The Influence of pH Values on the Rheological, Textural and Release Properties of Carbomer Polacril® 40P-Based Dental Gel Formulation with Plant-Derived and Synthetic Active Components

A recyclable dispersant based on carbomer utilizing controllable viscosity for high-efficiency dispersion of carbon fibers

Good dispersion of carbon fibers is important for the carbon paper production, which is usually achieved using low carbon fiber concentrations and disposable dispersants. In this study, we developed carbomer as a recyclable and high-efficiency dispersant for carbon fibers. When the carbon fiber concentration was 0.1 wt%, carbon fiber suspension showed improved dispersion performance as increasing the carbomer dosage. It exhibited low Turbiscan Stability Index (TSI) of 0.41 and small change of delta backscattering between -0.5 to 0.8 % when using 0.5 wt% carbomer. However, the good dispersibility fade away when increasing the concentration of carbon fibers. Subsequently, the pH of the carbon fiber suspension was adjusted to 7.0 to improve the dispersibility by increasing the viscosity, but causing a worse flowability. Then the pH was further adjusted to 13.0 to ensure good flowability in the wet-forming process and good dispersibility at carbon fiber concentration of 0.5 wt%. More importantly, the dispersant was successfully recycled and still exhibited excellent dispersion effects for carbon fibers after 5 cycles. Notably, the high-efficiency dispersion of carbon fibers and the recyclability of dispersant were achieved simultaneously for the first time, which is suitable for the eco-friendly and sustainable production of carbon paper.

Development and Evaluation of Oromucosal Spray Formulation Containing Plant-Derived Compounds for the Treatment of Infectious and Inflammatory Diseases of the Oral Cavity

According to data in the literature, natural products and essential oils are often used in dental practice. To develop a new oromucosal spray for the treatment of infectious and inflammatory diseases of the oral cavity, clove CO2 extract and essential oils of lavender and grapefruit were used as active pharmaceutical ingredients. Clove extract was obtained by the method of subcritical extraction from various raw materials, the choice of which was based on the yield of the CO2 extract and the study of its phytochemical and microbiological properties. Based on the results of microscopic and diffraction analyses, the rational time of ultrasonic exposure for the emulsion of active pharmaceutical ingredients was established. Mucoadhesive polymers were used as stabilizers of the two-phase system and prolongators. This article discusses the impact of the type and concentration of mucoadhesive polymers on the stability of the emulsion system; the viscous, textural, adhesive, and film characteristics of oromucosal spray; and the parameters determining sprayability.

Predicting tactile sensory attributes of personal care emulsions based on instrumental characterizations: A review

Emulsions in the form of creams, lotions, gels or foams are the most widely used personal care formulations to improve the condition and feel of the skin. Achieving an optimal balance between their performance, effectiveness and sensory profile is essential, with the sensory profile being a key factor in consumer satisfaction and the success of these products in the market. Well-established methods using highly trained and semi-trained panels (e.g. Spectrum descriptive analysis, Flash Profile method, Quantitative Descriptive Analysis method and 'Check-all-that-apply') are available and commonly used for the sensory assessment of personal care products. Nevertheless, a common drawback among all these methods is their inherent cost, both in terms of financial resources and time requirements. In recent years, research studies have emerged to address this limitation by investigating potential correlations between tactile sensory attributes and instrumental data associated with the physical characteristics of topical formulations. In other words, significant efforts have been invested in the development of robust instrumental methods specifically designed to accurately predict the sensory description that a panel of assessors could establish. These methods are not only faster, cheaper and more objective compared to traditional sensory testing, but they can also be applied to formulations that have not undergone extensive safety and toxicological testing. This review summarizes the most relevant findings, trends and current challenges in predicting tactile sensory attributes of personal care emulsions based on instrumental parameters.

