Hydroxyl radical scavenging activity of a new ophthalmic viscosurgical device.
OBJECTIVE
To quantify the hydroxyl radical scavenging activity of a new ophthalmic viscosurgical device (OVD) based on sodium hyaluronate and hydroxypropylmethylcellulose (named VISC28) in comparison with Viscoat, Healon, and Amvisc Plus.


METHODS
The hydroxyl radicals that represent the principal free-radical species generated during phacoemulsification were produced by the Fenton reaction, and the scavenging activity of the tested viscoelastic substances was evaluated in vitro by the 2-deoxy-D-ribose (2-DR) oxidation method that produces the thiobarbituric acid-malondialdehyde (TBA-MDA), complex. An aliquot of viscosurgical formulation was added to phosphate buffer and mixed with 2-DR, Fe2 +/ethylenediaminetetraacetic acid (EDTA), and H2O2. The sample mix was incubated and thiobarbituric acid-trichloroacetic acid solution was added. The sample was then incubated for 30 min, and a chromatographic analysis was performed to quantify the TBA-MDA complex. The data were expressed as micromoles of MDA per milliliter of sample.


RESULTS
All tested OVDs showed a marked hydroxyl radical scavenging activity. The MDA level was significantly lower in VISC28 (0.045 +/- 0.007 micromol/ml) compared with Viscoat (0.070 +/- 0.012 micromol/ ml, p < 0.05), Amvisc Plus (0.111 +/- 0.008 micromol/ml, p < 0.001), and Healon (0.175 +/- 0.016 micromol/ml, p < 0.001). A reduced scavenging activity was shown by VISC28 phosphate-buffered solution (PBS) (no TRIS and no sorbitol) compared with VISC28 (p < 0.001).


CONCLUSIONS
The new OVD, VISC28, showed significantly higher hydroxyl radical inhibition compared with the other viscosurgical formulations. The following rank order for the scavenging activity was established: VISC28 > Viscoat > Amvisc Plus > Healon.
Maugeri
Francesco
F
Global Preclinical Development. Bausch & Lomb, Catania, Italy.
Maltese
Adriana
A
Ward
Keith W
KW
Bucolo
Claudio
C
D002807:Chondroitin / Q000494:pharmacology; D002809:Chondroitin Sulfates; D003855:Deoxyribose / Q000378:metabolism; D004338:Drug Combinations; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006820:Hyaluronic Acid / Q000494:pharmacology; D006861:Hydrogen Peroxide; D017665:Hydroxyl Radical / Q000378:metabolism*; D065347:Hypromellose Derivatives; D007501:Iron; D008315:Malondialdehyde / Q000378:metabolism; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000494:pharmacology; D013508:Ophthalmologic Surgical Procedures / Q000295:instrumentation*; D010084:Oxidation-Reduction; D013012:Sorbitol / Q000494:pharmacology*; D013858:Thiobarbiturates / Q000378:metabolism; D014325:Tromethamine / Q000494:pharmacology*
D004338:Drug Combinations; C045076:Fenton's reagent; D016166:Free Radical Scavengers; D013858:Thiobarbiturates; C501944:chondroitin sulfate, sodium hyaluronate drug combination; D014325:Tromethamine; D017665:Hydroxyl Radical; D065347:Hypromellose Derivatives; D008315:Malondialdehyde; D013012:Sorbitol; D003855:Deoxyribose; D006820:Hyaluronic Acid; D008747:Methylcellulose; D002807:Chondroitin; D002809:Chondroitin Sulfates; D006861:Hydrogen Peroxide; D007501:Iron; C029684:thiobarbituric acid