Poloxamer-Based Thermoreversible Gel for Topical Delivery of Emodin: Influence of P407 and P188 on Solubility of Emodin and Its Application in Cellular Activity Screening

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.

The role of chitosan in enhancing the solubility and antibacterial activity of emodin against drug-resistant bacteria

Similar to most anthraquinone compounds, the pharmacological properties of emodin are limited because of its low water solubility. In this study, the formulation of chitosan and emodin (EMD/CS) was prepared by a bottom-up method with precipitation and sonication steps in order to enhance the solubility of emodin. Thanks to the interactions of oxygen-and nitrogen-containing groups in chitosan with emodin molecules, the solubility of emodin in the formulation was remarkably increased to 0.5 mg/mL. The EMD/CS particles were well dispersed and distributed in a range of sub-micrometer with an average particle size of 342 nm. The EMD/CS formulation exhibited synergic antibacterial activity of emodin and chitosan, against drug-resistant bacterial strains, namely Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli O157:H7 (E. coli O157:H7). When the compositions of emodin and chitosan increased, the antibacterial effectiveness of the EMD/CS formulation increased. The EMD/CS formulation with compositions of 0.5 mg/mL of emodin and 9.0 mg/mL of chitosan could significantly inhibit the proliferation of E. coli O157:H7. Meanwhile, the EMD/CS formulation with a lower concentration of emodin (0.4 mg/mL) and chitosan (7.2 mg/mL) could cause an extermination effect on MRSA. The enhanced solubility of EMD/CS formulation suggests that this formulation can be a potential candidate for the treatment of infectious diseases caused by drug-resistant bacterial pathogens.

Sprayable ciprofloxacin-loaded poloxamer hydrogels for wound infection treatment

Topical antimicrobial treatments for severe burns and chronic wounds provide effective treatment against infections, but cause pain and discomfort with application. This study aimed to develop an antimicrobial topical formulation comprising thermoreversible poloxamers (Pluronic F127 and F68) and a broad-spectrum antimicrobial agent (ciprofloxacin hydrochloride, CH), that could be sprayed to eliminate application pain while maintaining antimicrobial activity. Formulations were characterized to determine their sprayability under cold conditions, gelation temperature, final storage modulus at skin temperature, drug release profile, ex vivo permeation through impaired porcine skin, and inhibition against common bacterial pathogens that colonize wounds. All cold formulations were sprayable from simple hand-held, pump-action sprayers due to their low viscosity. Upon heating, 17 and 20% Pluronic F127 formulations produced hydrogels eight to ten degrees below skin temperature, independent of ciprofloxacin loading. Increasing concentrations of Pluronic F127 increased the final storage modulus and viscosity of the gels, while inclusion of Pluronic F68 reduced these properties, showing that hydrogel rheological properties at skin temperature can be tuned via choice of formulation. Drug release was directly correlated to the rheological properties, with stiffer gels resulting in a decrease in drug release rate. Overall, gels released about 65-90% of their load within 12 hours. Ex vivo skin permeation demonstrated that drug was well retained in impaired porcine skin, which is desired to continuously treat bacteria localized to the wound. A well-diffusion assay indicated that the hydrogels had greater bacterial inhibition against Pseudomonas aeruginosa, Escherichia coli, and two strains of Staphylococcus aureus when compared to commercial controls. Overall, the results show the potential of CH-loaded poloxamer formulations as suitable sprayable topical dressings to deliver antimicrobials directly to wounds.

Novel Sprayable Thermosensitive Benzydamine Hydrogels for Topical Application: Development, Characterization, and In Vitro Biological Activities

Benzydamine hydrochloride (BZD) having analgesic, anesthetic, and anti-inflammatory effects is used orally or topically in the treatment of disorders such as joint inflammation and muscle pain. Within the scope of this study, sprayable thermosensitive BZD hydrogels were developed using thermoresponsive poloxamers to avoid systemic side effects and to provide better compliance for topical administration. Also, hydroxypropyl methyl cellulose (HPMC) was employed to improve the mechanical strength and bioadhesive properties of the hydrogel. The addition of BZD generally decreased the viscosity of the formulations (p < 0.05), while increasing the gelation temperature (p < 0.05). The formulations that did not have any clogs or leaks in the nozzle of the bottle during the spraying process were considered lead formulations. To spray the formulations easily, it was found that the viscosity at RT should be less than 200 mPa·s, and their gelation temperature should be between 26 and 34°C. Increasing HPMC and poloxamer improved bioadhesion. The amount of HPMC and poloxamers did not cause a significant change in the release characteristics of the formulations (p > 0.05); the release profiles of BZD from the formulations were similar according to model-independent kinetic (f2 > 50). HPMC and poloxamers had important roles in the accumulation of BZD in the skin. In vitro biological activity studies demonstrated that the formulations presented their anti-inflammatory activity with TNF-α inhibition but did not have any effect on the inhibition of COX enzymes as expected. As a result, thermosensitive hydrogels containing BZD might be an appropriate alternative, providing an advantage in terms of easier application compared to conventional gels.

Pluronic F-68 and F-127 Based Nanomedicines for Advancing Combination Cancer Therapy

Pluronics are amphiphilic triblock copolymers composed of two hydrophilic poly (ethylene oxide) (PEO) chains linked via a central hydrophobic polypropylene oxide (PPO). Owing to their low molecular weight polymer and greater number of PEO segments, Pluronics induce micelle formation and gelation at critical micelle concentrations and temperatures. Pluronics F-68 and F-127 are the only United States (U.S.) FDA-approved classes of Pluronics and have been extensively used as materials for living bodies. Owing to the fascinating characteristics of Pluronics, many studies have suggested their role in biomedical applications, such as drug delivery systems, tissue regeneration scaffolders, and biosurfactants. As a result, various studies have been performed using Pluronics as a tool in nanomedicine and targeted delivery systems. This review sought to describe the delivery of therapeutic cargos using Pluronic F-68 and F-127-based cancer nanomedicines and their composites for combination therapy.

Enhancement of polymer thermoresponsiveness and drug delivery across biological barriers by addition of small molecules

Thermoresponsive polymers that undergo sol-gel transitions in the physiological temperature range have been widely used in biomedical applications. However, some commercially and clinically available thermoresponsive materials, particularly poloxamer 407 (P407), have the significant drawback of insufficient gel strength, which limit their performance. Furthermore, co-delivery with some small molecules, including chemical permeation enhancers (CPEs) can further impair the physical properties of P407. Here, we have developed a thermoresponsive platform by combination of CPEs with the poloxamer P188 to enable gelation at physiological temperatures and enhance gel strength. P188 gels at 60 °C, which is far above the physiological range. In combination with limonene (LIM) and sodium dodecyl sulfate (SDS), P188 gels at ∼25 °C, a temperature that in useful for biomedical applications. Gelation behavior was studied by small angle neutron scattering (SANS) experiments, which identified micelle-to-cubic mesophase transitions with increasing temperature. Analysis of the SANS intensities revealed that P188 micelles became larger as LIM or SDS molecules were incorporated, making it easier to form a micellar gel structure. P188-3CPE (i.e., 2% LIM, 1% SDS and 0.5% bupivacaine (BUP)) had low viscosity at room temperature, facilitating administration, but rapidly gelled at body temperature. P188-3CPE enabled the flux of the antibiotic ciprofloxacin across the TM and completely eradicated otitis media from nontypable Haemophilus influenzae (NTHi) in chinchillas after a single administration.

