scholarly journals Molecular Encapsulation of Herbicide Terbuthylazine in Native and Modifiedβ-Cyclodextrin

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
E. Manuela Garrido ◽  
Daniela Rodrigues ◽  
Nuno Milhazes ◽  
Fernanda Borges ◽  
Jorge Garrido
Keyword(s):  
Water Solubility ◽  
Analytical Techniques ◽  
Aqueous Solubility ◽  
Mean Values ◽  
H Nmr ◽  
Nmr Data ◽  
Kneading Method ◽  
Other Substances ◽  
The Mean ◽  
The Stability

The herbicide terbuthylazine (TBA) is widely used for preemergence or postemergence control of many grass and broadleaf weeds and has, besides other issues, a poor aqueous solubility profile that results in reduced bioavailability. Cyclodextrins and modified cyclodextrins were considered, among other substances, appropriate agents for improving pesticide water solubility. Therefore, the inclusion complex formation of terbuthylazine withβ-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) was studied to attain its aqueous solubility enhancement. Their characterization was accomplished with different analytical techniques, namely, by UV-Vis, DSC, FTIR, and1H NMR. From the analysis of the complexation performance of the herbicide it was concluded that the interaction of terbuthylazine with CDs leads to the formation of inclusion complexes with a stoichiometry of 1 : 1. The association constants of the TBA/β-CD and TBA/HP-β-CD complexes were determined by UV. The mean values obtained for the stability constants are 460.4 ± 26.5 and 532.1 ± 27.6 to TBA/β-CD and TBA/HP-β-CD, respectively.1H NMR data corroborate the formation of the TBA/β-CD and TBA/HP-β-CD complexes synthesized by the kneading method. A formulation incorporating TBA cyclodextrin complexes might lead to an improvement in terbuthylazine bioavailability. The development of TBA-CD formulations may be interesting since it would enable, through their inclusion into the hydrophobic cavity of CDs, enhancement of solubility, bioavailability, and stability of the herbicide.

NephroCheck® Quality Test

2020 ◽  
pp. 1-3
Author(s):  
Thummaporn Naorungroj ◽  
Ary Serpa Neto ◽  
Fumitaka Yanase ◽  
Intissar Bittar ◽  
Glenn M. Eastwood ◽  
...  
Keyword(s):  
Risk Score ◽  
Rank Correlation ◽  
Kidney Injury ◽  
Mean Values ◽  
Spearman’S Rank Correlation ◽  
Different Temperatures ◽  
Urine Storage ◽  
The Mean ◽  
The Stability ◽  
Fresh Urine

<b><i>Background:</i></b> The acute kidney injury (AKI) risk score helps detect moderate and severe AKI in the next 12–24 h. However, inappropriate urine collection may impact its results. <b><i>Aim:</i></b> The aim of this study was to evaluate the stability of NephroCheck® after urine storage at different temperatures. <b><i>Methods:</i></b> The urine sample was centrifuged and split into 3 tubes. One was tested as soon as possible by the laboratory. The other 2 samples were frozen at −20 and −80°C, and the NephroCheck® test was performed 8 weeks later. <b><i>Results:</i></b> The mean values of the AKI risk score were 1.19 ± 0.93, 1.15 ± 1.14, and 1.20 ± 1.11 (ng/mL)<sup>2</sup>/1,000 for fresh urine, −20, and −80°C, respectively (<i>p</i> = 0.70). Spearman’s rank correlation for −20 and −80°C versus immediate processing was strong with a rho of 0.82 and 0.98, respectively. <b><i>Conclusion:</i></b> The AKI risk score was relatively stable. Urine could be collected without dry ice or liquid nitrogen and kept for up to 8 weeks with either −20 or −80°C freezing with stable NephroCheck® results.

The analysis of temperature fluctuations by pulse-counting techniques

1959 ◽  
Vol 6 (2) ◽  
pp. 261-271 ◽  
Author(s):  
A. A. Townsend
Keyword(s):  
Time Derivative ◽  
Temperature Fluctuations ◽  
Mean Value ◽  
Time Intervals ◽  
Mean Values ◽  
Average Value ◽  
Electrical Pulses ◽  
The Mean ◽  
The Stability ◽  
Better Than

To determine experimentally the mean value of a randomly fluctuating quantity, it may be necessary to measure the average value over a considerable interval of time. This problem arose in a recent study of the temperature fluctuations over a heated horizontal plate, and a system was used that depended on the counting of electrical pulses generated at a rate proportional to the quantity being measured. The advantage of this technique is that mean values may be measured over time intervals of almost unlimited length with little added difficulty for the experimenter. Circuits are described which measure: (a) the mean square of a fluctuating quantity and of its time-derivative, (b) the statistical distribution of the fluctuations, (c) the mean frequency of the fluctuation assuming a particular value, and (d) the mean product of two fluctuating quantities. Over the range of use, the stability and linearity of the calibrations is better than 1%, more than sufficient for work on natural convection. In its present form, the equipment responds uniformly to all frequencies below 100 c/s, but it would not be difficult to extend this range of response to higher frequencies.

