Effect of Polymers nature and Stirring Speeds on Physicochemical Properties and the Controlled Release of Allopurinol-loaded Microspheres

Allopurinol is an antigout drug therapy, commonly used in the treatment of chronic gout or hyperuricaemia associated with treatment of diuretic conditions. In the present study, new formulations based on Allopurinol, have been prepared with the microencapsulation by solvent evaporation process. Microspheres were prepared using pure Allopurinol and polymeric matrices (ethylcellulose EC, poly (ε-caprolactone) PCL, β-cyclodextrin CD and hydroxypropylmethylcellulose HPMC) at different compositions and stirring speeds to investigate the effect of these parameters on loading efficiency and drug release kinetics. The formulations produced were characterized by various methods : Fourier transforms infrared spectroscopy (FTIR), X-ray powder diffractometry, optical microscopy, surface morphology by scanning electron microscopy (SEM) and drug loading, as well as in vitro release studies in the simulated stomach tract. Depending on the stirring speed and the composition of the microparticles, the active ingredient loading is in a range from 10.46 ± 1.45 to 46.40 ± 0.5%. The microspheres are spherical and the mean Sauter diameter (d32) of the microparticles obtained is smaller and is in the range of 47.71 to 151.01 µm. Different release profiles were obtained and show that the release rate is strongly influenced by the characteristics of the microparticles ; namely, the stirring rates and the composition of the microparticles. The release mechanism was identified by modelling using Higuchi and Korsmeyer-Peppas models. Resumen. Alopurinol es una droga terapéutica para tratar la gota, y se utiliza en el tratamiento de gota crónica o hiperuricemia asociada con el tratamiento de condiciones diuréticas. En este estudio, nuevas formulaciones basadas en Alopurinol se prepararon mediante microencapsulación por el proceso de evaporación de disolvente. Microesferas se prepararon usando Alopurinol puro y diferentes matrices poliméricas (etil-celulosa EC, poli(-caprolactona) PCL, β-cyclodextrina CD e hidroxipropil-metil-celulose HPMC) en diferentes composiciones y velocidades de agitación, para investigar el efecto de estos parámetros en la eficiencia de carga y en la cinética de liberación del fármaco. Las formulaciones obtenidas fueron caracterizadas por diferentes técnicas : Espectroscopía infrarroja de transformadas de Fourier (FTIR), difractometría de rayos X de polvos, microscopía óptica, morfología de superficies mediante microscopía electrónica de barrido electrónico, y la eficiencia de carga del fármaco, así como estudios de liberación in vitro en tracto estomacal simulado. Dependiendo de la velocidad de agitación y la composición de las micropartículas, la carga del ingrediente activo se encuentra en el rango de 10.46 ± 1.45 a 46.40 ± 0.5%. Las microesferas son esféricas y el diámetro medio de Sauter (d32) de las micropartículas obtenidas es menor, y se encuentra en el rango de 47.71 a 151.01 µm. Se obtuvieron diferentes perfiles de liberación y se observa que la velocidad de liberación está influenciada principalmente por las características propias de la producción de las micropartículas ; en particualr, las velocidades de agitación y las composición de las micropartículas. El mecanismo de liberación se ajusta mejor a los modelos matemáticos de Higuchi and Korsmeyer-Peppas.

Assessment of Corrosion Performance of Steel Rebar in Snail Shell Ash Blended Cements under Marine Environments

An attempt has been made on a constructive approach to evaluate the performance of snail shell ash (SSA) for its corrosion performance under marine environments. Corrosion performance of steel rebar in chloride-contaminated SSA with (0% to 50%) replacement levels of cement extract medium was examined through electrochemical and weight loss techniques. Initially, snail shell powder (SSP) is made by pulverizing and subsequently SSA is by thermal decomposition methods. Both SSP and SSA were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy, scanning electron microscopy, and energy dispersion X-ray spectroscopy. Concrete cubes with 0% to 50% replacement levels of cement by SSA were evaluated for their mechanical properties. A critical level of 20 to 30% SSA improved both corrosion resistance and strength of concrete. Extrapolation modeling for the strength and corrosion rate with respect to later age were made. SSA is a suitable replacement material for natural limestone in cement productions.

