Evaluation of Stability of a Sucrose-Formulated, Full-Length rFVIII for Use in Continuous Infusion Therapy.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4114-4114
Author(s):  
Uri Martinowitz ◽  
Aaron Lubetsky ◽  
Ilia Tamarin ◽  
Jacob Luboshitz
Keyword(s):  
Continuous Infusion ◽  
Room Temperature ◽  
Infusion Therapy ◽  
Low Molecular Weight ◽  
Fviii Activity ◽  
Normal Water ◽  
Recombinant Fviii ◽  
The Stability ◽  
Excellent Stability ◽  
Mini Pump

Abstract Introduction: Stability of a FVIII preparation in mini-pumps is an important consideration for its use in a continuous infusion manner. Our goal was to evaluate the stability of a specific recombinant FVIII (Kogenate®FS; KOGENATE®Bayer) in two commonly used infusion mini-pumps, with and without anticoagulant additives that may be used in clinical practice to prevent local thrombophlebitis. Methods: Kogenate® FS (250 IU/vial and 1000 IU/vial) was reconstituted using aseptic technique according to the manufacturer’s instructions with normal water for injection (100 IU/ml and 400 IU/ml, respectively); an additional dilution of 100 IU/ml was made from the 1000 IU/vial size. Reconstituted material was spiked with unfractionated heparin (UFH) or low molecular weight heparin (LMWH; Enoxaparin/Clexane) to a final concentration ~5 U/ml, or left untreated and then transferred to reservoirs of 2 mini-pumps (Walkmed, Medfusion Inc., Duluth, GA and CADD, Deltec, Inc., St. Paul, MN). All bags were stored in a light-protected environment at room temperature (22°C) for 7 days. Samples were drawn at baseline (immediately post reconstitution), 3h, 6h, 12h, 24h, and days 2–7, frozen at −30°C, and assayed for FVIII activity by one-stage assay. On Day 7, the residual volume of the mini-pump containers was cultured for bacteria. Results: All samples except one* had FVIII activity >90% of baseline. Conclusions: Kogenate® FS appears to retain excellent stability at room temperature during 7 days in both CADD and Walkmed infusion pumps with and without addition of UFH or LMWFH. No bacterial growth was observed. These results indicate that Kogenate® FS may be useful in continuous infusion therapy. Figure Figure

Stability of Tacrolimus Injection in Total Parenteral Nutrition Solution

1996 ◽  
Vol 12 (2) ◽  
pp. 58-61
Author(s):  
Yi-Min Ku ◽  
David I Min ◽  
Vijay Kumar ◽  
Saleem A Noormohamed
Keyword(s):  
Amino Acids ◽  
Parenteral Nutrition ◽  
Continuous Infusion ◽  
Total Parenteral Nutrition ◽  
Room Temperature ◽  
Color Change ◽  
Storage Conditions ◽  
Black Background ◽  
Lighting Conditions ◽  
The Stability

Objective: To examine the stability of tacrolimus in a total parenteral nutrition (TPN) solution over 24 hours at room temperature. Study Method: Admixtures of tacrolimus 0.1 mg/mL in TPN, containing amino acids 4.25%, dextrose 25%, and electrolytes, were prepared and visually inspected under normal lighting conditions against a white and black background for color change, turbidity, cloudiness, and precipitation. The concentration of tacrolimus in the admixtures was determined by HPLC at 0, 1, 2, 4, 8, 12, and 24 hours after preparation. Results: The concentration of tacrolimus did not change over the 24-hour study period. No color change, precipitation, or cloudiness was observed in any of the solutions under the storage conditions. Conclusions: Tacrolimus is chemically stable in TPN for 24 hours at room temperature, and therefore can be administered to patients as a 24-hour continuous infusion with TPN.

In-Vitro Stability of B-Domain Deleted Recombinant Factor VIII in Syringe-Based Continuous Infusion Devices.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3969-3969
Author(s):  
Donna M.M. Woloschuk ◽  
Jennifer M. Dyck ◽  
Sara J. Israels ◽  
Peter Toogood
Keyword(s):  
Factor Viii ◽  
Continuous Infusion ◽  
Clinical Settings ◽  
Glass Vial ◽  
Automated Assay ◽  
Fviii Activity ◽  
Priming Volume ◽  
Infusion Devices ◽  
Recombinant Fviii

