Peroxide Degradation Research Articles

Experimental and COSMO-RS theoretical exploration of rutin formulations in natural deep eutectic solvents: Solubility, stability, antioxidant activity, and bioaccessibility

The present study aimed to estimate the solubility of rutin in twelve natural deep eutectic solvents (NADES) and to compare experimental results with the theoretical prediction by the COSMO-RS program. The mandatory component in all investigated systems was choline chloride (ChCl), and the variable component was hydrogen bond donor (HBD), including organic acids, sugars, alcohols, and urea. The FRAP method tested the antioxidant activity of rutin formulations in NADES systems. It was found that theoretical prediction and experimentally determined solubilities of rutin were in excellent agreement. The highest solubility of rutin was observed in 1,2-propanediol (ChCl:1,2PD), 59.30 mg/mL and urea-based systems (ChCl:Ur), 57.99 mg/mL. These systems were further investigated, including dissolution efficiency study, stability to UV and hydrogen-peroxide degradation, and bioaccessibility of rutin by in vitro digestion model. It was found that ChCl:Ur protected rutin against UV-induced oxidation. It was also found that rutin solubilization in ChCl:Ur and ChCl:1,2PD retained rutin for 78.64% and 76.57% in digestive fluids after in vitro digestion and enhanced bioaccessibility compared to the control for more than 60%.

A NOVEL METHOD DEVELOPMENT AND VALIDATION FOR THE QUANTIFICATION OF NEFOPAM HYDROCHLORIDE IN PARENTERAL DOSAGE FORM BY RP-HPLC METHOD

Objective: Using RP-HPLC, a simple, accurate, and exact method for estimating the Nefopam Hydrochloride parenteral dose form was devised.
 Methods: The isocratic mode of the RP-HPLC method used an Inertsil C8 column as the stationary phase and a mobile phase of potassium dihydrogen phosphate with pH 3.0: Acetonitrile (70:30) at a flow rate of 1 ml/min. With UV detection at 220 nm, a flow rate of 1 ml/min was established.
 Results: The developed RP-HPLC technique revealed acceptable linearity (R2 = 0.9998) and good assay results in the concentration range of 0.004–0.08 mg/ml (103.3 percent). Further forced degradation investigations using 0.1N Hydrochloric acid (acid degradation), 0.1NNaOH (base degradation), and 3 percent H2O2 (Hydrogen peroxide) were carried out using RP-HPLC, and percent degradation values were determined. In peroxide degradation conditions, the medication was shown to be unstable.
 Conclusion: In compliance with ICH requirements, the developed procedures were validated.

Efficiently Enhanced Fenton-Like Reaction via CuO@γ-Al2O3 Particles for the Catalytic Hydrogen Peroxide Degradation of Polyvinyl Alcohol, Rhodamine-B, and Reactive red X-3B over a Wide pH Range

Efficiently Enhanced Fenton-Like Reaction via CuO@γ-Al2O3 Particles for the Catalytic Hydrogen Peroxide Degradation of Polyvinyl Alcohol, Rhodamine-B, and Reactive red X-3B over a Wide pH Range

Enhanced thermal activation of persulfate by coupling hydrogen peroxide for efficient degradation of pyrene

In this study, H2O2 was introduced into thermally activated persulfate oxidation system (T-HPS), and the oxidation of pyrene (PYR) was investigated by the combined T-HPS technology. The results showed that H2O2 could significantly improve the reactivity of the thermally activated persulfate system (T-PS), with 240-min PYR degradation ratio increasing from 79.3% to 97.2% at 70 °C. In the T-HPS system, as persulfate initial concentration increased from 5 to 100 μM, the kinetic rate constant (kobs) of PYR degradation increased from 4.70 × 10−3 to 3.01 × 10−2 min−1, but the kobs did not show a positive association with H2O2 concentration with the same range, and the highest kobs was obtained at the H2O2 initial concentration of 20 μM. The optimal ratio of PS and H2O2 was set at 1:1 with the initial concentrations of the two oxidants both being 20 μM. Furthermore, PYR could be removed efficiently in a wide range of pH, and the best PYR degradation performance was obtained under neutral pH. Scavenging experiments demonstrated that OH played a more important role in PYR degradation in the T-HPS system than in the T-PS system. As suggested by the Arrhenius equation, the activation energy decreased from 124.5 to 107.4 kJ mol−1 after adding H2O2 to the T-PS system. This study provides a new oxidation approach that could prompt the T-PS activity by adding a suitable dosage of H2O2.

