ingredient berberine hydrochloride liposomes to disrupt the biofilm and thereby accelerate the healing of infected wounds in mice. Methods: We determined the ability of berberine hydrochloride liposomes to eradicate the biofilm by means of studies such as crystalline violet staining, measuring the inhibition circle, and dilution coating plate method. Encouraged by the in vitro efficacy, we chose to coat the berberine hydrochloride liposomes on the Poloxamer range of in-situ thermosensitive hydrogels to allow fuller contact with the wound surface and sustained efficacy. Eventually, relevant pathological and immunological analyses were carried out on wound tissue from mice treated for 14 days. Results: The final results show that the number of wound tissue biofilms decreases abruptly after treatment and that the various inflammatory factors in them are significantly reduced within a short period. In the meantime, the number of collagen fibers in the treated wound tissue, as well as the proteins involved in healing in the wound tissue, showed significant differences compared to the model group. Conclusion: From the results, we found that berberine liposome gel can accelerate wound healing in Staphylococcus aureus infections by inhibiting the inflammatory response and promoting re-epithelialization as well as vascular regeneration. Our work exemplifies the efficacy of liposomal isolation of toxins. This innovative antimicrobial strategy opens up new perspectives for tackling drug resistance and fighting wound infections.

Recent advances of Pluronic-based copolymers functionalization in biomedical applications

The design of polymeric biocompatible nanomaterials for biological and medical applications has received special attention in recent years. Among different polymers, the triblock type copolymers (EO)_x(PO)_y(EO)_x or Pluronics® stand out due its favorable characteristics such as biocompatibility, low tissue adhesion, thermosensitivity, and structural capacity to produce different types of macro and nanostructures, e.g. micelles, vesicles, nanocapsules, nanospheres, and hydrogels. However, Pluronic itself is not the "magic bullet" and its functionalization via chemical synthesis following biologically oriented design rules is usually required aiming to improve its properties. Therefore, this paper presents some of the main publications on new methodologies for synthetic modifications and applications of Pluronic-based nanoconstructs in the biomedical field in the last 15 years. In general, the polymer modifications aim to improve physical-chemical properties related to the micellization process or physical entrapment of drug cargo, responsive stimuli, active targeting, thermosensitivity, gelling ability, and hydrogel formation. Among these applications, it can be highlighted the treatment of malignant neoplasms, infectious diseases, wound healing, cellular regeneration, and tissue engineering. Functionalized Pluronic has also been used for various purposes, including medical diagnosis, medical imaging, and even miniaturization, such as the creation of lab-on-a-chip devices. In this context, this review discusses the main scientific contributions to the designing, optimization, and improvement of covalently functionalized Pluronics aiming at new strategies focused on the multiple areas of the biomedical field.

A Critical Review on Classified Excipient Sodium-Alginate-Based Hydrogels: Modification, Characterization, and Application in Soft Tissue Engineering

Alginates are polysaccharides that are produced naturally and can be isolated from brown sea algae and bacteria. Sodium alginate (SA) is utilized extensively in the field of biological soft tissue repair and regeneration owing to its low cost, high biological compatibility, and quick and moderate crosslinking. In addition to their high printability, SA hydrogels have found growing popularity in tissue engineering, particularly due to the advent of 3D bioprinting. There is a developing curiosity in tissue engineering with SA-based composite hydrogels and their potential for further improvement in terms of material modification, the molding process, and their application. This has resulted in numerous productive outcomes. The use of 3D scaffolds for growing cells and tissues in tissue engineering and 3D cell culture is an innovative technique for developing in vitro culture models that mimic the in vivo environment. Especially compared to in vivo models, in vitro models were more ethical and cost-effective, and they stimulate tissue growth. This article discusses the use of sodium alginate (SA) in tissue engineering, focusing on SA modification techniques and providing a comparative examination of the properties of several SA-based hydrogels. This review also covers hydrogel preparation techniques, and a catalogue of patents covering different hydrogel formulations is also discussed. Finally, SA-based hydrogel applications and future research areas concerning SA-based hydrogels in tissue engineering were examined.

