Poloxamer Hydrogels for Biomedical Applications

Poloxamer-based drug delivery systems: Frontiers for treatment of solid tumors

Pluronics or poloxamers are a type of triblock copolymer. These non-ionic molecules consist of a hydrophobic block embedded in two hydrophilic parts. Pluronics have become favorite materials for use in the field of biomedical research due to having favorable physicochemical and biological properties such as amphiphilicity, solubility in ionic and non-ionic solutions, biocompatibility, biodegradability, self-assembly and low toxicity. The scope of these applications can vary from tissue engineering to drug delivery. One of the important uses of pluronics is to deliver drugs to various cancer cells. Herein we first provide an overview on variety of ploronic biomaterials. And then intensively evaluate their potential as drug delivery systems (DDSs) for treatment of solid tumors with special focus on breast cancers. After explaining the pros and cons of pluronics, the current status in clinical settings and future prospects are highlighted.

Physicochemical Properties and Efficacy of Poloxamer Bone Wax on Hemostasis at the Bone-Amputation Site

Bone wax, an essential material for bone hemostasis in orthopedic, thoracic, and neurological surgeries, is defined as a substance that physically controls bleeding caused by bone fractures. Absorbable bone-wax products such as poloxamer multiblock copolymers can be topically applied, form a physical barrier, are biocompatible, and can be absorbed by/excreted from the body. However, absorbable bone waxes continue to have limited physical properties, poor bone adhesion, and low hemostatic quality. When applied to the affected area, they quickly dissolve in blood and body fluids, preventing maintenance of the physical barrier over a certain period and thereby reducing the hemostatic effect. This study introduces a new type of absorbable bone wax (OSSTOP) constructed from 2 poloxamer multiblock copolymers with different molecular weight ranges. To determine whether OSSTOP overcomes the limitations of the existing products, the physicochemical properties and efficacy of OSSTOP were compared with those of 2 existing absorbable bone-wax products, OSTENE and NOVOSEAL. The adhesive strengths, yield loads, and solubilities of the products were evaluated and compared in vitro. Hemostasis at the bone-amputation site and absorption/degradation of the products were then evaluated through animal experiments in vivo. The biological safety (cytotoxicity) of the newly developed OSSTOP was also assessed. A histological analysis confirmed superior hemostasis at the bone-amputation site and a favorable biological response after treatment with OSSTOP. We expect that OSSTOP will improve the convenience, hemostatic performance, and biocompatibility of bleeding cessation at bone-amputation sites in the clinical environment.

Formulation and evaluation of oxygen microbubbles stabilised in a hydrogel to potentiate radiotherapy

BACKGROUND

Tumour hypoxia poses a significant challenge in cancer treatment. There is mounting evidence that reoxygenating tumours increases their sensitivity to conventional cancer therapies. Oxygenated microbubbles (OMB) show promise for this application but suffer from poor stability and rapid clearance. Embedding OMB in a thermosensitive hydrogel (OMBHG) may prolong tumour oxygenation and improve therapeutic outcomes.

OBJECTIVES

To formulate and evaluate OMB loaded in a temperature sensitive hydrogel on an in vitro model of tumour hypoxia.

METHODS

OMB generated from a liposomal precursor were dispersed at various concentrations in a poloxamer hydrogel. OMB size, hydrogel rheology, injectability, oxygen loading/release, and impact on efficacy of radiotherapy against HCT116 colon cancer cells under hypoxia/normoxia were evaluated.

RESULTS

DSPC:DSPE-PEG2000 (94:6 molar ratio) liposomes dispersed in a poloxamer 407: poloxamer 188 (21:6.5 % w/w) hydrogel generated OMB predominantly sized < 1 µm. OMBHG formulations were deemed injectable (force to inject < 38 N) at 20 °C and gelled before 37 °C and demonstrated both greater oxygen loading and prolonged oxygen release than OMB alone. Cancer cells were significantly less sensitive to radiotherapy under hypoxic conditions. Pre-treatment of the cells with OMB or OMBHG enhanced radiotherapy significantly, reducing clonogenic survival rates in HCT116 cells by 78 % in hypoxic conditions and by 68 % in normoxic conditions (p < 0.0001 in both cases). Notably, this treatment restored the radiotherapy sensitivity of hypoxic cells to the levels seen with normoxic cells.

CONCLUSION

Reoxygenation with a newly developed OMB hydrogel formulation effectively sensitised HCT116 to radiotherapy in vitro. Ongoing studies are exploring the importance of reoxygenation rate and extent for optimal tumour sensitisation.

Curcumin encapsulation in self-assembled nanoparticles based on amphiphilic stearic acid-grafted inulin: Preparation, characterization, and functional evaluation

The clinical application of curcumin (CUR) is restricted by its low solubility, instability, and poor bioavailability. To overcome these limitations, we developed a novel stearic acid-grafted inulin-based nano-delivery system for CUR encapsulation. The structure of stearoyl inulin (SA-IN) was characterized using Fourier-transform infrared spectroscopy, hydrogen nuclear magnetic resonance, thermogravimetric analysis, and contact angle measurements. CUR-loaded SA-IN nanoparticles (CUR@SA-IN NPs) demonstrated a high encapsulation efficiency of 91.59 % ± 3.26 %, nanoscale dispersion, and an average particle size of 190.6 ± 11.2 nm. The CUR@SA-IN NPs exhibited excellent stability and sustained-release properties. Compared with free CUR, the minimum inhibitory concentration of CUR@SA-IN NPs against Escherichia coli and Staphylococcus aureus decreased by 1.5- and 1.6-fold, respectively. The antioxidant activity increased by 2.34-fold with CUR@SA-IN NPs compared with free CUR. Also, the NPs showed superior efficacy in suppressing the expression of inflammatory cytokines and inhibiting cancer cell proliferation. The cellular uptake studies confirmed enhanced CUR absorption from the NPs compared with free CUR. The CUR@SA-IN NPs exhibited good biocompatibility. These findings highlighted the potential of amphiphilic SA-IN as an effective delivery vector for hydrophobic bioactive compounds, thereby offering a promising approach for developing efficient nanoparticle-based delivery systems.

Amorphous Roxithromycin Loaded in-situ Gel for the Treatment of Staphylococcus aureus Induced Upper Respiratory Tract Infection

Objective

Upper respiratory tract infections are among the most prevalent respiratory diseases, imposing both financial and physical burdens on affected individuals. Roxithromycin (ROX), a primary drug for treating bacterial-induced respiratory tract infections, is typically administered orally due to its hydrophobic nature. However, the non-specific distribution resulting from oral administration reduces bioavailability and can cause side effects such as diarrhea.

Methods

In this study, we prepared a thermo-sensitive in-situ gel using a facile and highly reproducible method by simply mixing two types of poloxamers with ROX.

Results

The ROX can be well dissolved in the poloxamer matrix in amorphous state to give solution. Upon intranasal administration, the ROX solution undergoes a phase transition to form in-situ gel under body temperature. This gel remains in the nasal cavity for an extended period, releasing the drug directly to the site of infection and minimizing non-specific distribution. Pharmacokinetic experiments revealed that, compared to oral administration, the bioavailability of local nasal administration increased by 1.5 times, and the drug concentration in the local nasal cavity increased by 8 times. In contrast, concentrations in the liver and small intestine did not significantly differ from those following oral administration. In vivo antibacterial experiments also showed that the ROX in-situ gel has superior antibacterial efficacy and excellent biocompatibility.

Conclusion

These results suggest that the thermo-sensitive ROX in-situ gel is a promising formulation for treating bacterial upper respiratory tract infections.

A Viscoelastic Supramolecular Hydrogel Co-Assembled from Gatifloxacin and Deoxyguanosine for the Treatment of Bacterial Keratitis

Bacterial keratitis is the most prevalent ocular surface infection, causing significant inconvenience to patients' lives and posing a risk of blindness if mismanaged. The application of antibiotic gels has been a principal clinic therapeutic intervention due to the retarded ocular surface medication retention. However, current clinical gel formulations rely on high viscosity polymer matrices to improve retention, which often results in uneven gel layers, causing sticky sensation and prone to adhesion to periocular tissues during blinking, leading to clearance. In this study, we propose a supramolecular hydrogel assembled from antibiotic and natural nucleotide molecules with viscoelastic rheology and low cohesion texture. These features enabled it spread to uniformly on the ocular surface, recover deformation after blinking, and are less likely to adhere to periocular tissues, significantly improving drug retention on the ocular surface and achieving better therapeutic effects in the treatment of bacterial keratitis. Additionally, the hydrogel is easy to prepare, has good visibility and safety, offering a new strategy for the development of ophthalmic gels.

Novel Thermosensitive Hydrogel Encapsulated Carvedilol for the Treatment of Rosacea

BACKGROUND

Carvedilol can be used in the treatment of rosacea. However, their oral administration often results in a series of adverse effects.

