Long-Term Toxicity Study of Topical Administration of a Highly-Stable rh-aFGF Carbomer 940 Hydrogel in a Rabbit Skin Wound Model

Engineering Titanium-Hydroxyapatite Nanocomposite Hydrogels for Enhanced Antibacterial and Wound Healing Efficacy

External factors often lead to predictable damage, such as chemical injuries, burns, incisions, and wounds. Bacterial resistance to antibiotics at wound sites underscores the importance of developing hydrogel composite systems with inorganic nanoparticles possessing antibacterial properties to treat infected wounds and expedite the skin regeneration process. In this study, a promising TiO2-HAp@PF-127@CBM inorganic and organic integrated hydrogel system was designed to address challenges associated with bacterial resistance and wound healing. The synthesized TiO2-hydroxyapatite (HAp) nanocomposites were coated with an FDA-approved PluronicF-127 polymer and combined with a carbomer hydrogel (CBM) to accomplish the final product. The synthesized nanoparticles exhibit enhanced biocompatibility against L929 and HUVECs and cell proliferation effects. To mitigate oxidative stress caused by TiO2-induced reactive oxygen species in dark environments for effective antibacterial effects, HAp promotes cell proliferation, expediting wound skin layer formation. CBM binds to inorganic nanoparticles, facilitating their gradual release and promoting wound healing. The reduced inflammation and enhanced tissue regeneration observed in the TiO2-HAp@PF-127@CBM group suggest a favorable environment for wound repair. These results align with prior findings highlighting the biocompatibility and wound-healing properties of titanium-HAp-based materials. The ability of the TiO2-HAp@PF-127@CBM hydrogel dressing to promote granulation tissue formation and facilitate epidermal regeneration underscores its potential for promoting antibacterial effects and wound healing applications.

Comprehensive Biosafety Profile of Carbomer-Based Hydrogel Formulations Incorporating Phosphorus Derivatives

Determining the safety of a newly developed experimental product is a crucial condition for its medical use, especially for clinical trials. In this regard, four hydrogel-type formulations were manufactured, all of which were based on carbomer (Blank-CP940) and encapsulated with caffeine (CAF-CP940), phosphorus derivatives (phenyl phosphinic (CAF-S1-CP940) and 2-carboxyethyl phenyl phosphinic acids (CAF-S2-CP940)). The main aim of this research was to provide a comprehensive outline of the biosafety profile of the above-mentioned hydrogels. The complex in vitro screening (cell viability, cytotoxicity, morphological changes in response to exposure, and changes in nuclei morphology) on two types of healthy skin cell lines (HaCaT-human keratinocytes and JB6 Cl 41-5a-murine epidermal cells) exhibited a good biosafety profile when both cell lines were treated for 24 h with 150 μg/mL of each hydrogel. A comprehensive analysis of the hydrogel's impact on the genetic profile of HaCaT cells sustains the in vitro experiments. The biosafety profile was completed with the in vivo and in ovo assays. The outcome revealed that the developed hydrogels exerted good biocompatibility after topical application on BALB/c nude mice's skin. It also revealed a lack of toxicity after exposure to the hen's chicken embryo. Further investigations are needed, regarding the in vitro and in vivo therapeutic efficacy and safety for long-term use and potential clinical translatability.

Highly Absorbent Egg White/Carbomer-940 Hydrofilm as a Potential Diabetic Wound Dressing

Diabetic foot ulcer (DFU) is the most critical problem in diabetic patients. Managing exudate in this kind of wound presents significant challenges in clinics. Advanced wound dressings serve as the most effective approach to managing DFU. Herein, a highly absorbent hydrofilm is presented through a combination of egg white (EW) and Carbomer-940, benefiting from the bioactivity of the EW component and superabsorption capacity of Carbomer-940. The crystallinity of samples rises due to the presence of Carbomer-940. Regarding the high water absorption capacity of Carbomer-940, the swelling ratio and water-holding capacity of samples are also improved via its incorporation of up to 1005%. In contrast, the transmission of water vapor and in vitro degradation rate decreases as Carbomer-940 powers the crystallinity of hydrofilms. Carbomer-940 incorporation in the EW structure accelerates protein release during the time, while this acceleration is partially compensated by the crystallization effect. The cell viability assay demonstrates no toxicity as well as high human foreskin fibroblast cell proliferation for the hybrid hydrofilm sample, where the cell migration is positively affected in the presence of the bioactive components extracted from the dressing. Taken together, the optimized hybrid hydrofilm could be suggested as a promising wound dressing for managing DFUs.

