Interfacial Phenomena at the Interface in the System «Carbon Primary Materials-Water Solutions of Surfactants» for Cement Materials

The formation of sustainable concrete is directly relaed to the intensity of the processes occurring at the interface of phases. The study of the surface properties of CNPLUS carbon nanotubes in solutions of various plasticizers was carried out by measuring and calculating adsorption. The applicability of the adsorption value is for forecasting both the efficiency of dispersion and aggregative and sedimentative stability of the obtained dispersion systems. It was stated that two-dimensional pressure arising at the interface of adsorption layers in the dispersive medium with the surfactant Tensafor 2553.2 J/m2 is sufficient to overcome adhesive strength on a small area of the localized contact of carbon nanoparticles CNPLUS, which explains the peptization and stabilization of the particles’ surface. It was established that full stabilization of nanoparticles in the aqueous dispersive medium could be ensured only by means of soap-like surfactants, with the compound potassium naphthalene sulfonate (Tensafor). It ensures formation of the micelle-like structure in coagulation layers that forms a structural and mechanical barrier with the external hydrophilic surface. This leads to the increase in the ultimate tensile strength of the concrete grout specimens by 38%.

SPRAY DRYING APPROACH IN PREPARATION AND CHARACTERIZATION OF SOLID DISPERSION OF EPROSARTAN MESYLATE

Spray drying methods were used to make solid dispersions of the medication Eprosartan Mesylate, which is poorly water-soluble. X-ray Powder diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry were used to characterize the products' physicochemical features as well as drug-polymer interactions. Eprosartan Mesylate was shown to be dispersed amorphously in both solid dispersion systems, with a drug to polymer weight ratio of 1:4.The drug and polymer created hydrogen bonds, according to the spectrum data. Both techniques utilized in this investigation enhanced Eprosartan Mesylate solubility. Solid dispersions, on the other hand, performed significantly better, dissolving completely in 5 minutes and at a rate that was about 20 times faster than API within the first 15 minutes. Spray drying is a good way to boost the bioavailability of drugs that are poor water solubility.

Application of Fuel Ash as a Microfiller in Cement Dispersion Systems

The paper shows studies of modified cement compositions with micro-filler. As such a micro-filler, an ash product is used - an activated waste of an ash-and-slag mixture. The enriched aluminosilicate waste is characterized by a fairly stable chemical and particle size distribution. The used activation of the ash product allows for a more dense packing of particles in the composition of the binder dispersed system. The high dispersion of the ash component requires additional plasticization of the dispersed system. Despite the fact that during the activation process the destruction of large-pore particles remaining after flotation occurs, the introduction of a plasticizer also improves the rheological characteristics of the compositions, and, consequently, increases the strength and density of the modified cement stone with the addition of a microfiller.

Comparative Pharmacokinetics Study of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil Substance and its Solid Dispersion Systems on Rabbits

Introduction. The study of pharmacokinetics of medicinal substances and evaluation of their pharmacokinetic parameters is a necessary stage of pharmaceutical development of original medicinal agents, allowing to choose the composition and dosage form of the preparation. This is due to obtaining characteristics of all processes that occur in the body of an animal (human), from the absorption of a drug from the place of administration to its excretion from the body.Aim. To conduct a study of the pharmacokinetics of the pharmaceutical substance and the complex compounds based on it to confirm the pharmaceutical development of a drug of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil and to justify the optimal composition of the ready dosage form (GLP).Materials and methods. The study was carried out on male rabbits with a single oral administration of investigated objects in one dose. Plasma concentrations of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil were determined by high performance liquid chromatography (HPLC) with ultraviolet (UV) detection. Pharmacokinetic parameters were calculated by extramodel method of statistical moments.Results and discussion. Assay 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil quantification in rabbit blood plasma by HPLC has been developed and validated in the concentration range 10–720 ng/ml in accordance with modern requirements and satisfies them for all indicators. Assay was applicated to analysis of plasma samples obtained from laboratory animals after a single oral administration of a substance and solid dispersion systems of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil in one dose. The main pharmacokinetic parameters of the studied objects were calculated after obtained plasma concentrations of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil. It was found that the solid dispersion system with Kollidon 17PF has the greatest relative bioavailability from the examined objects; its relative bioavailability to the substance by oral administration was 583 %.Conclusion. The solid dispersion system method increased the bioavailability of 1-[2-(2-benzoylphenoxy)ethyl]-6-methyluracil. Obtained results confirmed correctness of solid dispersion system selection drug e composition and technology development.

