Protein binding of chloroquine enantiomers and desethylchloroquine.

Abstract
The protein binding of racemic chloroquine, its enantiomers and desethylchloroquine to plasma, purified human albumin, and alpha 1‐acid glycoprotein (alpha 1‐AGP) was determined by equilibrium dialysis. The binding was not concentration dependent. (+)‐Chloroquine bound more to plasma (66.6 +/‐ 1.9%) and albumin (45.9 +/‐ 0.8%) than (‐)‐chloroquine (48.5 +/‐ 2.4% and 35.3 +/‐ 0.6%, respectively). These differences were statistically significant. (‐)‐Chloroquine bound more to alpha 1‐AGP (47.5 +/‐ 0.7%) than (+)‐chloroquine (34.5 +/‐ 0.5%). The binding of desethylchloroquine to alpha 1‐AGP is higher than to albumin (38.9 +/‐ 0.9% and 21.1 +/‐ 0.4%, respectively.