Related Experiment Video
Updated: Jun 2, 2026

A Rapid and Quantitative Fluorimetric Method for Protein-Targeting Small Molecule Drug Screening
Published on: October 16, 2015
Study of the interaction between ofloxacin and human serum albumin by spectroscopic methods
Aurica Varlan1, Sorana Ionescu, Mihaela Hillebrand
1Department of Physical Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, Bucharest, Romania.
Abstract:
The binding of ofloxacin (OFLX) to human serum albumin (HSA) was investigated by fluorescence and circular dichroism (CD) techniques. The binding parameters have been evaluated by a fluorescence quenching method. Competitive binding measurements were performed in the presence of warfarin and ibuprofen and suggest binding to the warfarin site I of HSA. The distance r between donor (HSA) and acceptor (OFLX) was estimated according to the Forster's theory of non-radiatiative energy transfer. CD spectra revealed that the binding of OFLX to HSA induced conformational changes in HSA. Molecular docking was performed and shows that for the lowest energy complex OFLX is located in site I of HSA, which correlate to the competitive binding experiments.
Related Concept Videos
Factors Affecting Protein-Drug Binding: Protein-Related Factors
The physicochemical properties of a drug play a significant role in its ability to bind to proteins. Lipophilic drugs, which dissolve in fats, oils, and lipids, can be bound by...
Drug Distribution: Plasma Protein Binding
Protein-Drug Binding: Determination Methods
Indirect methods involve isolating the bound drug from its free form in biological samples such as blood, serum, or plasma. These techniques aim to measure the percentage of drugs bound to proteins. Equilibrium dialysis is a commonly used method where the free drug concentration at equilibrium is measured by separating the bound...
Factors Affecting Protein-Drug Binding: Drug-Related Factors
One crucial factor in drug-protein binding is the drug's lipophilicity or its affinity for fat. More lipophilic drugs tend to have higher binding extents. For example, highly lipophilic drugs like cloxacillin exhibit substantial protein binding, with as much as 95% of the drug binding to proteins. In contrast,...
Measurement of Bioavailability: Pharmacokinetic Methods
Measurement of Bioavailability: Pharmacodynamic Methods

