Evaluation of the Influence of Stirring Speed on the Release Kinetics of Fexofenadine HCl Polymeric Microspheres

Microspheres, a potential drug delivery approach, has opened a new era for attaining versatile release patterns needed. By optimizing the formulation variables, they can be prepared to obtain targeted release, immediate release, sustained release patterns. The release of the active drug material depends upon a number of formulation parameters such as polymers, stirring speed (rpm), methodology, surfactants, etc. Fexofenadine hydrochloride (HCl) is a second generation antihistamine. Our present research has explored the effects of using different rpm (600- 1000 rpm) in preparing fexofenadine hydrochloride (HCl) microspheres by emulsion solvent evaporation method. The formulation is aimed to provide sustained release for the required long period with a high margin of safety. We used a blended mixture of Hydroxy Propyl Methyl Cellulose (HPMC) K 100 MCR and Eudragit RL100 polymers to have sustained-release microspheres. The impact of different rpm on Yield, drug encapsulation efficiency, flow properties, and dissolution pattern were appraised. We observed the release of the drug for 10 hours in phosphate buffer (pH 6.8) and evaluated the drug release spectrophotometrically. Our study finds that the release of fexofenadine HCl from the microspheres was significantly increased with drug loading. We found the dosage forms to follow Higuchi release kinetics and Hixson-Crowell release kinetics the most, indicating successful achievement of sustained-release pattern in the dosage form. The change in drug release rate was statistically significant for variation in the stirring rate. We found that 600 rpm was the most optimized stirring rate for preparing microspheres in the emulsion solvent evaporation method.

Ethanolysis of Waste Cooking oils using KOH Catalyst

The transesterification of waste cooking oils (WCO) with ethanol was investigated by means of potassium hydroxide (KOH) as catalyst. This work aimed to study the influences of catalyst concentration, temperature, ethanol to WCO molar ratio, reaction time, and stirring rate on the biodiesel conversion. Gas chromatography (GC) was used during the process of transesterification to determine the evolution of ethyl esters concentration with time. Biodiesel with maximum yield was obtained (92.5%) when 2 wt% KOH, temperature of 75°C, and ethanol/oil molar ratio of 11:1 were utilized.

Parameter selection of Polystyrene-Dietilenetriaminepenta acetate Resin Synthesis for the separation of rare Earth Elements by using Plackett-Burman Experimental Design

The development of the separation method has an essential role in developing science and technology for the separation and purification of an element or compound from other mixtures based on differences in physical and chemical properties. This research is more focused on the selection parameters of polystyrene-based resin production using diethylene triamine penta-acetate (DTPA) light, which used as a prototype for improved scale production. The Plackett-Burman design was used to select variables that have significant influence in Methylaminopolystyrene-Diethylenetriaminepentaacetate (MAP-DTPA) resin synthesis. Eleven variables such as mol ratio of Methylamino Polystyrene and diethylene triamine penta-acetate ligands, solvent volume, reaction time, stirring rate, reaction temperature, total volume, reaction pH, incubation time, ammonia concentration, and the addition of methanol were carried out for the selection of parameters or variables in the process of MAP-DTPA resin synthesis through a statistical approach in studies for design experiments using Software Design Expert 9.0.6.2. Of the eleven variables in resin synthesis obtained, six variables have a positive influence on the yield ratio value (percent yield ratio) of MAP-DTPA resin are the mol ratio of MAP and DTPA, Stirring Rate, reaction temperature, total volume, degree of acidity, and ammonia concentration.

Optimization of Zinc Recovery from Sphalerite Using Response Surface Methodology and Particle Swarm Optimization

Hydrometallurgical leaching process has been identified as a viable procedure for recovering metals of value from their matrices. The optimization of zinc recovery from sphalerite in nitric acid solution was carried out in this study. The Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) and Particle Swarm Optimization (PSO) tool in matlab were deployed for the optimization studies. RSM modeling gave optimum conditions of 73.0 °C leaching temperature, 3.48 M acid concentration, 0.027 g/mL solid/liquid ratio, 411.02 rpm stirring rate, and 82.82 minutes leaching time; with a zinc yield of 87.67 %. With PSO, about 86.9 % zinc was recovered at a leaching temperature of 69.1 °C, acid concentration of 1.8 M, solid/liquid ratio of 0.031 g/mL, stirring rate of 270 rpm and leaching time of 85 minutes. Thus, PSO and RSM proved to be good optimization tools.