PURPOSE

A novel thermosensitive hydrogel was developed to improve the administration of carvedilol in the treatment of rosacea and to evaluate its safety and efficacy.

METHODS

The thermosensitive hydrogel was formulated using varying ratios of poloxamer 407 (P407) and poloxamer 188 (P188), with carvedilol being encapsulated during the process. The gel temperature and time of the hydrogel were observed, its phase transition was assessed through the inverted tube test, its microstructure was examined using scanning electron microscopy (SEM), and its characteristic functional groups were identified with Fourier transform infrared spectrometry (FTIR). The hydrogel's therapeutic efficacy on a rosacea-like phenotype in mice was evaluated through in vitro experiments.

RESULTS

It is observed that the microstructure of the hydrogel possesses a porous structure, with pores uniformly arranged in a square lattice measuring 8-12 μm in diameter. Thermosensitive hydrogel encapsulated carvedilol (Car-P40724/P1881) had favorable drug release rate and swelling properties. Live/dead cell assays indicated minimal toxicity of the hydrogel to HaCaT cells, and the carvedilol encapsulated with hydrogel possessed a better therapeutic effect on the rosacea-like phenotype in mice.

CONCLUSION

Car-P40724/P1881 was not significantly cytotoxic and possessed good cellular biocompatibility. Furthermore, it exhibits a good therapeutic effect on rosacea-associated facial flushing and erythema. It possesses some anti-inflammatory properties and exhibits great potential for future use in rosacea treatment.

An in-situ forming controlled release soft hydrogel-based C5a peptidase drug delivery system to treat psoriasis

The potent pro-inflammatory cytokine, interferon gamma (IFN-γ), is an enticing therapeutic target because of its accelerator role in several acute and chronic inflammatory processes. In this work, poloxamer 407 is developed as an in-situ gelling polymer for a long-acting formulation to deliver a serine protease, C5a peptidase (ScpA) from Streptococcus pyogenes. ScpA is well known for its activity against the complement factor C5a but has also recently been shown to cleave IFN-γ in vitro into inactive fragments. A compact and uniform gel microstructure was obtained by including dextran in the gel formulation. The sol-gel transition at physiologically temperatures occurred above 19 % w/w poloxamer 407 resulting in a release profile of active ScpA for up to 8 days, with no loss in specific enzymatic activity. No cytotoxicity from ScpA before or after release from the hydrogels to a human immortalized keratinocyte cell lines was detected. Using an in vitro psoriatic skin model with IFN- γ inducing the psoriatic state, the constant and prolonged release of ScpA from this simple thermo-responsive hydrogel, administered once, restored health as effectively as two doses of free enzyme over a 5 day period. These promising results confirm the feasibility of developing ScpA as a long-acting therapeutic using a poloxamer based in-situ forming parenteral gel for local delivery.

Development of lacosamide-loaded in-situ gels through experimental design for evaluation of ocular irritation in vitro and in vivo

Lacosamide (LCM) selectively increases the slow inactivation of voltage-gated sodium channels (VGSCs) and is a N-methyl d-aspartate acid (NMDA) receptor glycine site antagonist. Therefore, it can be used in dryness-related hyperexcitability of corneal cold receptor nerve terminals. Ocular in-situ gels remain in liquid form until they reach the target site, where they undergo a sol-gel transformation in response to specific stimuli. They can show mucoadhesive properties related to the polymer used and increase the residence time of the drug in the mucosa. In the presented study, ocular in-situ gel formulation of LCM, which has potential for use in ocular diseases and consists of hyaluronic acid and poloxamer 407 as polymers, was developed using cold method. The effect of formulation components on target product properties (pH, gelation temperature and viscosity) was evaluated by design of experiments (DoE) design. The optimized LCM-loaded in-situ gel had a pH value of 6.90 ± 0.01, showed pseudo-plastic flow with a viscosity of 562 ± 58 cP at 25 °C, gelled at 33 ± 0.47 °C, and released drugs via the Peppas-Sahlin mechanism. Ocular safety was confirmed via in vitro tests using two different cell lines (L929 and Arpe-19), along with in vivo Draize tests, histological examinations, and Hen's Egg Chario-Allontioc-Membrane (HET-CAM) analysis. In vitro studies confirmed the optimized LCM-loaded in-situ gel's suitability for ocular use, demonstrating long-acting effects through controlled release. In addition, ocular irritation and histological studies have supported that it will not show any toxic effect on the eye tissue.

Synergistic enhancement of spinal fusion in preclinical models using low-dose rhBMP-2 and stromal vascular fraction in an injectable hydrogel composite

Spinal fusion surgery remains a significant challenge due to limitations in current bone graft materials, particularly in terms of bioactivity, integration, and safety. This study presents an innovative approach using an injectable hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) hydrogel combined with stromal vascular fraction (SVF) and low-dose recombinant human BMP-2 (rhBMP-2) to enhance osteodifferentiation and angiogenesis. Through a series of in vitro studies and preclinical models involving rats and minipigs, we demonstrated that the hydrogel system enables the sustained release of rhBMP-2, resulting in significantly improved bone density and integration, alongside reduced inflammatory responses. The combination of rhBMP-2 and SVF in this injectable formulation yielded superior spinal fusion outcomes, with enhanced mechanical properties and increased bone mass in both small and large animal models. These findings suggest that this strategy offers a promising and safer alternative for spinal fusion, with strong potential for clinical application.

Alteration of gel point of poloxamer 338 induced by pharmaceutical actives and excipients

Poloxamer 338 is used as versatile thermo-responsive gelling agent in topical and sub-cutaneous applications. Due to application specific needs a gel point below body or even below room temperature is required. The influence of inorganic salts and active pharmaceutical ingredients (APIs) on the gel point was investigated using oscillatory rheology to identify the driving forces and predictors for gel point alteration. While most inorganic salts decreased the gel point, API salts exhibited an increase. Consistent with previous findings, the extent of gel point alteration caused by inorganic salts could be empirically described by the Hofmeister series, primarily influenced by the anion. Notably, this study revealed a concentration-dependent increase in the gel point in the presence of API salts. Moreover, this increase could be accurately predicted in a linear manner by considering the respective logP value. By utilizing the proposed prediction model, the effect of API addition on the gel point can be estimated, facilitating formulation development to achieve the desired gelling behavior for specific applications.

Balancing sterilization and functional properties in Poloxamer 407 hydrogels: comparing heat and radiation techniques

Poloxamer 407, also known as Pluronic® F127, is gaining interest in the cosmetic, biomedical and pharmaceutical fields for its biocompatibility, safety and thermo-sensitive properties. Ensuring sterility is critical in clinical applications, and sterilization is often preferred over aseptic processing. However, sterilization can impact the functional properties of the hydrogel. In this study, we investigate the effects of steam heat (121°C, 20 min), dry heat (160°C, 1 h), gamma irradiation (25 kGy) and electron beam (e-beam) irradiation (15 and 25 kGy) on a 30% w/v Poloxamer 407 hydrogel formulation. Our analysis encompasses gelling properties, pH, Fourier-transform infrared spectroscopy, gel permeation chromatography, small-angle X-ray scattering, rheology, swelling, degradation by-products and lactate dehydrogenase release of the sterilized hydrogels, comparing them to a non-sterile counterpart. We demonstrated that heat sterilization alters the hydrogel's gelling and structural properties due to water evaporation and oxidation under harsh temperature conditions, especially when applying the dry heat method. Gamma irradiation proved unsuitable, resulting in an acidic and cytotoxic hydrogel due to oxidative degradation. In contrast, e-beam irradiation preserves the hydrogel's elasticity, gelling and structural properties while enhancing mechanical resilience and moderating swelling. Therefore, e-beam irradiation within the 15-25 kGy range appears to be the most suitable method for sterilizing a 30% w/v Poloxamer 407 hydrogel.

Marine-Derived Polysaccharide Hydrogels as Delivery Platforms for Natural Bioactive Compounds

Marine polysaccharide hydrogels have emerged as an innovative platform for regulating the in vivo release of natural bioactive compounds for medical purposes. These hydrogels, which have exceptional biocompatibility, biodegradability, and high water absorption capacity, create effective matrices for encapsulating different bioactive molecules. In addition, by modifying the physical and chemical properties of marine hydrogels, including cross-linking density, swelling behavior, and response to external stimuli like pH, temperature, or ionic strength, the release profile of encapsulated bioactive compounds is strictly regulated, thus maximizing therapeutic efficacy and minimizing side effects. Finally, by using naturally sourced polysaccharides in hydrogel formulations, sustainability is promoted by reducing dependence on synthetic polymers, meeting the growing demand for eco-friendly materials. This review analyzes the interaction between marine polysaccharide hydrogels and encapsulating compounds and offers examples of how bioactive molecules can be encapsulated, released, and stabilized.

