Radical degradation of high molecular weight hyaluronan: Inhibition of thereaction by ibuprofen enantiomers

The antioxidative and/or free-radical-scavenging activities of R-(-)- and S -(+)-ibuprofen enantiomers, as well as of the drug racemate, were studied i n vitro on measuring the kinetics of (uninhibited or drug-inhibited) degrad ation of high molecular weight hyaluronan by hydroxyl radicals. The continu al flux of OH radicals at aerobic conditions was maintained by the H2O2 +Ca 2+ system. The kinetics of hyaluronan degradation was monitored indirectly by capillary viscometry. under experimental conditions, with no drug additi on, the relative viscosity ([eta](rel)) decreased continuously, reaching 13 % of the initial [eta](rel.)value in 4 h. Each drug tested exhibited a dose -dependent protective effect against hyaluronan degradation, however R-(-)- ibuprofen demonstrated a slightly greater activity than the drug S-(+)-enan tiomer. (C) 2001 Prous Science. All rights reserved.