Competitive binding of fluoroquinolone antibiotics and some other drugs to human serum albumin: a luminescence spectroscopic study

Abstract

Co-administration of several drugs in multidrug therapy may alter the binding of each to human serum albumin (HSA) and hence their pharmacological activity. Thirty-two frequently prescribed drug combinations, consisting of four fluoroquinolone antibiotics and eight competing drugs, have been studied using fluorescence and circular dichroism spectroscopic techniques. Competitive binding studies on the drug combinations are not available in the literature. In most cases, the presence of competing drug decreased the binding affinity of fluoroquinolone, resulting in an increase in the concentration of free pharmacologically active drug. The competitive binding mechanism involved could be interpreted in terms of the site specificity of the binding and competing drugs. For levofloxacin, the change in the binding affinity was small because in the presence of site II-specific competing drugs, levofloxacin mainly occupied site I. A competitive interference mechanism was operative for sparfloxacin, whereas competitive interference as well as site-to-site displacement of competing drugs was observed in the case of ciprofloxacin hydrochloride. For enrofloxacin, a different behavior was observed for different combinations; site-to-site displacement and conformational changes as well as independent binding has been observed for various drug combinations. Circular dichroism spectral studies showed that competitive binding did not cause any major structural changes in the HSA molecule.

The Effect of Tigecycline on the Binding of Fluoroquinolones to Human Serum Albumin

“…The number of binding sites (n) is approximately 1, indicating that there is one binding site in HSA for SPF and LVF. The binding constants of the HSA-SPF and HSA-LVF system that were found in this research are in agreement with previous studies (34,35). The relatively high values of the stability constants suggest a strong interaction between define the quenching type.…”

“…In such a case, the binding of FQ will not be affected by the presence of TGC (independent binding). The simultaneous binding of two drugs may also cause structural changes in the albumin molecule (non-competitive interference), thereby creating more binding sites or increasing the accessibility of the existing sites and hence increasing the degree of binding of the parent drug (34).…”

SARS-CoV-2 Bound Human Serum Albumin and Systemic Septic Shock

“…Free fatty Acids (FFA), melatonin (2,(48)(49)(50) and the SARS-CoV-2 virions are transported bound to albumin as are glycolates. Studies on drug interactions confirm both competitive and non-competitive binding (49,(51)(52)(53)(54). The role of albumin is well accepted in regulation of hormones (55)(56)(57).…”

In vivo Raman measurement of levofloxacin lactate in blood using a nanoparticle-coated optical fiber probe

“…Among them, the 1404 cm −1 and 1621 cm −1 are the characteristic peaks of levofloxacin lactate [17]. Other characteristic peaks of levofloxacin lactate could have potentially been shifted by an interaction between the drug and the albumin in the blood, which may affect the drug's molecular conformation [19,20]. After the intraperitoneal injection of levofloxacin lactate, the Raman spectra were measured in vivo and in real-time using the optical fiber.…”