scholarly journals Effect of UV-light, temperature, indoor dark and day light storage, on the stability and biological effectiveness of some insecticides

2011 ◽  
Vol 3 (1) ◽  
pp. 33-42
Author(s):  
Mahmoud Soliman
Keyword(s):  
Uv Light ◽  
Light Storage ◽  
Biological Effectiveness ◽  
The Stability

scholarly journals Effects of UV-Light, Temperature and Storage on the Stability and Biological Effectiveness of Some Insecticides

2012 ◽  
Vol 52 (2) ◽  
pp. 275-280 ◽  
Author(s):  
Mahmoud Soliman
Keyword(s):  
Uv Light ◽  
Immature Stages ◽  
Light Storage ◽  
Degradation Rates ◽  
Residual Level ◽  
Different Temperatures ◽  
Biological Effectiveness ◽  
The Stability ◽  
And Storage ◽  
Uv Rays

Effects of UV-Light, Temperature and Storage on the Stability and Biological Effectiveness of Some InsecticidesThe degradation and biological effectiveness of five insecticides, ES-Fenvalerate (Soumi Gold), pirimicarb (Afox), imidacloprid (Emax), buprofenzin (Ablloud) and methomyl (Methiolate) in their aqueous preparations and emulsifiable concentrates, on immature stages of whitefly insectBemisia tabaci. when exposed to UV-light, two different temperatures and daylight and dark storage after exposure intervals was studied. The results indicated the degradation rates of the five tested insecticides varied according to the chemical structure, time of exposure and wavelength of UV-rays used. Of all the five insecticides, methomyl was the most affected by UV-rays. Losses of ES-Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl within this period were 11.30, 14.80, 29.03, 31.83 and 39%, respectively after one hour to UV-ray exposure. A significant increase in LC50value was obtained when ES-Fenvalerate in aqueous preparation was exposed to UV-light for 6 hr. The LC50values and their confidence ranges in aqueous preparations and emulsifiable concentrates were 107.5 ppm (51.7-199.2) and 93.10 ppm (48.3-150.4). The residual level of Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl were 13.52, 17.54 ppm; 12.67, 15.87 ppm; 11.78, 16.47 ppm; 11.38, 14.73 ppm; and 11.36, 11.83 ppm for two days exposed to daylight and dark storage. Insecticides could be arranged according to LC50values at zero-time as follow: ES-Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl. The corresponding values of LC50were 3.40, 15.4, 15.6, 16.2 and 23.5 ppm for daylight storage. On the other hand, the dark storage exposure for the tested insecticides could be arranged according to LC50values as follow: ES-Fenvalerate, imidacloprid, pirimicarb, buprofenzin and methomyl. The corresponding LC50were 3.20, 14.8, 14.9, 15.9 and 21.3 ppm, respectively. In general, the amount recovered after a one day, 45°C exposure were 14.63, 12.84, 12.79, 12.14 and 11.76 ppm, for ES-Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl, respectively. While the amounts recovered after a three day 45°C exposure were 9.28, 8.34, 7.76, 7.72 and 5.83 ppm for ES-Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl, respectively. Efficiency against whitefly insect,B. tabaciimmature stages was affected when aqueous preparations of the five tested insecticides were stored at 45°C for one and three days, compared to those stored under normal condition of 25°C for the same periods of time. Generally it could be concluded that buprofenzin n and methomyl, were more affected by UV-light, storage and temperature than ES-Fenvalerate, pirimicarb, imidacloprid.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

scholarly journals Stability and ocular biodistribution of topically administered PLGA nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sean Swetledge ◽  
Renee Carter ◽  
Rhett Stout ◽  
Carlos E. Astete ◽  
Jangwook P. Jung ◽  
...  
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Polymeric Nanoparticles ◽  
Plga Nanoparticles ◽  
Eye Disease ◽  
Control Group ◽  
Eye Tissues ◽  
Nanoparticle Morphology ◽  
The Stability

AbstractPolymeric nanoparticles have been investigated as potential delivery systems for therapeutic compounds to address many ailments including eye disease. The stability and spatiotemporal distribution of polymeric nanoparticles in the eye are important regarding the practical applicability and efficacy of the delivery system in treating eye disease. We selected poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with lutein, a carotenoid antioxidant associated with eye health, as our model ophthalmic nanodelivery system and evaluated its stability when suspended in various conditions involving temperature and light exposure. We also assessed the ocular biodistribution of the fluorescently labeled nanoparticle vehicle when administered topically. Lutein-loaded nanoparticles were stable in suspension when stored at 4 °C with only 26% lutein release and no significant lutein decay or changes in nanoparticle morphology. When stored at 25 °C and 37 °C, these NPs showed signs of bulk degradation, had significant lutein decay compared to 4 °C, and released over 40% lutein after 5 weeks in suspension. Lutein-loaded nanoparticles were also more resistant to photodegradation compared to free lutein when exposed to ultraviolet (UV) light, decaying approximately 5 times slower. When applied topically in vivo, Cy5-labled nanoparticles showed high uptake in exterior eye tissues including the cornea, episcleral tissue, and sclera. The choroid was the only inner eye tissue that was significantly higher than the control group. Decreased fluorescence in all exterior eye tissues and the choroid at 1 h compared to 30 min indicated rapid elimination of nanoparticles from the eye.

