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Cocaine and cocaethylene binding in human serum
1Department of Pathology, University of California Medical Center, San Diego 92103-8320, USA.
American Journal of Clinical Pathology
|August 1, 1995
Summary
Cocaine and cocaethylene bind to human serum proteins. Alpha-1-acid glycoprotein is the high-affinity binder, while albumin is the low-affinity binder for these drugs.
Area of Science:
- Pharmacology
- Biochemistry
- Toxicology
Background:
- Cocaine (COC) and cocaethylene (CE) are psychoactive substances with known interactions in the human body.
- Understanding their binding characteristics in serum is crucial for pharmacokinetic and toxicological studies.
Purpose of the Study:
- To investigate the binding kinetics of cocaine and cocaethylene in human serum.
- To identify the specific serum proteins responsible for the high- and low-affinity binding of these compounds.
Main Methods:
- Equilibrium dialysis was employed to measure the binding of COC and CE to human serum.
- Scatchard analysis was utilized to determine binding affinities (Ka) and capacities (Bo).
- Serum was supplemented with specific proteins (alpha-1-acid glycoprotein and albumin) to identify binding sites.
Main Results:
- Scatchard analysis revealed both high- and low-affinity binding sites for COC in human serum.
- Two high-affinity binding sites and a very-low-affinity, high-capacity site were identified for CE.
- Supplementation experiments indicated that alpha-1-acid glycoprotein mediates high-affinity binding, and albumin mediates low-affinity binding for both COC and CE.
Conclusions:
- Human serum exhibits complex binding characteristics for cocaine and cocaethylene.
- Alpha-1-acid glycoprotein and albumin are the primary determinants of high- and low-affinity drug binding, respectively.
- These findings contribute to a better understanding of the disposition and potential toxicity of cocaine and cocaethylene.