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

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

Carbomer Hydrogels with Microencapsulated α-Tocopherol: Focus on the Biocompatibility of the Microcapsules, Topical Application Attributes, and In Vitro Release Study

The microencapsulation of α-tocopherol based on the complex coacervation of low-molecular-weight chitosan (LMWC) and sodium lauryl ether sulphate (SLES) without harmful crosslinkers can provide biocompatible carriers that protect it from photodegradation and air oxidation. In this study, the influence of the microcapsule wall composition on carrier performance, compatibility with a high-water-content vehicle for topical application, and release of α-tocopherol were investigated. Although the absence of aldehyde crosslinkers decreased the encapsulation efficiency of α-tocopherol (~70%), the variation in the LMWC/SLES mass ratio (2:1 or 1:1) had no significant effect on the moisture content and microcapsule size. The prepared microcapsule-loaded carbomer hydrogels were soft semisolids with pseudoplastic flow behavior. The integrity of microcapsules embedded in the hydrogel was confirmed by light microscopy. The microcapsules reduced the pH, apparent viscosity, and hysteresis area of the hydrogels, while increasing their spreading ability on a flat inert surface and dispersion rate in artificial sweat. The in vitro release of α-tocopherol from crosslinker-free microcapsule-loaded hydrogels was diffusion-controlled. The release profile was influenced by the LMWC/SLES mass ratio, apparent viscosity, type of synthetic membrane, and acceptor medium composition. Better data quality for the model-independent analysis was achieved when a cellulose nitrate membrane and ethyl alcohol 60% w/w as acceptor medium were used.

Investigating Bioactive-Glass-Infused Gels for Enamel Remineralization: An In Vitro Study

OBJECTIVE

Dental hypersensitivity remains widespread, underscoring the need for materials that can effectively seal dental tubules. This study evaluated the potential of bioactive-glass-infused hydroxyethyl cellulose gels in this context.

METHODS

Five gels were synthesized, each containing 20% bioactive glass (specifically, 45S5, S53P4, Biomin F, and Biomin C), with an additional blank gel serving as a control. Subjected to two months of accelerated aging at 37 ± 2 °C, these gels were assessed for key properties: viscosity, water disintegration time, pH level, consistency, adhesion to glass, and element release capability.

RESULTS

Across the board, the gels facilitated the release of calcium, phosphate, and silicon ions, raising the pH from 9.00 ± 0.10 to 9.7 ± 0.0-a range conducive to remineralization. Dissolution in water occurred within 30-50 min post-application. Viscosity readings showed variability, with 45S5 reaching 6337 ± 24 mPa/s and Biomin F at 3269 ± 18 mPa/s after two months. Initial adhesion for the blank gel was measured at 0.27 ± 0.04 Pa, increasing to 0.73 ± 0.06 Pa for the others over time. Gels can release elements upon contact with water (Ca- Biomin C 104.8 ± 15.7 mg/L; Na- Biomin F 76.30 ± 11.44 mg/L; P- Biomin C 2.623 ± 0.393 mg/L; Si- 45S5-45.15 ± 6.77mg/L, F- Biomin F- 3.256 ± 0.651mg/L; Cl- Biomin C 135.5 ± 20.3 mg/L after 45 min).

CONCLUSIONS

These findings highlight the gels' capacity to kickstart the remineralization process by delivering critical ions needed for enamel layer reconstruction. Further exploration in more dynamic, real-world conditions is recommended to fully ascertain their practical utility.

Formulation optimization and evaluation of oromucosal in situ gel loaded with silver nanoparticles prepared by green biosynthesis

