scholarly journals Formulation Composition and Process Affect Counterion for CSP7 Peptide

Pharmaceutics ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 498 ◽  
Author(s):  
Sawittree Sahakijpijarn ◽  
Chaeho Moon ◽  
John J. Koleng ◽  
Robert O. Williams
Keyword(s):  
Volatile Compounds ◽  
Molar Ratio ◽  
Chamber Pressure ◽  
Ph Change ◽  
Sublimation Rate ◽  
19F Nmr Spectra ◽  
Caveolin 1 ◽  
Ph Modifier ◽  
Peak Areas ◽  
The Stability

Counterions commonly remain with peptides in salt form after peptide purification. In animal and human studies, acetate counterions are a safer and more acceptable choice for peptides than others (e.g., trifluoroacetate counterions). Various salt forms of caveolin-1 scaffolding domain (CSP7) affect counterion volatilization. The development of lyophilized formulations containing volatile compounds is a challenge because these compounds sublimate away during the process. This work aims to investigate the effect of excipients and lyophilization parameters on the preservation of volatile compounds after lyophilization. The peak areas obtained from 1H and 19F NMR spectra were used to calculate the molar ratio of counterions to CSP7. We found that the pH modifier excipient had the greatest impact on the loss of counterions. By optimizing the molar ratio of bulking agent to CSP7, volatile compounds can be preserved after lyophilization. Higher chamber pressure during lyophilization can lower the sublimation rate of volatile compounds. Moreover, the loss of volatile compounds affects the stability of CSP7 due to the pH shift of reconstituted solutions, thereby causing peptide aggregation. The optimization of the formulation and processing helps preserve volatile compounds, thus minimizing the pH change of reconstituted solutions and maintaining the stability of peptide.

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 Optical Analysis of RF Sputtering Plasma through Colour Characterization

Coatings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 315 ◽  
Author(s):  
Ali Salimian ◽  
Roohollah Haghpanahan ◽  
Abul Hasnath ◽  
Hari Upadhyaya
Keyword(s):  
Rf Sputtering ◽  
Plasma Source ◽  
Film Coating ◽  
Chamber Pressure ◽  
Plasma Power ◽  
Plasma Sputtering ◽  
Chromaticity Index ◽  
Colour Parameters ◽  
The Stability

The photometric properties of an radio frequency (RF)-based sputtering plasma source were monitored through optical spectroscopy. The colour of the plasma source was deduced based on conventional chromaticity index analysis and it was compared to the direct spectral data plots of the emission peaks to investigate the possibility of characterising the plasma based on its specific colour and exploring the potential of defining a new method by which the plasma sputtering process can be addressed based on the plasma colour parameters. The intention of this investigation is to evaluate the possibility of simplifying the monitoring and assessment of the sputtering process for applied scientists operating plasma sputter deposition systems. We demonstrate a viable potential for this technique in terms of providing information regarding the stability of the plasma, chamber pressure, and plasma power; however, further work is underway to verify and assess a relationship between the quality of the thin film coating and the colour characteristics of the deposition plasma. Here, we only focus on the feasibility of such an approach and demonstrate interesting observations. We observed a linear relationship between the colour functions and the plasma power, while the stability of the sputtering plasma can be assessed based on the plasma colour functions. The colour functions also follow a unique pattern when the working gas pressure is increased.

Calcium-activated proteases in the bovine parathyroid gland: potential role in degradation of parathyroid hormone to peptide fragments

1995 ◽  
Vol 15 (1) ◽  
pp. 61-71 ◽  
Author(s):  
P H Watson ◽  
S T Mortimer ◽  
K K W Wang ◽  
D E Croall ◽  
D A Hanley
Keyword(s):  
Parathyroid Hormone ◽  
Parathyroid Tissue ◽  
Area Under The Curve ◽  
Molar Ratio ◽  
Cell Protein ◽  
Parathyroid Cell ◽  
Peptide Fragments ◽  
Intracellular Degradation ◽  
Peak Areas