Development of Thermoresponsive Composite Hydrogel Loaded with Indocyanine Green and Camptothecin for Photochemotherapy of Skin Cancer After Surgery

Skin cancer is the world's fifth most diagnosed malignancy and is increasingly occurring in young adults. The elevated morbidity and mortality of skin cancer are known to be highly correlated with its frequent recurrence after tumor excision. Although regimens such as chemotherapy and/or immunotherapy are often administered following surgical treatments, the patients may suffer from severe side effects, drug resistance, and/or high cost during treatments, indicating that the development of an effective and safe modality for skin cancer after surgery is still highly demanded nowadays. In this study, an injectable and thermoresponsive hyaluronic acid/hexamethylene diisocyanate-Pluronic F127 block copolymer crosslinking composite hydrogel loaded with indocyanine green (ICG) and camptothecin (CPT), called ICHHPG, was developed for photochemotherapy of skin cancer after surgery. ICHHPG can be self-gelationed at 37 °C and stabilizes ICG in the gel matrix. Upon NIR exposure, ICHHPG can generate hyperthermia and consequently provide photothermal therapy when the ICG dosage is >5 μM. Furthermore, ICHHPG may provide a remarkably enhanced cancericidal effect compared to the equal concentration of free ICG (≤10 μM) or CPT (≤1000 μM) alone, and more than 95% of cancer cells can be destroyed as the intra-gel doses of ICG/CPT were elevated to 10/800 μM. Given the confirmed cytotoxicity together with its fluidic and thermoresponsive characteristics which are foreseeably favorable for wound coverage, the developed ICHHPG is highly applicable for use in skin cancer treatment after surgical excision.

Harnessing polysialic acid (PSA)-embedded exudate-absorbing hydrogel for on-demand trigeminal neuralgia treatment

A key characteristic of trigeminal neuralgia (TN) is cytokine-enriched exudate and a "reactive oxygen species (ROS) storm" generated from the inflammatory cascade, resulting in demyelination of the sensory root of the trigeminal nerve, tissue swelling, and intense electric shock-like pain. The clinically approved drug carbamazepine (CBZ) is capable of inhibiting pain, reducing inflammatory factors, and alleviating oxidative stress, but its clinical application is restricted by its systemic toxicity. Herein, we developed an exudate-absorbing hydrogel incorporating polysialic acid (PSA) and CBZ (F127@PSA@CBZ) for on-demand TN treatment. Owing to the strong water absorption properties of PSA and F127, the F127@PSA@CBZ hydrogel can quickly absorb the lesion exudate and swell into a larger volume with a looser structure, thus releasing payloads sustainably, such as CBZ and PSA, for approximately 7 days in vivo. The released CBZ can scavenges the ROS storm and inhibits the levels of proinflammatory factors. More importantly, the residual PSA was found to promoted the proliferation of Schwann cells by upregulating the expression of STAT3 and Ki67, contributing to enhanced myelin sheath regeneration in a rat TN model. These findings highlight that the PSA-embedded exudate-absorbing hydrogel has great potential for facilitating the repair of the trigeminal nerve myelin sheath.

A Review of Basic Fibroblast Growth Factor Delivery Strategies and Applications in Regenerative Medicine

Basic fibroblast growth factor (bFGF) is a significant member of the fibroblast growth factor (FGF) family. The bFGF has a three-dimensional structure comprising 12 reverse parallel β-folds. This structure facilitates tissue wound repair, angiogenesis, bone formation, cartilage repair, and nerve regeneration. Consequently, it has garnered significant attention from scholars both domestically and internationally. However, the instability and degradation properties of bFGF in vivo have limited its clinical application. Significant interest has arisen in the development of novel bFGF delivery systems that can address the shortcomings of bFGF and enhance its bioavailability by controlling the release amount, timing, and location. This article offers a comprehensive overview of the research and recent advances in various bFGF delivery systems, including hydrogels, liposomes, microspheres, and nanoparticles. Subsequently, the applications of bFGF pharmaceutical preparations in various fields are described. Finally, the current clinical applications of bFGF drug formulations and those in clinical trials are discussed, along with their clinical translation and future trends.

Thermosensitive In Situ Ophthalmic Gel for Effective Local Delivery and Antifungal Activity of Ketoconazole Nanoparticles

Fungal keratitis is a severe ocular infection caused by pathogenic fungi, leading to potential vision loss if untreated. Current antifungal treatments face limitations such as low solubility, poor corneal penetration, and limited therapeutic options. This study aimed to develop a thermosensitive in situ gel incorporating ketoconazole nanoparticles (NPs) to enhance drug solubility, stability, and antifungal activity. Ketoconazole NPs were prepared using the solvent displacement method, achieving a particle size of 198.25 ± 27.51 nm, encapsulation efficiency of 94.08 ± 0.51%, polydispersity index of 0.42 ± 0.08, and a positive zeta potential value of +10.08 ± 0.19 mV. The NPs exhibited sustained zero-order release kinetics. The optimized NPs were incorporated into a poloxamer-based in situ gel, demonstrating a gelation temperature of 34.67 ± 0.58 °C and the shortest gelation time. The formulation provided a 5-fold increase in solubility and a 10-fold improvement in drug release compared to pure ketoconazole. Stability studies confirmed the gel retained its physicochemical and rheological properties for three months under various storage conditions. The in situ gel showed sustained release, effective antifungal activity against Malassezia furfur, and good tolerability, suggesting it as a promising alternative for treating fungal keratitis with improved bioavailability and patient compliance.

Multifunctional poloxamer-based thermo-responsive hydrogel loaded with human lactoferricin niosomes: In vitro study on anti-bacterial activity, accelerate wound healing, and anti-inflammation

Chronic wound infections are attributed to delayed tissue repair, which remains a major clinical challenge in long-term health care. Particularly, infections with antibiotic resistance have more serious effects on health, often resulting in unsuccessful treatments. Thus, antimicrobial peptide (AMP)-based therapy holds promise as a potential therapeutic approach to overcoming drug resistance. Conventional wound dressing is a passive strategy for wound care that is not capable of eradicating pathogens and promoting tissue repair. In this study, we aim to construct an advanced wound dressing; a thermo-responsive hydrogel incorporated with lactoferricin (Lfcin) niosome (Lfcin-Nio/hydrogel) for bacterial pathogen treatment. The Lfcin-loaded niosome (Lfcin-Nio) has a particle size of 396.91 ± 20.96 nm, 0.38 ± 0.01 of PdI, -10.5 ± 0.3 mV of ζ potential, and 72.30 ± 7.05 % Lfcin entrapment efficiency. Lfcin-Nio exhibited broad antibacterial activity on both drug-susceptible and drug-resistant strains, and also on bacteria residing in the biofilm matrix. The Lfcin-Nio/hydrogel was fabricated from 0.5 % w/v poloxamer 188-20 % w/v poloxamer 407, and supplemented with Lfcin-Nio and epidermal growth factor (EGF). The physical properties of Lfcin-Nio/hydrogels showed elasticity, swelling ability, and strong injectability with responsiveness to 33-37 °C temperatures. The biological properties of Lfcin-Nio/hydrogels exhibited a bactericidal effect against drug-resistant strains of S. aureus and P. aeruginosa, and showed less toxicity to the human skin fibroblast. It also promoted the healing of scratches by 55 % within 6 h, compared to the wound closure rate of 20 % in the cell control. The inflammatory response of the Lfcin-Nio/hydrogel-treated cells was reduced via suppression of IL-1β and COX-2 mRNA expressions. From this study, Lfcin-Nio/hydrogels can be suggested as a modern wound dressing that possesses multifunctional and beneficial properties for the management of chronic wound infections.

Hydrogel local drug delivery systems for postsurgical management of tumors: Status Quo and perspectives

Surgery is one of the primary treatments for solid tumors. However, the incomplete resection of tumor cells and the immunosuppressive microenvironment make the issue of postsurgical tumor recurrence a great challenge. Furthermore, a wide range of requirements, including ensuring effective hemostasis, implementing prophylactic measures against infection, and promoting wound healing, were also raised in the postsurgical management of tumors. To fulfill these demands, multiple hydrogel local drug delivery systems (HLDDS) were developed recently. These HLDDS are expected to offer numerous advantages in the postsurgical management of tumors, such as achieving high local drug concentrations at the lesion, efficient delivery to surgical microcavities, mitigating systemic side effects, and addressing the diverse demand. Thus, in this review, a detailed discussion of the diverse demands of postsurgical management of tumors is provided. And the current publication trend on HLDDS in the postsurgical management of tumors is analyzed and discussed. Then, the applications of different types of HLDDS, in-situ HLDDS and non-in-situ HLDDS, in postsurgical management of tumors were introduced and summarized. Besides, the current problems and future perspectives are discussed. The review is expected to provide an overview of HLDDS in postsurgical management of tumors and promote their clinical application.