Temperature and Salinity Effects on Photocatalytic Performance of Cerium Doped Zinc Oxide

2020 ◽  
Vol 307 ◽  
pp. 223-228
Author(s):  
Wan Rafizah Wan Abdullah ◽  
Lee Chia Siang ◽  
Maishara Syazrinni Rooshde ◽  
Mohd Sabri Mohd Ghazali
Keyword(s):  
Photocatalytic Performance ◽  
Catalyst Surface ◽  
Uv Light ◽  
Operating Temperature ◽  
Chloride Ions ◽  
Photocatalytic Efficiency ◽  
Electron Hole ◽  
Doped Zno ◽  
The Stability ◽  
Uv C

Cerium (Ce) doped ZnO is a promising material for advanced photocatalysis. It is useful for inducing the treatment of many organic pollutants in water. However, the stability of its performance under varying temperature and saline condition has never been not fully assessed. In this study, powder form photocatalyst comprising 99.0 mol% ZnO and 1 mol% CeO2 has been synthesized via modified citrate gelation technique and solid-state sintering at 1200 °C for 5 hours. The conversion of Ce doped ZnO from its precursors has been confirmed using XRD, SEM, and EDX techniques. The photocatalytic efficiency of the synthesized Ce doped ZnO under UV-C light (λ=265 nm) was determined. In the experiment, the operating temperature was varied between 25 to 40 °C, and the salinity of the treated solution was increased from 0 to 40 g/L NaCl. The findings revealed that the photocatalytic efficiency of Ce doped ZnO under UV light improved from 78.2% to 88.6% as the temperature increased from 25 to 40 °C. The performance of Ce doped ZnO decreased from 86.7% to 36.7% when the salinity increased from 0 g/L to 40 g/L. The elevation of temperature encouraged the photogeneration of electron-hole pairs on catalyst surface while the presence of chloride ions in treated medium caused scavenging of hydroxyl radicals or hole.

scholarly journals Effect of Nanocrystallization of Anthocyanins Extracted from Two Types of Red-Fleshed Apple Varieties on Its Stability and Antioxidant Activity

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3366 ◽  
Author(s):  
Jihua Xu ◽  
Xinxin Li ◽  
Shifeng Liu ◽  
Peilei Zhao ◽  
Heqiang Huo ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Corn Starch ◽  
Uv Light ◽  
Radical Scavenging ◽  
Malus Sieversii ◽  
Total Anthocyanins ◽  
High Antioxidant Activity ◽  
Starch Nanoparticles ◽  
The Stability

Red-fleshed apple (Malus sieversii f. neidzwetzkyana (Dieck) Langenf) has attracted more and more attention due to its enriched anthocyanins and high antioxidant activity. In this study we extracted total anthocyanins and phenols from two types of red-fleshed apples—Xinjing No.4 (XJ4) and Red Laiyang (RL)—to study the stability and antioxidant activity of anthocyanins after encapsulation onto Corn Starch Nanoparticles (CSNPs). The results indicated the anthocyanins and total phenol levels of XJ4 were 2.96 and 2.25 times higher than those of RL respectively. The anthocyanin concentration and loading time had a significant effect on CSNPs encapsulation, and XJ4 anthocyanins always showed significantly higher loading capacity than RL. After encapsulation, the morphology of RL-CSNPs and XJ4-CSNPs was still spherical with a smooth surface as CSNPs, but the particle size increased compared to CSNPs especially for RL-CSNPs. Different stress treatments including UV light, pH, temperature, and salinity suggested that XJ4-CSNPs exhibited consistently higher stability than RL-CSNPs. A significantly enhanced free radical scavenging rate under stress conditions was observed, and XJ4-CSNPs had stronger antioxidant activity than RL-CSNPs. Furthermore, XJ4-CSNPs exhibited a slower released rate than RL-CSNPs in simulated gastric (pH 2.0) and intestinal (pH 7.0) environments. Our research suggests that nanocrystallization of anthocyanins is an effective method to keep the anthocyanin ingredients intact and active while maintaining a slow release rate. Compared to RL, encapsulation of XJ4 anthocyanins has more advantages, which might be caused by the significant differences in the metabolites of XJ4. These findings give an insight into understanding the role of nanocrystallization using CSNPs in enhancing the antioxidant ability of anthocyanins from different types of red-fleshed apples, and provide theoretical foundations for red-fleshed apple anthocyanin application.