ABSTRACT Our studies suggest that protein kinase C is involved in low calcium (Ca2+)-stimulated secretion of parathyroid hormone (PTH) but not directly in high Ca2+-stimulated intracellular degradation of PTH to secreted carboxyl-terminal fragments (C-PTH), an important component of Ca2+-regulated PTH secretion. The present study was undertaken to determine the presence of calciumactivated proteases, 84 kDa (micro)-calpain and 80 kDa (milli)-calpain, in the bovine parathyroid, and whether they could degrade PTH to C-terminal fragments. Immunocytochemistry of bovine parathyroid tissue using antibodies raised against bovine heart micro- and milli-calpain detected both isoforms of calpain. Western blotting of total bovine parathyroid cell protein prepared from primary cell cultures confirmed the presence of both isoforms of calpain, demonstrated by specific milli- and micro-calpain bands. Purified bovine PTH (bPTH) was incubated in vitro with human erythrocyte micro-calpain and the cleavage products were separated by reverse-phase HPLC. Eluant fractions were assayed with an RIA with equimolar sensitivity to C-PTH and bPTH, and peak areas integrated. Micro-calpain produced a C-PTH peak from bPTH which co-eluted with the major C-PTH secreted by parathyroid cells in culture. C-PTH production by micro-calpain, expressed as per cent area under the curve, increased from 0% in the absence of either micro-calpain or Ca2+, to 71·5% when a 5:1 molar ratio of bPTH to calpain was used. Amino acid sequencing and analysis of the immunoreactive PTH cleavage products indicated the presence of two fragments of bPTH in the C-PTH peak, bPTH47–84 and bPTH69–84. In summary, both isoforms of calpain are present in the bovine parathyroid and calpains may play a role in the Ca2+-dependent degradation of PTH to secreted C-terminal fragments.

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 Co-Amorphous Simvastatin-Nifedipine with Enhanced Solubility for Possible Use in Combination Therapy of Hypertension and Hypercholesterolemia

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2161 ◽  
Author(s):  
Cecilia Martínez-Jiménez ◽  
Jorge Cruz-Angeles ◽  
Marcelo Videa ◽  
Luz Martínez
Keyword(s):  
Combination Therapy ◽  
Amorphous State ◽  
Active Pharmaceutical Ingredient ◽  
Molar Ratio ◽  
Amorphous System ◽  
Enhanced Solubility ◽  
Significant Area ◽  
One Year ◽  
The Stability ◽  
Therapy Of Hypertension

The high index of simultaneous incidence of hypertension and hypercholesterolemia in the population of many countries demands the preparation of more efficient drugs. Therefore, there is a significant area of opportunity to provide as many alternatives as possible to treat these illnesses. Taking advantage of the solubility enhancement that can be achieved when an active pharmaceutical ingredient (API) is obtained and stabilized in its amorphous state, in the present work, new drug-drug co-amorphous formulations (Simvastatin SIM- Nifedipine NIF) with enhanced solubility and stability were prepared and characterized. Results show that the co-amorphous system (molar ratio 1:1) is more soluble than the pure commercial APIs studied separately. Aqueous dissolution profiles showed increments of solubility of 3.7 and 1.7 times for SIM and NIF, correspondingly, in the co-amorphous system. The new co-amorphous formulations, monitored in time, (molar fractions 0.3, 0.5 and 0.7 of SIM) remained stable in the amorphous state for more than one year when stored at room temperature and did not show any signs of crystallization when re-heating. Inspection on the remainder of a sample after six hours of dissolution showed no recrystallization, confirming the stability of co-amorphous system. The enhanced solubility of the co-amorphous formulations makes them promising for simultaneously targeting of hypertension and hypercholesterolemia through combination therapy.

scholarly journals EFFECT OF STERILIZATION BY HEATING IN THE PRESENCE OF BACTERICIDE AND BACTERIAL FILTERED MEMBRANE ON THE STABILITY OF EYE DROPS CONTAINING 0.5% CHLORAMPHENICOL AT VARIOUS pH

2019 ◽  
pp. 103-109
Author(s):  
SRI AGUNG FITRI KUSUMA ◽  
MARLINE ABDASSAH
Keyword(s):  
Room Temperature ◽  
Membrane Filter ◽  
Storage Period ◽  
Eye Drops ◽  
Percentage Reduction ◽  
Ph Change ◽  
Sterilization Method ◽  
Filter Membrane ◽  
The Stability ◽  
Antibacterial Potential

Objective: The purpose of this study was to determine a sterile 0.5% chloramphenicol eye drop formula with the best potency of antibacterial by determining the appropriate sterilization method and the supporting pH. Methods: 0.5% chloramphenicol was formulated with 0.01% thimerosal, which act as a bactericide and combines with borate buffer to produce eye drop formulas with variations in pH (6.8, 7.0 and 7.4). All formulas were stored at room temperature for 28 d and were evaluated, including: organoleptic of the preparations, sterility, pH stability, and the antibacterial potency of chloramphenicol in eye drops. Results: All dosage formulas did not undergo photodegradation reactions which were marked by no change in color until the end of the storage period. However, the formula with pH 6.8 which was sterilized by heating in a presence of bactericide, showed the presence of more particulate precipitates than in the pH 6.8 formula which was sterilized using membrane filter bacteria. However, both methods of sterilization produced sterile chloramphenicol eye drops. The preparation using a method of heat sterilization with bactericide decreased the pH greater than the preparation using a sterile bacterial filter sterilization method. C2 preparations at pH 7.0 and sterilized using the bacterial filter membrane sterilization method were more stable because they had the smallest pH change of 0.05 and the percentage reduction in antibacterial potential was smaller at 1.15%. Conclusion: The best treatment for the chloramphenicol eye drop was kept the pH formula at pH 7 and sterilized using bacterial filter membrane sterilization method.

