Preparation and Characterization of Theophylline Controlled Release Matrix System Incorporating Poloxamer 407, Stearyl Alcohol, and Hydroxypropyl Methylcellulose: A Novel Formulation and Development Study

BACKGROUND

Theophylline (THN), a bronchodilator with potential applications in emerging conditions like COVID-19, requires a controlled-release delivery system due to its narrow therapeutic range and short half-life. This need is particularly crucial as some existing formulations demonstrate impaired functionality. This study aims to develop a new 12-h controlled-release matrix system (CRMS) in the form of a capsule to optimize dosing intervals.

METHODS

CRMSs were developed using varying proportions of poloxamer 407 (P-407), stearyl alcohol (STA), and hydroxypropyl methylcellulose (HPMC) through the fusion technique. Their in vitro dissolution profiles were then compared with an FDA-approved THN drug across different pH media. The candidate formulation underwent characterization using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Additionally, a comprehensive stability study was conducted.

RESULTS

In vitro studies showed that adjusting the concentrations of excipients effectively controlled drug release. Notably, the CRMS formulation 15 (CRMS-F15), which was composed of 30% P-407, 30% STA, and 10% HPMC, closely matched the 12 h controlled-release profile of an FDA-approved drug across various pH media. Characterization techniques verified the successful dispersion of the drug within the matrix. Furthermore, CRMS-F15 maintained a consistent controlled drug release and demonstrated stability under a range of storage conditions.

CONCLUSIONS

The newly developed CRMS-F15 achieved a 12 h controlled release, comparable to its FDA-approved counterpart.

A heparin-based nanogel system for redox and pH dual-responsive delivery of cisplatin

Heparin recently has been discovered as a novel anti-cancer agent. The combinations of heparin with other agents was reported not only to reduce the undesired effects of free heparin and increase the cellular uptake of the delivered molecules, but also is the basis for the design and development of multi-stimulation response systems to improve their killing cancer cell efficiency at the target positions. This study aimed to design a redox and pH dual-responsive anticancer system based on heparin for cisplatin (CPT) therapy. Heparin was first cross-linked with Poloxamer 407 chains via disulfide bridges to form a redox-sensitive system Hep-P407. CPT was then encapsulated into the Hep-P407 system via the complex of Platin and carboxyl groups to form the redox/pH-responsive system CPT@Hep-P407. The obtained Hep-P407 systems were proved and characterized using specific techniques including1H-NMR, zeta potential, Dynamic Light Scattering (DLS) and Fourier-transform infrared spectroscopy. The dual-responsive behavior to redox and pH of CPT@Hep-P407 was proved through DLS, zeta andin vitrorelease analysis meanwhile its cytotoxicity was investigated using Resazurin assay. The CPT@Hep-P407 system is expected to be a promising redox/pH-responsive anticancer system based on heparin for CPT therapy.

Fabricating Polymer/Surfactant/Cyclodextrin Hybrid Particles for Possible Nose-to-Brain Delivery of Ropinirole Hydrochloride: In Vitro and Ex Vivo Evaluation

Ropinirole is a non-ergolinic dopamine agonist used to manage Parkinson's disease and it is characterized by poor oral bioavailability. This study aimed to design and develop advanced drug delivery systems composed of poloxamer 407, a non-ionic surfactant (Tween 80), and cyclodextrins (methyl-β-CD or hydroxy-propyl-β-CD) for possible brain targeting of ropinirole after nasal administration for the treatment of Parkinson's disease. The hybrid systems were formed by the thin-film hydration method, followed by an extensive physicochemical and morphological characterization. The in vitro cytotoxicity of the systems on HEK293 cell lines was also tested. In vitro release and ex vivo mucosal permeation of ropinirole were assessed using Franz cells at 34 °C and with phosphate buffer solution at pH 5.6 in the donor compartment, simulating the conditions of the nasal cavity. The results indicated that the diffusion-controlled drug release exhibited a progressive increase throughout the experiment, while a proof-of-concept experiment on ex vivo permeation through rabbit nasal mucosa revealed a better performance of the prepared hybrid systems in comparison to ropinirole solution. The encouraging results in drug release and mucosal permeation indicate that these hybrid systems can serve as attractive platforms for effective and targeted nose-to-brain delivery of ropinirole with a possible application in Parkinson's disease. Further ex vivo and in vivo studies to support the results of the present work are ongoing.

Development and Characterization of Sulfasalazine Cubosomes for Potential Transdermal Drug Delivery

BACKGROUND

Rheumatoid arthritis is indeed a constant, progressive autoimmune disease that acts on the synovial membrane, distinguished by joint pain, swelling, and tenderness. Sulfasala- zine belongs to BCS Class IV having low solubility and low permeability. To overcome the issue and provide a localized effect Cubosomes were chosen for the transdermal drug delivery system.

OBJECTIVE

The primary objective of this investigation was to pass on sulfasalazine-loaded cubo- somes over the skin to treat rheumatoid arthritis. On the way to overcome this issue of oral sulfasala- zine and provide localized effect, Cubosomes were chosen for the transdermal drug delivery system.

METHODS

Sulfasalazine-loaded cubosomes were prepared by the top-down method using GMO and Poloxamer 407. Different concentrations of lipid and surfactant were used in the formulation using 32 full factorial designs. The prepared formulations were assessed for p.s, z,p, %EE, FTIR, SEM, in- vitro release, ex-vivo permeation, and deposition studies with pH 7.4 phosphate buffer saline.

RESULTS

The particle size varies between 65 nm to 129 nm, while the negative zeta potential ranged from - 18.8 mV to -24.8 mV. The entrapment efficiency was between 87% and 95%. The formulations' in-vitro drug release was carried out for 12 hours. The optimized formulation showed a controlled release of sul- fasalazine and better ex-vivo permeation and deposition properties than sulfasalazine suspension.

CONCLUSION

Overall study findings support the possibility of applying transdermal sulfasalazine- loaded cubosomes to alleviate rheumatoid arthritis.

Formulation development and evaluation of nasal in situ gel of promethazine hydrochloride

OBJECTIVE

The present work aims to develop mucoadhesive thermosensitive nasal in situ gel for Promethazine hydrochloride using quality by design (QbD) approach. It can reduce nasal mucociliary clearance (MCC) and increase residence of the drug on nasal mucosa. This might increase drug absorption to improve bioavailability of the drug as compared to oral dosage form.

SIGNIFICANCE

Promethazine hydrochloride is an antiemetic drug administered by oral, parenteral and rectal routes. These routes have poor patient compliance or low bioavailability. Nasal route is a better alternative as it has large surface area, high drug absorption rate and no first pass effect. Its only limitation is short drug retention time due to MCC. By formulating a mucoadhesive in situ gel, the MCC can be reduced, and drug absorption will be prolonged. Thus, improving bioavailability.

METHOD

In-situ gel was prepared by cold method having material attributes as concentration of Poloxamer 407 (X1) as gelling agent and hydroxypropyl methyl cellulose K4M (X2) as mucoadhesive agent. Critical Quality Attributes (CQA) were gelation temperature, mucoadhesive force and ex-vivo diffusion. Central composite design (CCD) was adopted for optimization.

RESULT

Optimized formulation satisfied all the CQA significant for nasal administration. Moreover, the formulation was found to be stable in accelerated stability studies for 3 months.

CONCLUSION

It can be concluded that since the drug can easily permeate through nasal mucosa and can gain access directly in the brain without undergoing first pass metabolism along with increased residence due to mucoadhesion, mucoadhesive in situ gel has potential to increase drug bioavailability.