Glatiramer acetate in situ forming gel, a new approach for multiple sclerosis treatment

BACKGROUND

Glatiramer acetate (GA), a commonly used treatment for multiple sclerosis (MS), requires long-term frequent injections to ensure its effectiveness. This often leads to adverse effects, patient noncompliance, and economic inefficiency.

OBJECTIVES

In this study, poloxamer, as a thermosensitive polymer modified by chitosan (CS) and hyaluronic acid (HA), was employed to prepare an in situ forming prolonged release formulation of GA to overcome the problems derived from frequent repeated injections and to enhance the patient compliance.

METHODS

The sol-gel formulation was produced through a cold method and optimized using design of experiments. The final product was characterized in terms of gelation time (GT), rheological behaviors, morphological properties, assay, and drug release kinetics.

RESULTS

The in vitro release rate of GA during the first 24 h was quite rapid, but then it continued at a slower rate of 0.05 mg ml-1h-1. The in vivo analysis after the subcutaneous injections showed lower levels of IL-5, IL-13, and uric acid (UA) in mice treated with the gel formulation compared with those receiving free GA in the first few days. However, after 10 days, significantly higher concentrations were detected, which continued to increase slowly.

CONCLUSION

It can be concluded that the designed thermosensitive sol-gel formula is capable of extending the effectiveness of GA and can be considered as a promising sustained release formulation for the treatment of MS.

Bioactive substance contents and therapeutic potential for skin inflammation of an herbal gel containing Derris reticulata and Glycyrrhiza glabra

CONTEXT

Derris reticulata Craib. and Glycyrrhiza glabra L., of the Fabaceae, have been used as active components in Thai herbal formulas for the treatment of fever and skin diseases.

OBJECTIVE

To evaluate the physicochemical and pharmacological properties of the developed herbal gel formulation containing the combined extract from D. reticulata stem wood and G. glabra root (RGF).

MATERIALS AND METHODS

The potential of the herbal gel formulation containing RGF (8% w/w) as the active ingredient was studied by evaluating the anti-inflammatory, antioxidant, and anti-Staphylococcus aureus activities using quantitative reverse transcription-polymerase chain reaction assay, spectrophotometric method, and broth microdilution technique, respectively. The reference standards for the biological testing included Nω-nitro-L-arginine (L-NA), ascorbic acid, catechin, and penicillin G. The stability study of the RGF herbal gel was performed by a heating-cooling test (at 45 °C for 24 h and at 4 °C for 24 h/1 cycle; for 6 cycles), and the bioactive marker compounds in the herbal gel were investigated by the HPLC technique.

RESULTS

RGF showed promising pharmacological effects, particularly on its anti-inflammatory property (IC50 73.86 µg/mL), compared to L-NA (IC50 47.10 µg/mL). The RGF-containing gel demonstrated anti-inflammatory (IC50 3.59 mg/mL) and free radical scavenging effects (IC50 0.05-4.39 mg/mL), whereas it had no anti-S. aureus activity (MIC > 10 mg/mL). The active ingredient in the developed herbal gel significantly inhibited lipopolysaccharide-induced nitric oxide production by downregulating iNOS mRNA levels. The contents of the bioactive markers in the RGF gel (lupinifolin and glabridin) did not change significantly after stability testing.

DISCUSSION AND CONCLUSIONS

The RGF-containing gel has potential to be further developed as an herbal product for the treatment of skin inflammation.

Recent advances of injectable in situ-forming hydrogels for preventing postoperative tumor recurrence

The unavoidable residual tumor tissue from surgery and the strong aggressiveness of tumor cells pose challenges to the postoperative treatment of tumor patients, accompanied by in situ tumor recurrence and decreased quality of life. Therefore, there is an urgent need to explore appropriate postoperative therapeutic strategies to remove residual tumor cells after surgery to inhibit tumor recurrence and metastasis after surgery. In recent years, with the rapid development of biomedical materials, the study of local delivery systems as postoperative delivery of therapeutic agents has gradually attracted the attention of researchers. Injectable in situ-forming hydrogel is a locally administered agent injected in situ as a solution that can be loaded with various therapeutic agents and rapidly gels to form a semi-solid gel at the treatment site. This type of hydrogel tightly fills the surgical site and covers irregular excision surfaces. In this paper, we review the recent advances in the application of injectable in situ-forming hydrogels in postoperative therapy, focusing on the matrix materials of this type of hydrogel and its application in the postoperative treatment of different types of tumors, as well as discussing the challenges and prospects of its clinical application.

Development of a fish oil-nanoemulsion gel as a drug-delivery system to prevent capsular contracture

Capsular contracture, a significant complication of breast-implant surgery, causes pain and deformation following the formation of a tight capsule around an implant. Current surgical and non-surgical treatment options are invasive, expensive, and typically administered for prolonged periods, potentially leading to side effects. To address these challenges, we developed a novel fish oil-encapsulated, poloxamer-based nanoemulsion gel with omega-3 (ω3) as the primary active component (NE-ω3 gel; N3G). This formulation can be injected during surgery, reducing the need for prolonged administration of medications and minimizing associated side effects. N3G was prepared through a two-step process involving the emulsification of fish oil followed by gelation with poloxamer to create a thermoreversible gel. Dynamic light-scattering analysis confirmed a uniform distribution of nanoemulsion particles, which had a mean diameter of 287 ± 8.599 nm and a PDI of 0.29 ± 0.047. FTIR and DSC analyses validated the encapsulation of fish oil within poloxamer micelles. Drug-release analysis demonstrated that more than 96% of fish oil was released within 10 h. In in vivo experiments, rats (n = 30) were divided into three groups: a negative control group (G1), a positive control group receiving fish oil (G2), and an experimental group with implants coated with N3G (G3). G3 exhibited a 21.2% reduction in capsular thickness compared to G1 and a 5.6% reduction compared to G2. In addition, significant decreases in fibrosis and myofibroblast counts were observed in G3. These results, supported by histological and gene expression analyses, highlight the effectiveness of N3G in reducing inflammation and fibrosis. This study underscores the therapeutic potential of N3G for capsular contracture, based on its persistence, thermoreversibility, and improved dosing and storage characteristics.

Adhesion Reduction Agent Guardix-SG® Versus MegaShield® for Postoperative Swallowing Function Analysis in Thyroidectomy Patients

Background

Antiadhesion products are essential for postoperative care in patients after thyroidectomy by providing a physical barrier to cover the exposed tissue and thus preventing abnormal adhesion of adjacent tissues. Since thyroidectomy may result in swallowing difficulties arising from damage or inflammation of the surrounding tissues, the use of antiadhesion agents such as MegaShield® or Guardix-SG® will help reduce scar formation. This may thus improve postoperative swallowing function in patients.

Methods

Patients were enrolled and followed up between October 4, 2018, and March 26, 2020. Patients during the postoperative follow-up sessions were randomly allocated to the standard care with Guardix-SG® and clinical trial medical device application group with MegaShield® (test group) in a 1:1 ratio by the permuted block randomization method. Patient performance on penetration aspiration scale (PAS), National Institutes of Health-Swallow Safety Scale (NIH-SSS), videofluoroscopic dysphagia scale (VDS), Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) based on Videofluoroscopic swallowing study (VFSS) were collected. Nonadhesion-reducing agent patient data were used as a control group.

Results

No statistical significance was shown (P > .05) between the 2 groups of MegaShield® and Guardix-SG® in various phases from thick semisolid, thin semisolid to liquid for both PAS and NIH-SSS. Several statistical significances were reported in the results comparing various criteria of PAS, NIH-SSS, VDS at different oral and pharyngeal phases, and DIGEST in all 3 stages among MegaShield®, Guardix-SG®, and nonadhesion-reducing agent group.

Conclusions

These results prove the noninferiority of MegaShield® compared with Guardix-SG® as an antiadhesion agent in postthyroidectomy care.

Self-assembly of Pluronics: A critical review and relevant applications

Pluronics, alias poloxamers, are synthetic amphiphilic copolymers owning a triblock structure with a central hydrophobic poly(propylene oxide) (PPO) segment linked to two lateral hydrophilic poly(ethylene oxide) (PEO) chains. Commercially, Pluronics exist in numerous types according to the length of PPO and PEO chains, exhibiting different behavior and phase diagrams in solution. Concentrated aqueous solutions of Pluronics form thermoreversible gel-like systems. Properties, such as versatility, biocompatibility, nontoxicity, thermosensitivity and self-assembling behavior, make them extremely attractive for numerous applications. This review paper provides an overview on Pluronics, with a focus on their properties and phase behaviors, and on the effect of the presence of salts and additives. Different strategies to endow Pluronics with improved and extra properties, such as their chemical modification and mixed micelles, are briefly illustrated. Furthermore, a synopsis of useful experimental methodologies for understanding the flow properties of Pluronic-based systems is presented, providing a practical guide to their experimental characterization. Eventually, significant advances of Pluronic-based materials are briefly reviewed to elucidate their role in diverse applications, ranging from drug delivery and tissue engineering to bioprinting, cell cultures, personal care industry, conductive hydrogels, and electrocatalytic science. The current article is a critical review of Pluronic block copolymers, not intended as just inert materials but also as systems with functional properties able to revolutionize the paradigm of many technological fields.