Circulating Factors Provoke Endothelial Dysfunction in the Human Microcirculation Following Doxorubicin Chemotherapy

RationaleAnthracyclines (e.g., doxorubicin) are among the most effective anti‐cancer therapies (CTx), yet their use is limited by cardiotoxic side effects. We sought to characterize the impact of anthracycline‐based CTx on microvascular endothelial function in breast cancer patients and determine if circulating factors are sufficient to induce endothelial dysfunction.MethodsWe assessed microvascular endothelium‐dependent vasodilation and its underlying mechanisms in two groups of breast cancer patients: 1) CTx‐naïve controls and 2) CTx‐treated patients (one month post‐CTx). Adipose samples were obtained at the time of surgical procedures. Freshly‐dissected arterioles were cannulated and pressurized, then flow‐induced production of nitric oxide (NO) and mitochondria‐derived hydrogen peroxide (H2O2) were visualized with fluorescent indicator probes. Next, we assessed whether plasma obtained from breast cancer patients one month following completion of CTx would evoke endothelial dysfunction. Adipose arterioles from healthy donors were exposed to diluted plasma from either CTx patients or healthy controls. Vessels were cannulated and filled with 10% plasma for overnight incubation prior to assessing flow‐mediated dilation (FMD; videomicroscopy). Data are expressed as area under the curve (AUC) for percentage change in diameter across five flow gradients and are shown as mean ± SE for n = 3–9 per condition.ResultsIn the cross‐sectional study, FMD was ~65% lower in vessels from breast cancer patients who had undergone CTx compared to those who were CTx‐naïve (AUC: 23 ± 10 vs. 61 ± 6, P = 0.004). Preliminary results suggest flow‐induced NO production is abolished in vessels from patients one month after CTx (Panel A, fold change in NO: −0.2 ± 0.2 vs. CTx‐naïve group: 11.3 ± 5.6; P = 0.08), whereas mitochondrial H2O2 production is elevated (Panel B, fold change in mtH2O2: 0.52 ± 0.25 vs. −0.51 ± 0.23; P = 0.03). FMD was also ~40% lower in vessels exposed to CTx plasma vs. healthy plasma (Panels C & D, AUC: 45 ± 7 vs. 75 ± 7, P = 0.049). Degradation of hydrogen peroxide (H2O2) with PEG‐catalase further reduced FMD in vessels exposed to CTx plasma (AUC: 22 ± 12), whereas PEG‐catalase did not affect dilation in vessels exposed to healthy plasma (AUC: 62 ± 17). Inhibition of NO synthase (NOS) with L‐NAME restored FMD in vessels exposed to CTx plasma (AUC: 77 ± 6), while L‐NAME had minimal impact on dilation in vessels exposed to healthy plasma (AUC: 60 ± 9). Future studies are needed to determine whether this reflects NOS uncoupling.Summary & ConclusionsMicrovascular endothelial function is impaired in breast cancer patients following doxorubicin chemotherapy. This is accompanied by a loss of NO and elevation of H2O2. Plasma obtained from breast cancer patients one month after cessation of CTx recapitulates these effects in otherwise healthy vessels, which suggest that circulating factors may contribute to endothelial dysfunction following treatment. Our preliminary findings reveal long‐term defects in the microcirculation that may contribute to adverse cardiovascular outcomes associated with doxorubicin chemotherapy.

Insights into the Mechanisms of Lactobacillus acidophilus Activity against Entamoeba histolytica by Using Thiol Redox Proteomics.