Intranasally administered thermosensitive gel for brain-targeted delivery of rhynchophylline to treat Parkinson's disease

The aim of this study is to overcome the obstacle of the blood-brain barrier (BBB) in therapeutic drugs of Parkinson's disease (PD), like rhynchophylline (RIN) entry by intranasal administration and to solve the problem of short residence time of drugs in the nasal cavity by the dosage form design of thermosensitive gel. We first conducted a study of the screening of absorption enhancers and 3% hydroxypropyl-β-cyclodextrin (HP-β-CD) was effective to improve the nasal mucosal permeability of RIN. By adjusting the ratio of different components in order to make the gel with adhesion and rapid gelation which were determined to be Poloxamer 407 (P407) 20%, Poloxamer 188 (P188) 1%, polyethylene glycol 6000 (PEG-6000) 1% and HP-β-CD 3%. In addition, the characterization showed that the thermosensitive gel was network cross-linked, rapidly gelation upon entry into the nasal cavity and was stable as semi-solid state with adhesion as well as sustained release properties. Moreover, pharmacokinetic study was performed to evaluate the bioavailability and brain targeting of RIN thermosensitive gel and which were 1.6 times and 2.1 times higher than those of oral administration. We also evaluated the anti-PD effects of RIN thermosensitive gel in-vitro as well as in-vivo. The results showed that RIN thermosensitive gel was effective in repairing the motor function impairment, dysregulated expression levels of oxidative stress factors, and positive neuronal damage within the substantia nigra and dopamine caused by PD. The constructed intranasal drug administration strategy through thermosensitive gel provided a new choice for targeted treatment of PD together with other central nervous system diseases.

Stimuli-Responsive in situ Spray Gel of Miconazole Nitrate for Vaginal Candidiasis

Vaginal candidiasis is a common form of infection in women caused by Candida species. Due to several drawbacks of conventional treatments, the current research is attempted to formulate and optimize a miconazole nitrate-loaded in situ spray gel for vaginal candidiasis. The stimuli-responsive (pH and thermo-responsive) polymers selected for the in situ gel were chitosan and poloxamer 407, respectively, whereas hydroxypropyl methylcellulose (HPMC) was introduced in the formulation to further improve the mucoadhesive property. The dispersion of each polymer was carried out using the cold method, whereas the optimization of the formulation was achieved using Box-Behnken statistical design considering viscosity and gelation temperature as dependent variables. Present design achieved the optimized outcome with HPMC, poloxamer and chitosan at 0.52% (w/v), 18.68% (w/v) and 0.41% (w/v), respectively. Evaluation of drug-excipients compatibility was performed using differential scanning calorimetry, Fourier transform infrared spectroscopy, and thermogravimetric analysis where the results showed the absence of any chemical interaction between the polymers and drug component. The optimized formulation showed gelation temperature at 31°C allowing in situ phase transition in a vaginal environment; pH of 4.21 is suitable for use in the vaginal cavity, and appropriate viscosity (290 cP) at storage temperature (below 30°C) would allow spraying at ease, whereas strong mucoadhesive force (22.4±0.513 g) would prevent leaking of the formulation after application. The drug release profile showed sustained release up to 24 h with a cumulative drug release of 81.72%, which is significantly better than the marketed miconazole nitrate cream. In addition, an improved antifungal activity could be correlated to the sustained release of the drug from the formulation. Finally, the safety of the formulation was established while tested on HaCaT cell lines. Based on our findings, it could be concluded that the in situ hydrogel formulation using stimuli-responsive polymers could be a viable alternative to the conventional dosage form that can help to reduce the frequency of administration with ease of application to the site of infection, thus will provide better patient compliance.

Exploration of hemocompatibility and intratumoral accumulation of paclitaxel after loco-regional administration of thermoresponsive hydrogel composed of poloxamer and xanthan gum: An application to dose-dense chemotherapy

Although paclitaxel is a front-line chemotherapeutic agent for the treatment of metastatic breast cancer, its intravenous therapy produces deleterious adverse effects. In an attempt to address the issue, the present study aimed to develop a paclitaxel loaded thermosensitive/thermoresponsive hydrogel (PTXNp-TGel) for loco-regional administration to breast tumors to provide dose-dense chemotherapy. Poloxamer and xanthan gum were used to prepare TGel by the cold method. In vitro and in vivo performance of PTXNp-TGel was compared with TGel, pure drug loaded TGel (PTX-TGel) and marketed formulation, Taxol®. The formulated PTXNp-TGel showed acceptable gelation temperature and time (37 °C and 57 s), lower viscosity at room temperature and higher viscosity at body temperature to support sol-gel transition with increasing temperature, and sustained drug release up to 21 days. Additionally, PTXNp-TGel showed negligible hemolytic toxicity as compared to PTX-TGel and Taxol®. Intratumoral administration of PTXNp-TGel produced significantly higher antitumor activity as indicated by lowest relative tumor volume (1.50) and relative antitumor proliferation rate (27.71 %) in comparison with PTX-TGel, Taxol®, and PTXNp (p < 0.05). Finally, insignificant body weight loss during the experimental period, lack of hematotoxicity, nephrotoxicity, and hepatotoxicity imply improved therapeutic performance of the locally administrated dose-dense therapy of PTXNp-TGel as compared to Taxol®.

Potential Hemostatic and Wound Healing Effects of Thermoresponsive Wound Dressing Gel Loaded with Lignosus rhinocerotis and Punica granatum Extracts

Biologically active compounds in Lignosus rhinocerotis and Punica granatum are found to facilitate wound healing and exhibit hemostatic activity, making them a good combination as bioactives for wound dressings. This study, therefore, aimed to evaluate the potential of thermoresponsive gels loaded with L. rhinocerotis (HLRE) and P. granatum (PPE) extracts as dressings for wound treatment. The gels were prepared using Pluronic PF127 polymer and mixed with PEG 400 and/or starch prior to incorporation with both extracts (0.06 to 1 mg/mL). The gelation temperature (Tgel) at the skin temperature was achieved when Pluronic PF127 was mixed with 22% w/v PEG 400 and reduced to 25.7 ± 0.3-26.7 ± 1.2 °C after adding HLRE and PPE. The gels exhibited satisfactory hardness (2.02 ± 0.19-6.45 ± 0.53 N), cohesiveness (0.9 ± 0.07-2.28 ± 0.4 mJ), adhesiveness (5.07 ± 2.41-19.6 ± 1.1 mJ), and viscosity (0.15 ± 0.04-0.95 ± 0.03 Pa.s), suitable for wound dressings. The optimized gels displayed high thrombin activity and cell migration rate (wound closure of 74% ± 12-89% ± 2 within 24 h), demonstrating hemostatic and healing effects. The thermoresponsive gels demonstrated advantages to be used as dressings for treating acute and open wounds.