Optimization of Glibenclamide Loaded Thermoresponsive SNEDDS Using Design of Experiment Approach: Paving the Way to Enhance Pharmaceutical Applicability

Thermoresponsive self-nanoemulsifying drug delivery systems (T-SNEDDS) offer a promising solution to the limitations of conventional SNEDDS formulations. Liquid SNEDDS are expected to enhance drug solubility; however, they are susceptible to leakage during storage. Even though solid SNEDDS offers a solution to this storage instability, they introduce new challenges, namely increased total dosage and potential for drug trapping within the formulation. The invented T-SNEDDS was used to overcome these limitations and improve the dissolution of glibenclamide (GBC). Solubility and transmittance studies were performed to select a suitable oil and surfactant. Design of Experiments (DoE) software was used to study the impact of propylene glycol and Poloxamer 188 concentrations on measured responses (liquefying temperature, liquefying time, and GBC solubility). The optimized formulation was subjected to an in vitro dissolution study. The optimized T-SNEDDS consisted of Kolliphor EL and Imwitor 308 as surfactants and oil. The optimized propylene glycol and Poloxamer 188 concentrations were 13.7 and 7.9% w/w, respectively. It exhibited a liquefying temperature of 35.0 °C, a liquefying time of 119 s, and a GBC solubility of 5.51 mg/g. In vitro dissolution study showed that optimized T-SNEDDS exhibited 98.8% dissolution efficiency compared with 2.5% for raw drugs. This study presents a promising approach to enhance pharmaceutical applicability by resolving the limitations of traditional SNEDDS.

In vivo evaluation of a Nano-enabled therapeutic vitreous substitute for the precise delivery of triamcinolone to the posterior segment of the eye

This study focused on the design of a thermoresponsive, nano-enabled vitreous substitute for the treatment of retinal diseases. Synthesis of a hydrogel composed of hyaluronic acid and a poloxamer blend was undertaken. Poly(D,L-lactide-co-glycolide) acid nanoparticles encapsulating triamcinolone acetonide (TA) were synthesised with a spherical morphology and mean diameter of ~ 153 nm. Hydrogel fabrication and nanoparticle loading within the hydrogel was confirmed via physicochemical analysis. Gelation studies indicated that hydrogels formed in nine minutes and 10 min for the unloaded and nanoparticle-loaded hydrogels, respectively. The hydrogels displayed in situ gel formation properties, and rheometric viscoelastic studies indicated the unloaded and loaded hydrogels to have modulus values similar to those of the natural vitreous at 37 °C. Administration of the hydrogels was possible via 26G needles allowing for clinical application and drug release of triamcinolone acetonide from the nanoparticle-loaded hydrogel, which provided sustained in vitro drug release over nine weeks. The hydrogels displayed minimal swelling, reaching equilibrium swelling within 12 h for the unloaded hydrogel, and eight hours for the nanoparticle-loaded hydrogel. Biodegradation in simulated vitreous humour with lysozyme showed < 20% degradation within nine weeks. Biocompatibility of both unloaded and loaded hydrogels was shown with mouse fibroblast and human retinal pigment epithelium cell lines. Lastly, a pilot in vivo study in a New Zealand White rabbit model displayed minimal toxicity with precise, localised drug release behaviour, and ocular TA levels maintained within the therapeutic window for the 28-day investigation period, which supports the potential applicability of the unloaded and nanoparticle-loaded hydrogels as vitreous substitutes that function as drug delivery systems following vitrectomy surgery.

Engineered Bacteriophage-Polymer Nanoassemblies for Treatment of Wound Biofilm Infections

The antibacterial efficacy and specificity of lytic bacteriophages (phages) make them promising therapeutics for treatment of multidrug-resistant bacterial infections. Restricted penetration of phages through the protective matrix of biofilms, however, may limit their efficacy against biofilm infections. Here, engineered polymers were used to generate noncovalent phage-polymer nanoassemblies (PPNs) that penetrate bacterial biofilms and kill resident bacteria. Phage K, active against multiple strains of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), was assembled with cationic poly(oxanorbornene) polymers into PPNs. The PPNs retained phage infectivity, while demonstrating enhanced biofilm penetration and killing relative to free phages. PPNs achieved 3-log10 bacterial reduction (∼99.9%) against MRSA biofilms in vitro. PPNs were then incorporated into Poloxamer 407 (P407) hydrogels and applied onto in vivo wound biofilms, demonstrating controlled and sustained release. Hydrogel-incorporated PPNs were effective in a murine MRSA wound biofilm model, showing a 1.5-log10 reduction in bacterial load compared to a 0.5 log reduction with phage K in P407 hydrogel. Overall, this work showcases the therapeutic potential of phage K engineered with cationic polymers for treating wound biofilm infections.

Thermoresponsive and Supramolecular Polymers: Interesting Biomaterials for Drug Delivery

How to use and deliver drugs to diseased and damaged areas has been one of the main concerns of pharmacologists and doctors for a long time. With the efforts of researchers, the advancement of technology, and the involvement of engineering in the health field, diverse and promising approaches have been studied and used to achieve this goal. A better understanding of biomaterials and the ability of production equipment led researchers to offer new drug delivery systems to the world. In recent decades, responsive polymers (exclusively to temperature and pH) and supramolecular polymers have received much attention due to their unique capabilities. Although this field of research still needs to be scrutinized and studied more, their recognition, examination, and use as drug delivery systems is a start for a promising future. This review study, focusing on temperature-responsive and supramolecular biomaterials and their application as drug delivery systems, deals with their structure, properties, and role in the noninvasive and effective delivery of medicinal agents.

Diazepam nanocapsules as an alternative for sleep induction: Development study and toxicity assessment

Diazepam (DZP) is a sedative medication prescribed to treat anxiety and as a sleep inducer, although its residual effects are unfavorable to patients. Nanotechnology represents a tool to improve the pharmacological characteristics of drugs, reducing their side effects. This study aimed to develop and characterize DZP nanocapsules and to evaluate their toxicity in alternative models and the hypnotic-sedative effect in mice. Nanocapsules were prepared by the nanoprecipitation method and properly characterized. Long-term and accelerated stability studies were performed. The in vitro release profile was determined by diffusion in Franz cells. The safety of the formulation was evaluated in the Caenorhabditis elegans (C. elegans) and the oral acute toxicity in mice. Pharmacological evaluation was performed using thiopental-induced sleeping time. DZP was successfully incorporated into Poly-(ɛ-caprolactone) (PCL) nanocapsules, with high entrapment efficiency. The nanocapsule did not affect the development or survival of C. elegans, different from the free drug, which affected the nematode development at the higher tested dose. No signs of toxicity, nor body mass or feed consumption changes were observed during the 14 days evaluated. Finally, this innovative formulation carrying DZP can produce a hypnotic-effect at a reduced dose compared to the free drug, with no toxicity in alternative models.

Parenteral iron nutrition: Iron dextran-poloxamer thermosensitive hydrogel for prolonged intramuscular iron supplementation

The objective of this study was to evaluate the potential of novel poloxamer thermosensitive hydrogels (PTHs) formulations for prolonged release of iron dextran particles (IDP) for intramuscular (IM) injection. The thermosensitive behaviour helps to avoid hepcidin overexpression and toxicity by releasing IDPs without iron accumulation in injection or deposit sites. We hypothesized that novel PTH formulation would prolong iron liberation compared to the commercial iron dextran formulation (FEDEX). PTHs loaded with IDPs were developed with increasing iron content (0.1, 0.2 and 0.4 g of iron/g of poloxamer) and characterized as a prolonged release IM iron supplement. The PTHs had a biocompatible pH for IM injection (6.4) and thermosensitive viscosity, increasing from ∼50 (4 °C) to ∼3000 mPa.s (37 °C). PTHs were successfully injected in the sol state (at 4 °C) into pork meat at 37 °C, transitioning to the gel state in situ (in ∼60-190 s). Structural characterization indicated that there were no PTH-IDP chemical interactions, suggesting that IDP entrapment in PTHs was physical upon gelation. In vitro release studies revealed that iron release from PTH (0.4 g of iron/g of poloxamer) reached 100 % by day 10, whereas 100 % release from FEDEX was complete in 4 h. This novel iron PTH formulation achieved a 60 times long iron release compared to the commercial product. In conclusion, the reported strategy shows adequate IDP entrapment/release properties for prolonged iron release following ex vivo IM injection using biocompatible materials. These results provide a strong basis for future preclinical evaluation to elucidate aspects such as drug release, local irritation, biocompatibility, and efficacy.