Amebiasis is an intestinal disease transmitted by the protist parasite, Entamoeba histolytica. Lactobacillus acidophilus is a common inhabitant of healthy human gut and a probiotic that has antimicrobial properties against a number of pathogenic bacteria, fungi, and parasites. The aim of this study was to investigate the amebicide activity of L. acidophilus and its mechanisms. For this purpose, E. histolytica and L. acidophilus were co-incubated and the parasite’s viability was determined by eosin dye exclusion. The level of ozidized proteins (OXs) in the parasite was determined by resin-assisted capture RAC (OX–RAC). Incubation with L. acidophilus for two hours reduced the viability of E. histolytica trophozoites by 50%. As a result of the interaction with catalase, an enzyme that degrades hydrogen peroxide (H2O2) to water and oxygen, this amebicide activity is lost, indicating that it is mediated by H2O2 produced by L. acidophilus. Redox proteomics shows that L. acidophilus triggers the oxidation of many essential amebic enzymes such as pyruvate: ferredoxin oxidoreductase, the lectin Gal/GalNAc, and cysteine proteases (CPs). Further, trophozoites of E. histolytica incubated with L. acidophilus show reduced binding to mammalian cells. These results support L. acidophilus as a prophylactic candidate against amebiasis.

Effects of UV/H2O2 degradation and step gradient ethanol precipitation on Sargassum fusiforme polysaccharides: Physicochemical characterization and protective effects against intestinal epithelial injury

In this study, the degraded purified fraction from Sargassum fusiforme polysaccharides (SFP), named DSFP, was produced by the treatment of ultraviolet/hydrogen peroxide (UV/H2O2) degradation and step gradient ethanol precipitation. Results showed that the treatment significantly reduced the molecular weight of polysaccharides, from 282.83 kDa to 18.54 kDa, and influenced their surface morphology and roughness. SFP and DSFP were typical sulfated polysaccharides, mainly composed of fucose, galacturonic acid, glucuronic acid, galactose, and mannose. Both SFP and DSFP increased cell migration during intestinal epithelial wound healing and stimulated the cell cycle progression by promoting the transition from G0/G1 to S phase in the rat intestine epithelium cells (IEC-6). But DSFP had a stronger positive effect on wound healing and cell migration than SFP. It reinforced the intestinal barrier function and attenuated lipopolysaccharides-induced intestinal inflammation. DSFP significantly downregulated the expression of Toll-like receptor 4, tumor necrosis factor-α, interleukin-6, interleukin-1β, and inducible nitric oxide synthase by 53.14%, 92.41%, 66.01%, 68.24%, and 78.09%, respectively, and upregulated that of interleukin-10 by 2.48 folds when compared to the model. Therefore, the treatment (UV/H2O2 degradation and step gradient ethanol precipitation) could effectively improve the protective effects against intestinal epithelial injury.

Development and Validation of Stability Indicating Method of UV-Spectrophotometry for the Estimation of Flavoxate in Bulk and Tablet Dosage form

Literature survey reveals that few spectrophotometric, high performance liquid chromatographic (HPLC) and High Performance Thin Layer Chromatographic (HPTLC) methods were reported for the estimation of Flavoxate HCl in single and in combined dosage forms. But there is no any stability indicating UV spectroscopic study is reported for Flavoxate in single dosage form. So the present study was aimed to development of simple, accurate, rapid and economical UV-spectrophotometric stability indicating assay method were established for the determination of Flavoxate HCl in bulk and tablet formulation. The solvent was selected for stock solution preparation is water and required concentrations were prepared by using the same solvent. The λmax for detection of Flavoxate HCl is 211nm. In this method Flavoxate followed linearity in the concentrations of 1, 3, 5, 7, 9µg/ml with regression coefficient (r2) 0.999. The percent drug content was found to be 98.81±0.39 for FLV in tablet formulation. Recovery study results of FLV ranges from 99.11 to 100.49%. The method was found to be accurate and precise, as indicate by recovery studies as recoveries were close to 100% and %RSD is less than 2. Inter-day and intraday variation was found to be 0.75 and 0.45%, respectively. The LOD and LOQ values were found to be 0.719µg/ml and 2.186µg/ml, respectively. The stability study of Flavoxate was investigated when the drug was subjected to hydrolytic, peroxide, heat and photolytic (UV and sunlight) degradation. The results express that the Flavoxate is under thermal and photolytic (sunlight and UV light) conditions are more stable. In acidic, basic and hydrogen peroxide conditions Flavoxate is degraded in higher amount.

