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Determination of compound binding to plasma proteins
1Covance Laboratories, Inc., Madison, Wisconsin, USA.
Current Protocols in Pharmacology
|February 2, 2012
Summary
Determining plasma protein binding is crucial for drug development. This study details ultrafiltration and equilibrium dialysis methods, with equilibrium dialysis being more robust and ultrafiltration faster for assessing drug compound properties.
Area of Science:
- Pharmacology and Drug Development
- Biochemistry
- Analytical Chemistry
Background:
- Plasma protein binding significantly influences a compound's pharmacokinetic and pharmacodynamic properties.
- Accurate determination of plasma protein binding is essential for effective drug development and lead compound prioritization.
Purpose of the Study:
- To detail established protocols for determining plasma protein binding.
- To compare the efficacy and throughput of different methodologies.
Main Methods:
- Ultrafiltration: A rapid technique for assessing plasma protein binding.
- Equilibrium Dialysis: A robust method for plasma protein binding determination, including a traditional and a high-throughput 96-well plate format.
Main Results:
- Equilibrium dialysis offers greater robustness compared to ultrafiltration.
- Ultrafiltration provides a faster alternative for plasma protein binding assessment.
- A high-throughput 96-well plate version of equilibrium dialysis is available for increased efficiency.
Conclusions:
- Both ultrafiltration and equilibrium dialysis are vital techniques for evaluating plasma protein binding during drug development.
- The choice of method depends on the specific requirements for speed and robustness.
- The development of a 96-well plate equilibrium dialysis method enhances the capacity for high-throughput screening.
Related Concept Videos
01:22Protein-Drug Binding: Determination Methods
Determining protein-drug binding can be achieved through indirect and direct methods, each providing valuable insights into the interaction between proteins and drugs.
Indirect methods involve isolating the bound drug from its free form in biological samples such as blood, serum, or plasma. These techniques aim to measure the percentage of drugs bound to proteins. Equilibrium dialysis is a commonly used method where the free drug concentration at equilibrium is measured by separating the bound...
Indirect methods involve isolating the bound drug from its free form in biological samples such as blood, serum, or plasma. These techniques aim to measure the percentage of drugs bound to proteins. Equilibrium dialysis is a commonly used method where the free drug concentration at equilibrium is measured by separating the bound...
01:29Drug Distribution: Plasma Protein Binding
Drugs predominantly attach to plasma proteins, with only a small percentage remaining unbound. The unbound portion can be calculated as one minus the bound fraction. Acidic drugs form large, inactive complexes by reversibly binding to plasma albumin, which prevents them from diffusing across biological barriers. These drug-protein complexes act as reservoirs for the drugs. As the concentration of unbound drugs decreases, these complexes quickly dissociate to release the free drug, maintaining...
02:18The Equilibrium Binding Constant and Binding Strength
The equilibrium binding constant (Kb) quantifies the strength of a protein-ligand interaction. Kb can be calculated as follows when the reaction is at equilibrium:
01:20Factors Affecting Protein-Drug Binding: Protein-Related Factors
Drug binding to proteins is a key aspect of pharmacokinetics and can influence a drug's distribution, absorption, and elimination in the body. Several factors, including the drug's physiochemical properties, protein concentration, disease states, and the number of binding sites on the protein, influence this process.
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...
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...
01:16Protein-Drug Binding: Mechanism and Kinetics
Protein-drug binding refers to the interaction between drugs and proteins within the body. This binding process can occur intracellularly, involving drug interactions with enzymes or receptors within cells, or extracellularly, involving plasma proteins in the blood.
Various forces drive these interactions, including hydrogen bonds, hydrophobic interactions, ionic bonds, electrostatic interactions, and van der Waals forces. These bonds enable drugs to bind to specific sites on proteins,...
Various forces drive these interactions, including hydrogen bonds, hydrophobic interactions, ionic bonds, electrostatic interactions, and van der Waals forces. These bonds enable drugs to bind to specific sites on proteins,...
01:18Factors Affecting Protein-Drug Binding: Drug-Related Factors
Drug binding to proteins is a complex phenomenon influenced by various drug-related factors, each playing a significant role in the interaction between drugs and proteins within the body.
One crucial factor in drug-protein binding is the drug's lipophilicity or its affinity for fat. More lipophilic drugs tend to have higher binding extents. For example, highly lipophilic drugs like cloxacillin exhibit substantial protein binding, with as much as 95% of the drug binding to proteins. In contrast,...
One crucial factor in drug-protein binding is the drug's lipophilicity or its affinity for fat. More lipophilic drugs tend to have higher binding extents. For example, highly lipophilic drugs like cloxacillin exhibit substantial protein binding, with as much as 95% of the drug binding to proteins. In contrast,...