Development of Thermoresponsive Hydrogels with Mucoadhesion Properties Loaded with Metronidazole Gel-Flakes for Improved Bacterial Vaginosis Treatment

Bacterial vaginosis is an infectious disease that has significantly affected women's health. Metronidazole has been widely used as a drug for treating bacterial vaginosis. Nevertheless, the currently available therapies have been found to be inefficient and inconvenient. Here, we developed the combination approach of gel flake and thermoresponsive hydrogel systems. The gel flakes were prepared using gellan gum and chitosan, showing that the incorporation of metronidazole was able to provide a sustained release pattern for 24 h with an entrapment efficiency of >90%. Moreover, the gel flakes were incorporated into Pluronics-based thermoresponsive hydrogel using the combination of Pluronic F127 and F68. The hydrogels were found to exhibit the desired thermoresponsive properties, showing sol-gel transition at vaginal temperature. Following the addition of sodium alginate as a mucoadhesive agent, the hydrogel was retained in the vaginal tissue for more than 8 h, with more than 5 mg of metronidazole retained in the ex vivo evaluation. Finally, using the bacterial vaginosis infection model in rats, this approach could decrease the viability of Escherichia coli and Staphylococcus aureus with reduction percentages of more than 95% after 3 days of treatment, with the healing ability similar to normal vaginal tissue. In conclusion, this study offers an effective approach for the treatment of bacterial vaginosis.

TRAF-STOP alleviates osteoclastogenesis in periodontitis

The enhanced osteoclastogenesis contributes to alveolar bone resorption in periodontitis, which increases the risk of tooth loss. To reduce bone destruction, the inhibition of osteoclast development is proposed as a feasible treatment. CD40L-CD40-TRAF6 signal transduction plays a crucial role in inflammation, but how it regulates osteoclast activity in periodontitis has not been elucidated. In this study, we showed the potential role of CD40L-CD40-TRAF6 signaling in periodontitis. CD40L obviously promoted osteoclast formation and bone resorption capacity in vitro. Mechanistically, we found that osteoclastogenesis was enhanced by the overexpression of NFATc1 and NF-κB activation. Importantly, osteoclast activity was effectively suppressed by TRAF-STOP, a small molecular inhibitor of TRAF6. Furthermore, local injection of TRAF-STOP-loaded injectable PLGA-PEG-PLGA hydrogel could alleviate ligation-induced periodontitis in vivo. Taken together, TRAF-STOP shows promising clinical efficacy in periodontitis through alleviating osteoclastogenesis.

Consequences of poly(ethylene oxide) and poloxamer P188 on transcription in healthy and stressed myoblasts

Poly(ethylene oxide) (PEO) and poloxamers, a class of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers, have many personal and medical care applications, including the stabilization of stressed cellular membranes. Despite the widespread use, the cellular transcriptional response to these molecules is relatively unknown. C2C12 myoblasts, a model muscle cell, were subjected to short-term Poloxamer 188 (P188) and PEO181 (8,000 g/mol) treatment in culture. RNA was extracted and sequenced to quantify transcriptomic impact. The addition of moderate concentrations (14 µM) of either polymer to unstressed cells caused substantial differential gene expression, including at least twofold modulation of 357 and 588 genes, respectively. In addition, evaluation of the transcriptome response to osmotic stress without polymer treatment revealed dramatic change in RNA expression. Interestingly, the addition of polymer to stressed cells-at concentrations that provide physiological protection-did not yield a significant difference in expression of any gene relative to stress alone. Genome-scale expression analysis was corroborated by single-gene quantitative real-time PCR. Changes in protein expression were measured via western blot, which revealed partial alignment with the RNA results. Collectively, the significant changes to expression of multiple genes and resultant protein translation demonstrates an unexpectedly broad biochemical response to these polymers in healthy myoblasts in vitro. Meanwhile, the lack of substantial transcriptional response to polymer treatment in stressed cells highlights the physical nature of that protective mechanism.