Ileo-Colon Targeting of the Poorly Water-Soluble Drug Celecoxib Using a pH-Dependent Coating in Combination with Self-Emulsifying Drug Delivery or Solid Dispersion Systems

Targeting celecoxib to the ileo-colonic region could be beneficial for the treatment and prevention of colon cancer. Ileo-colonic targeting can be achieved by using pH-dependent coating systems such as ColoPulse. Celecoxib has poor aqueous solubility, which may jeopardize optimal treatment. Therefore, we combined a pH-dependent coating with self-emulsifying drug delivery systems (SEDDS) or with solid dispersion systems (SD); two approaches that are often used to improve the dissolution behavior of lipophilic drugs. The dissolution behavior of various formulations of both systems was investigated. Optimized formulations with and without precipitation inhibitors were coated with the ColoPulse and the release of celecoxib was tested under non-sink conditions using an in vitro dissolution system, simulating the pH gradient of the gastrointestinal tract. The dissolution behavior of SDs with and without precipitation inhibitor (sodium dodecyl sulfate) and the SEDDS without precipitation inhibitor was negatively impacted by the coating. Control experiments indicated that components of the coating released in the dissolution medium acted as precipitation mediators. However, the SEDDS formulation with HPMC 4000 cps as a precipitation inhibitor showed excellent dissolution behavior. We hypothesize that HPMC accumulates at the oil/water interface of the emulsion thereby stabilizing the emulsion resulting in maintenance of the supersaturated state.

Preparation of solid dispersion systems for enhanced dissolution of poorly water soluble diacerein: In-vitro evaluation, optimization and physiologically based pharmacokinetic modeling

Diacerein (DCN), a BCS II compound, suffers from poor aqueous solubility and limited bioavailability. Solid dispersion systems (SD) of DCN were prepared by solvent evaporation, using hydrophilic polymers. In-vitro dissolution studies were performed and dissolution parameters were evaluated. I-Optimal factorial design was employed to study the effect of formulation variables (drug:polymer ratio and polymer type) on the measured responses including; drug content (DC) (%), dissolution efficiency at 15 min (DE (15 min)%) and 60 min (DE (60 min)%) and mean dissolution time (MDT) (min). The optimized SD was selected, prepared and evaluated, allowing 10.83 and 3.42 fold increase in DE (15 min)%, DE (60 min)%, respectively and 6.07 decrease in MDT, compared to plain drug. DSC, XRD analysis and SEM micrographs confirmed complete amorphization of DCN within the optimized SD. Physiologically based pharmacokinetic (PBPK) modeling was employed to predict PK parameters of DCN in middle aged healthy adults and geriatrics. Simcyp® software established in-vivo plasma concentration time curves of the optimized SD, compared to plain DCN. Relative bioavailability of the optimized SD compared to plain drug was 229.52% and 262.02% in healthy adults and geriatrics, respectively. Our study reports the utility of PBPK modeling for formulation development of BCS II APIs, via predicting their oral bio-performance.

Modification of dispersion systems and its motion in cylindrical pipes

This paper analyzes the dependence of properties of turbid flow on the dispersion composition and concentration of solid particles. The article presents the features of the transfer of river suspended solids and water in the pressure stations, that is, the effect on the distribution of kinematic and dynamic parameters of the flow of suspended particles of hydraulic transport.