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Cocaine and cocaethylene binding to human liver
1Department of Pathology, University of California Medical Center, San Diego 92103-8320, USA.
Journal of Analytical Toxicology
|September 16, 1998
Summary
Cocaine and cocaethylene exhibit complex binding in human liver, involving high-affinity and low-affinity sites. These findings are crucial for understanding drug metabolism and toxicity.
Area of Science:
- Pharmacology
- Toxicology
- Biochemistry
Background:
- Cocaine (COC) and its metabolite cocaethylene (CE) are psychoactive substances with significant public health implications.
- Understanding their interaction with biological matrices like the liver is essential for predicting their pharmacokinetic and toxicodynamic profiles.
Purpose of the Study:
- To investigate the in vitro binding characteristics of cocaine and cocaethylene to human liver homogenates.
- To compare the binding profiles of COC and CE in the liver with previously studied matrices such as human serum and placenta.
Main Methods:
- Equilibrium dialysis was employed to study the binding of COC and CE to whole human liver homogenates.
- High-performance liquid chromatography (HPLC) was utilized for the quantitative measurement of the drugs.
Main Results:
- Significant binding of both COC (up to 32%) and CE (up to 43%) to liver homogenates was observed.
- Scatchard analysis revealed the presence of multiple binding sites for both compounds, including high-affinity, low-capacity sites and low-affinity, high-capacity sites.
- Very low-affinity, high-capacity binding, likely nonspecific, was also characterized for both COC and CE.
Conclusions:
- Human liver exhibits complex binding interactions with both cocaine and cocaethylene.
- The characterized binding profiles provide insights into the distribution and potential disposition of these drugs within the liver.
- Comparison with serum and placental binding data can further elucidate tissue-specific drug interactions and toxicological risks.