Lamotrigine-Loaded Poloxamer-Based Thermo-Responsive Sol-Gel: Formulation, In Vitro Assessment, Ex Vivo Permeation, and Toxicology Study

The present study aimed to prepare, characterize, and evaluate a thermo-responsive sol-gel for intranasal delivery of lamotrigine (LTG), which was designed for sustained drug delivery to treat epilepsy. LTG sol-gel was prepared using the cold method by changing the concentrations of poloxamer 407 and poloxamer 188, which were used as thermo-reversible polymers. The optimized formulations of sol-gel were analyzed for clarity, pH, viscosity, gelation temperature, gelation time, spreadability, drug content, in vitro drug release studies, ex vivo permeation studies, and in vivo toxicological studies. FTIR, XRD, and DSC were performed to determine the thermal stability of the drug and polymers. The prepared formulations had a clear appearance in sol form; they were liquid at room temperature and became gel at temperatures between 31 °C and 36 °C. The pH was within the range of the nasal pH, between 6.2 and 6.4. The drug content was found to be between 92% and 94%. In vitro drug release studies indicated that the formulations released up to 92% of the drug within 24 h. The FTIR, DSC, and XRD analyses showed no interaction between the drug and the polymer. A short-term stability study indicated that the formulation was stable at room temperature and at 4-8 °C. There was a slight increase in viscosity at room temperature, which may be due to the evaporation of the vehicle. A histological study indicated that there were no signs of toxicity seen in vital organs, such as the brain, kidney, liver, heart, and spleen. It can be concluded from the above results that the prepared intranasal sol-gel for the delivery of LTG is safe for direct nose-to-brain delivery to overcome the first-pass effect and thus enhance bioavailability. It can be considered an effective alternative to conventional drug delivery for the treatment of epilepsy.

Factors affecting on in vitro release of miconazole from in situ ocular gel

The reason for conducting this study is to prolong release of miconazole in the ocular site of action by ocular-based gels (OBGs) formulations. The formulation factors affecting on the release from OBG should be studied using various gelling agents in various concentrations to achieve the improvement in retention and residence time in response to prolonged release. In this study, the formulations were prepared using carbopol 940, pectin, sodium alginate, poloxamer 407, and poly(methacrylic acid) at 0.5%, 1%, and 1.5% w/v, respectively. Hydroxypropyl methylcellulose E5 (HPMC E5) 1% was added as thickening agent/viscosity builder. The formulation containing carbopol 940, pectin and sodium alginate at 1.5% w/v, displayed a noticable improvement in viscosity, gelling capacity, and extended release for 7 h in comparison with the reference drug. Overall, the release showed that the sodium alginate with HPMC E5 form in situ gel which had longer time of release reach to 12 h compared with other polymers. the release of miconazole from the OBGs affected significantly by two factors includes gelling capacity and viscosity builder. The novelty of this study is supporting the delivery of ocular drugs through a cornea as an important key of the eye instead of dependence on an internal blood supply using an oral or a parental administration.

Influence of poly-L-ornithine-bile acid nano hydrogels on cellular bioactivity and potential pharmacological applications

Aim: Cellular bioactivity and pathophysiological changes associated with chronic disorders are considered pivotal detrimental factors when developing novel formulations for biomedical applications. Methods: This paper investigates the use of bile acids and synthetic polypeptide poly-L-ornithine (PLO) in formulations and their impacts on a variety of cell lines, with a particular focus on their cellular bioactivity. Results: The hepatic cell line was the most negatively affected by the presence of PLO, while the muscle and beta-pancreatic cell lines did not show as profound of a negative impact of PLO on cellular viability. PLO was the least disruptive regarding mitochondrial function for muscle and beta cells. Conclusion: The addition of bile acids generally decreased mitochondrial respiration and altered bioenergetic parameters in all cell lines.

Effects of Hyperlipidemia on the Pharmacokinetics of Tofacitinib, a JAK 1/3 Inhibitor, in Rats

Tofacitinib, an inhibitor of Janus kinases (JAKs) 1 and 3, has been shown to be effective in the treatment of rheumatoid arthritis. The incidence of hyperlipidemia has been found to be higher in patients with rheumatoid arthritis. The present study therefore investigated the pharmacokinetics of tofacitinib after its intravenous (10 mg/kg) or oral (20 mg/kg) administration in poloxamer-407-induced hyperlipidemic (PHL) rats. The area under the plasma concentration-time curve from zero to infinity (AUC0-∞) after intravenous administration of tofacitinib was 73.5% higher in PHL than in control rats, owing to slower time-averaged nonrenal clearance (CLNR) in the former. Evaluation of in vitro metabolism showed that the intrinsic clearance (CLint) of tofacitinib was 38.6% lower in PHL than in control rats, owing to the decreased protein expression of hepatic cytochrome P450 (CYP) 3A1/2 and CYP2C11 in PHL rats. Similar results were observed in PHL rats after oral administration of tofacitinib. These results were likely due to the decreased CLNR, CLint, and P-glycoprotein (P-gp) expression in the intestines of PHL compared to control rats. Overall, these findings indicated that hyperlipidemia slowed the metabolism of tofacitinib, increasing its plasma concentrations, and that this reduced metabolism was due to alterations in expression of the proteins CYP3A1/2, CYP2C11, and P-gp in the liver and/or intestines of PHL rats.

Role of Bovine Serum Albumin Addition in Micellization and Gel Formation of Poloxamer 407

The combination of the thermoresponsive polymer and protein has demonstrated great promise in its applications in drug delivery and tissue engineering fields. This study described the impact of bovine serum albumin (BSA) on the micellization and sol-gel transition behaviors of poloxamer 407 (PX). The micellization of aqueous PX solutions with and without BSA was examined using isothermal titration calorimetry. In the calorimetric titration curves, the pre-micellar region, the transition concentration region, and the post-micellar region were observed. The presence of BSA had no noticeable impact on critical micellization concentration, but the inclusion of BSA caused the pre-micellar region to expand. In addition to studying the self-organization of PX at a particular temperature, the temperature-induced micellization and gelation of PX were also explored using differential scanning calorimetry and rheology. The incorporation of BSA had no discernible effect on critical micellization temperature (CMT), but it did affect gelation temperature (T_gel) and gel integrity of PX-based systems. The response surface approach illustrated the linear relation between the compositions and the CMT. The major factor affecting the CMT of the mixtures was the concentration of PX. The alteration of the T_gel and the gel integrity were discovered to be a consequence of the intricate interaction between PX and BSA. BSA mitigated the inter-micellar entanglements. Hence, the addition of BSA demonstrated a modulating influence on T_gel and a softening effect on gel integrity. Understanding the influence of serum albumin on the self-assembly and gelation of PX will enable the creation of thermoresponsive drug delivery and tissue engineering systems with controlled gelation temperatures and gel strength.

Caspofungin-Loaded Formulations for Treating Ocular Infections Caused by Candida spp

Fungal keratitis causes corneal blindness worldwide. The treatment includes antibiotics, with Natamycin being the most commonly used; however, fungal keratitis is difficult to treat, so alternative therapies are needed. In situ gelling formulations are a promising alternative; this type of formulation has the advantages of eye drops combined with the advantages of ointments. This study was designed to develop and characterize three formulations containing 0.5% CSP: CSP-O1, CSP-O2, and CSP-O3. CSP is an antifungal drug that acts against a diverse variety of fungi, and Poloxamer 407 (P407) is a polymer of synthetic origin that is able to produce biocompatible, biodegradable, highly permeable gels and is known to be thermoreversible. Short-term stability showed that formulations are best stored at 4 °C, and rheological analysis showed that the only formulation able to gel in situ was CSP-O3. In vitro release studies indicated that CSP-O1 releases CSP most rapidly, while in vitro permeation studies showed that CSP-O3 permeated the most. The ocular tolerance study showed that none of the formulations caused eye irritation. However, CSP-O1 decreased the cornea's transparency. Histological results indicate that the formulations are suitable for use, with the exception of CSP-O3, which induced slight structural changes in the scleral structure. All formulations were shown to have antifungal activity. In view of the results obtained, these formulations could be promising candidates for use in the treatment of fungal keratitis.

