biostudies-literatureZheng XNIDDK NIH HHSNational Institutes of HealthNIGMS NIH HHS6454-60https://www.ebi.ac.uk/biostudies/studies/S-EPMC4082384biostudies-literatureUnknown86(13)A method was created on the basis of ultrafast affinity extraction to determine both the dissociation rate constants and equilibrium constants for drug-protein interactions in solution. Human serum albumin (HSA), an important binding agent for many drugs in blood, was used as both a model soluble protein and as an immobilized binding agent in affinity microcolumns for the analysis of free drug fractions. Several drugs were examined that are known to bind to HSA. Various conditions to optimize in the use of ultrafast affinity extraction for equilibrium and kinetic studies were considered, and several approaches for these measurements were examined. The dissociation rate constants obtained for soluble HSA with each drug gave good agreement with previous rate constants reported for the same dAnalytical chemistryDetermination of rate constants and equilibrium constants for solution-phase drug-protein interactions by ultrafast affinity extraction.PMC4082384R01 DK069629R01 GM044931Zheng XLi ZHage DSPodariu MIfalseDetermination of rate constants and equilibrium constants for solution-phase drug-protein interactions by ultrafast affinity extraction.A method was created on the basis of ultrafast affinity extraction to determine both the dissociation rate constants and equilibrium constants for drug-protein interactions in solution. Human serum albumin (HSA), an important binding agent for many drugs in blood, was used as both a model soluble protein and as an immobilized binding agent in affinity microcolumns for the analysis of free drug fractions. Several drugs were examined that are known to bind to HSA. Various conditions to optimize in the use of ultrafast affinity extraction for equilibrium and kinetic studies were considered, and several approaches for these measurements were examined. The dissociation rate constants obtained for soluble HSA with each drug gave good agreement with previous rate constants reported for the same d2014-01-01T00:00:00Z2014 Jul2025-04-04T18:33:52.793Z2019-03-27T01:31:26ZS-EPMC40823842491126710.1021/ac501031y