Interaction of disopyramide enantiomers for sites on plasma protein.
The binding of disopyramide enantiomers to donor plasma to which had been added human alpha-1 acid glycoprotein (AAG) was characterized alone and in the presence of the opposite enantiomer. At pre-dialysis concentrations of 10(-5) M, S(+)-disopyramide increased the percent of R(-)-disopyramide free (unbound) 2.6-fold from 11 to 30%. At similar pre-dialysis concentrations, R(-)-disopyramide increased the percent of S(+)-disopyramide free 2-fold from 4.1 to 9.0%. Differences in the binding of one enantiomer due to the presence of the other were due to apparent changes in association constant; no changes in capacity to bind the enantiomers were observed. It is concluded that the enantiomers of disopyramide compete with each other for one site on AAG.
Division of Pharmacy Practice, College of Pharmacy, Ohio State University, Columbus.
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JJ
Lima
D001798:Blood Proteins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004206:Disopyramide / Q000097:blood*; D006801:Humans; D007700:Kinetics; D011485:Protein Binding; D013237:Stereoisomerism
D001798:Blood Proteins; D004206:Disopyramide