A flow-injection ultrafiltration sampling chemiluminescence system for on-line determination of drug-protein interaction.
A flow-injection ultrafiltration sampling chemiluminescence system for on-line determination of cimetidine-bovine serum albumin (BSA) interaction is proposed in this paper. Cimetidine can be oxidized by N-bromosuccinimide (NBS) and sensitized by fluorescein to produce high chemiluminescence emission in basic media. The concentration of cimetidine is linear with the CL intensity in the range 3 x 10(-7) - 1 x 10(-4) mol L(-1) with a detection limit of 1 x 10(-7) mol L(-1) (3 sigma). The drug and protein were mixed in different molar ratios in 0.067 mol L(-1) phosphate buffer, pH 7.4, and incubated at 37 degrees C in a water bath. The ultrafiltration probe was utilized to sample the mixed solution at a flow rate of 5 micro L min(-1). The data obtained by the proposed ultrafiltration flow-injection chemiluminescence method was analyzed with Scrathard analysis and a Klotz plot. The estimated association constant ( K) and the number of the binding site ( n) on one molecule of BSA by Scrathard analysis and Klotz plot were 3.15 x 10(4) L mol(-1) and 0.95, 3.25 x 10(4) L mol(-1) and 0.92, respectively. The proposed system proved that flow-injection chemiluminescence analysis coupled with on-line ultrafiltration sampling is a simple and reliable technique for the study of drug-protein interaction.
Wang
Zhouping
Z
Department of Chemistry, Institute of Analytical Science, Southwest China Normal University, 400715, Chongqing, P.R. China.
Zhang
Zhujun
Z
Fu
Zhifeng
Z
Xiong
Yan
Y
Zhang
Xiao
X
D001665:Binding Sites; D001974:Bromosuccinimide / Q000737:chemistry; D002927:Cimetidine / Q000737:chemistry; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods*; D019793:Fluorescein; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012972:Sodium Hydroxide; D013696:Temperature; D014462:Ultrafiltration
D004364:Pharmaceutical Preparations; D011506:Proteins; D012710:Serum Albumin, Bovine; D012972:Sodium Hydroxide; D002927:Cimetidine; D001974:Bromosuccinimide; D019793:Fluorescein