Use of factorial design in formulation and evaluation of intrarectal in situ gel of sumatriptan

The study's goal was to create an in situ intrarectal mucoadhesive gel of sumatriptan (SMT) combining mucoadhesive polymer (xyloglucan) and thermosensitive polymers (poloxamer 407 and poloxamer 188) to prolong rectal residence time for treatment of migraines. Nine SMT mucoadhesive rectal in situ gel (RIG) formulas were created by mixing poloxamer 407 (18%, 19%, or 20%) with poloxamer 188 (5%), a mucoadhesive polymer at various doses (0.1, 0.2, and 0.3) as well as SMT (25 mg/ml). The prepared suppositories underwent for mucoadhesive force, gelation temperature, and gelation time. When SMT and mucoadhesive polymer were added to the poloxamer mixture, the gelation temperature dropped; however, poloxamer 188 had the opposite effect. These polymers supported the prepared liquids' ability to adhere to mucous membranes and form a strong gel. The transition gelation temperature of the poloxamer solution rose as a result of the addition of poloxamer 188. The findings showed that the formula RIG5 which is composed of poloxamer 407 (19%), poloxamer 188 (5%), and xyloglucan (0.2%) had an ideal transition temperature of 36.33°C, gel strength of 44.66°C, mucoadhesive force of 6409°C, and in vitro drug release of 93.98% over an 8-hour period. In light of this, it can be said that SMT was successfully manufactured as RIG without causing any chemical reaction with its additives.

Preparation and optimization of surface stabilized cryptotanshinone nanocrystals with enhanced bioavailability

Cryptotanshinone (CTS) is a plant product extracted from Salvia miltiorrhiza Bunge with various pharmacological significances. In addition to its activities against coronary heart disease, hyperlipidemia, stroke, hepatitis and chronic renal failure, it demonstrates antimetastatic effects. However, its clinical use is limited due to its poor aqueous solubility and oral bioavailability. Herein, CTS nanocrystals were prepared with the precipitation method followed by high-pressure homogenization using Poloxamer 407 as the stabilizer. A stable product was further obtained by lyophilization. The particle size of the CTS nanocrystals was 315.67 ± 11.02 nm, and the zeta potential was near 0 mV. The crystallinity was confirmed by DSC and PXRD. The saturation solubility was substantially increased from 0.97 ± 0.12 μg/ml to 62.29 ± 1.91 μg/ml, and the dissolution rate was also significantly accelerated. A pharmacokinetic study in rats revealed an improvement in oral bioavailability (2.87-fold) with CTS nanocrystals compared to the raw drug. In conclusion, the results of this study suggest a feasible formulation for the oral delivery of CTS.

Optimization of an Injectable Hydrogel Depot System for the Controlled Release of Retinal-Targeted Hybrid Nanoparticles

A drawback in the development of treatments that can reach the retina is the presence of barriers in the eye that restrain compounds from reaching the target. Intravitreal injections hold promise for retinal delivery, but the natural defenses in the vitreous can rapidly degrade or eliminate therapeutic molecules. Injectable hydrogel implants, which act as a reservoir, can allow for long-term drug delivery with a single injection into the eye, but still suffer due to the fast clearance of the released drugs when traversing the vitreous and random diffusion that leads to lower pharmaceutic efficacy. A combination with HA-covered nanoparticles, which can be released from the gel and more readily pass through the vitreous to increase the delivery of therapeutic agents to the retina, represents an advanced and elegant way to overcome some of the limitations in eye drug delivery. In this article, we developed hybrid PLGA-Dotap NPs that, due to their hyaluronic acid coating, can improve in vivo distribution throughout the vitreous and delivery to retinal cells. Moreover, a hydrogel implant was developed to act as a depot for the hybrid NPs to better control and slow their release. These results are a first step to improve the treatment of retinal diseases by protecting and transporting the therapeutic treatment across the vitreous and to improve treatment options by creating a depot system for long-term treatments.

Ex vivo study of detergent-assisted intraosseous bone wash treatment of osteonecrosis

Avascular necrosis (AVN) involves ischemic cell death of the bone. AVN leaves an abundance of necrotic lipids and debris in the bone marrow, which instigates inflammatory bone repair. Consequently, the necrotic bone microenvironment stimulates excessive bone resorption, leading to joint deformities and osteoarthritis. Here, we performed a detergent-assisted bone wash using poloxamer 407 (P407) to clean the necrotic bone environment by removing lipids and necrotic debris. The new concept was tested using an established ex vivo AVN model of porcine cadaver humeral heads. The P407 wash was performed using P407 solution and followed with saline via two intraosseous needles. Visual inspection and image analyses of average pixel light intensity showed that the P407 wash produced a better-cleaned bone than the saline wash. Analyses of the collected bone wash solution showed a two-fold increase in triglycerides (101 vs. 53 mmol/head, p = 0.006) and a 10-fold increase in the dry weight of the removed debris (1.34 vs. 0.13 g/head, p = 0.02) with the P407 wash compared to saline. The histological evaluation showed significantly decreased Oil-Red-O (fats) staining in the P407-washed bone compared with the saline-washed bone. The in vitro assays of Alizarin red and qPCR showed the P407 wash neither altered the osteogenic behaviors of porcine bone marrow-derived mesenchymal cells (pBMMCs) nor raised inflammatory responses of porcine bone marrow-derived macrophages (pBMMs). In conclusion, detergent-assisted bone wash using P407 produced a better removal of nonsoluble debris from the bone marrow space than the saline wash without causing changes to osteogenesis or inflammatory reactions.

Thermosensitive Hydrogel Wound Dressing Loaded with Bacteriophage Lysin LysP53

Wound infections are prone to attacks from infectious pathogens, including multidrug resistant bacteria that render conventional antimicrobials ineffective. Recently, lysins have been proposed as alternatives to conventional antimicrobials to tackle the menace of multidrug resistance pathogens. The coupling of lysins with a material that will cover the wound may prove beneficial in both protecting and treating wound infections. Hence, in this study, a Gram-negative lysin, LysP53, was coupled with a thermosensitive hydrogel, poloxamer P407, and its efficacy to treat wound infection was tested. In vitro, the addition of LysP53 to the poloxamer did not affect its thermosensitive characteristics, nor did it affect the hydrogel structure. Moreover, the lysin hydrogel could hydrolyze the peptidoglycan, demonstrating that it may have bactericidal activity. Up to 10.4% of LysP53 was released from the hydrogel gradually within 24 h, which led to a 4-log reduction of stationary phase Acinetobacter baumannii. Lastly, the lysin hydrogel was found safe with no cytotoxic effects observed in cells. Ex vivo, LysP53 hydrogel could inhibit bacterial growth on a pig skin decolonization model, with 3-log differences compared to non-treated groups. Overall, our results suggest that lysin-loaded hydrogels may provide a novel solution to treat wound infections caused by resistant bacteria.

Design and Optimization of In Situ Gelling Mucoadhesive Eye Drops Containing Dexamethasone

Poor bioavailability of eye drops is a well-known issue, which can be improved by increasing the residence time on the eye surface and the penetration of the active pharmaceutical ingredient (API). This study aims to formulate in situ gelling mucoadhesive ophthalmic preparations. To increase the residence time, the formulations were based on a thermosensitive polymer (Poloxamer 407 (P407)) and were combined with two types of mucoadhesive polymers. Dexamethasone (DXM) was solubilized by complexation with cyclodextrins (CD). The effect of the composition on the gel structure, mucoadhesion, dissolution, and permeability was investigated with 3³ full factorial design. These parameters of the gels were measured by rheological studies, tensile test, dialysis membrane diffusion, and in vitro permeability assay. The dissolution and permeability of the gels were also compared with DXM suspension and CD-DXM solution. The gelation is strongly determined by P407; however, the mucoadhesive polymers also influenced it. Mucoadhesion increased with the polymer concentration. The first phase of drug release was similar to that of the CD-DXM solution, then it became prolonged. The permeability of DXM was significantly improved. The factorial design helped to identify the most important factors, thereby facilitating the formulation of a suitable carrier for the CD-DXM complex.