Effects of Nutrient Enrichment on a Realistic Food Web

2014 ◽  
Vol 700 ◽  
pp. 711-714
Author(s):  
Lei Zhao ◽  
Hua Yong Zhang ◽  
Fang Zhao ◽  
Wang Tian
Keyword(s):  
Food Web ◽  
Population Distribution ◽  
Species Abundance ◽  
Nutrient Supply ◽  
Mean Values ◽  
Applied Ecology ◽  
Limiting Nutrient ◽  
The Mean ◽  
The Stability ◽  
Consumer Interactions

Nutrients supplies play a crucial role in population distribution of food webs, and it is one of the most important challenges in both theoretical and applied ecology to better understand the ‘bottom-up’ effect. Here we analyzed a realistic food web containing one limiting nutrient and two producer-consumer interactions. Through the simulations of the mean population size and the variability of each species, we found that 1) in infertile environment the coexistence of species increases with nutrient supply; 2) the mean values of species abundance increase dramatically at then remain constant with the increase of nutrient supply; and 3) the stability of each population also increases and then remains constant. These results are inconsistent with the traditional predictions known as the ‘paradox of enrichment’, and our analysis may provide a solution to this paradox.

Lutein encapsulated oleic - linoleic acid nanoemulsion boosts oral bioavailability of retinal protective carotenoid lutein in rat model

2021 ◽  
Author(s):  
Veeresh B Toragall ◽  
Twinkle Godhwani ◽  
V Baskaran ◽  
Naveen Jayapala
Keyword(s):  
Linoleic Acid ◽  
Oral Bioavailability ◽  
Mixed Micelles ◽  
Water Solubility ◽  
Health Benefits ◽  
Aqueous Solubility ◽  
Mean Size ◽  
The Mean

Abstract There is excessive interest in emerging colloidal delivery systems to enhance the water solubility and oral bioavailability of lutein, which is a hydrophobic carotenoid claimed to possess health benefits. The present study aimed to design lutein-enriched nanoemulsions with improved physicochemical properties and to achieve various health benefits of lutein. The prepared lutein nanoemulsion was characterized, and its bioavailability was examined in vitro (simulated gastrointestinal digestion) and in vivo. The mean size, PDI and zeta potential of the lutein nanoemulsion were 110 ± 8 nm, 0.271 and 36 ± 2 mV, respectively. Furthermore, TEM examination revealed that the particles are nanosized and spherical in shape. Notably, the aqueous solubility of the nanoemulsion was 726-fold higher than that of free lutein. The composite nanoemulsion also showed exceptionally higher (87.4%) in vitro bioaccessibility than that of nonencapsulated or free lutein (15%). The in vivo bioavailability of lutein nanoemulsion (112.6 ng/mL) was much higher than that of nonencapsulated lutein (48.6 ng/ml) and mixed micelles (68.5 ng/mL), and the tissue distribution pattern of lutein nanoemulsion showed higher lutein accumulation in the liver (2.80- and 1.70-fold) and eye (1.91- and 1.48-fold) compared to free lutein and mixed micelle-fed groups. These results suggested that oleic acid-linoleic acid composite nanoemulsions may be a promising delivery system for lutein and may help enhance the solubility, oral bioavailability and bioefficacy of lutein and could be used as an ingredient for the formulation of beverages or functional foods.

NMR Complexation Study of Several Oxyethylated Calix[4]arenes with Lithium, Sodium and Potassium Ions

1996 ◽  
Vol 61 (12) ◽  
pp. 1783-1797 ◽  
Author(s):  
Jaroslav Havlíček ◽  
Marcela Tkadlecová ◽  
Michaela Vyhnánková ◽  
Evgueni Pinkhassik ◽  
Ivan Stibor
Keyword(s):  
Sodium Cation ◽  
H Nmr ◽  
Nmr Data ◽  
Constant Determination ◽  
Close Proximity ◽  
Dinitro Derivative ◽  
The Stability ◽  
Upper Rim ◽  
Sodium And Potassium ◽  
C Nmr