Treating oral diseases remains challenging as API is quickly washed out of the application site by saliva turnover and mouth movements. In situ gels are a class of application forms that present sol-gel transition's ability as a response to stimuli. Their tunable properties are provided using smart polymers responsible for stimuli sensitivity, often providing mucoadhesivity. In this study, antimicrobial in situ gels of thermosensitive and pH-sensitive polymers loaded with silver nanoparticles were prepared and evaluated. The nanoparticles were prepared by green synthesis using Agrimonia eupatoria L. extract. According to the data analysis, the in situ gel with the most promising profile contained 15 % of Pluronic® F-127, 0.25 % of methylcellulose, and 0.1 % of Noveon® AA-1. Pluronic® F-127 and methylcellulose significantly increased the viscosity of in situ gels at 37 °C and shear rates similar to speaking and swallowing. At 20 °C, a behavior close to a Newtonian fluid was observed while being easily injectable (injection force 13.455 ± 1.973 N). The viscosity of the formulation increased with temperature and reached 2962.77 ± 63.37 mPa·s (37 °C). A temperature increase led to increased adhesiveness and rigidity of the formulation. The critical sol-gel transition temperature at physiological pH was 32.65 ± 0.35 °C. 96.77 ± 3.26 % of Ag NPs were released by erosion and dissolution of the gel after 40 min. The determination of MIC showed effect against E. coli and S. aureus (0.0625 mM and 0.5000 mM, respectively). The relative inhibition zone diameter of the in situ gel was 73.32 ± 11.06 % compared to gentamicin sulfate. This work discusses the optimization of the formulation of novel antibacterial in situ gel for oromucosal delivery, analyses the impact of the concentration of excipients on the dependent variables, and suggests appropriate evaluation of the formulation in terms of its indication. This study offers a promising dosage form for local treatment of oral diseases.

Post-Orthodontic Relapse Prevention through Administration of a Novel Synthetic Carbonated Hydroxyapatite-Chitosan Hydrogel Derived from Blood Cockle Shell (Anadara granosa L.)

Relapse during passive orthodontic treatment is a major issue, with 70-90% frequency. This study examines whether blood cockle shells may be used to extract carbonated hydroxyapatite (CHA)-chitosan (CS). This study also aims to analyze the effect of CHA-CS on orthodontic relapse in rats. This study utilized 18 male Wistar rats which were randomly divided into two groups: CHA-CS and the control group (CG). The rats were subjected to a 35 cN orthodontic force for a duration of 7 days, after which the rats were conditioned to be passive. During this phase, the CHA-CS group received daily administration of CHA-CS hydrogel derived from the blood cockle shell. Subsequently, the appliances were detached to facilitate relapse. The distance between the mesial tips was measured using a digital caliper at three consecutive time points: 1, 5, and 7 days after debonding. The number of osteoblasts, osteoclasts, and fibroblasts was examined using hematoxylin-eosin staining. The data were subjected to statistical analysis using a t-test. The relapse distance of the CHA-CS group was lower than that of the control groups on day 7. Histological examinations using hematoxylin-eosin (HE) staining showed a significant increase in osteoblasts, a decrease in osteoclasts, and an increase in fibroblasts during orthodontic relapse movement (p < 0.05). This study found that blood cockle shell-derived CHA-CS may reduce orthodontic relapse by increasing osteoblasts and fibroblasts and by reducing the osteoclast number in rats.

Quality by Design Assisted Development of Luliconazole Transethosomes in Gel for the Management of Candida albicans Infection

The objective of this study was to develop and evaluate a novel vesicular formulation of luliconazole (LUL) for the management of Candida albicans infection through a topical route. LUL-loaded transethosomes (LUL-TE) were prepared by the film hydration method and various independent and dependent variables were optimized using the Box-Behnken design. Selected critical material attributes were the content of phospholipids (X1), concentration of ethanol (X2), and amount of sodium cholate (X3). Formulated LUL-TE were characterized for percent entrapment efficiency, percent drug loading, vesicle size, and polydispersity index (PDI) and were incorporated into the carbomer gel base and further evaluated for gel characterizations. The prepared transethosomal gel (LUL-TE-CHG) was evaluated for pH, spreadability, viscosity, antifungal activity, and in vitro study. From the observed results, it was evident that the prepared LUL-TE-CHG was in the desired pH (6.2 ± 0.45), spreadability [8.3 ± 0.42 g/(cm·s)], viscosity (236.1-19.2.26 mPa·s), nanovesicle size (252 ± 9.82), entrapment efficiency (85% ± 5.24%), zeta potential (-34.05 ± 3.52 mV), and PDI (0.233 ± 0.002). The zone of inhibition results suggested that the LUL-TE-CHG formulation has the highest antifungal activity, that is, 5.83 ± 0.15 mm3. The in vitro results showed that drug release within 2 h was 18.1% ± 2.0% and after that sustained release action, 83.2% ± 1.7% within 8 h. Finally, to confirm the therapeutic efficacy of the developed formulation, fungal infection was induced by using C. albicans in Wistar rats. In vivo, skin irritation study and histopathology studies were performed in the disease-induced model. Animal experiments revealed that LUL-TE-CHG has significantly improved the diseased condition in Wistar rats. The results observed from the skin permeation and skin deposition profile ensure that the prepared novel LUL-loaded TE system had a higher permeation rate and increased retention time compared with LUL-CHG. The hydrogel incorporated with LUL could be a novel approach with safe and effective fungal treatment.