Quercetin Loaded Cationic Solid Lipid Nanoparticles in a Mucoadhesive In Situ Gel-A Novel Intravesical Therapy Tackling Bladder Cancer

The study aim was to develop an intravesical delivery system of quercetin for bladder cancer management in order to improve drug efficacy, attain a controlled release profile and extend the residence time inside the bladder. Either uncoated or chitosan coated quercetin-loaded solid lipid nanoparticles (SLNs) were prepared and evaluated in terms of colloidal, morphological and thermal characteristics. Drug encapsulation efficiency and its release behaviour were assessed. Furthermore, cytotoxicity of SLNs on T-24 cells was evaluated. Ex vivo studies were carried out using bovine bladder mucosa. Spherical SLNs (≈250 nm) ensured good entrapment efficiencies (EE > 97%) and sustained drug release up to 142 h. Cytotoxicity profile revealed concentration-dependent toxicity recording an IC50 in the range of 1.6−8.9 μg/mL quercetin. SLNs were further dispersed in in situ hydrogels comprising poloxamer 407 (20%) with mucoadhesive polymers. In situ gels exhibited acceptable gelation temperatures (around 25 °C) and long erosion time (24−27 h). SLNs loaded gels displayed remarkably enhanced retention on bladder tissues relative to SLNs dispersions. Coated SLNs exhibited better penetration abilities compared to uncoated ones, while coated SLNs dispersed in gel (G10C-St-QCT-SLNs-2) showed the highest penetration up to 350 μm. Hence, G10C-St-QCT-SLNs-2 could be considered as a platform for intravesical quercetin delivery.

Thermosensitive In Situ Gels for Joint Disorders: Pharmaceutical Considerations in Intra-Articular Delivery

The intra-articular administration of conventional drug solutions or dispersions in joint diseases such as osteoarthritis has a relatively short retention time and, therefore, limited therapeutic effect. Thermosensitive polymer solutions that exhibit a sol-gel phase transition near body temperature after injection can prolong drug retention by providing a depot from which the drug release is sustained while relieving inflammation and preventing degradation of the joint complex. Thermosensitive hydrogels have in recent times garnered considerable attention in the intra-articular therapeutics of joint diseases such as osteoarthritis. Among the stimuli-responsive gelling systems, most research has focused on thermosensitive hydrogels. These gels are preferred over other stimuli-sensitive hydrogels since they have well-controlled in situ gelling properties and are also easier to load with drugs. Temperature-sensitive polymers, such as block copolymers or poloxamers, are frequently used to modify their gelation properties, usually in combination with other polymers. They are compatible with most drugs but may pose formulation challenges in terms of their low-response time, highly fragile nature, and low biocompatibility. The stability and biodegradability of implant hydrogels can control the drug release rate and treatment efficacy. This review stresses the application of thermosensitive gels in joint disorders and summarizes recent developments for intra-articular application, including the incorporation of nanoparticles. The hydrogel composition, drug release mechanisms, and the challenges involved in their formulation and storage are also discussed.

Thermoreversible Carbamazepine In Situ Gel for Intranasal Delivery: Development and In Vitro, Ex Vivo Evaluation

Over the past decade, intranasal (IN) delivery has been gaining attention as an alternative approach to conventional drug delivery routes targeting the brain. Carbamazepine (CBZ) is available as an orally ingestible formulation. The present study aims to develop a thermoreversible in situ gelling system for delivering CBZ via IN route. A cold method of synthesis has been used to tailor and optimize the thermoreversible gel composition, using poloxamer 407 (P407) (15-20% w/v) and iota carrageenan (ɩ-Cg) (0.15-0.25% w/v). The developed in situ gel showed gelation temperatures (28-33°C), pH (4.5-6.5), rheological properties (pseudoplastic, shear thinning), and mucoadhesive strength (1755.78-2495.05 dyne/cm²). The in vitro release study has shown sustained release behavior (24 h) for gel, containing significant retardation of CBZ release. The release kinetics fit to the Korsmeyer-Peppas model, suggesting the non-Fickian diffusion type controlled release behavior. Ex vivo permeation through goat nasal mucosa showed sustained release from the gel containing 18% P407 with the highest cumulative drug permeated (243.94 µg/cm²) and a permeation flux of 10.16 µg/cm²/h. After treatment with CBZ in situ gel, the barrier function of nasal mucosa remained unaffected. Permeation through goat nasal mucosa using in situ gel has demonstrated a harmless nasal delivery, which can provide a new dimension to deliver CBZ directly to the brain bypassing the blood-brain barrier.

Recent advances in the therapeutic potential of emodin for human health

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a bioactive compound, a natural anthraquinone aglycone, present mainly in herbaceous species of the families Fabaceae, Polygonaceae and Rhamnaceae, with a physiological role in protection against abiotic stress in vegetative tissues. Emodin is mainly used in traditional Chinese medicine to treat sore throats, carbuncles, sores, blood stasis, and damp-heat jaundice. Pharmacological research in the last decade has revealed other potential therapeutic applications such as anticancer, neuroprotective, antidiabetic, antioxidant and anti-inflammatory. The present study aimed to summarize recent studies on bioavailability, preclinical pharmacological effects with evidence of molecular mechanisms, clinical trials and clinical pitfalls, respectively the therapeutic limitations of emodin. For this purpose, extensive searches were performed using the PubMed/Medline, Scopus, Google scholar, TRIP database, Springer link, Wiley and SciFinder databases as a search engines. The in vitro and in vivo studies included in this updated review highlighted the signaling pathways and molecular mechanisms of emodin. Because its bioavailability is low, there are limitations in clinical therapeutic use. In conclusion, for an increase in pharmacotherapeutic efficacy, future studies with carrier molecules to the target, thus opening up new therapeutic perspectives.

Drug delivery to the brain: In situ gelling formulation enhances carbamazepine diffusion through nasal mucosa models with mucin

The objective of this work was to optimize a thermosensitive in situ gelling formulation to improve intranasal and nose-to-brain delivery of the antiepileptic drug carbamazepine (CBZ). A preliminary procedure of vehicles obtained just mixing different fractions of poloxamer 407 (P407) and poloxamer 188 (P188) revealed preparations with phase transition temperatures, times to gelation and pH values suitable for nasal delivery. Subsequently, the mucoadhesive properties of the most promising formulations were tuned by adding hydroxypropylmethylcellulose types of different viscosity grades, and the effect of the adhesive polymers was evaluated by testing in vitro time and strength of mucoadhesion on specimens of sheep nasal mucosa. The formulation that showed the greatest mucoadhesive potential in vitro, with a time and force of mucoadhesion equal to 1746,75 s and 3.66 × 10-4 N, respectively, was that composed of 22% P407, 5% P188 and 0.8% HPMC low-viscous and it was further investigated for its ability to increase drug solubility and to control the release of the drug. Lastly, the capability of the candidate vehicle to ensure drug permeation across the biomimetic membrane Permeapad®, an artificial phospholipid-based barrier with a stratified architecture, and the same barrier enriched with a mucin layer was verified. The final formulation was characterized by a pH value of 6.0, underwent gelation at 32.33°C in 37.85 s, thus showing all the features required by in situ gelling thermosensitive preparations designed for nasal delivery and, more notably, it conserved the ability to favor drug permeation in the presence of mucin. These findings suggest that the optimized gelling system could be a promising and easy to realize strategy to improve CBZ delivery to the brain exploiting both a direct and indirect pathway.

