Improving the accuracy of unbound fraction measurement of drug-protein binding by preconditioning the RED membrane inserts

Bioanalysis ◽  
2020 ◽  
Vol 12 (23) ◽  
pp. 1699-1708
Author(s):  
Zhengqi Ye ◽  
Qing Chen
Keyword(s):  
Protein Binding ◽  
Equilibrium Dialysis ◽  
Binding Assays ◽  
Unbound Fraction ◽  
Protein Binding Assay ◽  
Study Results ◽  
Measurement Methodology ◽  
Protein Matrices ◽  
Fraction Measurement ◽  
Drug Protein Binding

Aim: The objective of this study was to evaluate the rapid equilibrium dialysis (RED) device in protein binding assays in diluted protein matrices and to improve the accuracy of the unbound fraction ( fu) measurement. Methodology: Protein binding assays of drug compounds in bovine serum albumin solutions and human plasma with different folds of dilution were performed using the RED device with and without preconditioning of the dialysis membrane inserts, and the results were compared with those using other approaches in this study. Results & conclusion: Preconditioning of the RED membrane inserts improved the fu data accuracy of drug-protein binding assay in matrices with relatively low protein contents and such impact could be compound dependent.

scholarly journals Relationship between Protein Binding and Extravascular drug Concentrations of a Water-soluble Drug, Cytosine Arabinoside

1983 ◽  
Vol 76 (5) ◽  
pp. 365-368 ◽  
Author(s):  
A Johnston ◽  
E M Piall ◽  
P Turner ◽  
M L Slevin ◽  
R C Woollard ◽  
...  
Keyword(s):  
Protein Binding ◽  
Cytosine Arabinoside ◽  
Acute Leukaemia ◽  
Equilibrium Dialysis ◽  
Water Soluble ◽  
Lipid Solubility ◽  
Unbound Fraction ◽  
Extravascular Space ◽  
Physiological Measure ◽  
Drug Concentrations

The degree of binding of a drug to plasma proteins has a marked effect on its distribution, elimination, and pharmacological effect. Since only the unbound fraction is available for distribution into extravascular space, the ratio of drug in cerebrospinal fluid (CSF) or saliva to that in plasma is often regarded as a physiological measure of the free fraction of a drug. CSF: plasma and saliva: plasma ratios of cytosine arabinoside (araC) have been measured in patients with acute leukaemia and found to be 0.1–0.28, implying a binding of 72–90%. The protein binding of araC was measured by equilibrium dialysis in the plasma of patients with acute leukaemia at presentation. The mean binding ratio was 2.3 ± 6.8, implying that there was little or no protein binding. There was no correlation between alpha — 1 acid glycoprotein (AAG) levels and protein binding. The low CSF and saliva: plasma araC ratios found, suggest that drugs such as araC which have low lipid solubility do not pass freely into extravascular space. Thus the CSF or saliva: plasma ratio cannot be considered a good physiological measure of protein binding for drugs with poor lipid solubility.

Aspects of Drug-Protein Binding and Methods of Analyzing the Phenomenon

2018 ◽  
Vol 24 (25) ◽  
pp. 2974-2985 ◽  
Author(s):  
Karolina Wanat ◽  
Elżbieta Brzezińska ◽  
Anna W. Sobańska
Keyword(s):  
Molecular Modeling ◽  
Protein Binding ◽  
Human Milk ◽  
Physicochemical Properties ◽  
Protein Interactions ◽  
High Performance ◽  
Equilibrium Dialysis ◽  
Binding Ability ◽  
High Performance Affinity Chromatography ◽  
Drug Protein Binding

In recent decades, drug-protein interactions have been widely studied and several methods of analysis of these phenomena have been developed and improved. These can be classified into separation, physical, chromatographic and electrophoretic methods. This review depicts the assumptions and mechanisms of methods from each group, details their strengths and weaknesses, and presents examples of their usage from the literature. Equilibrium dialysis, ultrafiltration, Hummel-Dreyer method or high performance affinity chromatography are given as representative examples, but this issue is far more expanded. Nowadays, increasing attention is paid to the computational methods and molecular modeling which are convenient tools to estimate protein binding affinity based on the physicochemical properties of compounds. To gain a broader overview, the study also examines the protein binding ability and pharmacotherapy of drugs against a range of substrates such as plasma, skin, tissue and human milk.

Drug-Protein Binding during Continuous Ambulatory Peritoneal Dialysis

1986 ◽  
Vol 6 (3) ◽  
pp. 144-147 ◽  
Author(s):  
Gene D. Morse ◽  
Carolyn Rowinski ◽  
Patricia E. Lieveld ◽  
J. Joseph Walshe
Keyword(s):  
Peritoneal Dialysis ◽  
Protein Binding ◽  
Continuous Ambulatory Peritoneal Dialysis ◽  
High Performance ◽  
Equilibrium Dialysis ◽  
Active Form ◽  
Hemodialysis Patients ◽  
Chronic Hemodialysis ◽  
Normal Volunteers ◽  
Drug Protein Binding

This study of drug-protein binding in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) measured the serum and dialysate binding of cefamandole -an acidic, cephalosporin antibiotic. Ten CAPD patients, five with and five without peritonitis received a 1.0 g intraperitoneal dose of cefamandole; serum and dialysate was sampled at 4, 10, and 24 h after drug administration. Binding also was studied in serum obtained from five chronic hemodialysis patients and five normal volunteers. Equilibrium dialysis was used to determine protein binding and high performance liquid chromatography to measure cefamandole. Mean fraction unbound (fu) serum values for CAPD patients were 0.35 ± 0.04 (noninfected) and 0.37 ± 0.14 (peritonitis). In comparison, the fu values in hemodialysis patients were 0.41 ± 0.19 and 0.15 ± 0.02 in normal volunteers. Greater than 90% of cefamandole in dialysate was unbound suggesting that antibiotics, which cross the peritoneal membrane, are present in the free, microbiologically active form.

RELIABILITY CRITERIA FOR SATURATION ANALYSIS OF STEROIDS BY COMPETITIVE PROTEIN BINDING

1970 ◽  
Vol 65 (1_Suppl) ◽  
pp. S61-S78 ◽  
Author(s):  
Billy D. Reeves ◽  
David W. Calhoun
Keyword(s):  
Protein Binding ◽  
Assay Method ◽  
Statistical Control ◽  
Protein Binding Assay ◽  
Competitive Protein Binding Assay ◽  
System 2 ◽  
Competitive Protein Binding ◽  
Single Method ◽  
Assay Design ◽  
Proper Perspective

ABSTRACT This communication is an attempt to delineate and define reliability criteria for saturation analysis of steroids by competitive protein binding assay. The discussion of these criteria evolved from three major considerations of assay method that help to place the ultimate criterion of accuracy in proper perspective. These major considerations are: 1) the measurement system, 2) the assay design and 3) the calculations and statistical control. Such an approach permits an evaluation, both relative and absolute, for a single method or for multiple methods.

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