Pluronic F127 coating performance on PLGA nanoparticles: Enhanced flocculation and instability

Nanoparticles (NPs) can be incorporated into hydrogels to obtain multifunctional hybrid systems to meet the delivery needs of different drugs. However, the stability of NPs in hydrogels is rarely revealed. In this article, we tried to explore the underlying mechanism of an interesting phenomenon that poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PNPs) could flocculate and deposit in Pluronic F127 (F127) hydrogels at 4 °C. The results showed that this flocculation was relevant to the type of emulsifier formulated in PNPs, the particle materials and the F127 concentration, but independent of PLGA polymer end groups. Exactly, PNPs containing polyvinyl alcohol (PVA) as the emulsifier flocculated in F127 solution with a concentration above 15 %. The flocculated PNPs possessed increased particle size, decreased zeta potential, reduced hydrophobicity and an obvious coating layer, and these characteristics could be restored almost to the original state after two washes of flocculated PNPs with water. Moreover, the flocculation had no impact on the long-term size stability and drug-loading capacity of PNPs, and F127-treated PNPs showed improved cellular uptake than untreated PNPs. These results provide the evidence that adsorption of high concentrations of F127 on the surface of PNPs/PVA may lead to flocculation, and the flocculation is reversible by simply washing the flocs with water. To the best of our knowledge, this is the first study to scientifically explore the stability of PNPs in F127 hydrogels, providing theoretical and experimental support for the rational design and further development of nanoparticle-hydrogel composite.

Antibacterial effectiveness of multi-strain probiotics supernatants intracanal medication on Enterococcus faecalis biofilm in a tooth model

BACKGROUND

To assess the antibacterial activity of multi-strain probiotics supernatants (MSP); Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus acidophilus as an intracanal medication on Enterococcus faecalis (E. faecalis) biofilm in a tooth model.

METHODS

Sixty extracted human single-rooted teeth with single canals were instrumented, sterilized, and inoculated with E. faecalis. After 21 days of incubation, four specimens were randomly selected to validate the biofilm formation by scanning electron microscope (SEM). The remaining specimens were randomly divided (n = 14), according to the intracanal medication (ICM) received into: Ca(OH)₂: calcium hydroxide paste (35% Ultra Cal XS Ca(OH)₂), Probiotics supernatants: MSP in poloxamer gel vehicle Poloxamer: poloxamer gel vehicle and, Control: E. faecalis biofilm only. The tested groups were further subdivided into two equal subgroups (n = 7) according to the incubation period (24 h and 7 days). Shaved dentin chips were obtained and collected by H-files and paper points, respectively for bacterial culture. The antibacterial activity was assessed after each incubation period quantitatively and qualitatively using bacterial colony-forming units per milliliter (CFUs/ml) and SEM, respectively.

RESULTS

The lowest CFUs/ml was found in Ca (OH)₂ with a significant difference compared to other groups after 24 h. After 7 days, a similar outcome was found with a further significant reduction of CFUs/ml in all groups with no statistical difference between Ca(OH)₂ and probiotics supernatants groups. Ca (OH)₂ and Probiotics supernatants groups showed a significant (p < 0.05) percentage of overall bacterial reduction (100.00 ± 0.00% and 70.30 ± 12.95%, respectively) compared to poloxamer and control groups (27.80 ± 14.45 and 28.29 ± 19.79). SEM images showed a bacteria-free state in the Ca(OH)₂ group after 7 days while few bacteria were found in the probiotics supernatants group. An extensive invasion of bacteria was found in poloxamer and controls groups.

CONCLUSION

MSP has a potential antibacterial effect on E. faecalis growth closely similar to the routinely used Ca (OH)₂.

In vitro elution of amikacin from four hydrogel preparations: A pilot study

OBJECTIVE

To determine in vitro elution of amikacin from poloxamer 407 NF, 1% carboxymethylcellulose (CMC), 3% CMC, 5% CMC, and control (sterile water).

STUDY DESIGN

Descriptive in vitro.

SAMPLE POPULATION

Triplicate samples from each experimental group.

METHODS

Amikacin solution was prepared in poloxamer 407 NF, 1% CMC, 3% CMC, 5% CMC, or sterile water. Then, 1 ml of phosphate-buffered saline (PBS) was added to each of three aliquots per base and the samples were incubated at 37°C. PBS was removed and replaced at 1, 4, 8, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216, and 240 hours and amikacin concentration was measured.