Abstract Continuous infusion (CI) factor VIII (FVIII) replacement is commonly used for serious bleeds in patients with FVIII deficiency. Clinicians lack stability information for Refacto®, a B-domain deleted recombinant FVIII (BDDrFVIII), when it is diluted or stored in CI devices for extended time periods. We studied BDDrFVIII to determine its concentration- and time-dependent stability and sterility when stored (reconstituted; reconstituted then diluted with normal saline) at ambient temperature in syringe-based CI devices (CADD-MicroTM; Baxter ColleagueTM). Three replicates of BDDrFVIII 125unit/mL and 25unit/mL admixtures were admixed aseptically then placed in CI devices that operated continuously for 48 hours. Samples (0.5ml) were obtained from control solutions (stored in the manufacturer’s glass vial) or expressed from the distal end of tubing at Hour −0.25 (priming volume), 0, 1, 2, 4, 8, 12, 24 and 48. Samples were stored at −70C until assayed for Factor VIII activity using a 1-stage automated assay and Refacto® [chromogenic equivalent] Standard. Results of FVIII assays for each trio of replicates were averaged. BDDrFVIII admixtures were considered stable if they retained ≥80% baseline (control) FVIII values. Recoveries for BDDrFVIII 125unit/mL admixtures remained stable and sterile for 48 hours when stored in the manufacturer’s glass vial, Baxter ColleagueTM or CADD MicroTM devices, sufficient for clinical use (Table). BDDrFVIII, when diluted to 25unit/mL, remained sterile but not stable when stored in Baxter ColleagueTM or CADD MicroTM devices, and is not recommended for CI in clinical settings. Loss of FVIII activity in BDDrFVIII 25unit/mL admixtures is thought to be due to binding of BDDrFVIII to device components. %FVIII Activity of BDDrFVIII Stored in Infusion Devices Hr 0 Hr 1 Hr 2 Hr 4 Hr 12 Hr 24 Hr 48 Mfr Glass Vial (Control) 92.5 93 90.7 90.8 93.2 76 80.7 CADD-Micro 125unit/ml 80 84 86.3 78.3 86.3 80 81.7 Baxter Colleague 125unit/ml 86.3 79 74 85 77.7 81 82.3 CADD-Micro 25unit/ml 65.7 61.3 56.3 59 57.5 59.7 56.3 Baxter Colleague 25unit/ml 18.7 19.3 33 24.3 27 27 27.3

Methods for the Concentration of Bovine Ac-Globulin (Factor V)

1961 ◽  
Vol 06 (03) ◽  
pp. 435-444 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Room Temperature ◽  
Barium Carbonate ◽  
Deae Cellulose ◽  
Reducing Agents ◽  
Factor V ◽  
Isoelectric Precipitation ◽  
Stabilizing Agent ◽  
Bovine Plasma ◽  
The Stability

SummaryAn attempt was made to obtain Ac-globulin from bovine plasma. The concentrates contain mostly protein, and phosphorus is also present. The stability characteristics vary from one preparation to another, but in general there was no loss before 1 month in a deep freeze or before 1 week in an icebox, or before 5 hours at room temperature. Reducing agents destroy the activity rapidly. S-acetylmercaptosuccinic anhydride is an effective stabilizing agent. Greatest stability was at pH 6.0.In the purification bovine plasma is adsorbed with barium carbonate and diluted 6-fold with water. Protein is removed at pH 6.0 and the Ac-globulin is precipitated at pH 5.0. Rivanol and alcohol fractionation is followed by chromatography on Amberlite IRC-50 or DEAE-cellulose. The final product is obtained by isoelectric precipitation.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

Cholesterol in Serum and Lipoprotein Fractions

1956 ◽  
Vol 2 (3) ◽  
pp. 145-159 ◽  
Author(s):  
Joseph T Anderson ◽  
Ancel Keys
Keyword(s):  
Human Serum ◽  
Total Cholesterol ◽  
Filter Paper ◽  
Room Temperature ◽  
Paper Electrophoresis ◽  
Cholesterol Content ◽  
Intraindividual Variability ◽  
Detailed Data ◽  
The Stability ◽  
Source Of Error

Abstract 1. Methods are described for the separation, by paper electrophoresis and by cold ethanol, of α- and β-lipoproteins in 0.1 ml. of serum, with subsequent analysis of cholesterol in the separated portions. 2. It is shown that both methods of separation yield separated fractions containing substantially the same amounts of cholesterol. 3. Detailed data are given on the errors of measurement for total cholesterol and for cholesterol in the separated lipoprotein fractions. 4. Studies are reported on the stability of cholesterol in stored serum and on paper electrophoresis strips. It is shown that simple drying on filter paper causes no change in cholesterol content and yields a product that is stable for many weeks at ordinary room temperature. 5. The sources of variability in human serum cholesterol values are examined and it is shown that spontaneous intraindividual variability is a much greater source of error than the errors of measurement with these methods.