The Influence of H2O2 on The Photocatalytic Pretreatment of Cellulose for 5-Hydroxymethyl Furfural (5-HMF) Production

Photocatalysis has been widely known as a simple green technology to be applied in the synthesis and degradation process of organic molecules. An application of photocatalysis in a biomass pretreatment for a 5-hydroxymethylfurfural (5-HMF) production was investigated in this study. The results have revealed that photocatalysis, applied during pretreatment, facilitates the breakdown of cellulose. The presence of oxidizing agent (H2O2) in the ratios to cellulose of 11:1, 18:1, and 37:1 mol.mol-1 has been investigated for its effect on the production of 5-HMF. The optimum conditions obtained for the pretreatment process was the presence of H2O2 at 37:1 mol.mol-1, which was followed by the process of evaporation of the remaining H2O2 after pretreatment. The 5-HMF yield from the hydrolysis process involving pretreatment was 13.07%, while the yield from the process without pretreatment was 9.79%. The application of the pretreatment has succeeded in increasing the 5-HMF yield by 25.09%. The progress in the pretreatment was also marked by the presence of the carboxyl groups in the pretreated samples which were observed by the Fourier Transforms Infrared spectroscopy (FTIR). Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Effect on Thermal Properties of Nanocellulose Fibre (NCF) Reinforced Biodegradable Polyhydroxylalkanoates (PHA) Composite

Currently, biodegradable materials like polyhydroxyalkanoates (PHA) and polylactic acid (PLA) are receiving huge attention from the both scientific and industrial sectors. However, since PHA has poor thermal properties, there is a shortfall in the exploration of PHA ability with filler. Therefore, this research aim is to investigate the thermal effect of nanocellulose fiber (NCF) fillers with PHA polymer. The first solution of PHA composite is prepared by dissolving 1g of PHA in 40mL of dichloromethane at 30°C for 10 minutes. The PHA-NCF composite solution is prepared by adding 1wt%, 2wt%, 3wt%, and 4wt% of NCF dissolved in 40 mL of dichloromethane into the PHA solution. The mixture solution is agitated at 45°C with a magnetic stirrer for 10 minutes. The mixture is poured into a petri dish. The prepared films were characterized by Differential Scanning Calorimeter (DSC), Fourier Transforms Infrared Spectroscopy, (FTIR), and Thermogravimetric Analysis (TGA). The FTIR analysis shows that all PHA/NCF composite samples contain similar functional groups when compared with the pure PHA. No significant changes on the thermal properties of the PHA composite was observed with the addition of NCF fillers. However, comparison within the PHA/NCF samples shows that the PHA with 2% of NCF has a higher melting temperature and requires the highest enthalpy of melting. Hence, the addition of 2% of NCF is selected to be the optimum amount of NCF filler addition to the PHA composite.

Study of the Biodegradation of PLA/PBAT Films after Biodegradation Tests in Soil and the Aqueous Medium

The intense consumption of conventional plastics has been generating a series of problems for nature due to the accumulation of municipal solid waste because of its difficult degradation. Therefore, the use of biodegradable polymers becomes a good option to minimize these effects. Poly (lactide acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) is a biodegradable blend that can be used mainly in applications that have a short shelf life. So, it is important to know the total biodegradation time of this blend. For this reason, PLA/PBAT films (1.5 x 1.5 x 0.15 cm) were produced by thermal compression molding to be subjected to biodegradation tests in soil and aqueous medium for 180 days. The films were characterized by visual analysis, weight loss measurements, differential scanning calorimetry (DSC), Fourier transforms infrared spectroscopy (FT-IR), contact angle, and scanning electron microscopy (SEM). DSC showed an increase of 0.7% in PLA crystallinity subjected to the aqueous medium, while FT-IR showed a reduction in the bands at 1710 cm-1 and 1100 cm-1, as a result of hydrolysis for both methodologies. The blend's hydrophilic character was increased after both degradation processes, presenting a reduction of 34.5% in the contact angle after biodegradation in soil. From the results, it was possible to conclude that PLA/PBAT films did not degrade completely, as expected, but showed signs that indicated the beginning of the degradation. The degradation was more effective in the aqueous medium.

