The non-covalent binding of small molecules, ligands to proteins, is playing a crucial role in biopharmaceutical research. This interaction would alter the stereochemistry of a protein molecule (a drug candidate) and also could modify its molecular recognition ability and ultimately its bioactivity. Therefore, it is important to develop a suitable method which is able to quantitatively determinate the binding strengths of the molecule. A variety of different approaches have been developed to quantify molecular interactions. Methods applied to drug-protein binding studies in the pharmaceutical and biomedical sciences include equilibrium dialysis, ultra-filtration, ultra-centrifugation, gel filtration, calorimetry, microdialysis, spectroscopic, HPLC, and capillary electrophoresis-based methods.