Surface modified silver/magnetite nanocomposite activating hydrogen peroxide for efficient degradation of chlorophenols

The mixed-valent magnetite (Fe3O4) played a critical role in H2O2-based Fenton-like system for the removal of chlorophenols, but high activity and cycle stability of the Fe3O4-based catalysts are still a huge challenge. Herein, a series of surface hydroxyl- and carboxyl-modified Ag0/Fe3O4 nanocomposite catalysts were prepared and used to activate H2O2 for degradation chlorophenols pollutants. Under the optimized condition, nearly 100% degradation ratio were achieved within 2–30 min for 2,4-dichlorophenol, 2,3-dichlorophenol, 3,4-dichlorophenol, 2,4,6-trichlorophenol, p-nitrophenol, and 98% degradation ratio for 2,5-dichlorophenol, 2,6-dichlorophenol and 3,5-dichlorophenol,. Moreover, wide pH applicability was obtained for the Ag0/Fe3O4-H2O2 system, where 95% degradation ratio of 2,4-dichlorophenol was still obtained at pH 6.0. The excellent activity of Ag0/Fe3O4 catalyst can be ascribed to the incorporation of Ag0 nanoparticles that accelerated the Fe(III)/Fe(II) transformation with the assistance of surface hydroxyl and carboxyl groups. Detailed mechanism study indicated a pseudo-second-order kinetic model, where the oxidative degradation and reductive degradation pathways coexisted in the system. The surface-modified Ag0/Fe3O4-H2O2 provide a practical catalyst system for the removal of phenol contaminants with high reaction rate, wide pH adaptability, and validity for a series of chlorophenols.

Metalloporphyrins as Catalytic Models for Studying Hydrogen and Oxygen Evolution and Oxygen Reduction Reactions.

The hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) are involved in biological and artificial energy conversions. H-H and O-O bond formation/cleavage are essential steps in these reactions. In nature, intermediates involved in the H-H and O-O bond formation/cleavage are highly reactive and short-lived, making their identification and investigation difficult. In artificial catalysis, the realization of these reactions at considerable rates and close to their thermodynamic reaction equilibria remains a challenge. Therefore, the elucidation of the reaction mechanisms and structure-function relationships is of fundamental significance to understand these reactions and to develop catalysts.This Account describes our recent investigations on catalytic HER, OER, and ORR with metalloporphyrins and derivatives. Metalloporphyrins are used in nature for light harvesting, energy conversion, electron transfer, O2 activation, and peroxide degradation. Synthetic metal porphyrin complexes are shown to be active for these reactions. We focused on exploring metalloporphyrins to study reaction mechanisms and structure-function relationships because they have stable and tunable structures and characteristic spectroscopic properties.For HER, we identified three H-H bond formation mechanisms and established the correlation between these processes and metal hydride electronic structures. Importantly, we provided direct experimental evidence for the bimetallic homolytic H-H bond formation mechanism by using sterically bulky porphyrins. Homolytic HER has been long proposed but rarely verified because the coupling of active hydride intermediates occurs spontaneously and quickly, making their detection challenging. By blocking the bimolecular mechanism through steric effects, we stabilized and characterized the NiIII-H intermediate and verified homolytic HER by comparing the reaction behaviors of Ni porphyrins with and without steric effects. We therefore provided an unprecedented example to control homolytic versus heterolytic HER mechanisms through tuning steric effects of molecular catalysts.For the OER, the water nucleophilic attack (WNA) on high-valent terminal Mn-oxo has been proposed for the O-O bond formation in natural and artificial water oxidation. By using Mn tris(pentafluorophenyl)corrole, we identified MnV(O) and MnIV-peroxo intermediates in chemical and electrochemical OER and provided direct experimental evidence for the Mn-based WNA mechanism. Moreover, we demonstrated several catalyst design strategies to enhance the WNA rate, including the pioneering use of protective axial ligands. By studying Cu porphyrins, we proposed a bimolecular coupling mechanism between two metal-hydroxide radicals to form O-O bonds. Note that late-transition metals do not likely form terminal metal-oxo/oxyl.For the ORR, we presented several strategies to improve activity and selectivity, including providing rapid electron transfer, using electron-donating axial ligands, introducing hydrogen-bonding interactions, constructing dinuclear cooperation, and employing porphyrin-support domino catalysis. Importantly, we used Co porphyrin atropisomers to realize both two-electron and four-electron ORR, representing an unparalleled example to control ORR selectivity by tuning only steric effects without modifying molecular and/or electronic structures.Lastly, we developed several strategies to graft metalloporphyrins on various electrode materials through different covalent bonds. The molecular-engineered materials exhibit boosted electrocatalytic performance, highlighting promising applications of molecular electrocatalysis. Taken together, this Account demonstrates the benefits of exploring metalloporphyrins for the HER, OER, and ORR. The knowledge learned herein is valuable for the development of porphyrin-based catalysts and also other molecular and material catalysts for small molecule activation reactions.

