Chitosan-clay nanocomposite as a drug delivery system of ibuprofen

Chitosan/montmorillonite nanocomposite films were prepared by the solvent evaporation method to immobilize the drug ibuprofen (IBU) and delay its release in a medium that simulates the environment of the gastrointestinal tract. The effects of montmorillonite, at different mass proportions (10, 20, and 50%), on the morphological and physical properties of the films were studied. The samples were characterized by X-ray diffraction (XRD), Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), degree of swelling, drug encapsulation, and drug release efficiency. According to the XRD it was evidenced that the incorporation of montmorillonite to chitosan led to the formation of nanocomposites of ordered morphology. The infrared spectra confirmed the good interaction between montmorillonite and chitosan by the formation of nanocomposites. This fact, which favored the imprisonment of the IBU, reduced the diffusion coefficient in the studied systems. The micrographs comproved the formation of dense and uniform films. The controlled release profile, especially for the nanocomposite with 10% clay mass, showed a slow drug release rate. The incorporation of montmorillonite at different proportions produced different morphologies, with good encapsulation efficiency and an adequate profile for the controlled release of the drug.

Preparation and application of poly (hydroxyl ethyl methacrylate) nanocomposite hydrogels containing iron oxide nanoparticles as wound dressing

In recent years, polymeric hydrogels are widespread in the field of biological materials such as wound dressing and wound care. In this work, we report for the first time the preparation and application of pHEMA nanocomposite hydrogels containing iron oxide nanoparticles as wound dressings. For this purpose, nanocomposite hydrogels based on poly (hydroxyl ethyl methacrylate) (pHEMA) and various amounts of 5, 10, and 15 wt% iron oxide nanoparticles were successfully prepared via radical polymerization. The structure and morphology of nanocomposite hydrogels were determined by Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscope (FE-SEM), respectively. The results of gel fraction and the degree of swelling of hydrogels demonstrated that the gel percentage of pHEMA increased, and the degree of swelling decreased with increasing the percentage of nanoparticles. The WVRT and the porosity of hydrogels decreased by increasing the quantity of nanoparticles and were suitable for wound dressing applications. The effect of iron oxide nanoparticles on the mechanical properties of nanocomposite hydrogels was also studied using compression test and hardness shore A durometer. The results indicated that the compression strength, modulus, strain, and hardness are steadily increasing compared to pure hydrogel by adding nanoparticles. The maximum increase was obtained for a hydrogel sample with 15 wt% iron oxide nanoparticles. Antibacterial properties and biocompatibility were determined by the disk-diffusion and MTT assay methods, respectively. Based on the results, nanocomposite hydrogels exhibited higher percentages of cell survival and better antibacterial properties compared to pure pHEMA.

Comparison of Two Different Doses of Dexamethasone to Control Swelling and Trismus following Mandibular Third Molar Surgery

Introduction: Third molar surgery is one of the most common procedures performed by dental surgeons in clinical practice, where postoperative sequelae like pain, trismus, and swelling are often encountered. Thus, in this study, we compared medications employed to reduce such complications. Objective: To compare the effect of two different doses (4 and 8 mg) of dexamethasone in the control of swelling and trismus after the surgical extraction of mandibular impacted third molars. Methods: An experimental study consisted of twenty-seven (27) healthy adult patients of both genders with bilateral impacted lower third molars, where surgical extraction was indicated, 4 mg and 8 mg of dexamethasone were given orally to the patients 1 hour before the surgical procedure at both the surgeries. The swelling was recorded by measuring the length of 3 facial planes using a measuring tape. Trismus was evaluated by measuring the maximum interincisal distance. Recording of facial swelling and maximum interincisal distance was done preoperatively and on the 1st and 2nd days postoperatively. Results: Based on statistical analysis (Independent T-test), the results showed a difference in the measurements of the degree of swelling and trismus of the treated sample. 8 mg of dexamethasone promoted a greater reduction of symptoms than 4mg of dexamethasone though there was no statistically significant (p-value >0.05) difference between the two doses. Conclusions: 8 milligrams of the dexamethasone had better effectiveness than 4 milligrams of the dexamethasone in reducing the degree of swelling and trismus. Keywords: Dexamethasone; impacted third molars; swelling; trismus.

PREPARATION OF CHITOSAN GRAFT COPOLYMERS AND STUDY OF THEIR WATER-SWELLING PROPERTIES

In this work, graft copolymers of chitosan with trimethylmethacryloxyethylammonium methyl sulfate were synthesized by the method of controlled radical polymerization, and it was found that replacing the dimethylformamide aprotic solvent with water increases the degree of grafting. With the aim of the possible use of chitosan copolymers as a functional component for regulating the water-swelling properties of elastomers, the kinetics of swelling of the samples was investigated. An increase in the degree of swelling of the copolymers in comparison with the initial chitosan was revealed, and the influence of the molecular weight and the conditions of their synthesis was established.