Balsam Poplar Buds: Extraction of Potential Phenolic Compounds with Polyethylene Glycol Aqueous Solution, Thermal Sterilization of Extracts and Challenges to Their Application in Topical Ocular Formulations

Phenolic compounds of natural origin have been valued for their beneficial effects on health since ancient times. During our study, we performed the extraction of phenolic compounds from balsam poplar buds using different concentrations of aqueous polyethylene glycol 400 solvents (10-30% PEG400). The aqueous 30% PEG400 extract showed the best phenolic yield. The stability of the extract during autoclave sterilization was evaluated. The extract remained stable under heat sterilization. Ophthalmic formulations are formed using different concentrations (8-15%) of poloxamer 407 (P407) together with hydroxypropyl methylcellulose (0.3%), sodium carboxymethyl cellulose (0.3%) or hyaluronic acid (0.1%). Physicochemical parameters of the formulations remained significantly unchanged after sterilization. Formulations based on 12% P407 exhibited properties characteristic of in situ gels, the gelation point of the formulations was close to the temperature of the cornea. After evaluating the amount of released compounds, it was found that, as the concentration of polymers increases, the amount of released compounds decreases. Formulations based on 15% P407 released the least biologically active compounds. Sterilized formulations remained stable for 30 days.

Efficacy of instillation of MB49 cells and thermoreversible polymeric gel in urothelial bladder carcinoma immunization

Background

Activating the immune system for therapeutic benefit has long been a goal in immunology, especially in cancer treatment, but the low immunogenicity of antitumor vaccines remains a limiting factor in the fight against malignant neoplasms. The increase in the immunogenicity of weak antigens using biodegradable polymers, such as chitosan, has been observed in the field of cancer immunotherapy. However, the effects of the vaccine using a combination of tumor cells and a thermoreversible delivery system based on chitosan in bladder cancer models, mainly using the intravesical route to stimulate the antitumor immune response, are unknown. We propose to evaluate the efficacy of a polymeric gel matrix (TPG) formed by poloxamer 407 and chitosan, associated with MB49 cells, as an intravesical antitumor vaccine using a C57BL/6 murine model of bladder urothelial carcinoma. The effectiveness of immunization was analyzed with the formation of three experimental groups: Control, TPG and TPG + MB49. In the vaccination phase, the TPG + MB49 group underwent a traumatic injury to the bladder wall with immediate intravesical instillation of the vaccine compound containing MB49 cells embedded in TPG. The TPG group was subjected to the same procedures using the compound containing the gel diluted in medium, and the control group using only the medium. After 21 days, the animals were challenged with tumor induction.

Results

In vitro tests showed loss of viability and inability to proliferate after exposure to TPG. In vivo tests showed that animals previously immunized with TPG + MB49 had higher cumulative survival, as well as significantly lower bladder weight and size in contrast to the other two groups that did not show a statistically different tumor evolution. In addition, the splenocytes of these animals also showed a higher rate of antitumor cytotoxicity in relation to the TPG and control groups.

Conclusions

We can conclude that MB49 cells embedded in a polymeric thermoreversible gel matrix with chitosan used in the form of an intravesical vaccine are able to stimulate the immune response and affect the development of the bladder tumor in an orthotopic and syngeneic C57BL/6 murine model.

Promising Role of Emodin as Therapeutics to Against Viral Infections

Emodin is an anthraquinone derivative that is widely present in natural plants and has a wide spectrum of pharmacological effects, such as antibacterial, anti-inflammatory, anti-fibrotic and anticancer and so on. Through reviewing studies on antiviral effect of emodin in the past decades, we found that emodin exhibits ability of inhibiting the infection and replication of more than 10 viruses in vitro and in vivo, including herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), coxsackievirus B (CVB), hepatitis B virus (HBV), influenza A virus (IAV), SARS-CoV, viral haemorrhagic septicaemia rhabdovirus (VHSV), enterovirus 71 (EV71), dengue virus serotype 2 (DENV-2) and Zika virus (ZIKV). Therefore, this review aims to summarize the antiviral effect of emodin, in order to provide reference and hopes to support the further investigations.

Poloxamer 188 as surfactant in biological formulations - An alternative for polysorbate 20/80?

Surfactants are used to stabilize biologics. Particularly, polysorbates (Tween® 20 and Tween® 80) dominate the group of surfactants in protein and especially antibody drug products. Since decades drug developers rely on the ethoxylated sorbitan fatty acid ester mixtures to stabilize sensitive molecules such as proteins. Reasons are (i) excellent stabilizing properties, and (ii) well recognized safety and tolerability profile of these polysorbates in humans, especially for parenteral applications. However, over the past decade concerns regarding the stability of these two polysorbates were raised. The search of alternatives with preferably less reservations concerning degradation and product quality reducing issues leads, among others, to poloxamer 188 (e.g. Kolliphor® P188), a nonionic triblock-copolymer surfactant. This review sums up our current knowledge related to the characterization and physico-chemical properties of poloxamer 188, its analytics and stability properties for biological formulations. Furthermore, the advantages and disadvantages as a suitable polysorbate-alternative for the stabilization of biologics are discussed.

Therapeutic Potential of Emodin for Gastrointestinal Cancers

Gastrointestinal (GI) cancers cause one-third of all cancer-related deaths worldwide. Natural compounds are emerging as alternative or adjuvant cancer therapies given their distinct advantage of manipulating multiple pathways to both suppress tumor growth and alleviate cancer comorbidities; however, concerns regarding efficacy, bioavailability, and safety are barriers to their development for clinical use. Emodin (1,3,8-trihydroxy-6-methylanthraquinone), a Chinese herb-derived anthraquinone, has been shown to exert anti-tumor effects in colon, liver, and pancreatic cancers. While the mechanisms underlying emodin's tumoricidal effects continue to be unearthed, recent evidence highlights a role for mitochondrial mediated apoptosis, modulated stress and inflammatory signaling pathways, and blunted angiogenesis. The goals of this review are to (1) highlight emodin's anti-cancer properties within GI cancers, (2) discuss the known anti-cancer mechanisms of action of emodin, (3) address emodin's potential as a treatment complementary to standard chemotherapeutics, (4) assess the efficacy and bioavailability of emodin derivatives as they relate to cancer, and (5) evaluate the safety of emodin.

Thermoresponsive Hydrogel Containing Viscum album Extract for Topic and Transdermal Use: Development, Stability and Cytotoxicity Activity

Viscum album L. (Santalaceae), also known as European mistletoe, is a semi-parasitic plant that grows on different host trees. Our group recently demonstrated the antitumoral activity of ethanolic V. album extracts in vitro, depending on the dose and the host tree, V. album ssp abietis from Abies alba being the most active extract. The goal of this work focused on the development of a new topical formulation containing V. album extracts, evaluation of in vitro toxicity and ex vivo skin permeation assays. The Poloxamer 407 hydrogel containing 5% of dry (VA_DEH) or aqueous (VA_AEH) extract presented dermal compatible pH and microbiological stability for 180 days. The hydrogels flow curve presented a non-linear relation, characteristic of non-Newtonian fluids, and the mean viscosity for the VA_DEH and VA_AEH was 372.5 ± 7.78 and 331.0 ± 2.83 Pa.s, respectively, being statistically different (Welch’s t test; p < 0.01). Additionally, WST-1 in vitro assays revealed a dose-dependent toxicity for both formulations and VA_DEH presented a higher activity than the VA_AEH. The promising cytotoxic potential of VA_DEH lead to the ex vivo skin permeation assay with 2.73 ± 0.19 µg/cm² of chlorogenic acid, which permeated at 8 h, showing a transdermal potential. These in vitro results support the idea that VA_DEH is a novel promising candidate for mistletoe therapy. Therefore, further in vivo and pre-clinical experiments should be performed to evaluate the safety and efficacy of this new dermic delivery system.

