scholarly journals Insulin Complexation with Cyclodextrins—A Molecular Modeling Approach

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 465
Author(s):  
Pálma Bucur ◽  
Ibolya Fülöp ◽  
Emese Sipos
Keyword(s):  
Molecular Modeling ◽  
Storage Time ◽  
Active Form ◽  
Molar Ratio ◽  
Stable Complex ◽  
Intermolecular Hydrogen Bonds ◽  
Amyloid Fibrillation ◽  
Β Sheets ◽  
The Stability ◽  
Long Storage

Around 5% of the population of the world is affected with the disease called diabetes mellitus. The main medication of the diabetes is the insulin; the active form is the insulin monomer, which is an instable molecule, because the long storage time, or the high temperature, can cause the monomer insulin to adapt an alternative fold, rich in β-sheets, which is pharmaceutically inactive. The aim of this study is to form different insulin complexes with all the cyclodextrin used for pharmaceutical excipients (native cyclodextrin, methyl, hydroxyethyl, hydroxypropyl and sulfobutylether substituted β-cyclodextrin), in silico condition, with the AutoDock molecular modeling program, to determine the best type of cyclodextrin or cyclodextrin derivate to form a complex with an insulin monomer, to predict the molar ratio, the conformation of the complex, and the intermolecular hydrogen bonds formed between the cyclodextrin and the insulin. From the results calculated by the AutoDock program it can be predicted that insulin can make a stable complex with 5–7 molecules of hydroxypropyl-β-cyclodextrin or sulfobutylether-β-cyclodextrin, and by forming a complex potentially can prevent or delay the amyloid fibrillation of the insulin and increase the stability of the molecule.

Instant 99mTc-Labelled Glucoheptonate Kit for Kidney Imaging

1983 ◽  
Vol 22 (05) ◽  
pp. 246-250 ◽  
Author(s):  
M. Al-Hilli ◽  
H. M. A. Karim ◽  
M. H. S. Al-Hissoni ◽  
M. N. Jassim ◽  
N. H. Agha
Keyword(s):  
Sodium Hydroxide Solution ◽  
Normal Subjects ◽  
Organ Distribution ◽  
Stable Complex ◽  
Scintillation Camera ◽  
Ph Adjustment ◽  
The Mean ◽  
The Stability ◽  
Kidney Imaging ◽  
Mean Concentration

Gelchromatography column scanning has been used to study the fractions of reduced hydrolyzed 99mTc, 99mTc-pertechnetate and 99mTc-chelate in a 99mTc-glucoheptonate (GH) preparation. A stable high labelling yield of 99mTc-GH complex in the radiopharmaceutical has been obtained with a concentration of 40-50 mg of glucoheptonic acid-calcium salt and not less than 0.45 mg of SnCl2 2 H2O at an optimal pH between 6.5 and 7.0. The stability of the complex has been found significantly affected when sodium hydroxide solution was used for the pH adjustment. However, an alternative procedure for final pH adjustment of the preparation has been investigated providing a stable complex for the usual period of time prior to the injection. The organ distribution and the blood clearance data of 99mTc-GH in rabbits were relatively similar to those reported earlier. The mean concentration of the radiopharmaceutical in both kidneys has been studied in normal subjects for one hour with a scintillation camera and the results were satisfactory.

The Sterility of Reusable Surgical Instruments with Pouches Packaging on One of the Private Hospital in Bandung

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Kurniawansyah I. S. ◽  
Mita S. R. ◽  
Najla E. ◽  
Nindayani E.
Keyword(s):  
Storage Time ◽  
Private Hospital ◽  
Surgical Instruments ◽  
Healthcare Associated Infection ◽  
Sterility Testing ◽  
Reusable Instruments ◽  
Healthcare Associated ◽  
The Relationship ◽  
Common Infection ◽  
Long Storage

Healthcare associated infection is one of the common infection that happens in Indonesia. One form control to prevent healthcare associated infection is the sterilization process of the materials and medical instruments that used for taking care of patients. At the private hospital whereas a place of research, there’s never been done the study of sterility test for reusable instrument with pouches, based on previous studies showed that 8 sets from 40 sets of reusable instrument with linen were not sterile moreover there were positively influence from the amount of time to the sterility of reusable instrument. The purpose of these studies was to determining the relationship between a long storage time and the sterility of reusable instruments with pouches. The method that used in this study was the sterility testing of reusable instrument with pouches which were stored in a central operations room storage with a long storage time of 1 and 2 months. From 30 reusable instruments with pouches which were stored for nine months there were 5 instruments were not sterile. The results of statistic analysis showed that the amount of storage time not significantly associated to the sterility of reusable instrument with pouches in the operating room central storage space.