Photoinactivation of Catalase Sensitizes Candida albicans and Candida auris to ROS-Producing Agents and Immune Cells.

Microbes have developed their own specific strategies to cope with reactive oxygen species (ROS). Catalase, a heme‐containing tetramer expressed in a broad range of aerobic fungi, shows remarkable efficiency in degrading hydrogen peroxide (H2O2) for fungal survival and host invasion. Here, it is demonstrated that catalase inactivation by blue light renders fungal cells highly susceptible to ROS attack. To confirm catalase as a major molecular target of blue light, wild type Candida albicans are systematically compared with a catalase‐deficient mutant strain regarding their susceptibility to ROS through 410 nm treatment. Upon testing a wide range of fungal species, it is found that intracellular catalase can be effectively and universally inactivated by 410 nm blue light. It is also found that photoinactivation of catalase in combination with ROS‐generating agents is highly effective in total eradication of various fungal species, including multiple Candida auris strains, the causative agent of the global fungal epidemic. In addition, photoinactivation of catalase is shown to facilitate macrophage killing of intracellular Candida albicans. The antifungal efficacy of catalase photoinactivation is further validated using a C. albicans‐induced mouse model of skin abrasion. Taken together, the findings offer a novel catalase‐photoinactivation approach to address multidrug‐resistant Candida infections.

Evaluation of catalase activity of clinical and environmental isolates of Aspergillus species.

Background and Objectives:Catalases are a good scavenger of H2O2 which degrades hydrogen peroxide into water and oxygen. They are considered as a virulence factor that are present in both spores and hypha of fungi. There is limited data regarding catalase activity in Aspergillus species. This study aimed to assess the mycelial catalase activity of clinical and environmental isolates of Aspergillus niger, A. tubingensis, A. flavus, A. luchuensis, A. piperis and A. terreus.Materials and Methods:Briefly, clinical and environmental Aspergillus species were used in the current study. Catalase activity was assessed for both groups of isolates including 13 A. flavus (12 clinical, 1 environmental), 13 A. terreus (8 clinical, 5 environmental), 26 A. tubingensis (13 clinical, 13 environmental), and 44 A. niger (25 environmental, 19 clinical) species. Fungal balls of mycelia were separated from the liquid culture and were crushed using homogenizer. The supernatants were collected and used for a catalase activity assay.Results:Totally, in our study 98 Aspergillus including 45 environmental and 53 clinical isolates were assessed for catalase activity. High catalase activity was detected among environmental Aspergillus species (Mean= 1.62 mU/ml) and the mean of mycelial catalase activity among clinical A. terreus isolates was higher than environmental strains.Conclusion:In summary, mycelial catalase activity varied among species and environmental isolates demonstrated higher catalase activity. Totally a significant difference was found between clinical and environmental Aspergillus isolates.

Enhanced catalytic activation of H2O2 by CNTs/SCH through rapid Fe(III)/Fe(II) redox couple circulation: Insights into the role of functionalized multiwalled CNTs

How to achieve the efficient generation of Fe(II) from Fe(III) in Fenton reaction is a significant issue. In this work, a novel composite of oxidized multiwalled carbon nanotubes - Schwertmannite (CNTs-SCH) were successfully synthesized through a coprecipitation and hydrothermal strategy. The results indicated that the prepared 15%CNTs-SCH would exhibit an excellent catalytic performance in activation of hydrogen peroxide for degradation of tetracycline. The Fe(III)/Fe(II) redox couple circulation would be greatly enhanced from dynamic and thermodynamic aspects. The sulfate radicals generating from SO42− on the surface of Schwertmannite would contribute to TC degradation, which was in line with the enhanced generation rate of Fe(II) and hydroxyl radical in the 15%CNTs-SCH system. In addition, C = C and C = O (in CNTs) were acting as key active sites in prompting formation of Fe(II) and hydroxyl radical. What’s more, the effects of pH, CNTs-SCH, hydrogen peroxide dosages, and common anions on TC removal were assessed. This investigation showed that the prepared 15%CNTs-SCH was an effective catalyst for hydrogen peroxide activation in the heterogeneous system with a wide pH range and good recyclability, confirming its stronger potential practical application.