Antimicrobial Activities of Propolis in Poloxamer Based Topical Gels

Propolis contains a group of compounds with various activities. However, their low solubility is a drawback for the development of pharmaceutical formulations. In this study, poloxamers as a solubilizer and gelling agent were evaluated to develop a topical antimicrobial formulation of propolis. The effects of poloxamer type and concentration on the propolis solubility, release rate, and antimicrobial activities were investigated. Staphylococcus aureus (S. aureus) and Candida albicans (C. albicans) were the representative bacteria and fungi, respectively. At 5%, poloxamer 407 (P407) and poloxamer 188 (P188) enhanced the propolis solubility by 2.86 and 2.06 folds, respectively; at 10%, they were 2.81 and 2.59 folds, respectively. The micelle size in the P188 formulation increased in the presence of propolis, whereas there was no change in the P407 formulation. Release rates of propolis decreased with the P188 concentration increase, which was attributed to viscosity increase. Both P188 and P407 formulations showed antimicrobial activity against S. aureus in a time-kill kinetics assay. However, only the P188 formulation reduced the cell's numbers significantly against C. albicans, compared to the control. We speculate that P188 mixed micelles were more effective in releasing free active compounds to exhibit anti-microbial activity compared to the P407 micelles encapsulating the hydrophobic compounds in their cores. Propolis in P188 formulation is proposed as a potential topical antimicrobial agent based on its activity against both S. aureus and C. albicans.

Local drug delivery using poly(lactic-co-glycolic acid) nanoparticles in thermosensitive gels for inner ear disease treatment

Intratympanic (IT) therapies have been explored to address several side effects that could be caused by systemic administration of steroids to treat inner ear diseases. For effective drug delivery to the inner ear, an IT delivery system was developed using poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and thermosensitive gels to maintain sustained release. Dexamethasone (DEX) was used as a model drug. The size and zeta potential of PLGA NPs and the gelation time of the thermosensitive gel were measured. In vitro drug release was studied using a Franz diffusion cell. Cytotoxicity of the formulations was investigated using SK-MEL-31 cells. Inflammatory responses were evaluated by histological observation of spiral ganglion cells and stria vascularis in the mouse cochlea 24 h after IT administration. In addition, the biodistribution of the formulations in mouse ears was observed by fluorescence imaging using coumarin-6. DEX-NPs showed a particle size of 150.0 ± 3.2 nm in diameter and a zeta potential of −18.7 ± 0.6. The DEX-NP-gel showed a gelation time of approximately 64 s at 37 °C and presented a similar release profile and cytotoxicity as that for DEX-NP. Furthermore, no significant inflammatory response was observed after IT administration. Fluorescence imaging results suggested that DEX-NP-gel sustained release compared to the other formulations. In conclusion, the PLGA NP-loaded thermosensitive gel may be a potential drug delivery system for the inner ear.

Advances in the study of emodin: an update on pharmacological properties and mechanistic basis

Rhei Radix et Rhizoma, also known as rhubarb or Da Huang, has been widely used as a spice and as traditional herbal medicine for centuries, and is currently marketed in China as the principal herbs in various prescriptions, such as Da-Huang-Zhe-Chong pills and Da-Huang-Qing-Wei pills. Emodin, a major bioactive anthraquinone derivative extracted from rhubarb, represents multiple health benefits in the treatment of a host of diseases, such as immune-inflammatory abnormality, tumor progression, bacterial or viral infections, and metabolic syndrome. Emerging evidence has made great strides in clarifying the multi-targeting therapeutic mechanisms underlying the efficacious therapeutic potential of emodin, including anti-inflammatory, immunomodulatory, anti-fibrosis, anti-tumor, anti-viral, anti-bacterial, and anti-diabetic properties. This comprehensive review aims to provide an updated summary of recent developments on these pharmacological efficacies and molecular mechanisms of emodin, with a focus on the underlying molecular targets and signaling networks. We also reviewed recent attempts to improve the pharmacokinetic properties and biological activities of emodin by structural modification and novel material-based targeted delivery. In conclusion, emodin still has great potential to become promising therapeutic options to immune and inflammation abnormality, organ fibrosis, common malignancy, pathogenic bacteria or virus infections, and endocrine disease or disorder. Scientifically addressing concerns regarding the poor bioavailability and vague molecular targets would significantly contribute to the widespread acceptance of rhubarb not only as a dietary supplement in food flavorings and colorings but also as a health-promoting TCM in the coming years.

Evaluation of the anti-biofilm effect of poloxamer-based thermoreversible gel of silver nanoparticles as a potential medication for root canal therapy

The purpose of this study was to design silver nanoparticles (AgNPs) poloxamer thermoreversible gel (AgNPs-PL) and investigate whether this gel could provide sustained antibacterial activity against Enterococcus faecalis (E. faecalis) in the root canal. The gels fabricated were characterized in terms of gelatin temperature, particle size, in-vitro Ag⁺ release, and elemental content. Cytotoxicity of AgNPs-PL on primary human periodontal ligament fibroblasts (HPDLFs) was examined by CCK-8 assay. Characterization of AgNPs-PL gel revealed that it contained particles existing as large clumps/fused aggregates of different shapes, with a mean diameter of 21.624 ± 14.689 nm, exhibited sustained release of Ag⁺ for 9 days, and non-toxic to HPDLFs at a low dose (4–32 μg/mL) through 24, 48, and 72 h exposures. The antibacterial effect of 16 and 32 μg/mL concentrations of AgNPs-PL was compared with blank poloxamer gel (PL) and calcium hydroxide (CH) using three methods: (I) agar counting plate, (II) scanning electron microscope (SEM) observations, and (III) confocal laser scanning microscope (CLSM) analysis. AgNPs-PL at the two doses above was more effective than PL and CH in removing E. faecalis biofilm at 1, 3, 9 days. Thus, AgNPs-PL exhibits strong activity against E. faecalis and is easy to produce, with a continuous release profile of Ag⁺. AgNPs-PL gel may be a candidate for a new root canal disinfection.

Dual-action of thermoresponsive gels containing DsiRNA-loaded gold nanoparticles for diabetic wound therapy: Characterization, in vitro safety and healing efficacy

Diabetic wounds are difficult to treat due to multiple causes, including reduced blood flow and bacterial infections. Reduced blood flow is associated with overexpression of prostaglandin transporter (PGT) gene, induced by hyperglycaemia which causing poor vascularization and healing of the wound. Recently, gold nanoparticles (AuNPs) have been biosynthesized using cold and hot sclerotium of Lignosus rhinocerotis extracts (CLRE and HLRE, respectively) and capped with chitosan (CS) to produce biocompatible antibacterial nanocomposites. The AuNPs have shown to produce biostatic effects against selected gram positive and negative bacteria. Therefore, in this study, a dual therapy for diabetic wound consisting Dicer subtract small interfering RNA (DsiRNA) and AuNPs was developed to improve vascularization by inhibiting PGT gene expression and preventing bacterial infection, respectively. The nanocomposites were incorporated into thermoresponsive gel, made of pluronic and polyethylene glycol. The particle size of AuNPs synthesized using CLRE (AuNPs-CLRE) and HLRE (AuNPs-HLRE) was 202 ± 49 and 190 ± 31 nm, respectively with positive surface charge (+30 to + 45 mV). The thermoresponsive gels containing DsiRNA-AuNPs gelled at 32 ± 1 °C and released the active agents in sufficient amount with good texture and rheological profiles for topical application. DsiRNA-AuNPs and those incorporated into thermoresponsive pluronic gels demonstrated high cell viability, proliferation and cell migration rate via in vitro cultured cells of human dermal fibroblasts, indicating their non-cytotoxicity and wound healing properties. Taken together, the thermoresponsive gels are expected to be useful as a potential dressing that promotes healing of diabetic wounds.