Evaluation of Usnea barbata (L.) Weber ex F.H. Wigg Extract in Canola Oil Loaded in Bioadhesive Oral Films for Potential Applications in Oral Cavity Infections and Malignancy

Usnea lichens are known for their beneficial pharmacological effects with potential applications in oral medicine. This study aims to investigate the extract of Usnea barbata (L.) Weber ex F.H. Wigg from the Călimani Mountains in canola oil as an oral pharmaceutical formulation. In the present work, bioadhesive oral films (F-UBO) with U. barbata extract in canola oil (UBO) were formulated, characterized, and evaluated, evidencing their pharmacological potential. The UBO-loaded films were analyzed using standard methods regarding physicochemical and pharmacotechnical characteristics to verify their suitability for topical administration on the oral mucosa. F-UBO suitability confirmation allowed for the investigation of antimicrobial and anticancer potential. The antimicrobial properties against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27353, Candida albicans ATCC 10231, and Candida parapsilosis ATCC 22019 were evaluated by a resazurin-based 96-well plate microdilution method. The brine shrimp lethality assay (BSL assay) was the animal model cytotoxicity prescreen, followed by flow cytometry analyses on normal blood cells and oral epithelial squamous cell carcinoma CLS-354 cell line, determining cellular apoptosis, caspase-3/7 activity, nuclear condensation and lysosomal activity, oxidative stress, cell cycle, and cell proliferation. The results indicate that a UBO-loaded bioadhesive film’s weight is 63 ± 1.79 mg. It contains 315 µg UBO, has a pH = 6.97 ± 0.01, a disintegration time of 124 ± 3.67 s, and a bioadhesion time of 86 ± 4.12 min, being suitable for topical administration on the oral mucosa. F-UBO showed moderate dose-dependent inhibitory effects on the growth of both bacterial and fungal strains. Moreover, in CLS-354 tumor cells, F-UBO increased oxidative stress, diminished DNA synthesis, and induced cell cycle arrest in G0/G1. All these properties led to considering UBO-loaded bioadhesive oral films as a suitable phytotherapeutic formulation with potential application in oral infections and neoplasia.

Poloxamer 407 Induces Hypertriglyceridemia but Decreases Atherosclerosis in Ldlr-/- Mice

Background: Hypertriglyceridemia (HTG) increases the risk for atherosclerotic cardiovascular disease, but underlying mechanisms are incompletely understood. Circulating monocytes play an important role in atherogenesis by infiltrating arterial walls, where they differentiate into macrophages. We tested the hypothesis that HTG is mechanistically linked to atherogenesis by altering the monocyte phenotype and infiltration into atherosclerotic lesions in a model of diet-induced atherogenesis in Ldlr^−/− mice. Methods: HTG was induced in male Ldlr^−/− mice, fed a Western, high-fat high-cholesterol diet, by daily injection of poloxamer 407 (P407), a lipoprotein lipase inhibitor, for seven weeks. Atherosclerosis, monocyte phenotypes, and monocyte migration into atherosclerotic lesions were determined by well-validated methods. Results: Compared with the saline control, P407 injection in Ldlr^−/− mice rapidly induced profound and persistent HTG, modestly elevated plasma cholesterol levels, and increased levels of triglyceride and cholesterol carried in very-low-density lipoprotein and low-density lipoprotein. Unexpectedly, mice receiving P407 versus saline control showed less atherosclerosis. Following induction of HTG by P407, CD36⁺ (also CD11c⁺), but not CD36⁻ (CD11c⁻), monocytes showed early increases in lipid accumulation, but the number of CD36⁺ (not CD36⁻) monocytes was dramatically decreased afterwards in the circulation until the end of the test. Concurrently, CD36⁺ (CD11c⁺) monocyte migration into atherosclerotic lesions was also reduced in mice receiving P407 versus controls. Conclusions: P407 induced severe HTG, but reduced atherosclerosis, in Ldlr^−/− mice, possibly because of profound reductions of circulating CD36⁺ (CD11c⁺) monocytes, leading to decreased monocyte migration into atherosclerotic lesions.

A novel thermosensitive poloxamer-hyaluronic acid- kappa-carrageenan-based hydrogel anti-adhesive agent loaded with 5-fluorouracil: a preclinical study in Sprague-Dawley rats

Although the first-choice treatment for colorectal cancer is cytoreductive surgery combined with chemotherapy, post-surgical peritoneal adhesion and extant malignancy can cause fatal complications. Studies examining hydrogel-based postoperative anti-adhesion treatments are still limited. In this study, several formulations of 5-fluorouracil (5-FU) loaded into hyaluronic acid (HA) and kappa-carrageenan (kCGN)-poloxamer 407 (P407)-based cross-linked hydrogels were prepared and evaluated in vitro and in vivo for their efficacy in preventing adhesion. These hydrogels met a set of desired specifications such as thermosensitive behavior, strong elasticity at body temperature (tan δ < 1.0 at 37°C), and ability to encapsulate hydrophilic drug and deliver it in a sustained released manner. Our secondary purpose is to provide in situ 5-FU for additional local antitumor effect when the anti-adhesion agent is spread over the tumor site. Over 60% of the total loaded drug was released within 4 hours, and about 80% of 5-FU was released after three days. Both the Higuchi and Korsmeyer-Peppas models showed that the mechanism of sustained drug release involved diffusion. The constructed hydrogels were evaluated for in vivo intra-abdominal anti-adhesion barrier efficiency; the HA/kCGN 1%/3% w/v hydrogel formulation showed the best anti-adhesion effect in this preclinical study using Sprague-Dawley rat models.

Thermoresponsive sol-gel containing probiotic's cell free supernatant for dental caries prophylaxis

Background

Lactobacillus rhamnosus SD11 is a probiotic derived from the human oral cavity and has potential being used for dental prophylaxis. The cell free supernatant (CFS) of L. rhamnosus SD11 has good antimicrobial and antioxidant effects.

Aim

This study aimed to incorporate CFS of the probiotic into thermoresponsive copolymers to create a sol–gel formulation.

Methods

The sol–gel formulation was developed using Poloxamer 407 as the main polymer, which was mixed with natural polymers such as gellan gum, sodium alginate, and xyloglucan in different proportions. The sol–gel formulations were characterized based on their physicochemical parameters such as appearance, pH, viscosity, flow-ability in low temperature, antioxidant and antibacterial activity. An in vitro release study was performed using Franz’s diffusion cell and the stability was determined under freeze-thaw cycle conditions.

Results

The combination of 15% w/v of poloxamer 407 with 0.5% w/v of sodium alginate was the best sol–gel formulation to deliver the CFS of the probiotic.

Conclusion

This study was successful in creating a sol–gel formulation using a thermoresponsive copolymer, that could efficiently deliver CFS of the probiotic L. rhamnosus SD11.

The Investigation of Thymol Formulations Containing Poloxamer 407 and Hydroxypropyl Methylcellulose to Inhibit Candida Biofilm Formation and Demonstrate Improved Bio-Compatibility

The aim of this study was to investigate the potential of thymol to inhibit Candida biofilm formation and improve thymol biocompatibility in the presence of hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (P407), as possible drug carriers. Thymol with and without polymers were tested for its ability to inhibit biofilm formation, its effect on the viability of biofilm and biocompatibility studies were performed on HEK 293 (human embryonic kidney) cells. Thymol showed a concentration dependent biofilm inhibition; this effect was slightly improved when it was combined with HPMC. The Thymol-P407 combination completely inhibited the formation of biofilm and the antibiofilm effect of thymol decreased as the maturation of Candida biofilms increased. The effect of thymol on HEK 293 cells was a loss of nearly 100% in their viability at a concentration of 250 mg/L. However, in the presence of P407, the viability was 25% and 85% using neutral red uptake and sulforhodamine B assays, respectively. While, HPMC had less effect on thymol activity the thymol-P407 combination showed a superior inhibitory effect on biofilm formation and better biocompatibility with human cell lines. The combination demonstrates a potential medical use for the prevention of Candida biofilm formation.

Sustained Delivery of Lactoferrin Using Poloxamer Gels for Local Bone Regeneration in a Rat Calvarial Defect Model

Lactoferrin (LF) is a multifunctional milk glycoprotein that promotes bone regeneration. Local delivery of LF at the bone defect site is a promising approach for enhancement of bone regeneration, but efficient systems for sustained local delivery are still largely missing. The aim of this study was to investigate the potential of the poloxamers for sustained delivery of LF to enhance local bone regeneration. The developed LF/poloxamer formulations were liquid at room temperature (20 °C) transforming to a sustained releasing gel depot at body temperature (37 °C). In vitro release studies demonstrated an initial burst release (~50%), followed by slower release of LF for up to 72 h. Poloxamer, with and without LF, increased osteoblast viability at 72 h (p < 0.05) compared to control, and the immune response from THP-1 cells was mild when compared to the suture material. In rat calvarial defects, the LF/poloxamer group had lower bone volume than the controls (p = 0.0435). No difference was observed in tissue mineral density and lower bone defect coverage scores (p = 0.0267) at 12 weeks after surgery. In conclusion, LF/poloxamer formulations support cell viability and do not induce an unfavourable immune response; however, LF delivery via the current formulation of LF200/poloxamer gel did not demonstrate enhanced bone regeneration and was not compatible with the rat calvarial defect model.