Hydroxypropyl Cellulose Hydrogel Containing Origanum vulgare ssp. hirtum Essential-Oil-Loaded Polymeric Micelles for Enhanced Treatment of Melanoma

Origanum vulgare ssp. hirtum essential oil (OEO) is a natural oil with high therapeutic potential. For some applications, however, the development of novel formulations is still needed to improve the bioavailability and stability of OEO. In this study, we describe the fabrication of an original nanocomposite hydroxypropyl cellulose (HPC) physical hydrogel, containing OEO-loaded polymeric micelles, for topical delivery. The concentration of the main active compounds of OEO-carvacol and thymol-was determined using gas chromatography (GC) analysis. OEO was first encapsulated into Pluronic F127 micelles, and then embedded into HPC gel. Micellar and gel formulations of pure polymers and OEO-containing systems were characterized by dynamic light scattering (DLS) and rheology measurements, respectively. Selected formulations were evaluated for cytotoxicity and antiproliferative activity. The hydrogel formulation of HPC with micellar OEO (8% HPC, 2% F127, 1% OEO) exhibited sustained release of the oil and selectivity towards SH-4 tumor cells (an in vitro model of melanoma).

Development of Glycerosomal pH Triggered In Situ Gelling System to Ameliorate the Nasal Delivery of Sulpiride for Pediatric Psychosis

Sulpiride (Sul) is a medication that blocks dopamine D2 receptors. It is used to treat gastrointestinal disturbances and has antipsychotic effects depending on the dose given. Sulpiride is subject to P-glycoprotein efflux, resulting in limited bioavailability and erratic absorption. Hence, the aim of this study was to generate a glycerosomal in situ gel of sulpiride for intranasal administration, specifically targeting children with schizophrenia who may have difficulty swallowing traditional solid medications, for enhancing its bioavailability. This study aimed to demonstrate the efficacy of intranasal administration of glycerin-encapsulated lipid-nanovesicles (glycerosomes) mixed with in situ gels for prolonged release of anti-psychotic medication. A Box-Behnken design was utilized to create sulpiride-loaded glycerosomes (Sul-GMs), with the lipid amount (A), glycerin concentration (B), and sonication time (C) acting as independent variables. Their impact on the entrapment efficiency, EE% (Y1), and in vitro drug release (Y2) were evaluated. The sulpiride EE% showed an increase when the glycerin concentration was raised to 25% v/v. Nevertheless, when the glycerin concentration was raised to 40% v/v, there was a notable decrease in the EE%. The optimized glycerosome was added to pH triggered carbopol 974P in situ gel formulations including HPMC K15M with different concentrations. The in situ gel formulation (G3) comprising 0.6% carbopol 974P and 0.6% hydroxypropyl methyl cellulose-K15M (HPMC K15M) demonstrated suitable pH, viscosity, desired gel strength, spreadability, and mucoadhesive strength. Consequently, it was selected for in vitro study, ex vivo permeation investigation, and in vivo evaluations. The glycerosomal in situ gel exhibited favorable ex vivo permeability of SU when applied to the nasal mucosa. The pharmacokinetic investigation revealed that the optimized Sul-loaded glycerosomal in situ gel exhibited a significant fourfold and twofold enhancement in systemic bioavailability compared to both the control gel and the commercially available formulation. Finally, the intranasal administration of Sul-loaded glycerosomal in situ gel is a promising alternative to oral treatment for pediatric patients with psychosis.

Local Drug Delivery Systems as Novel Approach for Controlling NETosis in Periodontitis

Periodontitis is a chronic inflammation caused by periodontopathogenic bacteria in the dental biofilm, and also involves the inflammatory-immune response of the host. Polymorphonuclear neutrophils (PMNs) play essential roles in bacterial clearance by multiple mechanisms, including the formation of neutrophil extracellular traps (NETs) that retain and destroy pathogens. During PD progression, the interaction between PMNs, NETs, and bacteria leads to an exaggerated immune response and a prolonged inflammatory state. As a lesion matures, PMNs accumulate in the periodontal tissues and die via NETosis, ultimately resulting in tissue injury. A better understanding of the role of NETs, the associated molecules, and the pathogenic pathways of NET formation in periodontitis, could provide markers of NETosis as reliable diagnostic and prognostic tools. Moreover, an assessment of NET biomarker levels in biofluids, particularly in saliva or gingival crevicular fluid, could be useful for monitoring periodontitis progression and treatment efficacy. Preventing excessive NET accumulation in periodontal tissues, by both controlling NETs' formation and their appropriate removal, could be a key for further development of more efficient therapeutic approaches. In periodontal therapy, local drug delivery (LDD) systems are more targeted, enhancing the bioavailability of active pharmacological agents in the periodontal pocket and surrounding tissues for prolonged time to ensure an optimal therapeutic outcome.

An Injectable Thermosensitive Hydrogel with Antibacterial and Antioxidation Properties for Accelerating Wound Healing

As a new type of wound dressing, hydrogels have attracted more and more attention. However, traditional hydrogel wound dressings lack inherent antibacterial properties and are difficult to match irregular wounds, which leads to an easy wound bacterial infection. To solve the problems associated with traditional hydrogels, in this research, a thermosensitive hydrogel (PFLD) for wound dressings was developed based on Poloxamer 407 (PF127), lysine (Lys), and 3,4-dihydroxyphenylacetic acid (DOPAC). Rheological tests indicated that the PFLD hydrogel possesses injectability, adaptability to deformation, and sufficient mechanical strength for wound dressing applications. In addition, it could in situ gel at 33 °C, which indicated that the hydrogel could undergo sol-to-gel transition under body temperature. Upon using it in wound treatment, it could adapt to irregular wounds to achieve full coverage of the wound and promote the rapid hemostasis of wound bleeding. Due to the presence of DOPAC in the hydrogel, it exhibited excellent antibacterial and antioxidant properties on the wounds. The skin defect model showed that the wound shrinkage was the fastest after PFLD hydrogel treatment. On day 14, the wound shrinkage rates were 81.68 and 99.77% for the control and PFLD hydrogel groups, respectively. Therefore, the PFLD hydrogel has a broad application prospect as a dressing for the treatment of irregular wounds.

Clinic-oriented injectable smart material for the treatment of diabetic wounds: Coordinating the release of GM-CSF and VEGF

Chronic wounds are often caused by diabetes and present a challenging clinical problem due to vascular problems leading to ischemia. This inhibits proper wound healing by delaying inflammatory responses and angiogenesis. To address this problem, we have developed injectable particle-loaded hydrogels which sequentially release Granulocyte-macrophage- colony-stimulating-factor (GM-CSF) and Vascular endothelial growth factor (VEGF) encapsulated in polycaprolactone-lecithin-geleol mono-diglyceride hybrid particles. GM-CSF promotes inflammation, while VEGF facilitates angiogenesis. The hybrid particles (200-1000 nm) designed within the scope of the study can encapsulate the model proteins Bovine Serum Albumin 65 ± 5 % and Lysozyme 77 ± 10 % and can release stably for 21 days. In vivo tests and histological findings revealed that in the hydrogels containing GM-CSF/VEGF-loaded hybrid particles, wound depth decreased, inflammation phase increased, and fibrotic scar tissue decreased, while mature granulation tissue was formed on day 10. These findings confirm that the hybrid particles first initiate the inflammation phase by delivering GM-CSF, followed by VEGF, increasing the number of vascularization and thus increasing the healing rate of wounds. We emphasize the importance of multi-component and sequential release in wound healing and propose a unifying therapeutic strategy to sequentially deliver ligands targeting wound healing stages, which is very important in the treatment of the diabetic wounds.

Exploring the Dissolution, Solid-state Properties, and Long-term Storage Stability of Cryoprotectant-free Fenbendazole Nanoparticles

Fenbendazole is an antiparasitic drug widely used in veterinary medicine to treat parasitic infections caused in animals like cattle, horses, sheep, and dogs. Recently, it has been repositioned as a potential alternative for cancer treatment. However, it is a highly hydrophobic molecule (0.9 ug/mL), which can compromise its dissolution rate and absorption. Thus, this work aimed to apply a nanotechnological approach to improve drug solubility and dissolution performance. Fenbendazole nanoparticles stabilized by different poloxamers were obtained by lyophilization without cryoprotectants. The behavior of the drug in the solid state was analyzed by X-ray diffractometry, differential scanning calorimetry, and infrared spectroscopy. The nanosystems were also evaluated for solubility and dissolution rate. A long-term stability evaluation was performed for three years at room temperature. The yields of the lyophilization ranged between 75 and 81% for each lot. The nanoparticles showed a submicron size (< 340 nm) and a low polydispersity depending on the stabilizer. The physicochemical properties of the prepared systems indicated a remarkable amorphization of the drug, which influenced its solubility and dissolution performance. The drug dissolution from both the fresh and aged nanosystems was significantly higher than that of the raw drug. In particular, nanoparticles prepared with poloxamer 407 showed no significant modifications in their particle size in three years of storage. Physical stability studies indicated that the obtained systems prepared with P188, P237, and P407 suffered certain recrystallization during long storage at 25 °C. These findings confirm that selected poloxamers exhibited an important effect in formulating fenbendazole nanosystems with improved dissolution.