RESULTS

The highest median concentration of amikacin in the eluent of poloxamer 407 NF, 3% CMC, and 5% CMC was observed at 48 hours: 3300, 3030, and 2190 μg/ml, respectively. The highest median concentration of amikacin in the eluent of 1% CMC and sterile water were observed at 1 hour: 13300 and 15600 μg/ml, respectively. Median eluent concentration of amikacin exceeded 2000 μg/ml (the reported minimum inhibitory concentration [MIC] of certain biofilm-producing methicillin-resistant Staphylococcus pseudintermedius) from 24 to 96 hours for poloxamer 407 NF, 24-72 hours for 3% CMC, 48-72 hours for 5% CMC, 1-4 hours for 1% CMC, and 1-4 hours for sterile water.

CONCLUSION

Amikacin elution from tested substances reached or exceeded target MIC during the 240 hours tested.

CLINICAL SIGNIFICANCE

Hydrogel-amikacin solutions may be useful topical treatment options for some infected wounds. In vivo safety and efficacy should be evaluated.

Novel technologies for applying immune checkpoint blockers

Cancer cells develop several ways to subdue the immune system among others via upregulation of inhibitory immune checkpoint (ICP) proteins. These ICPs paralyze immune effector cells and thereby enable unfettered tumor growth. Monoclonal antibodies (mAbs) that block ICPs can prevent immune exhaustion. Due to their outstanding effects, mAbs revolutionized the field of cancer immunotherapy. However, current ICP therapy regimens suffer from issues related to systemic administration of mAbs, including the onset of immune related adverse events, poor pharmacokinetics, limited tumor accessibility and immunogenicity. These drawbacks and new insights on spatiality prompted the exploration of novel administration routes for mAbs for instance peritumoral delivery. Moreover, novel ICP drug classes that are adept to novel delivery technologies were developed to circumvent the drawbacks of mAbs. We therefore review the state-of-the-art and novel delivery strategies of ICP drugs.

Development of Polyurethane/Peptide-Based Carriers with Self-Healing Properties

In situ-forming gels with self-assembling and self-healing properties are materials of high interest for various biomedical applications, especially for drug delivery systems and tissue regeneration. The main goal of this research was the development of an innovative gel carrier based on dynamic inter- and intramolecular interactions between amphiphilic polyurethane and peptide structures. The polyurethane architecture was adapted to achieve the desired amphiphilicity for self-assembly into an aqueous solution and to facilitate an array of connections with peptides through physical interactions, such as hydrophobic interactions, dipole-dipole, electrostatic, π–π stacking, or hydrogen bonds. The mechanism of the gelation process and the macromolecular conformation in water were evaluated with DLS, ATR-FTIR, and rheological measurements at room and body temperatures. The DLS measurements revealed a bimodal distribution of small (~30–40 nm) and large (~300–400 nm) hydrodynamic diameters of micelles/aggregates at 25 °C for all samples. The increase in the peptide content led to a monomodal distribution of the peaks at 37 °C (~25 nm for the sample with the highest content of peptide). The sol–gel transition occurs very quickly for all samples (within 20–30 s), but the equilibrium state of the gel structure is reached after 1 h in absence of peptide and required more time as the content of peptide increases. Moreover, this system presented self-healing properties, as was revealed by rheological measurements. In the presence of peptide, the structure recovery after each cycle of deformation is a time-dependent process, the recovery is complete after about 300 s. Thus, the addition of the peptide enhanced the polymer chain entanglement through intermolecular interactions, leading to the preparation of a well-defined gel carrier. Undoubtedly, this type of polyurethane/peptide-based carrier, displaying a sol–gel transition at a biologically relevant temperature and enhanced viscoelastic properties, is of great interest in the development of medical devices for minimally invasive procedures or precision medicine.