The influence of calix[4]arene upper rim substitution on the complexation with Li+, Na+, K+ was studied by 1H NMR spectroscopy. Calix[4]arenes 1-4 namely 25,26,27,28-tetrakis(3-oxapentyloxy)calix[4]arene (1), its 5,17-diamino (2) and 5,17-dinitro derivative (3) as well as 25,26,27,28-tetrakis(3,6,9-trioxadecyloxy)calix[4]arene (4) having four monoalkyloligoethylene glycol chains on the lower rim have been studied. No complexation has been observed for Li+. Two electron-donating NH2 groups on the calixarene upper rim (compound 2) improve the complexation ability for Na+ and K+ compared with parent calixarene 1. The electron-withdrawing nitro groups in 3 have the opposite influence. It seems that the complexation of alkali metal ions studied is not significantly influenced by the increasing number of donor atoms (from eight in 1 to sixteen in 4) available for complexation on the lower rim. The position of sodium cation in 1 . Na+ and 4. Na+ is supposed to be in close proximity of phenolic oxygens based on 1H and 13C NMR data. The error analysis is given for the stability constant determination from NMR data.

Influence of Coracoglenoid Space on the Stability of Scapular Neck Fractures: Biomechanical Study

2021 ◽  
Author(s):  
Junfeng Chen ◽  
Wei Zhang ◽  
Gang Pang ◽  
Qingling Meng ◽  
Youyu Zhu ◽  
...  
Keyword(s):  
Anatomical Variation ◽  
Compressive Load ◽  
Biomechanical Study ◽  
Load Test ◽  
Mean Values ◽  
Average Maximum ◽  
Significant Difference ◽  
The Mean ◽  
The Stability ◽  
Scapular Neck Fractures

Abstract Background: The anatomical variation of the coracoglenoid space has the potential to influence the stability of scapular neck fractures. This paper aimed to investigate the path-mechanical mechanisms of different types of coracoglenoid space on the scapular neck fractures by morphometric analysis and biomechanical experiments.Methods: A total of 68 dry scapulae (left: 36; right: 32) were collected, the types of coracoglenoid space delimited by a boundary based on the ratio of the mean values of CGD to the mean values of CGN. Each specimen of a different type was under static axial compressive load test to failure. The average failure loads, stiffness, and energy for each specimen were calculated.Results: Two types of coracoglenoid space were identified. The incidence of Type Ⅰ (2.4 < ratio ≤ 3.5) (‘‘hook’’ shape) was found to be 53%, that of Type Ⅱ (3.5 < ratio ≤ 5.0) (‘‘square bracket’’ shape) was found to be 47%. There was no statistically significant difference in the two types between different body sides (P > 0.05). The average maximum failure load of these two types was 1270.82 ± 318.85 N and 1529.18 ± 467.29 N, respectively (P = 0.011). The measures of the average failure stiffness and energy of Type Ⅱ were significantly higher than Type Ⅰ (896.75 ± 281.14 N/mm vs. 692.91 ± 217.9 5N/mm, P = 0.001; 2100.38 ± 649.54 N⋅mm vs. 1712.71 ± 626.02 N⋅mm, P = 0.015, respectively).Conclusions: The variation of coracoglenoid space is large in different individuals, hook-like space is associated with fewer forces, stiffness, and energy, which constitute an anatomical predisposition to the scapular neck fractures.

scholarly journals In Vivo Biocompatible Self-Assembled Nanogel Based on Hyaluronic Acid for Aqueous Solubility and Stability Enhancement of Asiatic Acid

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4071
Author(s):  
Yu Yu Win ◽  
Penpimon Charoenkanburkang ◽  
Vudhiporn Limprasutr ◽  
Ratchanee Rodsiri ◽  
Yue Pan ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Water Solubility ◽  
Aqueous Solubility ◽  
Asiatic Acid ◽  
Cell Culture Study ◽  
Nmr Characterization ◽  
The Stability ◽  
Stability Enhancement

Asiatic acid (AA), a natural triterpene found in Centalla asiatica, possesses polypharmacological properties that can contribute to the treatment and prophylaxis of various diseases. However, its hydrophobic nature and rapid metabolic rate lead to poor bioavailability. The aim of this research was to develop a thermoresponsive nanogel from hyaluronic acid (HA) for solubility and stability enhancement of AA. Poly(N-isopropylacrylamide) (pNIPAM) was conjugated onto HA using a carbodiimide reaction followed by 1H NMR characterization. pNIPAM-grafted HA (HA-pNIPAM) nanogels were prepared with three concentrations of polymer, 0.1, 0.15 and 0.25% w/v, in water by the sonication method. AA was loaded into the nanogel by the incubation method. Size, morphology, AA loading capacity and encapsulation efficiency (EE) were analyzed. In vitro cytocompatibility was evaluated in fibroblast L-929 cells using the PrestoBlue assay. Single-dose toxicity was studied using rats. HA-pNIPAM nanogels at a 4.88% grafting degree showed reversible thermo-responsive behavior. All nanogel formulations could significantly increase AA water solubility and the stability was higher in nanogels prepared with high polymer concentrations over 180 days. The cell culture study showed that 12.5 µM AA in nanogel formulations was considered non-toxic to the L-929 cells; however, a dose-dependent cytotoxic effect was observed at higher AA-loaded concentrations. In vivo study proved the non-toxic effect of AA loaded in HA-pNIPAM nanogels compared with the control. Taken together, HA-pNIPAM nanogel is a promising biocompatible delivery system both in vitro and in vivo for hydrophobic AA molecules.