Development of Gelatin/Misoprostol Compounds for Use in Pregnancy Failures

Early abortion is one of the most common complications during pregnancy. However, the frequent handling of the genital region, more precisely the vagina, which causes discomfort to patients in this abortion process due to the frequency of drug insertion, as four pills are inserted every six hours, has led to the search for alternatives to alleviate the suffering caused by this practice in patients who are already in a shaken emotional state. Hence, this work aimed to develop composites of gelatin and misoprostol, using a conventional single-dose drug delivery system. These composites were prepared by freeze/lyophilization technique, by dissolving the gelatin in distilled water, with a concentration of 2.5% (w/v), and misoprostol was incorporated into the gelatin solution at the therapeutic concentration (800 mcg). They were subsequently molded, frozen and lyophilized. The samples of the composites were then crosslinked with sodium tripolyphosphate (TPP) 1% (v/v) with respect to the gelatin mass for 5 min. The characterization techniques used were: Optical Microscopy (OM), Fourier Transformed Infrared Spectroscopy (FTIR), Thermogravimetry (TG), Swelling, Biodegradation and Cytotoxicity. In OM it was observed that the addition of the drug improved the cylindrical appearance of the compounds, in comparison with the sample that was composed of only gelatin. There was a reduction in the degree of swelling with the addition of the drug and crosslinking. The cytotoxicity test indicated the biocompatibility of the material. Based on the results obtained in these tests, the composites have therapeutic potential for uterine emptying in pregnancy failures, especially in the first trimester.

Investigation of mechanical properties and biodegradability of compatibilized thermoplastic starch/ high impact polystyrene blends reinforced by organophilic montmorillonite

This work consists of preparation and characterization of composites produced from thermoplastic starch (TPS) and high impact polystyrene (HIPS). Due to the immiscibility of the system (TPS/HIPS), it was necessary to incorporate concentrations of 1, 2 and 3% of an organophilic montmorillonite (MMT) to improve the properties of the mixtures, in particular their rigidity. The composites thus prepared were characterized using XRD, FTIR, mechanical test, degree of swelling in water and biodegradability. The results show that the addition of MMT improves the mechanical properties of the mixtures such as the tensile strength and the Young’s modulus by 5% and 10%, respectively. In contrast, the resilience of the system has significantly decreased. Moreover, for 3% of MMT, the composites biodegradability is enhanced by 15% when compared to the TPS/HIPS mixture without MMT.

THE POTENTIAL OF URONIDE HYDROCOLLOIDS FOR THE FORMATION OF SENSORY CHARACTERISTICS OF HEALTH PRODUCTS FROM HYDROBIONTS

The article presents the theoretical basis and practical aspects of the using of binary compositions of uronid polysaccharides in the technology of culinary products from aquatic organisms in jelly fillings. The relevance of the composition of natural high molecular weight polysaccharides, such as sodium alginate and low-esterified pectin, to promote the improvement of sensory characteristics of culinary products from aquatic organisms in the menu of fish restaurants is shown. The objectives of the study were to obtain a jelly filling of viscous consistency, followed by the formation of a stable, elastic gel for using in the technology of aquatic products. Obtaining a jelly filling involves det-ermining the parameters of the preliminary preparation of hydrocolloids; study of the influence of technological par-ameters on the sensory characteristics of the gel. Creating a dry mixture of sodium alginate and low-esterified pectin with salt and sugar was necessary to ensure the dispersion of particles of dry hydrocolloid powders to prevent sticking when swelling in water at a temperature of 18-20 ° C for 15 minutes. Intense swelling of the mixture occurs in the first 10 minutes of hydration.The degree of swelling reaches 5.8%; further increase in time has almost no effect on the swe-lling process. The swelling kinetics of the hydrocolloid mixture was evaluated by determining the tangent of the angle of inclination tangent to the curve describing the degree of swelling. The rational mass fraction of calcium ions for the formation of a transparent gel of stable, homogeneous, elastic consistency, which is 0.3-0.4% of the 10% solution of calcium chloride, was experimentally established. It was studied that dispersions with a mass fraction of a mixture of alginate: low-esterified pectin substances - 1.8% have a viscous consistency with a dynamic viscosity of less than 0.94 Pa • s, which is important for the implementation of technological operations of transportation and packaging of jelly fillings. The conditions and speed of gelation, which provide the finished culinary products with high sensory cha-racteristics and elastic consistency due to the regulated melting temperature, which is provided by the composition of uronide hydrocolloids, have been studied. It was found that the strength of the gel more than 140 g forms a mixture of hydrocolloids with a mass fraction of from 1.6 to 1.8%.