Brain Targeting of Duloxetine HCL via Intranasal Delivery of Loaded Cubosomal Gel: In vitro Characterization, ex vivo Permeation, and in vivo Biodistribution Studies

Purpose

Duloxetine (DLX) is dual serotonin and norepinephrine reuptake inhibitor suffering from limited bioavailability (≈ 40%) due to extensive hepatic metabolism. This work aims to formulate and evaluate DLX intranasal thermoreversible cubosomal gels to enhance its bioavailability and ensure efficient brain targeting.

Materials and Methods

Cubo-gels were prepared by 3³ central composite design with three independent factors, lipid ratio (glycerol monooleate: glycerol tripalmitate), Pluronic F127%, and Pluronic F68%. The prepared formulations were evaluated for their particle size (PS), gelling temperature (GT), entrapment efficiency (EE%), and in vitro release. The cubo-gel with the highest desirability (0.88) was chosen as the optimized formulation. DLX cubo-gel was evaluated using differential scanning calorimetry, Fourier-transform infrared spectroscopy, X-ray powder diffraction, and transmission electron microscopy. Cytotoxicity study, ex vivo permeation study and in vivo bio-distribution study were conducted to evaluate the safety and efficacy of brain targeting.

Results

The optimum cubo-gel was composed of 3.76 lipid ratio, 20% w/v PF127, and 5% w/v PF68. It had PS of 265.13 ± 9.85 nm, GT of 32 ± 0.05°C, EE% of 98.13 ± 0.50%, and showed controlled release behavior where 33% DLX was released within 6 hrs. The plain in situ cubo-gel had a significantly higher IC₅₀ compared to DLX solution and DLX-loaded in situ cubo-gel. The ex vivo permeation study showed 1.27 enhancement in the drug permeation from DLX in situ cubo-gel. According to the in vivo bio-distribution study in plasma and brain, the intranasal DLX in situ cubo-gel showed a 1.96 fold improvement in brain bioavailability compared to the intranasal solution. Its BTE% and DTP% were 137.77 and 10.5, respectively, indicating efficient brain targeting after intranasal administration.

Conclusion

Accordingly, intranasal DLX in situ cubo-gel can be considered as an innovative nano-carrier delivery system for bioavailability enhancement and efficient brain targeting of DLX to maximize its effect.

Deformable Liposomal Hydrogel for Dermal and Transdermal Delivery of Meloxicam

Background and Aim

Meloxicam (MX) is a potent hydrophobic non-steroidal anti-inflammatory drug used to reduce inflammation and pain. However, its oral dosage form can cause many adverse gastrointestinal effects. In the present study, a poloxamer P407 based hydrogel system containing transfersomes or flavosomes has been prepared as a potential therapeutic vehicle for the topical delivery of MX.

Methods

In this study, MX was encapsulated in conventional liposomes, transfersomes, and flavosomes. The obtained liposomal vesicles were characterized in terms of size, drug entrapment efficiency, zeta potential, and stability. These MX-loaded liposomal formulations were further incorporated into a poloxamer P407 gel and evaluated using rheological properties, a stability study and an ex vivo permeation study through human cadaver skin by both HPLC analysis and confocal laser scanning microscopy (CLSM).

Results

The developed deformable liposomes exhibited homogeneous vesicle sizes less than 120 nm with a higher entrapment efficiency as compared to conventional liposomes. The deformable liposomal gel formulations showed improved permeability compared to a conventional liposomal gel and a liposome-free gel. The enhancement effect was also clearly visible by CLSM.

Conclusion

These deformable liposomal hydrogel formulations can be a promising alternative to conventional oral delivery of MX by topical administration. Notably, flavosome-loaded gel formulations displayed the highest permeability through the deeper layers of the skin and shortened lag time, indicating a potential faster on-site pain relief and anti-inflammatory effect.

Plant-Derived Natural Products in Cancer Research: Extraction, Mechanism of Action, and Drug Formulation

Cancer is one of the main causes of death globally and considered as a major challenge for the public health system. The high toxicity and the lack of selectivity of conventional anticancer therapies make the search for alternative treatments a priority. In this review, we describe the main plant-derived natural products used as anticancer agents. Natural sources, extraction methods, anticancer mechanisms, clinical studies, and pharmaceutical formulation are discussed in this review. Studies covered by this review should provide a solid foundation for researchers and physicians to enhance basic and clinical research on developing alternative anticancer therapies.

Stoichiometrically Governed Curcumin Solid Dispersion and Its Cytotoxic Evaluation on Colorectal Adenocarcinoma Cells

Background

Colorectal cancer (CRC) is the third most commonly occurring cancer in men and the second most commonly occurring cancer in women. Curcumin (CMN) is obtained from a natural source and has no toxicity, even at high doses (8,000 mg/kg body weight in 24 hours) and was determined to have anticancer potency on several kinds of carcinoma. However, its medical applications were limited because of its low solubility and poor bioavailability.

Materials and Methods

To improve the medical applications of CMN, various hydrophilic carriers such as poloxamer 407 (PMX-407), poloxamer 188 (PMX-188), Gelucire 50/13 (Gel-50/13), and mannitol (MNL) were used to prepare a binary complex solid dispersion (SD). These binary SDs were characterized for aqueous solubility in various solvents. Physical stability, thermal behaviors, and morphology were determined by Fourier transform infrared spectrophotometric analysis, powder X-ray diffraction analysis, thermogravimetric analysis, differential scanning calorimetric analysis, scanning electron microscopy, dynamic light scattering study, and the novel dyeing test. In vitro drug release was determined by dissolution study. Based on the characterization, the better SD complex was optimized using Box-Behnken design (BBD). The cytotoxicity and apoptosis study of prepared CMN (C-SD) were used to test for colorectal adenocarcinoma cell lines.

Results

These results showed that the solubility of CMN is greatly improved after complexation with PXM-407 in SD. CMN is practically insoluble in water at acidic and neutral pH; however, the SD of CMN with PXM-407 produced significant improvement in solubility (1.266±0.0242 mg/mL) and dissolution (91.36±0.431% at 30 minutes); similarly, these data fit with a phase solubility study and in silico molecular modeling. Moreover, the solid-state characterization revealed that the SD complex exhibits the intermolecular hydrogen bond with drug and carrier. Also, the complex does not undergo any chemical modification owing to the amorphous form, and the dye test showed better coloring impact indicating the solubility of CMN. The cell cycle arrest confirmed at G2/M phase from flow cytometry analysis, and Western blot investigation was recognized molecular level cell death and the complex induced more exploit DNA during apoptosis.

Conclusion

This study confirmed that the ideal stoichiometric ratio of CMN with carrier to enhance its solubility was 1:1. This molecular complex of PXM-407 was found to be more effective against colorectal cancer (CRC) than pure CMN.