Role of Berberine Thermosensitive Hydrogel in Periodontitis via PI3K/AKT Pathway In Vitro

Periodontitis is a long-term inflammatory illness and a leading contributor to tooth loss in humans. Due to the influence of the anatomic parameters of teeth, such as root bifurcation lesions and the depth of the periodontal pocket, basic periodontal treatment on its own often does not completely obliterate flora microorganisms. As a consequence, topical medication has become a significant supplement in the treatment of chronic periodontitis. Berberine (BBR) has various pharmacological effects, such as hypoglycemic, antitumor, antiarrhythmic, anti-inflammatory, etc. The target of our project is to develop a safe and non-toxic carrier that can effectively release berberine, which can significantly reduce periodontal tissue inflammation, and to investigate whether berberine thermosensitive hydrogel can exert anti-inflammatory and osteogenic effects by modulating phosphatifylinositol-3-kinase/Protein Kinase B (PI3K/AKT) signaling pathway. Consequently, firstly berberine temperature-sensitive hydrogel was prepared, and its characterizations showed that the mixed solution gelated within 3 min under 37 °C with a hole diameter of 10-130 µm, and the accumulation of berberine release amounted to 89.99% at 21 days. CCK-8 and live-dead cell staining results indicated that this hydrogel was not biotoxic, and it is also presumed that the optimum concentration of berberine is 5 µM, which was selected for subsequent experiments. Real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB)results demonstrated that inflammatory factors, as well as protein levels, were significantly reduced in the berberine-loaded hydrogel group, and LY294002 (PI3K inhibitor) could enhance this effect (p < 0.05). In the berberine-loaded hydrogel group, osteogenesis-related factor levels and protein profiles were visibly increased, along with an increase in alkaline phosphatase expression, which was inhibited by LY294002 (p < 0.05). Therefore, berberine thermosensitive hydrogel may be an effective treatment for periodontitis, and it may exert anti-inflammatory and osteogenic effects through the PI3K/AKT signaling pathway.

Phase behavior of medium-length hydrophobically associating PEO-PPO multiblock copolymers in aqueous media

HYPOTHESIS

The micellization of block copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) is driven by the dehydration of PPO at elevated temperatures. At low concentrations, a viscous solution of isolated micelles is obtained, whereas at higher concentrations, crowding of micelles results in an elastic gel. Alternating PEO-PPO multiblock copolymers are expected to exhibit different phase behavior, with altered phase boundaries and thermodynamics, as compared to PEO-PPO-PEO triblock copolymers (Pluronics®) with equal hydrophobicity, thereby proving the pivotal role of copolymer architecture and molecular weight.

EXPERIMENTS

Multiple characterization techniques were used to map the phase behavior as a function of temperature and concentration of PEO-PPO multiblock copolymers (ExpertGel®) in aqueous solution. These techniques include shear rheology, differential and adiabatic scanning calorimetry, isothermal titration calorimetry and light transmittance. The micellar size and topology were studied by dynamic light scattering.

FINDINGS

Multiblocks have lower transition temperatures and higher thermodynamic driving forces for micellization as compared to triblocks due to the presence of more than one PPO block per chain. With increasing concentration, the multiblock copolymers in solution gradually evolve into a viscoelastic network formed by soluble bridges in between micellar nodes, whereas hairy triblock micelles jam into liquid crystalline phases resembling an elastic colloidal crystal.

Terbinafine Nanohybrid: Proposing a Hydrogel Carrying Nanoparticles for Topical Release

A poloxamer 407 (P407)—Casein hydrogel was chosen to carry polycaprolactone nanoparticles carrying terbinafine (PCL-TBH-NP). In this study, terbinafine hydrochloride (TBH) was encapsulated into polycaprolactone (PCL) nanoparticles, which were further incorporated into a poloxamer-casein hydrogel in a different addition order to evaluate the effect of gel formation. Nanoparticles were prepared by the nanoprecipitation technique and characterized by evaluating their physicochemical characteristics and morphology. The nanoparticles had a mean diameter of 196.7 ± 0.7 nm, PDI of 0.07, negative ζ potential (−0.713 mV), high encapsulation efficiency (>98%), and did not show cytotoxic effects in primary human keratinocytes. PCL-NP modulated terbinafine was released in artificial sweat. Rheological properties were analyzed by temperature sweep tests at different addition orders of nanoparticles into hydrogel formation. The rheological behavior of nanohybrid hydrogels showed the influence of TBH-PCL nanoparticles addition in the mechanical properties of the hydrogel and a long-term release of the nanoparticles from it.