Development and Evaluation of Different Electrospun Cysteamine-Loaded Nanofibrous Webs: A Promising Option for Treating a Rare Lysosomal Storage Disorder

Nanofibers can be utilized to overcome the challenges faced by conventional ophthalmic formulations. This study aimed to develop and characterize cysteamine (Cys)-loaded nanofiber-based ophthalmic inserts (OIs) as a potential candidate for the treatment of ophthalmic cystinosis using water-soluble polyvinyl alcohol (PVA)/poloxamer 407 (PO-407) and water-insoluble tetraethoxysilane (TEOS)/PVA nanofibers. Plain and Cys-loaded fibers in different proportions were prepared by the electrospinning method and studied for their morphological, physicochemical, release study, cytocompatibility effects, and stability study. The fiber formation was confirmed by scanning electron microscopy, while Fourier transform infrared spectra showed the most critical peaks for the Cys and the excipients. The release of the Cys was fast from the two polymeric matrices (≤20 min). The release from TEOS/PVA nanofibers is characterized by Case II transport (0.75 < β < 1), while the release from PVA/PO-407 nanofibers follows Fickian diffusion (β < 0.75). The cytocompatibility of compositions was confirmed by hen eggs tested on the chorioallantoic membrane (HET-CAM) of chick embryos. All formulations remained stable under stress conditions (40 ± 2 °C, 75 ± 5% relative humidity) regarding morphology and physicochemical characteristics. The developed nanofibrous mats could be an excellent alternative to available Cys drops, with better stability and convenience of self-administration as OIs.

Design and evaluation of curcumin-loaded poloxamer hydrogels as injectable depot formulations

Poloxamer hydrogels are of interest as injectable depot delivery systems. However, their use for delivering hydrophobic drugs, such as curcumin, is limited due to poor loading capacity. Here, we evaluated the influence of incorporating hydrophobic medium chain triglycerides (MCT) or amphiphilic polyethylene glycol 400 (PEG400) on the physicochemical properties, drug loading, and in vitro compatibility of a curcumin-loaded poloxamer hydrogel. Poloxamer 407 and 188 hydrogel formulations (16:6 w/w) were prepared and MCT and PEG400 (saturated with curcumin) were added to these systems, either alone or in combination, up to a 10 % w/w additive solvent load. Formulation viscoelasticity, gelation behaviour, injectability, morphology and release profiles were assessed. The cytocompatibility of the formulations was also assessed on dermal fibroblasts (HDFn). Both additives increased curcumin loading into the formulation. Addition of MCT to the hydrogel significantly increased its gelation speed, while PEG400 had a less profound impact. Both additive solvents increased the force required to inject the formulation. PEG400 containing systems were single phase, whereas MCT addition created emulsion systems. All formulations released ∼20-30 % of their loaded curcumin in a sustained fashion over 24 h. The modified hydrogel systems showed good biocompatibility on cells when administering up to ∼100-150 µM curcumin into the culture. This study addresses a key limitation in loading hydrophobic drugs into hydrogels and provides a strategy to enhance drug loading and performance of hydrogels by integrating additives such as MCT and PEG400 into the systems.

99mTc-labeled, tofacitinib citrate encapsulated chitosan microspheres loaded in situ gel formulations for intra-articular treatment of rheumatoid arthritis

Inflammatory diseases including rheumatoid arthritis are major health problems. Although different techniques and drugs are clinically available for the diagnosis and therapy of the disease, novel approaches regarding radiolabeled drug delivery systems are researched. Hence, in the present study, it was aimed to design, prepare, and characterize 99mTc-radiolabeled and tofacitinib citrate-encapsulated microsphere loaded poloxamer in situ gel formulations for the intra-articular treatment. Among nine different microsphere formulations, MS/TOFA-9 was chosen as the most proper one due to particle size, high encapsulation efficiency, and in vitro drug release behavior. Poloxamer 338 at a concentration of 15% was used to prepare in situ gel formulations. For intra-articular administration, microspheres were dispersed in an in situ gel containing 15% Poloxamer 338 and characterized in terms of gelation temperature, viscosity, rheological, mechanical, and spreadability properties. After the determination of the safe dose for MS/TOFA-9 and PLX-MS/TOFA-9 as 40 µL/mL in the cell culture study performed on healthy cells, the high anti-inflammatory effects were due to significant cellular inhibition of fibroblasts. In the radiolabeling studies with 99mTc, the optimum radiolabeling condition was determined as 200 ppm SnCl2 and 0.5 mg ascorbic acid, and both 99mTc-MS/TOFA-9 and 99mTc-PLX-MS/TOFA-9 exhibited high cellular binding capacity. In conclusion, although further in vivo experiments are required, PLX-MS/TOFA-9 was found to be a promising agent for intra-articular injection in rheumatoid arthritis.

Biopolymeric Insulin Membranes for Antimicrobial, Antioxidant, and Wound Healing Applications

Delayed wound healing increases the wound's vulnerability to possible infections, which may have lethal outcomes. The treatments available can be effective, but the urgency is not fully encompassed. The drug repositioning strategy proposes effective alternatives for enhancing medical therapies for chronic diseases. Likewise, applying wound dressings as biodegradable membranes is extremely attractive due to their ease of application, therapeutic effectiveness, and feasibility in industrial manufacturing. This article aims to demonstrate the pleiotropic effects during insulin repositioning in wound closure by employing a biopolymeric membrane-type formulation with insulin. We prepared biopolymeric membranes with sodium alginate cross-linked with calcium chloride, supported in a mixture of xanthan gum and guar gum, and plasticized with glycerol and sorbitol. Human insulin was combined with poloxamer 188 as a protein stabilizing agent. Our investigation encompassed physicochemical and mechanical characterization, antioxidant and biological activity through antibacterial tests, cell viability assessments, and scratch assays as an in vitro and in vivo wound model. We demonstrated that our biopolymeric insulin membranes exhibited adequate manipulation and suitable mechanical resistance, transparency, high swelling capability (1100%), and 30% antioxidant activity. Furthermore, they exhibited antibacterial activity (growth inhibition of S. aureus at 85% and P. aeruginosa at 75%, respectively), and insulin promoted wound closure in vitro with a 5.5-fold increase and 72% closure at 24 h. Also, insulin promoted in vivo wound closure with a 3.2-fold increase and 92% closure at 10 days compared with the groups without insulin, and this is the first report that demonstrates this therapeutic effect with two administrations of 0.7 IU. In conclusion, we developed a multifunctional insulin-loaded biopolymeric membrane in this study, with the main activity derived from insulin's role in wound closure and antioxidant activity, augmented by the antimicrobial effect attributed to the polymer poloxamer 188. The synergistic combination of excipients enhances its usefulness and highlights our innovation as a promising material in wound healing materials.

Tailor-Made Polysaccharides for Biomedical Applications

Polysaccharides (PSAs) are carbohydrate-based macromolecules widely used in the biomedical field, either in their pure form or in blends/nanocomposites with other materials. The relationship between structure, properties, and functions has inspired scientists to design multifunctional PSAs for various biomedical applications by incorporating unique molecular structures and targeted bulk properties. Multiple strategies, such as conjugation, grafting, cross-linking, and functionalization, have been explored to control their mechanical properties, electrical conductivity, hydrophilicity, degradability, rheological features, and stimuli-responsiveness. For instance, custom-made PSAs are known for their worldwide biomedical applications in tissue engineering, drug/gene delivery, and regenerative medicine. Furthermore, the remarkable advancements in supramolecular engineering and chemistry have paved the way for mission-oriented biomaterial synthesis and the fabrication of customized biomaterials. These materials can synergistically combine the benefits of biology and chemistry to tackle important biomedical questions. Herein, we categorize and summarize PSAs based on their synthesis methods, and explore the main strategies used to customize their chemical structures. We then highlight various properties of PSAs using practical examples. Lastly, we thoroughly describe the biomedical applications of tailor-made PSAs, along with their current existing challenges and potential future directions.