Transparent silk fibroin film-facilitated infected-wound healing through antibacterial, improved fibroblast adhesion and immune modulation

The clinical application of regenerated silk fibroin (RSF) films for wound treatment is restricted by its undesirable mechanical properties and lack of antibacterial activity. Herein, different pluronic polymers were introduced to optimize their mechanical properties and the RSF film with 2.5% pluronic F127 (RSFPF127) stood out to address the above issues owing to its satisfactory mechanical properties, hydrophilicity, and transmittance. Diverse antibacterial agents (curcumin, Ag nanoparticles, and antimicrobial peptide KR-12) were separately encapsulated in RSFPF127 to endow it with antibacterial activity. In vitro experiments revealed that the medicated RSFPF127 could persistently release drugs and had desirable bioactivities toward killing bacteria, promoting fibroblast adhesion, and modulating macrophage polarization. In vivo experiments revealed that medicated RSFPF127 not only eradicated methicillin-resistant Staphylococcus aureus in the wound area and inhibited inflammatory responses, but also facilitated angiogenesis and re-epithelialization, regardless of the types of antibacterial agents, thus accelerating the recovery of infected wounds. These results demonstrate that RSFPF127 is an ideal matrix platform to load different types of drugs for application as wound dressings.

Hydrophobic Drug Carrier from Polycaprolactone-b-Poly(Ethylene Glycol) Star-Shaped Polymers Hydrogel Blend as Potential for Wound Healing Application

Blending hydrogel with an amphiphilic polymer can increase the hydrophobic drug loading and entrapment efficiency of hydrogel-based formulations. In this study, a hydrogel formulation with star-shaped polycaprolactone-b-poly(ethylene glycol) (PCL-b-PEG) as the hydrophobic drug cargo is produced. The 4-arm and 6-arm star-shaped PCL are synthesized with different molecular weights (5000, 10,000, 15,000 g/mol) via ROP and MPEG as the hydrophilic segment is attached via the Steglich esterification. FTIR and ¹H-NMR analysis showed the presence of all functional groups for homopolymers and copolymers. M_n for all synthesized polymers is close to the theoretical value while GPC spectra showed a monomodal peak with narrow molecular weight distribution (PDI:1.01-1.25). The thermal degradation temperature and crystalline melting point of synthesized polymers increase with the increase in molecular weight and number of arms. All formulations possess high drug loading and entrapment efficiency (>99%) and increase with increasing molecular weight, number of arms, and amount of polymer in the formulations. All formulations showed a sustained drug release pattern with no initial burst, which follows the Korsmeyer-Peppas kinetic model. The polymer hydrogel formulations showed antibacterial activity against E. coli and S. aureus. The hydrogel containing 4-arm PCL_15k-PEG is chosen as the best formulation due to its high drug release, good antimicrobial activity, and morphology.

Framework for defining pesticide maximum residue levels in feed: applications to cattle and sheep

BACKGROUND

Pesticide residues in animal feed can endanger animal health and compromise the safety of livestock products for human consumption. Even though policymakers such as the European Union and the World Health Organization have established maximum residue levels (MRLs) for pesticides in both human food and animal feed, there is no systematic management of pesticides in animal feed that considers the entire supply chain. In response, we propose a framework for defining consistent MRLs for pesticides in animal feed that assesses the impact of defined MRLs on upstream (e.g., MRLs in feed crops) and downstream (e.g., MRLs in livestock products) sectors of the livestock-product supply chain.

RESULTS

The MRLs determined for the selected pesticides in the feed of cattle and sheep as case study animals indicate that lipophilic pesticides tend to have lower MRLs than hydrophilic pesticides, primarily due to the relatively high toxicity and biotransfer factors of lipophilic pesticides. In addition, we observe that, primarily for lipophilic pesticides, upstream and downstream regulations are not aligned in terms of defining MRLs in feed using current MRLs in crops with relevance to feed and foods of animal origin.