Potential Efficient Separation of Oil from Bilgewater and Kitchen Wastewater by Fractional Freezing Process

Oily wastewater discharge to water bodies can have many negative consequences, especially on the marine ecological environment. Although there are numerous techniques for treating oily wastewater, this paper aims to introduce and evaluate the potential of the fractional freezing (FF) process as a new oil–water separation technique to overcome the several weaknesses found in the conventional oil–water separation methods. FF separates two liquid compounds based on their freezing point difference. In this study, two oily wastewater samples were used: oily bilgewater and oily kitchen wastewater. The effects of coolant temperature, freezing time, and stirring rate on the FF process efficiency were studied, and the significance of the data was supported by statistical analysis. The results show that a low coolant temperature is essential for allowing crystal nucleation formation and inducing crystal growth for an efficient separation process. However, the higher crystal growth rate that occurs at an even lower temperature might entrap the impurities inside the growing crystal. Consequently, continuing the crystallization for a longer time may yield a less efficient separation process. Furthermore, a too high stirring rate will rupture the solid formation, hence reducing the process efficiency. The final values of oil/grease and free fatty acids (FFA) obtained after the FF process of both samples were found to comply with the standard permitted by the International Maritime Organization (IMO) and Palm Oil Refiners Association of Malaysia (PORAM). Moreover, the p-values obtained for both of the above-mentioned samples were below 0.05 for all experiments. It can be concluded that this method has the potential to separate oil from the oily bilgewater and kitchen wastewater.

Spent Grain from Malt Whisky: Assessment of the Phenolic Compounds

In order to extract antioxidant phenolic compounds from spent grain (SG) two extraction methods were studied: the ultrasound-assisted method (US) and the Ultra-Turrax method (high stirring rate) (UT). Liquid to solid ratios, solvent concentration, time, and temperature/stirring rate were optimized. Spent grain extracts were analyzed for their total phenol content (TPC) (0.62 to 1.76 mg GAE/g SG DW for Ultra-Turrax pretreatment, and 0.57 to 2.11 mg GAE/g SG DW for ultrasound-assisted pretreatment), total flavonoid content (TFC) (0.6 to 1.67 mg QE/g SG DW for UT, and 0.5 to 1.63 mg QE/g SG DW for US), and antioxidant activity was measured using 2, 2-diphenyl-2-picrylhydrazyl (DPPH) free radical (25.88% to 79.58% for UT, and 27.49% to 78.30% for UT). TPC was greater at a high stirring rate and high exposure time up to a certain extent for the Ultra-Turrax method, and at a high temperature for the ultrasound-assisted method. P-coumaric acid (20.4 ± 1.72 mg/100 SG DW for UT, and 14.0 ± 1.14 mg/100 SG DW for US) accounted for the majority of the phenolic found compounds, followed by rosmarinic (6.5 ± 0.96 mg/100 SG DW for UT, and 4.0 ± 0.76 mg/100 SG DW for US), chlorogenic (5.4 ± 1.1 mg/100 SG DW for UT, and non-detectable for US), and vanillic acids (3.1 ± 0.8 mg/100 SG DW for UT, and 10.0 ± 1.03 mg/100 SG DW for US) were found in lower quantities. Protocatechuic (0.7 ± 0.05 mg/100 SG DW for UT, and non-detectable for US), 4-hydroxy benzoic (1.1 ± 0.06 mg/100 SG DW for UT, and non-detectable for US), and caffeic acids (0.7 ± 0.03 mg/100 SG DW for UT, and non-detectable for US) were present in very small amounts. Ultrasound-assisted and Ultra-Turrax pretreatments were demonstrated to be efficient methods to recover these value-added compounds.

Enhancing the anode performance of microbial fuel cells in the treatment of oil-based drill sludge by adjusting the stirring rate and supplementing oil-based drill cuttings

This was the first attempt to investigate the bioelectricity output based on solid-liquid cooperation in the microbial fuel cell (MFC) treatment of oil-based drill sludge by adjusting the stirring rate (SR) and supplementing oil-based drill cuttings (OBDCs). According to the results, the maximum power density output reached 671 mW/m2 (5.4 kW h/m2) when the stirring rate was 100 r/min and the OBDCs concentration was 2 g/L in the anode chamber, which was more than 2.4 times as high as that of the control group and significantly higher than those of other MFCs. Extremely high removal efficiencies of chemical oxygen demand (COD), ammonia and total inorganic nitrogen (TIN) were realized in optimization, with values of 52.3 ± 1.9% (the removal quality was 12081 ± 432 mg/L), 74.5 ± 0.2% and 58.9 ± 0.2%, respectively. Electrochemical analyses and high-throughput sequencing revealed that the cooperation of stir with OBDCs could activate microbial activity while reducing the overpotential loss in anode systems and thus responsible for the enrichment of electrogenic bacteria with extracellular electron transfer functions (such as Proteobacteria, Bacteroidetes and Actinobacteria) and denitrifying bacteria (such as Bacilli and Anaerolineae and Rhodopseudomonas). Moreover, substrate characterization (via Fourier-transform infrared spectrometry (FT-IR) and X-ray diffraction (XRD)) showed that organic matter might converted into small molecules without intermediates. This investigation offers a new strategy for the treatment /application of solid and liquid produced from oil and gas fields by bioelectrochemical technology.

