Related Experiment Video
Updated: Aug 19, 2026

A Portal Vein Injection Model to Study Liver Metastasis of Breast Cancer
Published on: December 26, 2016
Methadone plasma protein binding: alterations in cancer and displacement from alpha 1-acid glycoprotein
Abstract:
Because of their elevated concentrations of plasma alpha 1-acid glycoprotein (AAG), cancer patients had a lower free fraction of methadone in plasma than did members of a control group. This difference was not great (-20%), but there was a fourfold variation in free fraction among a group of 13 patients (0.064 to 0.23). The bound/free methadone concentration ratio correlated linearly with plasma AAG. The binding of methadone to AAG was characterized by two classes of binding sites, the more avid having an association constant of 4 X 10(5)M-1 and an N of 0.38. Methadone could be displaced from AAG binding sites by a number of drugs: propranolol, chlorpromazine, prochlorperazine, thioridazine, and imipramine. The concentrations required for significant displacement (27 microM), as well as the relatively low Ka for methadone, suggest that the free fraction of methadone will not be significantly affected by elevated methadone concentrations or through displacement by other drugs that also bind to AAG.
More Related Videos
09:53Using X-ray Crystallography, Biophysics, and Functional Assays to Determine the Mechanisms Governing T-cell Receptor Recognition of Cancer Antigens
Published on: February 6, 2017
10:46A Flow Cytometry-Based Cell Surface Protein Binding Assay for Assessing Selectivity and Specificity of an Anticancer Aptamer
Published on: September 13, 2022
Related Concept Videos
Drug Distribution: Plasma Protein Binding
Tissue-Drug Binding: Localization of Drugs and its Significance
Drugs can bind to different tissue components, enhancing their distribution and localization. The factors influencing drug localization in tissues include the drug's lipophilicity, structural characteristics, tissue perfusion rate, and pH differences. These factors determine the...
Factors Affecting Protein-Drug Binding: Protein-Related Factors
The physicochemical properties of a drug play a significant role in its ability to bind to proteins. Lipophilic drugs, which dissolve in fats, oils, and lipids, can be bound by...
Factors Affecting Protein-Drug Binding: Drug Interactions
Displacement interactions can have varying outcomes, ranging from toxicity to virtually...
Factors Affecting Protein-Drug Binding: Patient-Related Factors
Age stands as a key determinant in protein-drug binding. Neonates, characterized by low albumin content, experience heightened concentrations of unbound drugs such as phenytoin and...
Hepatic Drug Clearance: Effect of Protein Binding
For low-extraction-ratio drugs that are less than 80% protein-bound, minor changes in protein binding...