Background: A combination of phenylbutazone (PBZ) and ketoprofen (KP) is popular in therapy of rheumatoid arthritis (RA) but could be unsafe due to the uncontrolled growth of toxicity.
Methods: Quenching fluorescence of serum albumin in the presence of the both drugs has been characterized by dynamic KQ [M(-1)], static V [M(-1)] quenching constants and also association constants Ka [M(-1)].
Results: The quenching of tryptophanyl residues fluorescence by the KP and PBZ indicates the capability of these drugs to accept the energy from Trp-214 and Trp-135. Strong displacement of KP and PBZ bound to albumin cause by the binding of the second drug to SA close to Trp-214 (subdomain IIA) has been obtained. The displacement was also confirmed on the basis of quenching and association constants.
Conclusions: The conclusion, that both PBZ and KP form a binding site in the same subdomains (IIA or/and IB), points to the necessity of using a monitoring therapy owning to the possible increase of the uncontrolled toxic effects.
Keywords: Competition; Serum albumin; Spectrofluorescence.
Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.