FORMULATION AND EVALUATION OF AMPHOTERICIN B AND MILTEFOSINE COMBINATION NANOVESICLES

Objective: The aim of the present investigation is to formulate and evaluate amphotericin B-miltefosine combination nanovesicles for application in the treatment of visceral leishmaniasis. Methods: Amphotericin B-miltefosine combination (AmB-MTF) nanovesicles were prepared by ethanol injection method. Formulations of nanovesicles were evaluated at varying conditions of lipids composition, drug-lipid proportion, ethanol-water composition and stirring rate, on drug entrapment efficiency and particle size. Results: The study showed that entrapment efficiency was significantly affected (p<0.01) by the effects of lipids composition, drug-lipid proportion, ethanol-water composition, and stirring rate. Particle size of nanovesicles was significantly affected (p<0.05) by drug-lipid proportion and stirring rate. An optimized formulation of amphotericin B-miltefosine nanovesicles was prepared at optimal factors composition of: phosphatidylcholine-cholesterol-stearic acid 20:4:1, drug-lipid 1:8, AmB-MTF 1:1; ethanol-water 1:4 ratios, and stirring rate 1000 rpm. The AmB-MTF 1:1 nanovesicles formulation showed particle size of 145.6 nm, poly dispersity index 0.19, zeta potential-27.3 mV and drug entrapment efficiency 87%. Conclusion: Evaluation of AmB-MTF 1:1 nanovesicles showed development of a successful formulation with very good compatibility, extended drug release, convenient vesicle size and high drug entrapment efficiency. To conclude, AmB-MTF 1:1 nanovesicles formulation could be a safe and reliable therapeutic option over the conventional combination therapy provided further antileishmanial investigations are investigated in vitro and in vivo.

Alginate-chitosan core-shell microcapsule cultures of hepatic cells in a small scale stirred bioreactor: impact of shear forces and microcapsule core composition

A small scale stirred bioreactor was designed and the effect of different agitation rates (30, 60 and 100 rpm) was investigated on HepG2 cells cultured in alginate-chitosan (AC) core-shell microcapsule in terms of the cell proliferation and liver-specific function. The microencapsulated hepatic cells could proliferate well when they were cultured for 10 days at 30 rpm while the cell-laden microcapsules showed no cell proliferation at 100 rpm in the bioreactor system. Albumin production rate, as an important liver function, increased also 1.8- and 1.5- fold under stirring rate of 30 rpm compared to the static culture and 60 rpm of agitation, respectively. Moreover, In comparison with the static culture, about 1.5-fold increment in urea production was observed at 30 rpm. Similarly, the highest expressions of albumin and P450 genes were found at 30 rpm stirring rate, which were 4.9- and 19.2-fold of the static culture. Addition of collagen to the microcapsule core composition (ACol/C) could improve the cell proliferation and functionality at 60 rpm in comparison with the cell-laden microcapsules without collagen. The study demonstrated the hepatic cell-laden ACol/C microcapsule hydrogel cultured in the small scale stirred bioreactor at low mixing rate has a great potential for mass production of the hepatic cells while maintaining liver-specific functions.

Effect of Time, Temperature and Stirring Rate Used in the First Step of the Synthesis of SBA-15 on Its Application as Reductor of Tars in Tobacco Smoke

SBA-15 has been employed as a tobacco additive with the objective of reducing the toxic and carcinogenic components in tobacco smoke. The effect of the synthesis conditions (temperature, time, and stirring rate) on this application was studied in this paper. The SBA-15 was characterized (RDX, N2 adsorption isotherms, SEM and apparent density), mixed with the 3R4F reference tobacco, and smoked under standard conditions. The composition of the gas and condensed fractions also was analyzed. The morphology of the material plays an important role on this application and is highly influenced by the three variables studied. Long fibers show improved efficiency compared to short fibers. The tar reduction effect was improved when increasing the time of synthesis. Nevertheless, a maximum was observed with temperature (40 °C) and stirring rate (700 rpm). The optimal synthesis conditions obtained were 24 h, 40 °C and 700 rpm, yielding reductions as high as 68% for tar, 67% for nicotine, and 31% for CO. The scaling-up process has only been reported in terms of grams but never in a preindustrial scale (around 4 kg), and thus the results of this analysis show a promising material with properties and behavior similar with respect to the sample synthesized at laboratory scale.