Poloxamer 407-Based Thermosensitive Emulgel as a Novel Formulation Providing a Controlled Release of Oil-Soluble Pharmaceuticals-Ibuprofen Case Study

This article covers the design and evaluation of a novel drug vehicle: a thermosensitive, injectable, high-oil-content (50% w/w) emulgel providing a controlled release of lipophilic pharmaceuticals. Different vegetable (castor, canola, olive, peanut, grapeseed, linseed), mineral (paraffin) and semisynthetic (isopropyl myristate, oleic acid) oils were screened for ibuprofen (IBU) solubility and for their capacity for high-shear emulsification in a 17% (w/w) aqueous solution of poloxamer 407. Chosen emulgels were subject to a rheological evaluation, a syringeability test (TA.XT texture analyser; 2 mL syringe; 18 G, 20 G and 22 G needles) and a drug release study (48 h; cellulose membrane; 0.05 mol/L phosphate buffer at pH 7.4). Castor oil turned out to be an optimal component for IBU incorporation. Blank and drug-loaded castor oil emulgels were susceptible to administration via a syringe and needle, with the absolute injection force not exceeding 3 kg (29.4 N). The drug release test revealed dose-dependent, quasi-linear kinetics, with up to 44 h of controlled, steady, linear release. The results indicate the significant potential of high-oil-content, oil-in-water thermosensitive emulgel formulations as vehicles for the controlled release of lipophilic APIs.

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.

Development of a sterile morphine hydrogel for the local treatment of painful skin ulcers

OBJECTIVES

It is often difficult to relieve the pain from skin ulcers. In several patients, topical morphine, applied as a hydrogel, has been described as useful. There is no such product commercially available. We present a solution for compounding, packaging, sterilisation and chemical stability of a morphine containing hydrogel.

METHODS

We developed a morphine containing poloxamer 407 thermoreversible hydrogel with a concentration of 5 mg/g (0.5% w/w) morphine hydrochloride. The hydrogel was packaged into a plastic prefillable syringe system: BD Sterifill SCF. This syringe can be steam sterilised after it has been filled.

RESULTS

Sterility tests according to the European Pharmacopoeia showed the product to be sterile directly after production and sterilisation and after 20 months of storage. The stability of the morphine hydrochloride was assessed by monthly analysis of the concentration with a stability indicating HPLC-UV method. Morphine hydrochloride concentrations remained between 90% and 110% of the theoretical concentration for a period of 36 months, when stored at room temperature outside the influence of light.

CONCLUSION

With the described formulation, packaging, sterilisation and stability data, together with the previously reported biopharmaceutical dissolution profile, we present a complete solution for a morphine containing poloxamer 407 hydrogel that can be compounded in any pharmacy with a steam or hot water steriliser at their disposal. This might improve the availability of a sterile morphine hydrogel for the treatment of painful skin ulcers.

Thermosensitive Hydrogel Harboring CD146/IGF-1 Nanoparticles for Skeletal-Muscle Regeneration

In skeletal-muscle regeneration, it is critical to promote efferocytosis of immune cells and differentiation of satellite cells/postnatal muscle stem cells at the damaged sites. With the optimized poloxamer 407 composition gelled at body temperature, the drugs can be delivered locally. The purpose of this study is to develop a topical injection therapeutic agent for muscle regeneration, sarcopenia, and cachexia. Herein, we construct an injectable, in situ hydrogel system consisting of CD146, IGF-1, collagen I/III, and poloxamer 407, termed CIC gel. The secreted CD146 then binds to VEGFR2 on the muscle surface and effectively induces efferocytosis of neutrophils and macrophages. IGF-1 promotes satellite cell differentiation, and biocompatible collagen evades immune responses of the CIC gel. Consequently, these combined molecules activate muscle regeneration via autophagy and suppress muscle inflammation and apoptosis. Conclusively, we provide an applicable concept of the myogenesis-activating protein formulation, broadening the thermoreversible hydrogel to protein therapeutics for damaged muscle recovery.

Thermosensitive Poloxamer-graft-Carboxymethyl Pullulan: A Potential Injectable Hydrogel for Drug Delivery

A thermosensitive copolymer composed of amphiphilic triblock copolymer, poloxamer 407, grafted on hydrophilic pullulan with pendant carboxymethyl groups (CMP) was prepared and characterized. The structure of the new copolymer was assessed by Fourier transform infrared (FT-IR) and ¹H nuclear magnetic resonance (¹H NMR) spectroscopy. The content of the poloxamer in the grafted copolymer was 83.8% (w/w). The effect of the copolymer concentration on the gelation behavior was analyzed by the vertical method and rheological tests; the gel phase of the copolymer occurred at a lower concentration (11%, w/v) as compared with poloxamer (18%, w/v). The starting gelation time under the simulated physiological conditions (phosphate buffer with a pH of 7.4, at 37 °C) was sensitive on the rest temperature before the test, this being 990 s and 280 s after 24 h rest at 4 °C and 20 °C, respectively. The rheological tests evidenced a high elasticity and excellent ability of the copolymer to recover the initial structure after the removal of the applied force or external stimuli. Moreover, the hydrogel has proved a sustained release of amoxicillin (taken as a model drug) over 168 h. Taken together, the results clearly indicate that this copolymer can be used as an injectable hydrogel.

Development of thermosensitive poloxamer 407-based microbubble gel with ultrasound mediation for inner ear drug delivery

ABSTRACTSOur previous study first investigated feasibility of applying ultrasound (US) and microbubbles (MBs) via external auditory canal to facilitate drug delivery into inner ear. However, most drugs are in aqueous formulae and eliminated via Eustachian tubes after drug application. In this study, feasibility of sustained release of thermosensitive poloxamer 407 (P407)-based MB gel for US mediation-enhanced inner ear drug (dexamethasone, DEX) delivery was investigated. The sol-to-gel transition temperature showed that mixture of DEX and only 10% and 12.5% P407 in MBs can be used for in vitro and in vivo drug delivery experiments. In in vitro Franz diffusion experiments, the release rates of 12.5% P407-MBs + US groups in the model using DEX as the delivered reagent at 3 h resulted in values 1.52 times greater than those of 12.5% P407-MBs groups. In guinea pigs, by filling tympanic bulla with DEX in 12.5% P407-MBs (DEX-P407-MBs), USMB applied at post-treatment days 1 and 7 induced 109.13% and 66.67% increases in DEX delivery efficiencies, respectively, compared to the group without US. On the 28th day after US-mediated P407-MB treatment, the safety assessment showed no significant changes in the hearing thresholds and no damage to the integrity of cochlea or middle ear. These are the first results to demonstrate feasibility of US-modified liquid form DEX-P407-MB cavitation for enhancing permeability of round window membrane. Then, a gel form of DEX-P407-MBs was generated and thus prolonged the release of DEX in middle ear to maintain the therapeutic DEX level in inner ear for at least 7 days.

Enhancement of the Mechanical and Drug-Releasing Properties of Poloxamer 407 Hydrogels with Casein

PURPOSE

Topical therapy of local disease (e.g. skin) is advantageous over oral therapy since there is less systemic drug distribution (so fewer side-effects), no first-pass effect, etc. However, patient compliance with topical therapy can be poor as it may require many applications a day and can last months. Here we propose a topical controlled release formulation with thermoresponsive gelation at body temperature and improved adhesiveness, making it easier to remain in contact with the body.

METHODS

The formulation contains two excipients, poloxamer 407 (P407) and casein. Casein can modify the properties of the hydrogel through molecular entanglement. In addition, tissue reaction and drug release profile were evaluated.

RESULTS

Changes in casein concentration affected adhesive strength, viscosity, mechanical properties and drug release, presumably by hydrophobic interactions between casein and P407. Two different concentrations of P407 were tested with two different concentrations of casein. Formulations containing 5% and 10% casein released 80% of model drug in 48 h, while formulations without casein released the same fraction in around 24 h hours. Formulations with 10% casein had almost twice the adhesive strength of those without casein.