Highly Efficient Photocatalytic Production of Hydrogen Peroxide for Ciprofloxacin Degradation by a Cofeo/Pdism Z-Scheme Heterojunction

Highly Efficient Photocatalytic Production of Hydrogen Peroxide for Ciprofloxacin Degradation by a Cofeo/Pdism Z-Scheme Heterojunction

Stability-Indicating UHPLC Method for the Determination of Desvenlafaxine: Application to Degradation Kinetics

This study was aimed to investigate the degradation behavior and physicochemical stability of desvenlafaxine using reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) system. The chromatogram was developed on Eclipse XDB-C8 column (150 x 4.6 mm, 5μm). The eluents were monitored through a photo diode array plus (PDA+) detector at 210 nm using an isocratic method with a flow rate of 1.5 ml/min. Mobile phase composition was 30:70 v/v mixture of 0.1 % trifluoroacetic acid (TFA) in water and methanol. Forced degradation studies were performed on drug substance of desvenlafaxine as per International Conference on Harmonization (ICH) prescribed stressed conditions (Q1A(R2) and Q1B) using hydrolytic (acidic, basic, and neutral), oxidative and photolytic methods. The drug substance was found highly labile to acidic (0.5 N hydrochloric acid, 18.65 % degradation in 2 hours at 70°C), basic (1.0 N sodium hydroxide, 11.01 % degradation in 12 hours at 70°C) and oxidative (3 % hydrogen peroxide, 17.05 % degradation in 2 hours at 50°C) stressed conditions, but a great resistance was observed towards dry heat (maximum degradation 0.27 % in 10 days from ambient to higher temperature, 80°C), moist heat (maximum degradation 0.25 % in 2 hours at 80°C and 75 % relative humidity) as well as in photolytic degradation (maximum degradation 0.23 % in 10 days at UV light of 315 - 400 nm). A pseudo-first order kinetic was followed in acidic, basic and peroxide degradation methods which paved a way to calculate the half-life of the drug substance desvenlafaxine under ICH mentioned stressed conditions. The results were also statistically analyzed and the % RSD values were compared with recommended guidelines. Dhaka Univ. J. Pharm. Sci. 20(2): 167-176, 2021 (December)

The Peroxisome-Autophagy Redox Connection: A Double-Edged Sword?

Peroxisomes harbor numerous enzymes that can produce or degrade hydrogen peroxide (H2O2). Depending on its local concentration and environment, this oxidant can function as a redox signaling molecule or cause stochastic oxidative damage. Currently, it is well-accepted that dysfunctional peroxisomes are selectively removed by the autophagy-lysosome pathway. This process, known as “pexophagy,” may serve a protective role in curbing peroxisome-derived oxidative stress. Peroxisomes also have the intrinsic ability to mediate and modulate H2O2-driven processes, including (selective) autophagy. However, the molecular mechanisms underlying these phenomena are multifaceted and have only recently begun to receive the attention they deserve. This review provides a comprehensive overview of what is known about the bidirectional relationship between peroxisomal H2O2 metabolism and (selective) autophagy. After introducing the general concepts of (selective) autophagy, we critically examine the emerging roles of H2O2 as one of the key modulators of the lysosome-dependent catabolic program. In addition, we explore possible relationships among peroxisome functioning, cellular H2O2 levels, and autophagic signaling in health and disease. Finally, we highlight the most important challenges that need to be tackled to understand how alterations in peroxisomal H2O2 metabolism contribute to autophagy-related disorders.