CONCLUSION

Some of the current pesticide regulations in the livestock-product supply chain need to be re-evaluated to ensure that MRLs in the upstream sector (i.e., crops) do not result in unacceptable residues in the downstream sector (i.e., MRLs in livestock products affecting animal and human health). Finally, we provide recommendations for optimizing the derivation of MRLs in feed, including the evaluation of residue fate during feed and food manufacturing processes. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Ionic complexation improves wound healing in deep second-degree burns and reduces in-vitro ciprofloxacin cytotoxicity in fibroblasts

The development of new treatments capable of controlling infections and pain related to burns continues to be a challenge. Antimicrobials are necessary tools, but these can be cytotoxic for regenerating cells. In this study, antibiotic-anesthetic (AA) smart systems obtained by ionic complexation of polyelectrolytes with ciprofloxacin and lidocaine were obtained as films and hydrogels. Ionic complexation with sodium alginate and hyaluronate decreased cytotoxicity of ciprofloxacin above 70% in a primary culture of isolated fibroblasts (p < 0.05). In addition, the relative levels of the proteins involved in cell migration, integrin β1 and p-FAK, increased above 1.5 times (p < 0.05) with no significant differences in cell mobility. Evaluation of the systems in a deep second-degree burn model revealed that reepithelization rate was AA-films = AA-hydrogels > control films > no treated > reference cream (silver sulfadiazine cream). In addition, appendage conservation and complete dermis organization were achieved in AA-films and AA-hydrogels. Encouragingly, both the films and the hydrogels showed a significantly superior performance compared to the reference treatment. This work highlights the great potential of this smart system as an attractive dressing for burns, which surpasses currently available treatments.

Log P Determines Licorice Flavonoids Release Behaviors and Classification from CARBOMER Cross-Linked Hydrogel

The dynamic drug release mechanisms from Carbomer 940 (CP) hydrogels have not been systematically explored elsewhere. This study aimed to investigate the quantitative structure−activity relationship of licorice flavonoids (LFs) compounds on their drug release from CP hydrogels based on LFs-CP interactions and drug solubility in the release medium. Ten LFs-CP hydrogels were formulated, and their in vitro release study was conducted. The intermolecular forces of LFs-CP systems were characterized by FTIR, molecular docking and molecular dynamic simulation. Ten LFs compounds were classified into I (high-release capability) LFs and II (low-release capability) LFs according to the different negative correlations between drug release percent at 48 h and intermolecular forces of drugs-CP, respectively. Moreover, high-release LFs possessed significantly lower log P and higher drug solubility in the release medium than low-release LFs. All I LFs release behaviors best followed the first-order equation, while II LFs release characteristics best fitted the zero-order equation except for isoliquiritigenin. Log P mainly affect the hydrogel relaxation process for I drugs release and the drug diffusion process for II drugs release. Higher log P values for LFs resulted in higher intermolecular strength for I drugs-CP systems and lower drug solubility in the release medium for II drugs, which hindered drug release. Hydrophobic association forces in drug-CP hydrogel played a more and more dominant role in hindering I LFs release with increasing release time. On the other hand, lower drug solubility in the release medium restricted II LFs release, and the dominant role of drug solubility in the release medium increased in 24 h followed by a significant decline after 36 h. Collectively, log P of LFs served as a bridge to determine LFs compound release behaviors and classification from CP hydrogels, which provided guidelines for reasonable design of LFs hydrogels in pharmaceutical topical formulations.

Hypoglycemic Efficacy of Rh-aFGF Variants in Treatment of Diabetes in ZDF Rats

Acidic fibroblast growth factor (aFGF) is a promising regulator of glucose with no adverse effects of hypoglycemia. Previous researches revealed that aFGF mediated adipose tissue remodeling and insulin sensitivity. These findings supported rh-aFGF₁₃₅ would be used as a new candidate for the treatment of insulin resistance and type 2 diabetes. In this study, we aimed to investigate the hypoglycemic efficacy of recombinant human acidic fibroblast growth factor 135 (rh-aFGF₁₃₅) with low mitogenic in type 2 diabetic ZDF rats. ZDF rats were treated with rh-aFGF₁₃₅ at a daily dosage of 0.25 and 0.50 mg/kg by tail intravenous injection for 5 weeks. The blood glucose levels, oral glucose tolerance test, insulin tolerance test, HOMA-IR for insulin resistance, serum biochemical parameters, and the histopathological changes of adipose tissue, liver and other organs were detected at designed time point. The glucose uptake activity and anti-insulin resistance effect of rh-aFGF₁₃₅ were also detected in HepG2 cells. Results revealed that rh-aFGF₁₃₅ exhibited a better hypoglycemic effect compared with vehicle group and without the adverse effect of hypoglycemia in ZDF rats. Compared with vehicle group, rh-aFGF₁₃₅ significantly improved the situation of hyperglycemia and insulin resistance. Rh-aFGF₁₃₅ decreased ALT, AST, GSP, and FFA levels noticeably compared with vehicle control group (P < 0.01 or P < 0.001). After 5 weeks of treatment, high-dosage rh-aFGF₁₃₅ could remodel adipose tissue, and has no influence on other organs. H&E staining showed that rh-aFGF₁₃₅ reduced the size of adipocytes. In addition, rh-aFGF₁₃₅ may improve insulin resistance partly by increasing the protein expression of p-IRS-1 (human Ser 307). As a hypoglycemic drug for long-term treatment, rh-aFGF₁₃₅ would be a potentially safe candidate for the therapy of type 2 diabetes.