The Role of Hydrophobicity in the Stability and pH-Switchability of (RXDX)4 and Coumarin-RXDX Conjugate β-Sheets

2020 ◽  
Author(s):  
Ryan Weber ◽  
Martin McCullagh
Keyword(s):  
Biological Imaging ◽  
Ph Sensing ◽  
Hydrophobic Residue ◽  
Ideal Candidate ◽  
Self Assembling ◽  
Sensing Applications ◽  
Β Sheets ◽  
The Stability ◽  
Dynamics Simulations

<p>pH-switchable, self-assembling materials are of interest in biological imaging and sensing applications. Here we propose that combining the pH-switchability of RXDX (X=Ala, Val, Leu, Ile, Phe) peptides and the optical properties of coumarin creates an ideal candidate for these materials. This suggestion is tested with a thorough set of all-atom molecular dynamics simulations. We first investigate the dependence of pH-switchabiliy on the identity of the hydrophobic residue, X, in the bare (RXDX)<sub>4</sub> systems. Increasing the hydrophobicity stabilizes the fiber which, in turn, reduces the pH-switchabilty of the system. This behavior is found to be somewhat transferable to systems in which a single hydrophobic residue is replaced with a coumarin containing amino acid. In this case, conjugates with X=Ala are found to be unstable and both pHs while conjugates with X=Val, Leu, Ile and Phe are found to form stable β-sheets at least at neutral pH. The (RFDF)<sub>4</sub>-coumarin conjugate is found to have the largest relative entropy value of 0.884 +/- 0.001 between neutral and acidic coumarin ordering distributions. Thus, we posit that coumarin-(RFDF)<sub>4</sub> containing peptide sequences are ideal candidates for pH-sensing bioelectronic materials.</p>

scholarly journals Complexes of Copper and Iron with Pyridoxamine, Ascorbic Acid, and a Model Amadori Compound: Exploring Pyridoxamine’s Secondary Antioxidant Activity

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 208
Author(s):  
Guillermo García-Díez ◽  
Roger Monreal-Corona ◽  
Nelaine Mora-Diez
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Rate Constant ◽  
Stable Complex ◽  
Aqueous Environment ◽  
Oh Radicals ◽  
Bidentate Ligands ◽  
Superoxide Radical Anion ◽  
Amadori Compound ◽  
The Stability

The thermodynamic stability of 11 complexes of Cu(II) and 26 complexes of Fe(III) is studied, comprising the ligands pyridoxamine (PM), ascorbic acid (ASC), and a model Amadori compound (AMD). In addition, the secondary antioxidant activity of PM is analyzed when chelating both Cu(II) and Fe(III), relative to the rate constant of the first step of the Haber-Weiss cycle, in the presence of the superoxide radical anion (O2•−) or ascorbate (ASC−). Calculations are performed at the M05(SMD)/6-311+G(d,p) level of theory. The aqueous environment is modeled by making use of the SMD solvation method in all calculations. This level of theory accurately reproduces the experimental data available. When put in perspective with the stability of various complexes of aminoguanidine (AG) (which we have previously studied), the following stability trends can be found for the Cu(II) and Fe(III) complexes, respectively: ASC < AG < AMD < PM and AG < ASC < AMD < PM. The most stable complex of Cu(II) with PM (with two bidentate ligands) presents a ΔGf0 value of −35.8 kcal/mol, whereas the Fe(III) complex with the highest stability (with three bidentate ligands) possesses a ΔGf0 of −58.9 kcal/mol. These complexes can significantly reduce the rate constant of the first step of the Haber-Weiss cycle with both O2•− and ASC−. In the case of the copper-containing reaction, the rates are reduced up to 9.70 × 103 and 4.09 × 1013 times, respectively. With iron, the rates become 1.78 × 103 and 4.45 × 1015 times smaller, respectively. Thus, PM presents significant secondary antioxidant activity since it is able to inhibit the production of ·OH radicals. This work concludes a series of studies on secondary antioxidant activity and allows potentially new glycation inhibitors to be investigated and compared relative to both PM and AG.