Mining Polyethylene Glycol-Based Thermosensitive Hydrogel Materials: Preparation and Flame Retardant Properties

A new type of efficient and anti-extinguishing materials to inhibit coal spontaneous combustion is required because of the current situation of the short activity cycle of existing anti-extinguishing technology. Now, polyethylene glycol (PEG) was used as a water-absorbing monomer to polymerize various substances to prepare an AB-type mining thermosensitive hydrogel that was obviously thermoresponsive. The thermosensitive hydrogel, which is low-cost and stable, can be stored for a long time, and it is prepared by compounding A and B components. The orthogonal experiments determined the optimal ratio of component A, while the controlling variable experiments determined the optimal ratio of component B. The thermal stability and flame-retardant properties of the AB-type thermosensitive hydrogel were analyzed during the process of natural oxidation of coal, and the temperature responsiveness of thermosensitive hydrogels was investigated at different temperatures. The results showed that the optimal ratio of polyethylene glycol:methyl cellulose:sodium carboxymethyl cellulose:guar gum of component A was 6:6:1.2:1.5; and the ratio of bentonite:kaolin:Mg(OH)₂ of component B was 2:1:1. When the ratio of component A to component B was 1:2, the AB-type thermosensitive hydrogel shows the best flame retardant properties. When this ratio of gel was applied to coal samples, the weight loss was just 6%, and the reduction of CO was as high as 72.6%. The gel, which was convenient for transportation in mining pipelines, had strong fluidity at low temperatures and rapid temperature response. As the temperature rose, a phase transition occurred gradually, and after the phase transition, a high-viscosity solid substance was formed, whose viscosity was approximately 11 times that of the room temperature. It plugged the pores effectively, and in the high-temperature region, the occurred phase transition gathered to extinguish the fire. It is a new type of high-efficiency anti-extinguishing material with excellent properties.

Ultrasound-assisted extraction of oil from hempseed (Cannabis sativa L.): Part 2

BACKGROUND

Oilseed-matrix consolidation is a crucial factor when talking about oil expression because, as the cake consolidates, the coefficient of permeability inevitably decreases. Thus, any treatment that extensively ruptures cell walls reduces rigidity and hardness of the oilseed press-cake, while improving the oil expression. Such process intensification was investigated in the present study through the introduction of the ultrasound (US) technology. Screw pressing of Cannabis sativa L. seeds was operated using a pilot scale equipment set at three different pressures (low, medium and high) to understand the correlation with the ultrasound effectiveness. Samples of non-exhausted press-cakes were tested for objective instrumental indices of compressibility and oil expression yields prior and after the US treatment.

RESULTS

US led to a drag resistance reduction within press-cakes, improving oil flowability through a decrease in the material cohesiveness and adhesiveness. Consistently, sonication favoured oil extraction yields and oil antioxidant capacities, which increased with respect to the untreated samples, respectively equal to +19.2% and + 29.4% for the press-cake screwed at low pressure, to +21.8% and + 49.3% at medium pressure, and to +15.4% and + 0.5% at high pressure. Overall, US highest effectiveness was accounted for samples screwed at medium pressure.

CONCLUSION

Press-cake compressibility can be well described by macroscopic texture parameters; indeed, their decrease is linked to higher oil expression efficiencies. Sonication can help boosting oil extraction yields reducing drag resistance within the mechanical screwing equipment. These outcomes offer good potentials for US application in the hempseed technology and, more extensively, in the oil seed industry. © 2022 Society of Chemical Industry.