Development of a Gastro-retentive Dosage Form of a New Promising Anti-tuberculosis Drug Macozinone

Introduction. Due to increase in the frequency of detecting cases of tuberculosis caused by strains of mycobacteria with resistance not only to traditional, but also recently introduced into clinical circulation anti-tuberculosis drugs, it is urgent to search for and develop new drugs that can be effective against multidrug-resistant (MDR-TB) and extensively drug resistant (XDR-TB) strains. One of the most promising classes of such compounds are fluorine derivatives of benzothiazinones, and particularly compound PBTZ169 (INN macozinone). This antibiotic has a high specificity against mycobacteria tuberculosis (M. tuberculosis), inhibiting one of the key enzymes of cell wall synthesis. However, macozinone as an active pharmaceutical ingredient has significant features of physical and chemical properties that hinder the development of oral dosage forms based on it. It is classified as class IV by BCS and is characterized by a very low solubility and lipophilicity, a pronounced dependence of dissolution rate on the pH of the medium, and very low bioavailability when taken orally.Aim. To substantiate the target profile, critical quality attributes and to develop a prototype of an oral dosage form with modified release of macozinone, allowing to maximize its pharmacological activity.Materials and methods. Using pharmaceutical substance macozinone hydrochloride and various excipients, experimental tablets with a dosage of 500 mg macozinone were developed. The influence of the composition of the media and the added excipients on the solubility of macozinone in various biorelevant media, the degree of swelling in the liquid and the degree of mucoadhesion of the experimental tablets to the mucus of the pig stomach were evaluated. The HPLC method was used to evaluate the kinetics of the release of the active substance.Results and discussion. In this work, the expediency of creating macozinone-containing gastro-retentive dosage forms with a slow release of the active substance, the delay mechanism of which is provided by swelling and increased adhesion to the gastric mucosa, has been substantiated. Various tablet samples were experimentally tested in which the modification of the release of the active substance and the degree of swelling and mucoadhesion were varied by introducing various excipients into the formulations, including known swelling and bioadhesive matrix agents.Conclusion. According to the results of the experiments, samples of high-dose (500 mg) swellable and mucoadhesive tablets created by the technology of two-stage granulation with the inclusion of macozinone - hydroxypropyl-beta-cyclodextrin mixtures in the primary granules and introduction of combinations of soluble and insoluble hydrophilic matrix agents into the intergranular space were recognized as the most promising for subsequent pharmacokinetic studies.

Investigation of the rheological behavior of ABS plastic grades for the production of filaments for 3D printing by layer-by-layer deposition

A comprehensive study of the rheological properties of ABS-plastic grades used for the manufacture of fi laments for 3D printing by the FDM method has been carried out. It is shown that under the printing temperature-speed conditions, the viscous properties of melts of different grades and activation energy of their viscous flow differ significantly. The temporal parameters of the thermal stability of melts at an elevated (250°C) temperature were determined by the rheological method. It is shown that, under printing conditions, the polymer does not undergo noticeable degradation, assessed by the change in its effective viscosity. Viscoelasticity, which determines the dimensional accuracy of products and the thickness of the deposited layer, was evaluated by the degree of swelling of the extrudate under different flow conditions. Criteria for the applicability of ABS-plastic grades for fi lament production are proposed.

Production, Properties and Swelling of Composite Pectic-Gel Particles in an Artificial Gastric Environment

The purpose of the present work was to obtain and study the properties of composite calcium-pectic gel particles (CaPGPs) obtained from aqueous solutions of apple pectin (AP) in the concentration of 2% and pectin heracleuman (HS) in the concentration of 3% in the presence of Ca2+ ions (0.34 M). The swelling of the obtained CaPGPs in an artificial gastric environment was also investigated. Methods and Results: We used commercial AP AU701 (AP, Herbstreith & Fox KG, Germany) and HP isolated from the aerial part of the Sosnovskyi hogweed Heracleum sosnowskyi Manden. Composite CaPGPs were obtained from aqueous solutions of AP (2%) and HS (3%) in the presence of Ca2+ ions (0.34 M) by the method of ionotropic gelation. The diameter and density of CaPGPs were determined. Dry gel particles from 2% AP were larger (1.18±0.19 mm) than dry gel particles from 3% HS (1.04±0.07 mm) and dry composite gel particles (1.01±0.06 mm). However, dry composite gel particles and dry gel particles from HS were approximately 3 times denser than dry gel particles from AP. Composite CaPGPs swelled by 74.2% in simulated gastric fluid (SGF). The degree of swelling in SGF of CaPGPs formed from HS was 15.6% lower, and CaPGPs formed from AP –52.2%.