Method of obtaining drug-macromolecule binding parameters directly from dynamic dialysis data

General treatment of competitive binding of small molecules to macromolecules as applied to dynamic dialysis: theoretical analysis

A mathematical analysis of the dynamic dialysis process is presented, demonstrating how the process can be applied generally to study competitive and noncompetitive binding between small molecules and macromolecules. A law of mass action model for competitive binding with independent sites and classes with equivalent sites (CIE) is considered as a specific case without loss of generality. The escape profiles of two compounds are calculated to illustrate the effect of an increasing degree of binding competition. Noisy data are generated using the CIE model to test the presented method of estimating competitive binding parameters. The parameters estimated by the nonlinear regression technique came close to the true values, considering the degree of noise added to the exact dialysis data. A transformation approach is presented, enabling initial estimates of the binding parameters in the CIE model to be determined by multiple linear regression, thereby eliminating the main problem in the nonlinear estimation. The presented method of analysis is extended to strongly bound compounds, which also bind significantly to the dialysis membrane.