Thymoquinone-Loaded Essential Oil-Based Emulgel as an Armament for Anti-psoriatic Activity

Essential oils consist of oxygenated structures of secondary metabolites of aromatic plants with anti-psoriatic activities. Tea tree oil (TTO) is an essential oil with good anti-microbial and anti-inflammatory properties, exhibiting reduced levels of IL-1, IL-8, and PGE 2. Thymoquinone (TMQ) is popular herb in traditional medicine with known therapeutic benefits in several diseases and ailments. The ternary phase diagram was prepared with the weight ratio of S_mix (Tween® 80:Labrasol®): oil:water ratio for o/w emulsion preparation. The globule size was 16.54 ± 0.13 nm, and PDI around 0.22 ± 0.01 of the TTO-TMQ emulsion and found thermodynamically stable. The percentage drug content was found in the range of 98.97 ± 0.62 to 99.45 ± 0.17% with uniformity of the ThymoGel using Carbopol®. The extensive physicochemical properties were studied using different analytical techniques, and in vitro drug release was performed using Franz-diffusion apparatus. Anti-psoriatic activity of the formulations was studied using Imiquimod-induced psoriasis-like inflammation model in male Balb/c mice and parameters like PASI score, ear thickness, and spleen to body weight index were determined as well as histological staining, ELISA, skin compliance, and safety evaluation of TTO were performed. The combination of essential oils with TMQ shows synergistic activity and efficiently reduces the psoriasis disease condition.

Gold nanoclusters-loaded hydrogel formed by dimeric hydrogen bonds crosslinking: A novel strategy for multidrug-resistant bacteria-infected wound healing

Restoring skin integrity after wound infection remains a tougher health challenge due to the uncontrolled antibiotic-resistant pathogens caused by antibiotic abuse. Herein, an injectable hydrogel with dual antibacterial and anti-inflammatory activities composed of gold nanoclusters (GNCs) and carbomer (CBM) is developed for wound dressing to overcome multidrug-resistant infection. Firstly, both experimental investigations and molecular dynamics simulation validate the protonation state of 6-mercaptohexanoic acid (MHA) ligands play an important role in its antibacterial action of GNCs. The self-organizing GNCs-CBM composite hydrogel is then spontaneously cross-linked by the dimeric hydrogen bonds (H-bonds) between the MHA ligands and the acrylic acid groups of CBM. Benefitting from the dimeric H-bonds, the hydrogel becomes thickening enough as an ideal wound dressing and the GNCs exist in the hydrogel with a high protonation level that contributes to the enhanced bactericidal function. In all, by combining bactericidal and immunomodulatory actions, the GNCs-CBM hydrogel demonstrated excellent synergy in accelerating wound healing in animal infection models. Hence, the dimeric H-bonds strengthening strategy makes the GNCs-CBM hydrogel hold great potential as a safe and effective dressing for treating infected wounds.

Formulation and Evaluation of Natural Gel Containing Ethanolic Extract of Pandanus amaryllifolius R. Using Various Gelling Agents

Ethanol extract of Pandanus amaryllifolius leaves contains quercetin has anti-inflammatory properties. The gel dosage form is very appropriate for wound healing therapy because it gives a cold sensation to the skin. This study aims to formulate a P. amaryllifolius gel by variation of a gelling agent to compare the effect of a natural gelling agent, semi-synthetic gelling agent, and synthetic gelling agent on the physical characteristics of the gel. The gel formulation was made in three formulas. Evaluations include organoleptic, homogeneity, spreadability, adhesion, pH, and viscosity. The optimum gel formula was tested for release study using a dissolution apparatus 5. Determination of release kinetics model using the kinetics approach of zero-order, first-order, Higuchi, and Korsmeyer-Peppas. The organoleptic shows the gel's dark green color, P. amaryllifolius aromas, and good homogeneity. The gel formulas had pH values that matched the physical quality criteria of the gel. Data obtained for the spreadability test for F1, F2, and F3 were 12.16, 14.66, and 10.75 g.cm/sec, respectively. The F1, F2, and F3 adhesion test results were 11.66, 10, and 47.33, respectively. The viscosity of F1 was 15750 cps, F2 was 4807 cps, and F3 was 19380 cps. This study concludes that the optimum formula is obtained from the gelling agent of Na-CMC as a gelling agent. The number of quercetins released from F2 was 42.76%, and the release kinetics model followed the kinetics of Higuchi.

