Protein Binding Study of S-Ibuprofen Using High-Performance Frontal Analysis

Abstract

High-performance frontal analysis (HPFA) was used for the determination of the binding constant of Sibuprofen to human serum albumin (HSA). This experiment was based on an Inertsil 100 Diol 5 column and sodium phosphate buffer (pH 7.4 and ionic strength of 0.17) as the mobile phase. The mixture of S-ibuprofen and HSA (70 <TEX>$\mu$</TEX>M) solution were directly injected into the HPFA column. An injection volume of 200 <TEX>$\mu$</TEX>L and a “estricted injection”method were applied to ensure the drug to be eluted as a zonal peak with a plateau. The unbound drug concentration was calculated from the peak height of the zonal peak. Scatchard analysis was used for evaluation of the binding constant (K) and binding affinity (nK) of S-ibuprofen to HSA, and the results were K = 2.833 <TEX>${\times}$</TEX> 10<TEX>$^4$</TEX> [L mol<TEX>$^{-1}$</TEX>], nK = 4.935 <TEX>${\times}$</TEX> 10<TEX>$^4$</TEX> [L mol<TEX>$^{-1}$</TEX>], respectively.