Abstract
Abstract: :
Purpose: To evaluate the free radical scavenging activity of a novel viscoelastic formulation (VISC26), based on sodium hyaluronate and hydroxypropylmethylcellulose, in comparison to Viscoat®, based on sodium hyaluronate and chondroitin sulfate. Methods:The OH–radical scavenging activity of viscoelastic substances was evaluated in vitro by the 2–deoxy–D–ribose (2–DR) oxidation method that produces a pink colored thiobarbituric acid–malondialdehyde (TBA–MDA) complex. An aliquot of the formulation was added to phosphate buffer solution then was added 40mM 2–DR, 1mM Fe2+/EDTA and 10mM H2O2. The sample solutions were incubated for 1h at 37°C before addition of 2% TBA and 2% trichloroacetic acid (TCA). After addition of TBA–TCA, the samples were incubated for 30 min at 100°C and then cooled in an ice box. The samples were analysed in HPLC in order to detect the TBA–MDA complex. Results: The data of the experiment were graded as the percentage of the peak area of TBA–MDA complex of the control (without viscoelastic substance). The obtained results were 100, 8 and 21 for control, VISC26 and Viscoat®, respectively. The free radicals quenching effect of VISC26 was statistically higher (p<0.01) compared to Viscoat®. Conclusions: The new viscoelastic formulation shows an higher inhibition of the hydroxyl radical, the principal free radical species formed during phacoemulsification, compare to Viscoat® suggesting that VISC26 may be useful in ophthalmic surgery.
Keywords: oxidation/oxidative or free radical damage • antioxidants • cataract