Biocompatibility of antimicrobial melimine lenses: rabbit and human studies.
OBJECTIVE
Covalent immobilization of antimicrobial peptide melimine onto contact lenses can produce broad-spectrum antimicrobial lenses. The purpose of this study was to investigate the performance of melimine-coated contact lenses in an animal model and human clinical trial.


METHODS
Melimine was covalently attached onto the surface of contact lenses via EDC (1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride) coupling. A rabbit model of daily contralateral wear of lenses for 22 days was conducted to assess the lens safety. A prospective, randomized, double-masked, one-day human clinical trial was used to evaluate subjective responses and ocular physiology during contralateral wear of melimine-coated (test) and uncoated (control) lenses. Delayed reactions were monitored during follow-up visits after 1 and 4 weeks. Ex vivo retention of antimicrobial activity of worn lenses was assessed by reduction in numbers of viable Pseudomonas aeruginosa and Staphylococcus aureus.


RESULTS
Melimine-coated lenses produced no ocular signs or symptoms that would indicate cytotoxicity during the lens wear of rabbits. No histological changes were found in rabbit corneas. During the human trial, no differences were observed in wettability, surface deposition, lens-fitting centration, movement, tightness, and corneal coverage between test and control lenses (p > 0.05). There were no significant differences in bulbar, limbal, or palpebral redness or conjunctival staining (p > 0.05). Mean corneal (extent, depth, and type) staining was higher for test lenses compared with that for control lenses (p < 0.05). There was no significant difference in subjective responses for lens comfort, dryness, and awareness (p > 0.05). No delayed reactions were associated with the test lenses. Worn test lenses retained more than 1.5 log inhibition against both bacterial types.


CONCLUSIONS
Melimine-coated contact lenses were worn safely by humans. However, they were associated with higher corneal staining. The melimine-coated lenses retained high antibacterial activity after wear.
*BOptom †PhD, FAAO School of Optometry and Vision Science, The University of New South Wales, Sydney, New South Wales, Australia (DD, JO, MDPW); and Brien Holden Vision Institute, Sydney, New South Wales, Australia (DD, JO).
Debarun
D
Dutta
Jerome
J
Ozkan
Mark D P
MD
Willcox
D000328:Adult; D000818:Animals; D000890:Anti-Infective Agents / Q000009:adverse effects / Q000627:therapeutic use*; D023181:Antimicrobial Cationic Peptides / Q000009:adverse effects / Q000627:therapeutic use*; D020099:Coated Materials, Biocompatible / Q000009:adverse effects / Q000627:therapeutic use*; D015169:Colony Count, Microbial; D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000502:physiology; D004195:Disease Models, Animal; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008422:Materials Testing; D008689:Methacrylates; D011446:Prospective Studies; D017755:Prosthesis Fitting; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011817:Rabbits; D013211:Staphylococcus aureus / Q000187:drug effects; D017155:Wettability
D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D020099:Coated Materials, Biocompatible; D008689:Methacrylates; C114176:etafilcon; C541912:melimine