Phosphorus Removal from Manure by Mechanical Separation using Salt and Polymers: Theoretical Simulations and Experimental Data

2020 ◽  
Vol 36 (2) ◽  
pp. 175-185
Author(s):  
Morten Lykkegaard Christensen ◽  
Kristian Keiding ◽  
Peter Vittrup Christensen
Keyword(s):  
Calcium Phosphate ◽  
Chemical Equilibrium ◽  
Phosphorus Removal ◽  
Solid Material ◽  
Ion Concentration ◽  
Iron Sulfate ◽  
Molar Ratio ◽  
Pig Manure ◽  
Polymer Addition ◽  
The Stability

Abstract.Full-scale separation apparatuses were used to process mink and sow manure. Mink manure was pretreated with iron sulfate and polymer; pig manure was pretreated with only polymer. Testing was done to study how adding chemicals affected phosphorus removal. Chemical equilibrium simulations show that raw manure contains several minerals, i.e., struvite, calcium phosphate, and vivianite. The estimated mass of struvite fit well with the amount of magnesium measured in the solid material. The amount of calcium phosphate precipitation depended on the stability constant of the complexes of organic material and calcium ions, estimated at pK = 3.5–4. With polymer addition, it was possible to remove mineral-bound phosphorus but not organic-bound phosphorus and orthophosphate. With iron salt addition, it was possible to remove both phosphorus minerals and dissolved orthophosphate. The molar ratio between orthophosphate and iron ions in the precipitate was measured to be 2:3. These data fit well with the chemical equilibrium simulations, which predicted that vivianite would form when the iron ion concentration increased. The simulation also indicated that the amount of struvite decreased slightly with iron addition. Keywords: Coagulation, Flocculation, Solid-liquid separation, Vivianite, Wastewater.

scholarly journals Sol-gel prepared active ternary oxide coating on titanium in cathodic protection

2007 ◽  
Vol 72 (12) ◽  
pp. 1393-1402 ◽  
Author(s):  
Vladimir Panic ◽  
Branislav Nikolic
Keyword(s):  
Cathodic Protection ◽  
Sol Gel ◽  
Oxide Coating ◽  
Molar Ratio ◽  
Ternary Oxide ◽  
Electrochemical Characteristics ◽  
Accelerated Corrosion ◽  
Metal Chlorides ◽  
Corrosion Stability ◽  
The Stability

The characteristics of a ternary oxide coating, on titanium, which consisted of TiO2, RuO2 and IrO2 in the molar ratio 0.6:0.3:0.1, calculated on the metal atom, were investigated for potential application for cathodic protection in a seawater environment. The oxide coatings on titanium were prepared by the sol-gel procedure from a mixture of inorganic oxide sols, which were obtained by forced hydrolysis of metal chlorides. The morphology of the coating was examined by scanning electron microscopy. The electrochemical properties of activated titanium anodes were investigated by cyclic voltammetry and polarization measurements in a H2SO4- and NaCl-containing electrolyte, as well as in seawater sampled on the Adriatic coast in Tivat, Montenegro. The anode stability during operation in seawater was investigated by the galvanostatic accelerated corrosion stability test. The morphology and electrochemical characteristics of the ternary coating are compared to that of a sol-gel-prepared binary Ti0.6Ru0.4O2 coating. The activity of the ternary coating was similar to that of the binary Ti0.6Ru0.4O2 coating in the investigated solutions. However, the stability in seawater is found to be considerably greater for the ternary coating.

scholarly journals The impact of nitrogen gas flushing on the stability of seasonings: volatile compounds and sensory perception of cheese & onion seasoned potato crisps

2018 ◽  
Vol 9 (9) ◽  
pp. 4730-4741 ◽  
Author(s):  
Deepa Agarwal ◽  
Lim Mui ◽  
Emma Aldridge ◽  
Richard Mottram ◽  
James McKinney ◽  
...  
Keyword(s):  
Shelf Life ◽  
Volatile Compounds ◽  
Sensory Perception ◽  
Food Product ◽  
Snack Food ◽  
Nitrogen Gas ◽  
Potato Crisps ◽  
The Stability ◽  
The Impact

Flavoured potato crisps is the UK's most consumed snack food product. Addition of N2gas flushing extended shelf life by 2 weeks and the addition of seasoning further enhanced the shelf life of the base crisps by 2 weeks under accelerated conditions.

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