Modifying the Electronic and Optical Properties of Nano ZnS via Doping With Mn and Fe

5% Fe and Mn-doped nano ZnS (Zn0.95A0.05S, A=Fe or Mn) was prepared using the thermolysis technique. The effect of Fe and Mn doping on the lattice parameter, crystallite size, and lattice microstrain was examined applying Rietveld refinement. The analysis showed the incorporation of Fe and Mn substitutionally for Zn ions; a result confirmed by Fourier transforms infrared spectroscopy spectra from the shift in the vibration bands upon doping. The energy of ZnS band gap was reduced by doping, giving ZnS new applications. The different defects inside the different samples were investigated using photoluminescence spectroscopy. The effect of Fe/ Mn doping and incorporation of atmospheric oxygen on the bandgap characteristics, the absorption, optical conductivity, refractive index and the extinction coefficient, reflectance, the real and imaginary parts of the dielectric constant were explored using density function theory calculation (DFT).

Anisotropic acoustic phonon polariton-enhanced infrared spectroscopy for single molecule detection

Nanoscale Fourier transforms infrared spectroscopy (nano-FTIR) based on scanning probe microscopy enables identification of chemical composition and structure of surface species with a high spatial resolution (~10 nm), which is...

Zearalenone Removal by Using Banana Peel as an Adsorbent

Zearalenone (ZEA) is the most occurring Fusarium toxin in animal feed causing reproductive disorders and results in severe economical losses. A renewable bio adsorbent sourced from banana peel was tested for in vitro removal of ZEA from liquid mediums at different pH values. Efficacy of banana peel to sequester ZEA was evaluated by varying its pH, adsorbent dosage, equilibration time and quantified by using UHPLC-MS/MS. Adsorption was found to be efficient and completed in fifteen minutes with highest adsorption at alkaline pH (9). The adsorption and desorption studies have demonstrated the adsorption was strong enough to sustain the pH changes (3-9). Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscope (SEM) was used to characterize the surface of bio sorbent to explain the mechanism of adsorption. Langmuir and Freundlich isotherm was found to be best fitted model with maximum monolayer capacity (Q0) 8 ng/mg. The results of this study suggested that dried banana peel may be an effective low cost decontamination method to be incorporated in animal feed.

Biocarbon Derived from Opuntia ficus indica for p-Nitrophenol Retention

Activated carbon obtained from Opuntia ficus indica by sodium hydroxide activation was employed for the adsorption of p-nitrophenol from water. The activated carbons obtained were characterized by Fourier transforms infrared spectroscopy, sorption of nitrogen, scanning electron microscopy, and Boehm titration. Effects of pH, contact time, amount of adsorbent, and temperature on the adsorption of p-nitrophenol were studied. Adsorption isotherms were analyzed using Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich models, and the thermodynamic parameters have been determined. The adsorption of p-nitrophenol was spontaneous, exothermic, and propitious at 15 °C and adopted the pseudo-second order model, and the most credible isotherm was Langmuir’s one. The activated carbon used in this work has good p-nitrophenol adsorption characteristics, and the study of the desorption and reuse of this carbon shows that it retains a removal rate greater than 94% after five cycles of adsorption-desorption.

Physical, Mechanical and Structural Properties of Yttrium Oxide Doped Zinc Borate Glasses

In this project, the nominal glass composition with the form of (55-x) H3BO3-45ZnO-xY2O3 (x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol%) are synthesized by melt quenching techniques. The effect of Y2O3 on physical, mechanical and structural properties of glasses have been investigated using different characterization techniques. The parameters like density, molar volume and oxygen packing density have been calculated. Based on the micro hardness study, it has showed the decreasing trend from 518.80 N.mm-2 to 453.13 N.mm-2 with an increasing of Y2O3 content from 0.0 mol% to 2.5 mol%. The structural features of the yttrium oxide doped zinc borate glass were studied via X-Ray Diffraction (XRD) to confirm the amorphous nature of glass and Fourier Transforms Infrared Spectroscopy (FTIR) has been done to obtain the band positions and functional groups. FTIR spectral studies were recorded in the 400-4000 cm-1 wavenumber range at room temperature.