Lidocaine-loaded reduced graphene oxide hydrogel for prolongation of effects of local anesthesia: In vitro and in vivo analyses

Lidocaine is widely used as a local anesthetic for alleviation of post-operative pain and for management of acute and chronic painful conditions. Although several approaches are currently used to prolong the duration of action, an effective strategy to achieve neural blockage for several hours remains to be identified. In this study, a lidocaine-loaded Pluronic® F68-reduced graphene oxide hydrogel was developed to achieve sustained release of lidocaine. Fourier transform infrared spectroscopy, X-ray diffraction, and Raman spectroscopy confirmed the synthesis of Pluronic® F68-reduced graphene oxide. Transmission electron microscopy showed wrinkled, flat nanosheets with micelles attached. The developed hydrogel showed desirable pH, viscosity, adhesiveness, hardness, and cohesiveness for topical application. The ex vivo release study demonstrated the ability of the Pluronic® F68-reduced graphene oxide hydrogel to prolong release up to 10 h, owing to the strong π-π interactions between the graphene oxide and the lidocaine. In comparison with a commercial lidocaine ointment, the developed graphene oxide hydrogel showed sustained anesthetic effect in the radiant heat tail flick test and sciatic nerve block model. Thus, this study demonstrates the potential of using Pluronic® F68-reduced graphene oxide nanocarriers to realize prolonged effects of local anesthesia for effective pain management.

Sustained release of tulobuterol from graphene oxide laden hydrogel to manage asthma

Bronchial asthma is a chronic disease which is currently treated using various inhalants. However, the medication adherence with the inhalants is poor due to complex procedure to use them along with frequent dosing. In this paper, we have developed tulobuterol loaded Pluronic® F127-reduced graphene oxide transdermal hydrogel to sustain the release of tulobuterol to manage asthma for days. The synthesis of Pluronic^® F127-reduced graphene oxide was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, and Raman spectroscopy. The transmission electron microscope showed wrinkled flat nano sheets. The hydrogel showed sufficient mechanical properties for topical application and was safe in the skin irritation study (rabbit model). The ex vivo release data demonstrated the ability of reduced graphene oxide to sustain the release of tulobuterol for 72 h, due to strong π-π interaction between drug and graphene oxide. The pharmacokinetic profile in Sprague-Dawley rat model confirmed the potential of tulobuterol-Pluronic^® F127-reduced graphene oxide hydrogel to sustain the release of tulobuterol for effective management of asthma.

Topical recombinant human acidic fibroblast growth factor: An effective therapeutic agent for facemask wearing-induced pressure sores

Protecting health care workers is crucial during coronavirus disease 2019 pandemic and facemask wearing is considered an effective measure to prevent severe acute respiratory syndrome coronavirus 2 infection. However, long‐time use of a facemask can cause pressure sores on the ears and nose bridge and increase the risk of infection. The topical recombinant human acidic fibroblast growth factor (rh‐aFGF) was used to cure pressure sores for health care workers at Zhongfaxincheng campus of Tongji Hospital. The results from a small sample size survey conducted in Zhongfaxincheng campuses of Tongji Hospital showed that treatment with topical rh‐aFGF could significantly inhibit the progression of pressure sores and accelerate the wound healing with no apparent ill‐effects. Therefore, we propose that topical rh‐aFGF is an effective therapeutic agent for facemask wearing‐induced pressure sores and worth of popularizing and applying.