scholarly journals Chitosan–Azide Nanoparticle Coating as a Degradation Barrier in Multilayered Polyelectrolyte Drug Delivery Systems

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 573 ◽  
Author(s):  
Steffen Sydow ◽  
Armin Aniol ◽  
Christoph Hadler ◽  
Henning Menzel
Keyword(s):  
Drug Delivery Systems ◽  
Uv Light ◽  
Film Structure ◽  
Layer By Layer ◽  
Multilayer Systems ◽  
Ionotropic Gelation ◽  
Physiological Conditions ◽  
Degree Of Acetylation ◽  
Implant Coating ◽  
The Stability

Therapeutics, proteins or drugs, can be encapsulated into multilayer systems prepared from chitosan (CS)/tripolyphosphat (TPP) nanogels and polyanions. Such multilayers can be built-up by Layer-by-Layer (LbL) deposition. For use as drug-releasing implant coating, these multilayers must meet high requirements in terms of stability. Therefore, photochemically crosslinkable chitosan arylazide (CS–Az) was synthesized and nanoparticles were generated by ionotropic gelation with TPP. The particles were characterized with regard to particle size and stability and were used to form the top-layer in multilayer films consisting of CS–TPP and three different polysaccharides as polyanions, namely alginate, chondroitin sulfate or hyaluronic acid, respectively. Subsequently, photo-crosslinking was performed by irradiation with UV light. The stability of these films was investigated under physiological conditions and the influence of the blocking layer on layer thickness was investigated by ellipsometry. Furthermore, the polyanion and the degree of acetylation (DA) of chitosan were identified as additional parameters that influence the film structure and stability. Multilayer systems blocked with the photo-crosslinked chitosan arylazide showed enhanced stability against degradation.

UV Light Stability of α-Cyclodextrin/Resveratrol Host - Guest Complexes and Isomer Stability at Varying pH

2009 ◽  
Vol 62 (8) ◽  
pp. 921 ◽  
Author(s):  
Kerrilee E. Allan ◽  
Claire E. Lenehan ◽  
Amanda V. Ellis
Keyword(s):  
Inclusion Complex ◽  
Uv Light ◽  
Sodium Dodecyl ◽  
Molar Absorptivity ◽  
Photo Degradation ◽  
Light Stability ◽  
Uv Visible ◽  
The Stability ◽  
Ph Range ◽  
Cis Isomer

trans-Resveratrol is an antioxidant that readily isomerizes to the cis isomer under UV irradiation. Here we report on the UV-Visible analysis of the stability of both trans- and cis-resveratrol isomers in the presence of UV light over a pH range of 2.0–9.0 in a phosphate-borate buffer that contains sodium dodecyl sulphate and acetonitrile. The molar absorptivity of the trans-resveratrol solution absorbing at 320 nm (3.88 eV) and 305 nm (4.07 eV) was 33000 and 34000 M–1 cm–1, respectively. Results indicate that trans-resveratrol has a slower isomerization within a pH range of 5.0–8.0. A pH > 8.0 results in almost immediate isomerization of the sample, whereas at pH 2.0 a photo-degradation product appears at 260 nm (4.77 eV). This was not apparent at pH 8.0. By including trans-resveratrol into a trans-resveratrol/α-cyclodextrin host–guest inclusion complex in pH 8.0 buffer isomerization was greatly reduced, with enhanced trans-resveratrol photostability.

scholarly journals Novel Combination of Quaternary AgFeNi2S4 Semiconductor In Graphene-TiO2 Nanocomposite For The Enhanced Electrophotocatalytic Reduction of CO2

2021 ◽  
Author(s):  
Zambaga Otgonbayar ◽  
Won Chun Oh
Keyword(s):  
Catalytic Activity ◽  
Preparation Method ◽  
Uv Light ◽  
Pechini Method ◽  
Hydrocarbon Fuels ◽  
Working Electrode ◽  
The Stability ◽  
Reduction Of Co2 ◽  
Positive Effect ◽  
Morphological State