Improved Solubility and Oral Absorption of Emodin-Nicotinamide Cocrystal Over Emodin with PVP as a Solubility Enhancer and Crystallization Inhibitor

Emodin exerts anti-inflammatory and anti-cancer effects. However, its poor water solubility limits development into a pharmaceutical product. Although an emodin-nicotinamide cocrystal (ENC) with improved dissolution rate was proposed as a potential candidate, crystallization back to emodin after dissolution diminished the advantage of the cocrystal approach. The objectives of this study were to identify a crystallization inhibitor to maintain the emodin supersaturation generated by ENC dissolution, and to examine its effect on oral pharmacokinetics of ENC. Among various polymers, polyvinylpyrrolidone K30 (PVP) was the most effective solubilizer and crystallization inhibitor. The solubility of ENC in a simulated intestinal fluid containing 1.5% PVP was 2-fold higher than that of emodin. However, comparison of oral pharmacokinetics in rats between ENC and emodin did not reflect such improved solubility of ENC in vitro relative to emodin. Instead, the plasma concentrations of a major metabolite of emodin showed a positive correlation with in vitro dissolution results, suggesting rapid gastrointestinal metabolism of emodin during absorption. In conclusion, PVP contributes to enhanced dissolution rates of ENC and inhibits crystallization of emodin in vivo, so that more metabolites can be formed and absorbed. Therefore, a metabolism inhibitor would be necessary to improve the oral bioavailability of emodin further.

Characterization of a Topically Testable Model of Burn Injury on Human Skin Explants

Severe burn injuries remain a major health problem due to high rates of mortality, residual morbidity, and/or aesthetic damages. To find new therapies aimed at promoting a harmonious healing of skin burns, it is important to develop models which take into account the unique properties of the human skin. Based on previously described models of burn injury performed on human skin explants, we hypothesized that maintaining explants under constant tension forces would allow to more closely reproduce the pathophysiological processes of skin remodeling. We thus. Here, we set up and characterized an improved model of deep second-degree burn injury on ex vivo cultured human skin explants at air-liquid interface and maintained under conditions of constant tension forces. A spontaneous re-epithelialization of the lesion was observed 8 to 9 days post burn and was found to rely on the proliferation of basal keratinocytes at the wound edges. Collagen VII at the dermo-epidermal junction reformed along with the progression of re-epithelializatio and a synthesis of procollagen III was observed in the dermis at the wound site. These findings indicate that our model is suitable for the assessment of clinically-relevant therapies aimed at modulating the kinetics of re-epithelialization and/or the activation of fibroblasts following skin burn injuries. In this regard, we evaluated the use of a thermoreversible poloxamer hydrogel as a vehicle for topically-testable therapeutic molecules. Our data showed that, although useful for drug formulation, the p407/p188 poloxamer hydrogel induces a delay of skin re-epithelialization in humans skin explants submitted to experimental burn injury.

Rutin-Loaded Poloxamer 407-Based Hydrogels for In Situ Administration: Stability Profiles and Rheological Properties

Rutin is a flavone glycoside contained in many plants, and exhibits antioxidant, anti-inflammatory, anticancer, and wound-healing properties. The main disadvantage related to the use of this molecule for pharmaceutical application is its poor bioavailability, due to its low solubility in aqueous media. Poloxamer 407-hydrogels show interesting thermo-sensitive properties that make them attractive candidates as pharmaceutical formulations. The hydrophobic domains in the chemical structure of the copolymer, a polymer made up of two or more monomer species, are useful for retaining poorly water-soluble compounds. In this investigation various poloxamer 407-based hydrogels containing rutin were developed and characterized as a function of the drug concentration. In detail, the Turbiscan stability index, the micro- and dynamic rheological profiles and in vitro drug release were investigated and discussed. Rutin (either as a free powder or solubilized in ethanol) did not modify the stability or the rheological properties of these poloxamer 407-based hydrogels. The drug leakage was constant and prolonged for up to 72 h. The formulations described are expected to represent suitable systems for the in situ application of the bioactive as a consequence of their peculiar versatility.

Doxorubicin Loaded Poloxamer Thermosensitive Hydrogels: Chemical, Pharmacological and Biological Evaluation

(1) Background: doxorubicin is a potent chemotherapeutic agent, but it has limitations regarding its side effects and therapy resistance. Hydrogels potentially deal with these problems, but several characterizations need to be optimized to better understand how hydrogel assisted chemotherapy works. Poloxamer 407 (P407) hydrogels were mixed with doxorubicin and physico-chemical, biological, and pharmacological characterizations were considered. (2) Methods: hydrogels were prepared by mixing P407 in PBS at 4 °C. Doxorubicin was added upon solutions became clear. Time-to-gelation, hydrogel morphology, and micelles were studied first. The effects of P407-doxorubicin were evaluated on MC-38 colon cancer cells. Furthermore, doxorubicin release was assessed and contrasted with non-invasive in vivo whole body fluorescence imaging. (3) Results: 25% P407 had favorable gelation properties with pore sizes of 30–180 µm. P407 micelles were approximately 5 nm in size. Doxorubicin was fully released in vitro from 25% P407 hydrogel within 120 h. Furthermore, P407 micelles strongly enhanced the anti-neoplastic effects of doxorubicin on MC-38 cells. In vivo fluorescence imaging revealed that hydrogels retained fluorescence signals at the injection site for 168 h. (4) Conclusions: non-invasive imaging showed how P407 gels retained drug at the injection site. Doxorubicin P407 micelles strongly enhanced the anti-tumor effects.

Design and development of a commercially viable in situ nanoemulgel for the treatment of postmenopausal osteoporosis

Aim: To investigate the potential of a thermosensitive intranasal formulation of raloxifene hydrochloride (RH) for systemic delivery with the possibility of enhanced bioavailability and anti-osteoporotic efficacy. Methods: In this work, a commercially scalable nanoemulsion in thermosensitive gel, aligned with better clinical acceptability, has been developed and evaluated. Results: A significant 7.4-fold improvement in bioavailability of RH was recorded when compared with marketed tablets. Likewise, in vivo pharmacodynamics studies suggested 162% enhanced bone density and significantly improved biochemical markers compared with per-oral marketed tablet. Conclusion: The formulation, being safe and patient compliant, successfully tuned anti-osteoporotic effects with improved therapeutic performance. Further, the work provided an exceptional lead to carry out the study in clinical settings.

Plant-Based Antidiabetic Nanoformulations: The Emerging Paradigm for Effective Therapy

Diabetes mellitus is a life-threatening metabolic syndrome. Over the past few decades, the incidence of diabetes has climbed exponentially. Several therapeutic approaches have been undertaken, but the occurrence and risk still remain unabated. Several plant-derived small molecules have been proposed to be effective against diabetes and associated vascular complications via acting on several therapeutic targets. In addition, the biocompatibility of these phytochemicals increasingly enhances the interest of exploiting them as therapeutic negotiators. However, poor pharmacokinetic and biopharmaceutical attributes of these phytochemicals largely restrict their clinical usefulness as therapeutic agents. Several pharmaceutical attempts have been undertaken to enhance their compliance and therapeutic efficacy. In this regard, the application of nanotechnology has been proven to be the best approach to improve the compliance and clinical efficacy by overturning the pharmacokinetic and biopharmaceutical obstacles associated with the plant-derived antidiabetic agents. This review gives a comprehensive and up-to-date overview of the nanoformulations of phytochemicals in the management of diabetes and associated complications. The effects of nanosizing on pharmacokinetic, biopharmaceutical and therapeutic profiles of plant-derived small molecules, such as curcumin, resveratrol, naringenin, quercetin, apigenin, baicalin, luteolin, rosmarinic acid, berberine, gymnemic acid, emodin, scutellarin, catechins, thymoquinone, ferulic acid, stevioside, and others have been discussed comprehensively in this review.