DEVELOPMENT OF FORCED DEGRADATION STUDIES OF FAVIPIRAVIR BY RP-HPLC

Forced degradation studies and stability indicating method were developed for the estimation of Favipiravir by reverse phase High performance liquid chromatography in active Pharmaceutical ingredient and its tablet dosage form. The method was achieved by using C18 column (250 X 4.6mm X 4µm) with mobile phase mixture ortho phosphoric acid and acetonitrile in the ratio 60:40. The mobile phase was allowed to pump with the flow rate 1ml/min by maintaining detection wavelength at 324nm using ultra-violet detector. Favipiravir drug was subjected to various stress conditions according to International Conference of Harmonization Q1A(R2) guidelines to establish stability indicating method. Favipiravir drug was found to be sensitive at peroxide degradation. The impurity peak was characterized by mass spectral studies. The method was validated for analytical standards such as linearity, accuracy, Precision, sensitivity and robustness. A rapid and sensitive method was developed for the estimation of favipiravir which indicates its stability indicating behavior.

Co-delivery of enzymes and photosensitizers via metal-phenolic network capsules for enhanced photodynamic therapy

The intrinsic hypoxic tumor microenvironment and limited accumulation of photosensitizers (PSs) result in unsatisfied efficiency of photodynamic therapy (PDT). To enhance the PDT efficiency against solid tumors, a functional oxygen self-supplying and PS-delivering nanosystem is fabricated via the combination of catalase (CAT), chlorin e6 (Ce6) and metal-phenolic network (MPN) capsule. It is demonstrated that the CAT encapsulated in the capsules (named CCM capsules) could catalyze the degradation of hydrogen peroxide (H2O2) to produce molecular oxygen (O2), which could be converted into cytotoxicity reactive oxygen species (ROS) by surface-loaded Ce6 under 660 nm laser irradiation, leading to synergistic anticancer effects in vitro and in vivo. Therefore, the application of CCM capsule could be a promising strategy to improve PDT effectiveness.

Control Strategies for Reactive Extrusion of Polypropylene by Peroxide Degradation A Brief Review and an Experimental Study

AbstractIndustry 4.0 and digitalization are widely argued for the future success of numerous industrial solutions. Big data management might lead to the assumption that every issue can be solved numerically without any physical background. To some extent, this strategy will help within the plastics industry in general and in the extrusion technology in particular. However, a deep process knowledge together with process-relevant sensors, as well as the right process arrangements within the processing chain combined with smart data mining methods will be still the key success of industry 4.0. This presentation illustrates, based on a brief review on existing control strategies (Part 1), including sensory and predictive control models for reactive extrusion applied at a real-life on-site best practice project (Part 2), possibilities in combination of process tasks with digitalization approaches for PP-Polymer production. Specifically, rheological research conducted with a novel, patented multi-point rheometer (part 3), will provide a deeper insight into dynamic processes such as reactive extrusion. With those results and derivations thereof, improvements in predictive process control in addition to artificial control systems are made and might even lead to further interesting opportunities.

Pre-oxidation of spent lettuce wash water by continuous Advanced Oxidation Process to reduce chlorine demand and cross-contamination of pathogens during post-harvest washing

A continuous Photo-Fenton Advanced-Oxidation-Process (AOP) for reducing the chlorine-demand of spent lettuce wash water was developed based on the generation of hydroxyl-radicals from the UV-C degradation of hydrogen peroxide in the presence of ferric-catalyst. It was found that an interaction between UV-C and hydrogen peroxide or ferric-catalyst concentration was associated with high hydroxyl-radical generation as determined from the oxidation of methylene blue. The optimal AOP treatment was identified as 320 mJ/cm2 UV-C dose, 9.6 mg/L H2O2, and 9 mg/L ferric-catalyst. When the treatment was applied to simulated lettuce spent wash water (6.6 g romaine lettuce per liter of distilled water containing 100 mg bentonite; pH 6.9) the chlorine demand was reduced from 150 ppm to 130 ppm. The chlorination of AOP treated water did not result in a greater log reduction of pathogens (Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella) on lettuce but did reduce cross-contamination between batches during washing. The chlorinated byproducts formed in AOP treated water exhibited higher antimicrobial activity compared to untreated controls. Although the treatment was successful in reducing cross-contamination of lettuce batches the cytotoxicity of disinfection byproducts requires to be assessed.