scholarly journals Charge Transfer Complexes of Ketotifen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8-Tetracyanoquodimethane: Spectroscopic Characterization Studies

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2039
Author(s):  
Gamal A. E. Mostafa ◽  
Ahmed Bakheit ◽  
Najla AlMasoud ◽  
Haitham AlRabiah
Keyword(s):  
Charge Transfer ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
Charge Transfer Complexes ◽  
Physical Parameters ◽  
Spectrophotometric Methods ◽  
Theoretical Approaches ◽  
The Stability ◽  
Ct Complexes

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.

scholarly journals UV-VIS spectroscopy for monitoring yogurt stability during storage time

2016 ◽  
Vol 8 (30) ◽  
pp. 5962-5969 ◽  
Author(s):  
B. Aliakbarian ◽  
L. Bagnasco ◽  
P. Perego ◽  
R. Leardi ◽  
M. Casale
Keyword(s):  
Storage Time ◽  
Dairy Product ◽  
Entire Period ◽  
Vis Spectroscopy ◽  
The Stability ◽  
Color Texture

Color, texture and taste are key elements of a consumer's buying decision; thus, monitoring the stability of these features throughout the entire period of yogurt validity is fundamental for dairy product producers.

scholarly journals Factors involved in the stability of isolated β-sheets: Turn sequence, β-sheet twisting, and hydrophobic surface burial

2004 ◽  
Vol 13 (4) ◽  
pp. 1134-1147 ◽  
Author(s):  
Clara M. Santiveri ◽  
Jorge Santoro ◽  
Manuel Rico ◽  
M. Angeles Jiménez
Keyword(s):  
Hydrophobic Surface ◽  
Β Sheets ◽  
The Stability ◽  
Β Sheet

The stability of Fe(III)-As(V) co-precipitate in the presence of ascorbic acid: Effect of pH and Fe/As molar ratio

Chemosphere ◽  
2019 ◽  
Vol 218 ◽  
pp. 670-679 ◽  
Author(s):  
Zidan Yuan ◽  
Guoqing Zhang ◽  
Jinru Lin ◽  
Xiangfeng Zeng ◽  
Xu Ma ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Molar Ratio ◽  
Effect Of Ph ◽  
Acid Effect ◽  
The Stability

scholarly journals Enhance the Stability of Traditional Concentrated Yoghurt using Natural Antioxidants Additives

2020 ◽  
Vol 36 (05) ◽  
pp. 879-888
Author(s):  
Ziad Ayyad ◽  
Muhannad Qurie ◽  
Amal Odeh Natshe ◽  
Saleh Sawalha ◽  
Fuad Al-Rimawi
Keyword(s):  
Storage Time ◽  
Virgin Olive Oil ◽  
Control Sample ◽  
Storage Period ◽  
Natural Antioxidants ◽  
Total Phenol Content ◽  
Positive Trend ◽  
The Stability ◽  
Quality Indexes ◽  
Natural Additives

The stability of virgin olive oil (VOO) used as a packing medium for traditional concentrated Yoghurt decreased during time and the product could deteriorate during the storage time. In this investigation, different natural additives such as dried Arum Palaestinum leaves (AP), Tomato Peel (TP) and Chili Pepper (CP) have been used to enhance the quality and stability of packing medium VOO for traditional canned concentrated Yoghurt balls. Parts VOO samples added with natural additives were stored as packing medium for traditional canned concentrated Yoghurt balls. Other part was stored without concentrated Yoghurt in the same storage conditions. All samples were analyzed for their initial quality indexes and during the storage period of six months. At the end of storage, results revealed that the % acidity for all VOO samples used as a packing medium showed a higher value than the samples stored without concentrated Yoghurt balls. On the other side, peroxide values for all stored samples of both parts were less than the control sample without additives. Extinction coefficients (K232, K270) for VOO samples with the natural additives showed increased trend during the storage time, but it didn't exceed the accepted limit for VOO. Total phenol content for all samples were gradually decreased during storage period, whereas samples with the natural additives showed higher values than the controls. All the natural additives (CP, TP, AP) showed a positive trend in enhancing and improving the different VOO quality indexes in our study in particular those samples added with CP during the storage time.

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