Research on drug–receptor interactions and prediction of drug activity via oriented immobilized receptor capillary electrophoresis

Oriented covalent immobilized β 2 -adrenergic receptor (β 2 -AR) CE (OIRCE) was developed to determine the interactions between a set of natural extracts of Radix Paeoniae Rubra (NERPR) and β 2 -AR, and to predict the activity of NERPR. The inner capillary surface is chemically bonded with stable β 2 -AR coating via microwave-assisted technical synthesis. The modified capillaries were characterized via infrared spectroscopy and fluorescence microscopy. Furthermore, the bonding amounts of β 2 -AR were first obtained via fluorescence spectroscopy method. In determining the amount of bonded β 2 -AR, the regression equation A  =  576 707C + 35.449 and the correlation coefficient 0.9995 were obtained. This result revealed an excellent linear relationship in the range of 2 × 10 −4 mg/mL to 1 × 10 −3 mg/mL. The normalized capacity factor ( K RCE ) was obtained using OIRCE in evaluating drug–receptor interactions. Related theories and equations were used to calculate K RCE values from apparent migration times of a solute and EOF. The order of K RCE and the binding constant ( K b ) values between drugs and β 2 -AR was well consistent. The results confirmed that the OIRCE and K RCE values can be effectually used to investigate drug-receptor interactions, and OIRCE has the potential to predict drug activity and to select leading compounds from natural chemicals.