Long-Term Effect against Methicillin-Resistant Staphylococcus aureus of Emodin Released from Coaxial Electrospinning Nanofiber Membranes with a Biphasic Profile

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious and rapidly growing threat to human beings. Emodin has a potent activity against MRSA; however, its usage is limited due to high hydrophobicity and low oral bioavailability. Thus, the coaxial electrospinning nanofibers encapsulating emodin in the core of hydrophilic poly (vinylpyrrolidone), with a hygroscopic cellulose acetate sheath, have been fabricated to provide long-term effect against MRSA. Scanning electron microscopy and transmission electron microscopy confirmed the nanofibers had a linear morphology with nanometer in diameter, smooth surface, and core-shell structure. Attenuated total reflection-Fourier transform infrared spectra, X-ray diffraction patterns, and differential scanning calorimetric analyses verified emodin existed in amorphous form in the nanofibers. The nanofibers have 99.38 ± 1.00% entrapment efficiency of emodin and 167.8 ± 0.20% swelling ratio. Emodin released from nanofibers showed a biphasic drug release profile with an initial rapid release followed by a slower sustained release. CCK-8 assays confirmed the nontoxic nature of the emodin-loaded nanofibers to HaCaT cells. The anti-MRSA activity of the nanofibers can persist up to 9 days in AATCC147 and soft-agar overlay assays. These findings suggest that the emodin-loaded electrospun nanofibers with core-shell structure could be used as topical drug delivery system for wound infected by MRSA.

Anil Kumar N, Sharopov F, Ramírez-Alarcón K, Ruiz-Ortega A, Abdulmajid Ayatollahi S, Valere Tsouh Fokou P, Kobarfard F, Amiruddin Zakaria Z, Iriti M, Taheri Y, Martorell M, Sureda A, N. Setzer W, Durazzo A, Lucarini M, Santini A, Capasso R, Adrian Ostrander E, -ur-Rahman A, Iqbal Choudhary M, C. Cho W, Sharifi-Rad J. Antidiabetic Potential of Medicinal Plants and Their Active Components

Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Phages in a thermoreversible sustained-release formulation targeting E. faecalis in vitro and in vivo

Introduction

Enterococcus faecalis is a key pathogen recovered from root canals when conventional treatment fails. Phage therapy has generated new interest in combating pathogens. A sustained-release formulation using specific phages against E. faecalis may offer an alternative approach.

Objectives

To evaluate the efficacy of anti-E. faecalis phages formulated in a thermo- sustained-release system against E. faecalis in vitro and in vivo.

Methods

EFDG1 and EFLK1 phages were formulated with poloxamer P407. Gelation time, phage survival, activity and toxicity were evaluated. Lytic activity was evaluated in vitro against E. faecalis at various growth phases, including anti-biofilm activity. Methods included viable bacterial count (CFU/mL), biofilm biomass determination and electron microscopy (live/dead staining). Further evaluation included infected incisors in an in vivo rat model. Anti-E. faecalis phage-cocktail suspension and sustained-release phage formulation were evaluated by viable bacterial count (CFU/mL), histology, scanning electron microscopy (SEM) and 16S genome sequencing of the microbiota of the root canal.

Results

Gelation time for clinical use was established. Low toxicity and a high phage survival rate were recorded. Sustained-release phages reduced E. faecalis in logarithmic (4 logs), stationary (3 logs) and biofilm (4 logs) growth phases. Prolonged anti-biofilm activity of 88% and 95% reduction in biomass and viable counts, respectively, was recorded. Reduction of intracanal viable bacterial counts was observed (99% of enterococci) also seen in SEM. Phage treatment increased Proteobacteria and decreased Firmicutes. Histology showed reduced periapical inflammation and improved healing following phage treatment.

Conclusion

Poloxamer P407 formulated with phages has an effective and long-lasting effect in vitro and in vivo targeting E. faecalis.

Thermoreversible mucoadhesive polymer-drug dispersion for sustained local delivery of budesonide to treat inflammatory disorders of the GI tract

Mucoadhesive drug formulations have been studied and used as alternatives to conventional formulations in order to achieve prolonged retention at the intended site. In addition to providing a controlled drug release, several drugs and disease conditions might benefit from mucoadhesive formulations, contributing to better therapeutic outcomes. Here, we describe the development and the in vitro/in vivo characterization of a mucoadhesive in situ gellifying formulation using PF127, a thermo reversible polymer, entrapping budesonide (BUD), a potent corticosteroid used for the treatment of a wide range of inflammatory diseases, including those affecting mucosas, such as in the GI tract. PF127 formulations (15-17%) were successfully prepared by a cold method as a thermo reversible in situ gelling dispersion for mucosal drug delivery, as confirmed by DSC. Sol-gel temperatures of PF127 formulations (25-39 °C) were observed by dynamic gelation and determined by microrheology and oscillatory rheometry. X-ray diffractograms and TEM images showed that BUD was completely solubilized within the polymeric micelles. In vitro, the gels showed 5-14 g force of mucoadhesion, and the ex vivo studies confirmed that the formulation efficiently adhered to the mucosa. Histopathological analysis combined with fluorescence images and ex vivo intestinal permeation confirmed that the formulation remained on the TGI mucosa for at least 4 h after administration. In vivo studies conducted in a murine model of intestinal mucositis demonstrated that the 16% PF127 BUD formulation was able to resolve the inflammatory injury in the intestinal mucosa. Results demonstrate that fine-tuning of PF127 formulations along with adequate selection of the drug agent, thorough characterization of the dispersions and their interactions with biological interfaces leads to the development of effective controlled drug delivery systems targeted to GI inflammatory diseases.

Tolmetin sodium-loaded thermosensitive mucoadhesive liquid suppositories for rectal delivery; strategy to overcome oral delivery drawbacks

Tolmetin sodium (TS) is a nonsteroidal anti-inflammatory drug (NSAID) indicated for treatment of musculoskeletal issues. As other NSAID, TS displays a marked side effects on the gastro-intestinal (GI) tract after oral administration. Traditional solid suppositories can cause pain and discomfort for patients, may reach the end of the colon; consequently, the drug can undergo the first-pass effect. TS liquid suppository (TS-_LS) was developed to enhance patient compliance and rectal mucosal safety in high-risk patients receiving highly NSAID therapy. This work was conducted to optimize and evaluate Poloxamer P407/P188-based thermoresponsive TS-_LS by using mucoadhesive polymers such as methylcellulose (MC). TS-_LS was prepared by cold method and characterized their in vitro physicochemical properties as gelation temperature (GT), gel strength, bioadhesive properties, and in vitro release. The safety of the prepared suppository on rectum, stomach, and liver was evaluated histologically. Pharmacokinetic analyses were performed to compare rectal TS-_LS to orally Rhumtol^® capsules. The results showed that the optimized TS-_LS; composed of P407/P188/MC (21/9/0.5% w/w) displayed gelation at rectum temperature ∼32.90 °C, gel strength of 21.35 s and rectal retention force at the administration site of 24.25 × 10² dyne/cm². Moreover, TS-_LS did not cause any morphological damage to the rectal tissues. Pharmacokinetic parameters of optimized TS-_LS formulation revealed 4.6 fold increase in bioavailability as compared to Rhumtol^® capsules. Taken together, the results demonstrated that liquid suppository is a potential and physically safe rectal delivery carrier for improvement rectal bioavailability and in vivo safety of TS.