CONCLUSIONS

Addition of casein modified the mechanical properties and drug release rate of the hydrogel. There was no inflammation or injury after brief exposure in vivo.

Curcumin micelles entrapped in eudragit S-100 matrix: a synergistic strategy for enhanced oral delivery

Background:

Therapeutic activities of curcumin (CUR) via oral administration are hampered by the lack of bioavailability due to its poor water solubility and rapid degradation in GI tract.

Materials & methods:

This preliminary study developed CUR micelle-eudragit S100 (EUD) dry powder (CM-EDP) spray-dried formulations. Poloxamer 407 was used as a micelle-forming agent and EUD as an entrapping matrix for protection over hydrolysis and enzymes in the GI tract.

Results:

The morphology of CM-EDP showed agglomeration with cratering on the surface of particles. Differential thermal analysis and x-ray diffractometry data exhibited evidence that CUR was converted into amorphous solid. An increased concentration of micelle-forming and dispersion matrix polymers resulted in a high fraction of drug being converted into the amorphous state. A significant increase in dissolution by 7–10 times was achieved compared with that of raw CUR.

Conclusion:

The present study disclosed the CM-EDP potency for future development of CUR oral formulation.

Curcumin (CUR) is a natural compound that shows several pharmacological activities, including anti-inflammatory and potential actions against Parkinson’s and Alzheimer’s. However, several drawbacks need to be addressed its application as a therapeutic agent via oral administration. These drawbacks include its poor water solubility and rapid degradation in the GI tract. The present study developed CUR micelle-eudragit S100 (EUD) dry powder formulation involving poloxamer 407 as solubilizing agent and EUD as entrapping matrix for protection in acidic environments and the enzymes in the GI tract. The final product is in the form of dry powder, which showed potency in enhancing CUR absorption following oral administration.

Generation of SARS-CoV-2 Spike Pseudotyped Virus for Viral Entry and Neutralization Assays: A 1-Week Protocol

The COVID-19 pandemic caused by the SARS-CoV-2 coronavirus requires reliable assays for studying viral entry mechanisms which remains poorly understood. This knowledge is important for the development of therapeutic approaches to control SARS-CoV-2 infection by permitting the screening for neutralizing antibodies and other agents that can block infection. This is particularly important for patients who are at high risk for severe outcomes related to COVID-19. The production of pseudotyped viral particles may seem like a daunting task for a non-virology laboratory without experience in the two most commonly used pseudotyping systems, namely retro/lentiviruses and vesicular stomatitis virus (VSV) which lacks the VSV envelope glycoprotein (VSVΔG). By incorporating the most up-to-date knowledge, we have developed a detailed, easy-to-follow novel protocol for producing SARS-CoV-2 spike-bearing pseudovirus using the VSV-ΔG system. We describe the infection assay which uses GFP fluorescence as a measure of infection in a 24-well live imaging system. We present results of our optimization of the system to enhance viral infection levels through the over-expression of human ACE2 receptor and the overexpression of at least one of two proteases - TMPRSS2 or Furin, as well as, supplementation with Poloxamer 407 (P407) and Prostaglandin E2 (PGE2) as adjuvants. We show that the system works efficiently in three unrelated, clinically relevant cell lines: human 293T (renal epithelial) cells, human Calu-3 (lung epithelial) cells, and the non-human primate (African Green Monkey) cell line, Vero-E6 (renal epithelial) cells. In addition, we have used this system to show infection of human induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs). This system is efficient (virus generation, titration, and infection assays can be performed in 1 week), quantitative, inexpensive, and readily scalable for application in drug development and therapeutic screening approaches.

Melatonin nanogel promotes skin healing response in burn wounds of rats

Aim: Development of a melatonin nanogel intended for wound healing (WH) application. Materials & methods: The main components of the nanogel were poloxamer 407, chitosan and hyaluronic acid. The nanogel was characterized by the assessment of physical interactions, swelling, wettability, rheological properties and internal structure. The drug release, antimicrobial efficacy against different strains and biocompatibility with human keratinocytes were also tested. Finally, the WH efficacy was evaluated in rats. Results: The nanogel showed optimal physicochemical properties and an internal network of interconnected channels from which melatonin was released following first order kinetics. Antimicrobial activity was similar to commercial reference material and it promoted epidermis growth with evident wound contraction. Conclusion: Melatonin nanogel can be proposed as a promising system for WH.

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.

Thermoresponsive systems composed of poloxamer 407 and HPMC or NaCMC: mechanical, rheological and sol-gel transition analysis

Poloxamer 407 (polox407) is widely studied as thermogelling polymer, transitioning to a gel state when warmed Polox407 forms weak hydrogels with rapid dissolution in excess solvent. This study reports the development of binary systems composed of polox407 and hydroxypropyl methylcellulose (HPMC) or sodium carboxymethylcellulose (NaCMC) aiming to improve the rheological and mechanical properties of the hydrogel. The interaction between polox407 and cellulose derivatives was studied, and their interaction with biological surfaces predicted. The carbohydrates affected the mechanical and rheological behavior of polox407 in different ways, dependent on polymer type, concentration, and temperature. T_sol/gel and rheological interaction parameters were useful to select the most suitable formulations for topical or local application. Most of the binary systems exhibited plastic behavior, thixotropy and viscoelastic properties. Appropriate formulations were identified for local application, such as 17.5/3; 17.5/4; 20/3 and 20/4 (%, w/w) for polox407/HPMC; and 17.5/1; 17.5/1.5; 20/1 and 20/1.5 (%, w/w) for polox407/NaCMC.

Expert design and desirability function approach for the development of diazepam thermally sensitive rectal gel

Aim: The aim of the present work was to develop an in situ thermosensitive rectal gel for diazepam by using Expert-design for improving three factors and a three-level process was formed by using a cold method. Methods & materials: Response surface design was utilized to investigate the effect of independent variables like sodium chloride (NaCl, X1), poloxamer 407 (F-127, X2) and diazepam (X3), on different dependent variables such as gelation temperature, mucoadhesive strength, drug content, along with permeation and stability. Results: The obtained results revealed that the addition of diazepam enhanced the gelation temperature of hydrogel while it decreased the gel strength and mucoadhesive force. Conclusion: It is suggested that in situ hydrogels may be suitable candidates for rectal delivery.

Design of a nanostructured mucoadhesive system containing curcumin for buccal application: from physicochemical to biological aspects

Mucoadhesive nanostructured systems comprising poloxamer 407 and Carbopol 974P® have already demonstrated good mucoadhesion, as well as improved mechanical and rheological properties. Curcumin displays excellent biological activity, mainly in oral squamous cancer; however, its physicochemical characteristics hinder its application. Therefore, the aim of this study was to develop nanostructured formulations containing curcumin for oral cancer therapy. The photophysical interactions between curcumin and the formulations were elucidated by incorporation kinetics and location studies. They revealed that the drug was quickly incorporated and located in the hydrophobic portion of nanometer-sized polymeric micelles. Moreover, the systems displayed plastic behavior with rheopexy characteristics at 37 °C, viscoelastic properties and a gelation temperature of 36 °C, which ensures increased retention after application in the oral cavity. The mucoadhesion results confirmed the previous findings with the nanostructured systems showing a residence time of 20 min in porcine oral mucosa under flow system conditions. Curcumin was released after 8 h and could permeate through the porcine oral mucosa. Cytotoxicity testing revealed that the formulations were selective to cancer cells over healthy cells. Therefore, these systems could improve the physicochemical characteristics of curcumin by providing improved release and permeation, while selectivity targeting cancer cells.