A study of hydrophobic domain formation of polymeric drug precipitation inhibitors in aqueous solution

Despite the widespread use of polymers as precipitation inhibitors in supersaturating drug formulations, the current understanding of their mechanisms of action is still incomplete. Specifically, the role of hydrophobic drug interactions with polymers by considering possible supramolecular conformations in aqueous dispersion is an interesting topic. Accordingly, this study investigated the tendency of polymers to create hydrophobic domains, where lipophilic compounds may nest to support drug solubilisation and supersaturation. Fluorescence spectroscopy with the environment-sensitive probe pyrene was compared with atomistic molecular dynamics simulations of the model drug fenofibrate (FENO). Subsequently, kinetic drug supersaturation and thermodynamic solubility experiments were conducted. As a result, the different polymers showed hydrophobic domain formation to a varying degree and the molecular simulations supported interpretation of fluorescence spectroscopy data. Molecular insights were gained into the conformational structure of how the polymers interacted with FENO in solution phase, which apart from nucleation and crystal growth effects, determined drug concentrations in solution. Notable was that even at the lowest polymer concentration of 0.01 %, w/v, there were polymer-specific solubilisation effects of FENO observed and the resulting reduction in apparent drug supersaturation provided relevant knowledge both from a mechanistic and practical perspective.

Ceftazidime Poloxamer Gel: Expanding the Therapeutic Armamentarium for Ciprofloxacin-Resistant Pseudomonas Mastoid Cavity Otorrhea

OBJECTIVE

To present and evaluate the treatment of ciprofloxacin-resistant Pseudomonas mastoid cavity otorrhea with a ceftazidime thermosensitive poloxamer gel.

STUDY DESIGN

A retrospective clinical capsule report.

PATIENTS

Three patients diagnosed with ciprofloxacin-resistant Pseudomonas otorrhea in the setting of a previous canal-wall-down mastoidectomy between March 2019 and June 2023 visiting our tertiary care institution were retrospectively reviewed.

INTERVENTION

Application of a 2% ceftazidime thermosensitive poloxamer gel to mastoid cavity.

MAIN OUTCOME MEASURES

No evidence of disease during microscopic inspection of the ear within a month of initial treatment or bacterial eradication on subsequent culture.

RESULTS

Two patients had complete resolution of symptoms and achieved a safe and dry ear after topical application of the hydrogel. The second patient had pseudomonal eradication on culture, but persistent otorrhea due to other multidrug-resistant bacteria and an anatomically unfavorable mastoid cavity, which ultimately resolved after revision surgery.

CONCLUSIONS

This small case series suggests that topical treatment of mastoid cavity otorrhea with a 2% ceftazidime poloxomer gel is a potential therapeutic avenue in patients with ciprofloxacin-resistant Pseudomonas .

In Situ Gelling Behavior and Biopharmaceutical Characterization of Nano-Silver-Loaded Poloxamer Matrices Designed for Nasal Drug Delivery

A combination of Poloxamer 407 (P407) and hydroxypropyl methylcellulose (HPMC) hydrosols is proposed as an in situ thermo-gelling vehicle for the nasal drug delivery of chlorhexidine-silver nanoparticles conjugates (SN-CX). Optimization of the formulation was carried out by applying varying ratios of P407 and HPMC in the presence and absence of SN-CX so that gelation would occur in the temperature range of the nasal cavity (30-34 °C). Mechanisms for the observed gelation phenomena were suggested based on viscosimetry, texture analysis, and dynamic light scattering. Tests were carried out for sprayability, washout time, in vitro drug release, ex vivo permeation, and antimicrobial activity. When applied separately, HPMC was found to lower the P407 gelation temperature (Tg), whereas SN-CX increased it. However, in the presence of HPMC, SN-CX interfered with the P407 micellar organization in a principally contrasting way while leading to an even further decrease in Tg. SN-CX-loaded nasal formulations composed of P407 16% and HPMC 0.1% demonstrated a desired gelation at 31.9 °C, good sprayability (52.95% coverage of the anterior nasal cavity), mucoadhesion for 70 min under simulated nasal clearance, expedient release and permeation, and preserved anti-infective activity against seasonal Influenza virus and beta-coronavirus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and other pathogens. Our findings suggest that the current development could be considered a potential formulation of a protective nasal spray against respiratory infections.

Biotechnological Effects of Advanced Smart-Bile Acid Cyclodextrin-Based Nanogels for Ear Delivery and Treatment of Hearing Loss

Inner ear delivery requires safe and effective drug delivery vehicles incorporating high-viscosity formulations with permeation enhancers. This study designs novel thermoresponsive-smart polymer-bile acid and cyclodextrin-based nanogels for inner ear delivery. Nanogels are examined for their rheological and physical properties. The biocompatibility studies will be assessed on auditory and macrophage cell lines by investigating the impact of nanogels on cellular viability, mitochondrial respiration, glycolysis, intracellular oxidative stress, inflammatory profile, and macrophage polarization. Novel ther nanogels based on bile acid and beta-cyclodextrin show preserved porous nanogels' inner structure, exhibit non-Newtonian, shear-thinning fluid behavior, have fast gelation at 37 °C and minimal albumin adsorption on the surface. The nanogels have minimal impact on cellular viability, mitochondrial respiration, glycolysis, intracellular oxidative stress, and inflammatory profile of the auditory cell line House Ear Institute-Organ of Corti 1 after 24 h incubation. Nanogel exposure of 24 h to macrophage cell line RAW264.7 leads to decreased viability, mitochondrial dysfunction, and increased intracellular ROS and inflammatory cytokines. However, polarization changes from M2 anti-inflammatory to M1 pro-inflammatory macrophages are minimal, and inflammatory products of RAW264.7 macrophages do not overly disrupt the survivability of HEI-OC1 cells. Based on these results, thermoresponsive bile acid and cyclodextrin nanogels can be potential drug delivery vehicles for inner ear drug delivery.

Synthesis of PEG-Polycycloether Block Copolymers: Poloxamer Mimics Containing a Rigid Helical Block

Poloxamers are amphiphilic block copolymers consisting of poly(ethylene glycol) (PEG) and poly(propylene glycol) segments. Their self-assembly and interfacial properties are tied to the relative hydrophilicity and hydrophobicity of each block and can therefore be adjusted by changing block lengths. Here, a series of PEG-polycycloether block copolymers is synthesized that have the same structure as a poloxamer, but they encompass a rigid polycyclic backbone as the hydrophobic block. A variety of polymer structures are synthesized, for example diblock or triblock architectures, with/without olefinic units, atactic or isotactic backbone, and different block lengths. Due to their amphiphilicity, self-assembly into spherical aggregates (diameters ranging from 64 to 132 nm) at low concentrations (critical aggregation concentration as low as 0.04 mg mL-1) is observed in water. Low surface tensions (as low as 26.7 mN m-1) are observed as well as the formation of stable high internal phase emulsions (HIPEs) irrespective of the oil/water ratio. This contrasts with the properties of the commonly used poloxamers P188 or P407 and illustrates the significance of the rigid polycycloether block. These new colloidal properties offer new prospects for applications in emulsion formulations for biomedicine, cosmetics, and the food industry.

Effect of quince seed gum (QSG) on the performance of injectable hyaluronic acid hydrogels in terms of the rheological, morphological, and mechanical aspect

Injectable hydrogels play an important role in tissue engineering as a filling and repairing material. This study aimed to develop a new injectable hydrogel based on hyaluronic acid (HA) and quince seed gum (QSG) and investigate the effect of QSG on hydrogel performance. The amount of unreacted 1,4-Butanediol diglycidyl ether is maintained at an undetectable level for HA-QSG hydrogels. Amino acid analysis showed that the HA-QSG hydrogel had rich amino acid concentrations of leucine, arginine, and valine. After thermal sterilization, the elastic modulus of HA-QSG gels for dermal and intraarticular filler applications is 63 Pa and 92 Pa, respectively. Pore size was found below 200 μm and the dense homogeneous pore structure was observed.

Incorporation of Resveratrol-Hydroxypropyl-β-Cyclodextrin Complexes into Hydrogel Formulation for Wound Treatment

Resveratrol could be applied in wound healing therapies because of its antioxidant, anti-inflammatory and antibacterial effects. However, the main limitation of resveratrol is its low aqueous solubility. In this study, resveratrol was included in hydroxypropyl-β-cyclodextrin complexes and further formulated in Pluronic F-127 hydrogels for wound treatment therapy. IR-spectroscopy and XRD analysis confirmed the successful incorporation of resveratrol into complexes. The wound-healing ability of these complexes was estimated by a scratch assay on fibroblasts, which showed a tendency for improvement of the effect of resveratrol after complexation. The antimicrobial activity of resveratrol in aqueous dispersion and in the complexes was evaluated on methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Candida albicans strains. The results revealed a twofold decrease in the MIC and stronger inhibition of the metabolic activity of MRSA after treatment with resveratrol in the complexes compared to the suspended drug. Furthermore, the complexes were included in Pluronic hydrogel, which provided efficient drug release and appropriate viscoelastic properties. The formulated hydrogel showed excellent biocompatibility which was confirmed via skin irritation test on rabbits. In conclusion, Pluronic hydrogel containing resveratrol included in hydroxypropyl-β-cyclodextrin complexes is a promising topical formulation for further studies directed at wound therapy.

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.