Pressure dependent ultrasonic properties of hcp hafnium metal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ramanshu P. Singh ◽  
Shakti Yadav ◽  
Giridhar Mishra ◽  
Devraj Singh
Keyword(s):  
Elastic Constants ◽  
Pressure Range ◽  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Coupling Constants ◽  
Ultrasonic Properties ◽  
Acoustic Coupling ◽  
Third Order Elastic Constants ◽  
The Stability ◽  
The Given

Abstract The elastic and ultrasonic properties have been evaluated at room temperature between the pressure 0.6 and 10.4 GPa for hexagonal closed packed (hcp) hafnium (Hf) metal. The Lennard-Jones potential model has been used to compute the second and third order elastic constants for Hf. The elastic constants have been utilized to calculate the mechanical constants such as Young’s modulus, bulk modulus, shear modulus, Poisson’s ratio, and Zener anisotropy factor for finding the stability and durability of hcp hafnium metal within the chosen pressure range. The second order elastic constants were also used to compute the ultrasonic velocities along unique axis at different angles for the given pressure range. Further thermophysical properties such as specific heat per unit volume and energy density have been estimated at different pressures. Additionally, ultrasonic Grüneisen parameters and acoustic coupling constants have been found out at room temperature. Finally, the ultrasonic attenuation due to phonon–phonon interaction and thermoelastic mechanisms has been investigated for the chosen hafnium metal. The obtained results have been discussed in correlation with available findings for similar types of hcp metals.

Non-adhesive lotus and other hydrophobic materials

2008 ◽  
Vol 366 (1870) ◽  
pp. 1539-1556 ◽  
Author(s):  
David Quéré ◽  
Mathilde Reyssat
Keyword(s):  
Solid Surface ◽  
Room Temperature ◽  
Water Repellency ◽  
Short Review ◽  
Water Repellent ◽  
Practical Applications ◽  
Hydrophobic Materials ◽  
Volatile Liquid ◽  
Air Cushion ◽  
The Stability

Superhydrophobic materials recently attracted a lot of attention, owing to the potential practical applications of such surfaces—they literally repel water, which hardly sticks to them, bounces off after an impact and slips on them. In this short review, we describe how water repellency arises from the presence of hydrophobic microstructures at the solid surface. A drop deposited on such a substrate can float above the textures, mimicking at room temperature what happens on very hot plates; then, a vapour layer comes between the solid and the volatile liquid, as described long ago by Leidenfrost. We present several examples of superhydrophobic materials (either natural or synthetic), and stress more particularly the stability of the air cushion—the liquid could also penetrate the textures, inducing a very different wetting state, much more sticky, due to the possibility of pinning on the numerous defects. This description allows us to discuss (in quite a preliminary way) the optimal design to be given to a solid surface to make it robustly water repellent.

scholarly journals Longevity of Raw and Lyophilized Crude Urease Extracts

2021 ◽  
Vol 2 (2) ◽  
pp. 325-334
Author(s):  
Neda Javadi ◽  
Hamed Khodadadi Tirkolaei ◽  
Nasser Hamdan ◽  
Edward Kavazanjian
Keyword(s):  
Crude Extract ◽  
Room Temperature ◽  
Low Cost ◽  
Extraction Process ◽  
Crude Extracts ◽  
Simple Extraction ◽  
Commercial Applications ◽  
Stable Source ◽  
The Stability ◽  
The Cost

The stability (longevity of activity) of three crude urease extracts was evaluated in a laboratory study as part of an effort to reduce the cost of urease for applications that do not require high purity enzyme. A low-cost, stable source of urease will greatly facilitate engineering applications of urease such as biocementation of soil. Inexpensive crude extracts of urease have been shown to be effective at hydrolyzing urea for carbonate precipitation. However, some studies have suggested that the activity of a crude extract may decrease with time, limiting the potential for its mass production for commercial applications. The stability of crude urease extracts shown to be effective for biocementation was studied. The crude extracts were obtained from jack beans via a simple extraction process, stored at room temperature and at 4 ℃, and periodically tested to evaluate their stability. To facilitate storage and transportation of the extracted enzyme, the longevity of the enzyme following freeze drying (lyophilization) to reduce the crude extract to a powder and subsequent re-hydration into an aqueous solution was evaluated. In an attempt to improve the shelf life of the lyophilized extract, dextran and sucrose were added during lyophilization. The stability of purified commercial urease following rehydration was also investigated. Results of the laboratory tests showed that the lyophilized crude extract maintained its activity during storage more effectively than either the crude extract solution or the rehydrated commercial urease. While incorporating 2% dextran (w/v) prior to lyophilization of the crude extract increased the overall enzymatic activity, it did not enhance the stability of the urease during storage.

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