Ex Vivo Conjunctival Retention and Transconjunctival Transport of Poorly Soluble Drugs Using Polymeric Micelles

This paper addresses the problem of ocular delivery of lipophilic drugs. The aim of the paper is the evaluation of polymeric micelles, prepared using TPGS (d-α-Tocopheryl polyethylene glycol 1000 succinate), a water-soluble derivative of Vitamin E and/or poloxamer 407, as a vehicle for the ocular delivery of dexamethasone, cyclosporine, and econazole nitrate. The research steps were: (1) characterize polymeric micelles by dynamic light scattering (DLS) and X-ray scattering; (2) evaluate the solubility increase of the three drugs; (3) measure the in vitro transport and conjunctiva retention, in comparison to conventional vehicles; (4) investigate the mechanisms of enhancement, by studying drug release from the micelles and transconjunctival permeation of TPGS; and (5) study the effect of micelles application on the histology of conjunctiva. The data obtained demonstrate the application potential of polymeric micelles in ocular delivery, due to their ability to increase the solubility of lipophilic drugs and enhance transport in and across the conjunctival epithelium. The best-performing formulation was the one made of TPGS alone (micelles size ≈ 12 nm), probably because of the higher mobility of these micelles, an enhanced interaction with the conjunctival epithelium, and, possibly, the penetration of intact micelles.

Structural characterization and hypolipidemic activities of purified stigma maydis polysaccharides

This study aimed to investigate structural features and antihyperlipidemic effects of the stigma maydis polysaccharide, termed SMP-1. This polysaccharide was composed of D-mannose, L-rhamnose, D-glucose, D-galactose, L-arabinose, D-xylose, and D-galacturonic acid, with a molar ratio of 1.00:0.21:1.41:1.44:0.70:0.44:0.56. The SMP-1 was mainly bonded by (1 → 6) and (1 → 3) linkages, with various monosaccharides being evenly distributed in the main and side chains. Moreover, SMP-1 had neither triple-helical structure nor molecular aggregation. Importantly, the SMP-1 could effectively bind the bile acids in vitro and significantly lower the total cholesterol, triglyceride, low-density lipoprotein cholesterol levels, and moderately increase the high-density lipoprotein cholesterol level in poloxamer 407-induced hyperlipidemic mice. Moreover, pretreatment with SMP-1 (≥300 mg/kg) could remarkably reduce fat accumulation and restore hepatocyte morphology in the liver of hyperlipidemic mice. Altogether, these findings indicated that SMP-1 could be developed as a safe and effective food supplement for preventing and treating hyperlipidemic disorders.

Thermoreversible Gel-Loaded Amphotericin B for the Treatment of Dermal and Vaginal Candidiasis

The present study was designed to develop a thermoreversible gel of Pluronic (P407) loaded amphotericin B (AmB-gel) for the dermal and vaginal treatment of candidiasis. P407 was used as a copolymer to exploit potential advantages related to increasing drug concentration in the tissue layer in order to provide a local effect. Parameters including internal structure, swelling, porosity, and short-term stability were determined. In addition, drug release profile and ex vivo skin and vaginal permeation studies were carried out. Antifungal efficacy was evaluated against strains of Candida spp. and atomic force microscopy (AFM) supported the results. The tolerance of AmB-gel was studied by evaluating biomechanical properties of skin and determining the irritation level in scarified rabbit skin supported by histological analysis. Results confirmed the development of a thermoreversible AmB-gel with high porosity exhibiting Newtonian behavior at 4 °C and pseudoplasticity at 32 °C as well as optimal stability for at least 90 days. The Amb-gel provided a sustained drug release following a Boltzmann sigmoidal model. Non permeation was observed in skin and vaginal mucosa, showing a high retained amount of AmB of 960.0 and 737.3 µg/g/cm², respectively. In vitro antifungal efficacy showed that AmB-gel was more effective than Free-AmB in inhibiting strains of Candida spp. and these results were corroborated by AFM. Finally, tolerance studies showed that its application did not induce skin irritation nor alter its biophysical properties. Together, these results confirmed that AmB-gel could be proposed as a promising candidate for the clinical status in the treatment of skin and vaginal candidiasis.

Effect of the hyaluronic acid-poloxamer hydrogel on skin-wound healing: in vitro and in vivo studies

BACKGROUND

Recent research into skin injury and wound healing has focused mainly on post-trauma hemostasis, infection prevention, dermal regeneration and angiogenesis. However, less attention has been paid to air permeability and moisture loss prevention which also play important roles in injury healing.

METHODS

In the present work, we prepared a hyaluronic acid-poloxamer (HA-POL) hydrogel and tested the therapeutic effect of the hydrogel on skin-wound healing.

RESULTS

The HA-POL hydrogel transformed from sol to gel at 30°C, close to body temperature, and had stable moisturizing properties. HA-POL hydrogel promoted skin-wound healing and increased protein accumulation in the wound area. HA-POL hydrogel allowed greater air permeability than Band-aid, a typical wound covering. Results from transwell assays showed that the HA-POL hydrogel effectively isolated skin-wounds from bacterial invasion.

CONCLUSION

This work demonstrates the advantages of using HA-POL gel materials in the treatment of cutaneous wounds.

Addition of free poloxamer 407 to a new gene vector P407-PEI-K12 solution forms a sustained-release in situ hypergel that enhances cell transfection and extends gene expression

To address the concern around the efficiency/cytotoxicity ratio and the tumor-targeting effects of polyethylenimine (PEI), is a non-viral gene vector used for the delivery of the cancer therapy gene, poloxamer 407 (P407)-PEI-K12, was synthesized by cross-linking low-molecular weight PEI with P407 and further coupling a bifunctional peptide, K12, which is comprised of the tumor-targeting peptide tLyP-1 and the nuclear localization sequence. Furthermore, the addition of free P407 into the polymer/DNA complex solution produced a temperature-sensitive in situ gel-P407/P407-PEI-K12/DNA complex, which improved the effects of sustained-release gene delivery and transfection efficiency. The specificity, cytotoxicity and gene transfection efficiency of P407-PEI-K12 was investigated in Hela cells in vitro. The polymer efficiently prevented the degradation of plasmid DNA by DNase I and had a marked ability for serum tolerance. Agarose gel electrophoresis revealed that plasmid DNA was efficiently condensed and protected. The higher transfection efficiency of P407-PEI-K12h (the molar ratio of P407-PEI and K12 is 1:10) was achieved with a polymer and plasmid DNA ratio (w/w) of 20:1. The ability of free P407 to promote the transfection of the polymer/DNA complex was high (0.09%). The half-life of the P407/P407-PEI-K12-h/DNA gel complex was 228 min, and the transfection efficiency of the P407/P407-PEI-K12-h/DNA complex was markedly higher compared to that of the P407-PEI-K12-h/DNA complex at various release times.

Drug-Loaded Biocompatible Nanocarriers Embedded in Poloxamer 407 Hydrogels as Therapeutic Formulations

Hydrogels are three-dimensional networks of hydrophilic polymers able to absorb and retain a considerable amount of water or biological fluid while maintaining their structure. Among these, thermo-sensitive hydrogels, characterized by a temperature-dependent sol–gel transition, have been massively used as drug delivery systems for the controlled release of various bioactives. Poloxamer 407 (P407) is an ABA-type triblock copolymer with a center block of hydrophobic polypropylene oxide (PPO) between two hydrophilic polyethyleneoxide (PEO) lateral chains. Due to its unique thermo-reversible gelation properties, P407 has been widely investigated as a temperature-responsive material. The gelation phenomenon of P407 aqueous solutions is reversible and characterized by a sol–gel transition temperature. The nanoencapsulation of drugs within biocompatible delivery systems dispersed in P407 hydrogels is a strategy used to increase the local residence time of various bioactives at the injection site. In this mini-review, the state of the art of the most important mixed systems made up of colloidal carriers localized within a P407 hydrogel will be provided in order to illustrate the possibility of obtaining a controlled release of the entrapped drugs and an increase in their therapeutic efficacy as a function of the biomaterial used.

Mucosal Applications of Poloxamer 407-Based Hydrogels: An Overview

Poloxamer 407, also known by the trademark Pluronic^® F127, is a water-soluble, non-ionic triblock copolymer that is made up of a hydrophobic residue of polyoxypropylene (POP) between the two hydrophilic units of polyoxyethylene (POE). Poloxamer 407-based hydrogels exhibit an interesting reversible thermal characteristic. That is, they are liquid at room temperature, but they assume a gel form when administered at body temperature, which makes them attractive candidates as pharmaceutical drug carriers. These systems have been widely investigated in the development of mucoadhesive formulations because they do not irritate the mucosal membranes. Based on these mucoadhesive properties, a simple administration into a specific compartment should maintain the required drug concentration in situ for a prolonged period of time, decreasing the necessary dosages and side effects. Their main limitations are their modest mechanical strength and, notwithstanding their bioadhesive properties, their tendency to succumb to rapid elimination in physiological media. Various technological approaches have been investigated in the attempt to modulate these properties. This review focuses on the application of poloxamer 407-based hydrogels for mucosal drug delivery with particular attention being paid to the latest published works.