A kinetic and nuclear magnetic resonance study of methylated pyrimidine nucleosides

1983 ◽  
Vol 61 (10) ◽  
pp. 2397-2402 ◽  
Author(s):  
B. D. Allore ◽  
A. Queen ◽  
W. J. Blonski ◽  
F. E. Hruska
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Ph Dependence ◽  
Nuclear Magnetic Resonance Study ◽  
Magnetic Resonance Study ◽  
Pyrimidine Nucleosides ◽  
Spectrophotometric Methods ◽  
H Nmr ◽  
Nmr Data ◽  
The Stability ◽  
C Nmr

Alkylated pyrimidine nucleosides are of interest from the viewpoint of mutagenesis and carcinogenesis. 1H and 13C nmr data are presented for a series of 2′-deoxynucleosides methylated at the O2-, O4-, and N3-positions of the base, and discussed in terms of their physical properties. The pH dependence of the stability of the O2- and O4-methylated 2′-deoxyribosides as well as the corresponding ribosides was examined by 1H nmr and ultraviolet (uv) spectrophotometric methods.

scholarly journals Physicochemical Stability of Mozobil® (Plerixafor) Solution for Injection in Glass Vials and Plastic Syringes over a Three-Month Storage Period

2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Sun Hee Kim ◽  
Judith Thiesen ◽  
Irene Krämer
Keyword(s):  
Storage Temperature ◽  
Degradation Products ◽  
Storage Period ◽  
Injection Solution ◽  
Mean Values ◽  
Ph Values ◽  
Profound Knowledge ◽  
Physicochemical Stability ◽  
The Mean ◽  
The Stability

Abstract: The stability of ready-to-administer parenteral preparations is an important issue of drug safety. Profound knowledge about the physicochemical stability is necessary in order to determine the “beyond-use-dates” of solutions in injection vials after first opening and ready-to-administer preparations in syringes.: The aim of this study was to determine the physicochemical stability of plerixafor solution marketed as Mozobil: The stability of Mozobil: No plerixafor degradation products were detected in the HPLC chromatograms over the period of 84 days, independent of the storage temperature. In vials and syringes plerixafor concentrations declined less than 5 % over the entire test period of 84 days. The pH values remained unchanged; the mean values varied between 6.79 and 6.60 for Mozobil: Plerixafor injection solution (Mozobil

ANIONIC GEMINI SURFACTANTS: SYNTHESIS AND SURFACE ACTIVE PROPERTIES

2007 ◽  
Vol 14 (05) ◽  
pp. 991-997 ◽  
Author(s):  
DIPTI SHUKLA ◽  
V. K. TYAGI
Keyword(s):  
Water Solubility ◽  
Gemini Surfactants ◽  
Maximum Yield ◽  
Analytical Techniques ◽  
Molar Ratio ◽  
Foaming Properties ◽  
Wetting Ability ◽  
H Nmr ◽  
Surface Active Properties ◽  
Surface Active

New compounds bearing two phosphate groups and two long chain (dodecyl) were prepared by two-step reaction: (i) phosphorylation of dodecanol with pyrophosphoric acid, (ii) reaction of dodecyl phosphate with N ( CH 3)4 OH and 1,6-dibromo hexane. The effect of reaction variables like time and molar ratio of reactants on yield has also been reported. The 1:2:0.5 molar ratio of reactants (dodecyl phosphate, N ( CH 3)4 OH , and Br ( CH 2)6 Br , respectively) and 3 h duration resulted to give maximum yield of anionic gemini surfactants. The structure of synthesized surfactant was investigated by modern analytical techniques, viz. FT-IR, 1H NMR, 13C NMR. Amphipathic disodium phosphates were obtained by neutralization of free acids with sodium hydroxide and their surface active properties in aqueous solution were measured. These disodium phosphates possessed 77.3% anionic content and showed good water solubility. Foaming properties and wetting ability were also evaluated.

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