Improved penetration of aminoglycosides and fluoroquinolones into the aqueous humour of patients by means of Acuvue contact lenses

Objectives: In order to improve the penetration of topically applied drugs in ophthalmology, the suitability of hydrophilic contact lenses (Acuvue, Vi stacon, power -1.0 D) as a drug delivery system for antibiotics was tested. A prospective study was undertaken to determine the transcorneal penetrati on of five topically applied aminoglycosides and fluoroquinolones into the aqueous humour of patients. Methods: Two hundred and sixty-five patients undergoing cataract extraction received 0.3% gentamicin, kanamycin, tobramycin, ciprofloxacin or ofloxaci n solution by two different modes of administration: either as eye drops (n ine drops every 15 min, starting 2 h prior to surgery) or by means of a dru g delivery system (Acuvue contact lenses soaked for 1 h in eye drop solutio n without preservatives, 1-5 h prior to surgery). At the beginning of catar act extraction, 50-100 mu l aqueous fluid was aspirated from the anterior c hamber and immediately stored at -80 degrees C. Antibiotic concentrations w ere measured using fluorescence polarisation immunoassays (aminoglycosides) or high-performance liquid chromatography (fluoroquinolones). Results: After soaking for Ih in 0.3% eye drop solutions, Acuvue contact le nses released about 190-250 mu g aminoglycoside and ofloxacin and 1000 mu g ciprofloxacin. These amounts are considerably lower or in the same order o f magnitude than obtained with application of eye drops (1350 mu g). From the aminoglycosides tested, only gentamicin and tobramycin, but not ka namycin, were able to penetrate into the aqueous humour of patients. After the wearing of antibiotic-soaked lenses, mean aqueous humour concentrations were higher than after the use of eye drops. This difference reached signi ficance in tobramycin (1.09 (1.30) mu g . ml(-1) vs 0.49 (0.79) mu g . ml(- 1)), ciprofloxacin (1.09 (0.60) mu g . ml(-1) vs 0.38 (0.33) and ofloxacin (5.55 (2.53) mu g . ml(-1) vs 0.56 (0.37) mu g . ml(-1)). The percentage of patients with aqueous humour concentration above the MIC9 0 of Staphylococcus epidermidis, the most common cause of postoperative end ophthalmitis, was 92% and 100% after wearing ciprofloxacin- or ofloxacin-so aked lenses, respectively. Conclusion: Gentamicin and tobramycin penetrated into the aqueous humour of patients, whereas kanamycin was not able to ove rcome the corneal barrier. Acuvue contact lenses soaked in 0.3% eye drop so lutions can release sufficient amounts of gentamicin, ciprofloxacin and ofl oxacin to produce bacteriostatic concentrations in the humor aquosus. Acuvu e contact lenses can be recommended as a drug delivery system for fluoroqui nolones.