Assessment of Binary Agarose-Carbopol Buccal Gels for Mucoadhesive Drug Delivery: Ex Vivo and In Vivo Characterization

Agarose (AG) is a naturally occurring biocompatible marine seaweed extract that is converted to hydrocolloid gel in hot water with notable gel strength. Currently, its mucoadhesion properties have not been fully explored. Therefore, the main aim of this study was to evaluate the mucoadhesive potential of AG binary dispersions in combination with Carbopol 934P (CP) as mucoadhesive gel preparations. The gels fabricated via homogenization were evaluated for ex vivo mucoadhesion, swelling index (SI), dissolution and stability studies. The mucoadhesive properties of AG were concentration dependent and it was improved by the addition of CP. Maximum mucoadhesive strength (MS) (27.03 g), mucoadhesive flow time (FT) (192.2 min), mucoadhesive time in volunteers (MT) (203.2 min) and SI (23.6% at 4 h) were observed with formulation F9. The mucoadhesive time investigated in volunteers (MT) was influenced by AG concentration and was greater than corresponding FT values. Formulations containing 0.3%, w/v AG (F3 and F9) were able to sustain the release (~99%) for both drugs till 3 h. The optimized formulation (F9) did not evoke any inflammation, irritation or pain in the buccal cavity of healthy volunteers and was also stable up to 6 months. Therefore, AG could be considered a natural and potential polymer with profound mucoadhesive properties to deliver drugs through the mucosal route.

Poloxamer-Based Hydrogel as Drug Delivery System: How Polymeric Excipients Influence the Chemical-Physical Properties

Thermogelling amphiphilic block copolymers have been widely investigated in the development of pharmaceutical drug carriers. In particular, thermosensitive gels based on poloxamer 407 (P407) have great potential for periodontal disease treatment, thanks to their ability to be liquid at room temperature and become viscous gels at body temperature. However, some problems, related to short in situ residence time, reduce their feasible clinical use. Thus, in order to improve the effective applicability of these materials, we studied how P407 thermogels are affected by the pH and by the inclusion of different hydrophilic polymers, used as excipients for increasing the gel stiffness. For this scope, a complete chemical-physical characterization of the synthesized gels is provided, in terms of determination of sol-gel transition temperature, viscosity and erosion degree. The data are correlated according to a statistical multivariate approach based on Principal Component Analysis and their mucoadhesion properties are also tested by Tapping mode-Atomic Force Microscopy (TM-AFM) imaging. Finally, we studied how the different P407 formulations are able to influence the release pathway of two antibacterial drugs (i.e., chlorhexidine digluconate and doxycycline hyclate) largely used in oral diseases.

Role of mucoadhesive polymers in retention of toothpaste in the oral cavity

Retention of active ingredients of toothpastes in the mouth following brushing determines the efficiency of these oral care formulations. In this study, new in vitro methodologies for the observation and measurement of toothpaste retention in the oral cavity were developed and used to evaluate the efficiency of formulations containing different mucoadhesive hydrophilic polymers. The findings suggest that using Carbopol ETD 2020 and Carbopol Ultrez 10 as binders in toothpaste prolongs the retention time of these formulations in the oral cavity. The in vitro methodologies tested, coupled with texture analysis, were able to accurately characterise the behaviour of the toothpaste and produce detailed images showing how it is retained in the oral cavity. This study has not only produced a new method for studying the behaviour of toothpaste and other formulations in the oral cavity but is also the first to investigate how different types of mucoadhesive binders can be used to improve toothpaste retention.