Formulation and in vitro evaluation of a thermoreversible mucoadhesive nasal gel of itopride hydrochloride

Itopride hydrochloride (ITO HCl) is a prokinetic agent, used in the treatment of gastrointestinal motility disorders. The aim of the study was to develop stable mucoadhesive thermoreversible nasal gel to avoid first pass effect. ITO HCl was incorporated into the blends of thermoreversible polymers like poloxamer 407 and various mucoadhesive polymers in different concentrations to increase the contact of the formulations with nasal mucosa. The compatibility between the drug and the suggested polymers was studied by Fourier transform infrared and differential scanning calorimetry (DSC). The formulations were evaluated for clarity, pH, gelation temperature, mucoadhesive strength, gel strength, viscosity, and drug content. In addition, the in vitro drug release and the dissolution efficiency (DE)% were measured. The optimized formulations that showed the highest dissolution efficiency% (DE%) in saline phosphate buffer of pH 6.4 at 35 ± 0.5 °C were chosen for stability testing at temperatures of 4 ± 2 and 25 ± 2 °C/60 ± 5% RH. It was found that F1 and F17 that contain 18% w/v poloxamer 407 and 0.5% w/v of hydroxypropylmethyl cellulose K4M or methyl cellulose (MC), respectively, showed higher stability results as indicated by their higher t₉₀ values (days).

Thermosensitive Poloxamer 407/Poly(Acrylic Acid) Hydrogels with Potential Application as Injectable Drug Delivery System

Thermosensitive hydrogels are of great interest for in situ gelling drug delivery. The thermosensitive vehicle with a gelation temperature in a range of 30-36°C would be convenient to be injected as liquid and transform into gel after injection. To prepare novel hydrogels gelling near body temperature, the gelation temperature of poloxamer 407 (PX) were tailored by mixing PX with poly(acrylic acid) (PAA). The gelation behaviors of PX/PAA systems as well as the interaction mechanism were investigated by tube inversion, viscoelastic, shear viscosity, DSC, SEM, and FTIR studies. The gelation temperature of the plain PX solutions at high concentration of 18, 20, and 22% (w/w) gelled at temperature below 28°C, which is out of the suitable temperature range. Mixing PX with PAA to obtain 18 and 20% (w/w) PX with 1% (w/w) PAA increased the gelation temperature to the desired temperature range of 30-36°C. The intermolecular entanglements and hydrogen bonds between PX and PAA may be responsible for the modulation of the gelation features of PX. The mixtures behaved low viscosity liquid at room temperature with shear thinning behavior enabling their injectability and rapidly gelled at body temperature. The gel strength increased, while the pore size decreased with increasing PX concentration. Metronidazole, an antibiotic used for periodontitis, was incorporated into the matrices, and the drug did not hinder their gelling ability. The gels showed the sustained drug release characteristic. The thermosensitive PX/PAA hydrogel could be a promising injectable in situ gelling system for periodontal drug delivery.

Topical antifungal bigels: Formulation, characterization and evaluation

Bigels with antifungal substances, ciclopirox olamine and terbinafine hydrochloride, were made of hydrogel (poloxamer 407 gel) and oleogel (polyethylene and liquid paraffin mixture). Prepared bigels were found physically stable at room temperature for six months and at least four months at 40 °C. Released amount of drug decreased when oleogel concentration in the formulation increased. Release test results depended on the insertion place of active substances. The amount of released substance was highest when ciclopirox olamine was incorporated in both phases in an equal quantity, and terbinafine hydrochloride in oleogel or in hydrogel. All formulations showed great inhibition of Microsporum canis. Thus, bigels with ciclopirox olamine and terbinafine hydrochloride are a promising dosage form for topical use.

Application of Fluorescence Emission for Characterization of Albendazole and Ricobendazole Micellar Systems: Elucidation of the Molecular Mechanism of Drug Solubilization Process

Albendazole (ABZ) and ricobendazole (RBZ) are referred to as class II compounds in the Biopharmaceutical Classification System. These drugs exhibit poor solubility, which profoundly affects their oral bioavailability. Micellar systems are excellent pharmaceutical tools to enhance solubilization and absorption of poorly soluble compounds. Polysorbate 80 (P80), poloxamer 407 (P407), sodium cholate (Na-C), and sodium deoxycholate (Na-DC) have been selected as surfactants to study the solubilization process of these drugs. Fluorescence emission was applied in order to obtain surfactant/fluorophore (S/F) ratio, critical micellar concentration, protection efficiency of micelles, and thermodynamic parameters. Systems were characterized by their size and zeta potential. A blue shift from 350 to 345 nm was observed when ABZ was included in P80, Na-DC, and Na-C micelles, while RBZ showed a slight change in the fluorescence band. P80 showed a significant solubilization capacity: S/F values were 688 for ABZ at pH 4 and 656 for RBZ at pH 6. Additionally, P80 micellar systems presented the smallest size (10 nm) and their size was not affected by pH change. S/F ratio for bile salts was tenfold higher than for the other surfactants. Quenching plots were linear and their constant values (2.17/M for ABZ and 2.29/M for RBZ) decreased with the addition of the surfactants, indicating a protective effect of the micelles. Na-DC showed better protective efficacy for ABZ and RBZ than the other surfactants (constant values 0.54 and 1.57/M, respectively), showing the drug inclusion into the micelles. Entropic parameters were negative in agreement with micelle formation.

Thermo-sensitive composite hydrogels based on poloxamer 407 and alginate and their therapeutic effect in embolization in rabbit VX2 liver tumors

Interventional embolization therapy is an effective, most widely used method for inoperable liver tumors. Blood-vessel-embolic agents were essential in transarterial embolization (TAE). In this work, thermo-sensitive composite hydrogels based on poloxamer 407, sodium alginate, hydroxymethyl cellulose and iodixanol (PSHI), together with Ca2+ (PSHI-Ca2+) were prepared as liquid embolic agents for TAE therapy to liver cancer. With increasing temperature, PSHI exhibited two phase states: a flowing sol and a shrunken gel. Rheology tests showed good fluidity and excellent viscoelastic behavior with a gelation temperature (GT) of 26.5°C. The studies of erosion indicated that PSHI had calcium ion-related erosion characteristics and showed a slow erosion rate in an aqueous environment. When incubated with L929 cells, the thermo-sensitive composite hydrogels had low cytotoxicity in vitro. The results of analyzing the digital subtraction angiography and computed tomography images obtained from in vitro and in vivo assays indicated a good embolic effect in the renal arteries of normal rabbits. Angiography and histological studies on VX2 tumor-bearing rabbits indicated that PSHI-Ca2+ successfully occluded the tumors, including the peripheral vessels. In conclusion, PSHI-Ca2+ was a promising embolic agent for transarterial embolization therapy.

Combination of carvacrol with simvastatin improves the lipid-lowering efficacy and alleviates simvastatin side effects

The present investigation was designed to examine the possible additive hypolipidemic effect of carvacrol (CARV) in combination with simvastatin (SIM) on poloxamer 407 (P407)-induced hyperlipidemia. Rats were injected with P407, (500 mg/ kg; i.p.), twice a week, for 30 days. Treatment was carried out by administration of SIM (20 mg/kg/day; p.o.) or CARV (50 mg/kg/day; p.o.) or combination of them. Treatment with CARV significantly decreased total cholesterol, triglycerides, low-density lipoprotein, atherogenic index, leptin, and increased high-density lipoprotein and adiponectin. Moreover, CARV potentiated the hypolipidemic effect of SIM. Both SIM and CARV alleviated the oxidative stress induced by P407. Interestingly, CARV, when combined with SIM, significantly ameliorated SIM-induced liver and muscle injury by reducing the level of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, creatine kinase, and myoglobin and restoring the normal histological picture of both liver and muscle as well as apoptosis.