Cocaine and cocaethylene binding in human serum.
The binding of cocaine (COC) and cocaethylene (CE) in human serum was studied by equilibrium dialysis. Scatchard analysis suggested a high-affinity binder (Ka, 2.56 x 10(4)L/mol; Bo, 7.38 x 10(-5) mol/L) and a low-affinity binder (Ka, 4.47 x 10(3)L/mol; Bo, 2.77 x 10(-4) mol/L) for COC. Two high-affinity binders (Ka, 5.21 x 10(4) L/mol; Bo, 2.54 x 10(-5) mol/L; and Ka, 4.32 x 10(4) L/mol; Bo, 2.43 x 10(-5) mol/L) were discernible for CE. For both compounds additional, very-low-affinity, high-capacity (nonspecific) binding was also seen. Supplementation of serum with specific proteins suggested that the high-affinity binding was due to alpha-1-acid glycoprotein, whereas the low-affinity binding was due to albumin, inasmuch as such supplementation increased the ratio of bound to free drug for both COC and CE.
Bailey
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DN
Department of Pathology, University of California Medical Center, San Diego 92103-8320, USA.
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003042:Cocaine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism*; D003956:Dialysis / Q000379:methods; D006801:Humans; D009961:Orosomucoid / Q000378:metabolism; D011485:Protein Binding; D012709:Serum Albumin / Q000378:metabolism*
D009961:Orosomucoid; D012709:Serum Albumin; C066444:cocaethylene; D003042:Cocaine