Abstract For reduction of CO2 into hydrocarbon fuels, a quaternary AgFeNi2S4 semiconductor combined in Graphene-TiO2 nanocomposite material was synthesized via the Pechini method. The catalytic activity of the photocatalyst for photocatalytic and electrochemical CO2 evolution into hydrocarbon fuels was tested. The methanol yield under UV light was 8.679, 6.349, and 4.136 %, and the methanol yields under visible light were 6.291, 4.738, and 2.339 %, respectively. The stability and reusability of the photocatalyst remained high after a 4-cycle recycling test without a decrease in yield of the final photocatalytic CO2 reduction product. The enhanced photoreduction of CO2 through the as-prepared ternary photocatalyst can be ascribed to the catalyst's conformation and low recombination rate. In electrochemical CO2 reduction, the Faraday efficiency is the main parameter that defines the performance of the working electrode and the evolution of methanol. The Faraday efficiency of AFNSGT ternary nanocomposite was 44.25 %; this is an increase in the value of the Faraday efficiency, which proves that the design of the new nanocomposite successfully increases the activity of the working electrode and has a positive effect on the electrochemical reduction of CO2. The photocatalytic and electrochemical CO2 reduction data show that the preparation method, morphological state, and charge carrier properties of the photocatalyst are important for the catalytic activity and efficiency of the methanol evolution pathway.

scholarly journals Effect of Sunlight, Moisture, Temperature and Ultraviolet Radiation on the Quality Control Parameters of Ciprofloxacin Tablet Formulation

2016 ◽  
Vol 8 (3) ◽  
pp. 99 ◽  
Author(s):  
Kenneth Ezealisiji ◽  
Angenlina Pepple ◽  
Catherine Stanley
Keyword(s):  
Relative Humidity ◽  
Uv Light ◽  
Physical Stability ◽  
Accelerated Aging ◽  
Storage Conditions ◽  
Dissolution Behavior ◽  
Ciprofloxacin Hydrochloride ◽  
Label Claim ◽  
Aging Conditions ◽  
The Stability

<p>This work assesses the stability and quality of Ciprofloxacin hydrochloride tablets after subjection to accelerated stability conditions of sunlight, temperature of 40±1<sup>0</sup>C, 75% relative humidity, and UV light of 365 nm for 4 hours each day. This study was performed at time zero and at 4-day intervals for a period of 45 days (that is, days 0, 4, 8, 12…40, 44) according to the International Conference on Harmonization (ICH) accelerated aging conditions and the results obtained were subjected to statistical analysis. The results showed that with increasing time there was a gradual reduction in the dissolution rate with the tablets exposed to all four storage conditions failing the test on day 44 where they had less than 80 % release of the label claim. For content of Ciprofloxacin Hydrochloride, only those tablets exposed to UV light passed the test for all 44 days as they had a minimum of 96.83 % content on the 44<sup>th</sup> day. At day 0, all the tablets assayed passed this test, having a ciprofloxacin content of 99.43 %. For those tablets subjected to the other storage conditions including temperature of 40±1<sup>0</sup>C, 75 % relative humidity and sunlight, they had ciprofloxacin content of 70.22 %, 71.50 %, and 78.36 % respectively. The results further, indicated that the storage conditions used in the study had a greater impact on the dissolution behavior and content of the Ciprofloxacin tablets than they did on the physical stability (hardness, uniformity of weight, disintegration).</p>

scholarly journals RP-HPLC (STABILITY-INDICATING) BASED ASSAY METHOD FOR THE SIMULTANEOUS ESTIMATION OF DORAVIRINE, TENOFOVIR DISOPROXIL FUMARATE AND LAMIVUDINE

2021 ◽  
pp. 153-159
Author(s):  
V. L. N. BALAJI GUPTA TIRUVEEDHI ◽  
VENKATESWARA RAO BATTULA ◽  
KISHORE BABU BONIGE
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Uv Light ◽  
Volume Ratio ◽  
Assay Method ◽  
Simultaneous Estimation ◽  
Intermediate Precision ◽  
Stability Indicating ◽  
Rp Hplc ◽  
Relative Standard ◽  
The Stability

Objective: In this study, a RP-HPLC (stability-indicating) based assay method for the estimation of doravirine (DRV), tenofovir disoproxil fumarate (TFF) and lamivudine (LMV) simultaneously in the tablets was described. Methods: The simultaneous analysis of DRV, TFF and LMV was done with HPLC system (Agilent 1100 series) and Luna Phenomenex C18 (250 mm × 4.6 mm × 5 μ) column with isocratic mobile phase (35% volume ratio of methanol and 65% volume ratio of 20 mmol ammonium formate, pH 5). Validation of assay method was done on sensitivity, linearity, accuracy, selectivity, precision, robustness and specificity. Results: The calibration curves were linear through the range of 25-200 µg/ml for DRV and 75-600 µg/ml for TFF and LMV. The percent relative standard deviation for intraday variation/precision, interday variation/precision, intermediate precision/ruggedness and robustness were lower than 2%. The recovery of LMV (99.09-99.76%), TFF (99.10-99.41%) and DRV (98.65-99.28%) confirmed the good accuracy. The stability of LMV, TFF and DRV in 0.1N NaOH, 3% peroxide, 0.1 N HCl, UV light and dry heat of 60 °C was determined. Conclusion: The results have allowed the method to be implemented in the tablets to quantify DRV, TFF, and LMV.

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