Moxifloxacin punctum plug for sustained drug delivery.

Purpose: To assess the safety and feasibility of a moxifloxacin-loaded punctum plug (MP) in 2 groups of cataract patients.
Methods: Two prospective, single-arm, Phase I studies were conducted with 20 cataract patients (10 per study) at the Singapore National Eye Center. After cataract surgery, the MP was inserted into the punctum, and follow-up assessments were conducted at 1 h, 24 h, and on days 3, 7, 10, 20, and 30. Study endpoints included MP retention, ease of placement, and moxifloxacin concentrations in the tear fluid. Moxifloxacin concentrations were targeted to be ≥250 ng/mL through 7 days, with detectable levels through day 10. After the course of therapy, the plug would resorb and be absent from the punctum by day 30. Slit lamp evaluations were performed, and intraocular pressure measurements were performed on days 1, 3, 7, 10, 20, and 30. Patients were queried for the presence or absence of several ocular sensations in the operative eye. Due to the variability in tear film antibiotic concentrations observed in the first study, a second study was conducted with more stringent concomitant drop administration and tear sample collection criteria.
Results: MP retention in the punctum was 95% (19/20) through day 10, and all plugs were absent at day 30. Average moxifloxacin concentrations in the tear film ranged from 155 to 785 ng/mL for Study 1 and 2,465 to 3,236 ng/mL for Study 2 through day 7. These values were above the target of 250 ng/mL for all time points except for day 1 of Study 1. For both studies, moxifloxacin concentrations in the tear film were above detectable levels at day 10. The plugs were well tolerated, and there were no adverse events as defined by the protocol, and no ocular complaints or findings other than normal post-cataract symptoms.
Conclusions: The MP delivered and maintained moxifloxacin tear fluid concentrations at therapeutic levels above the MIC(90) values for common susceptible conjunctivitis pathogens for 7 days (Study 2). The MP also exhibited a favorable safety and tolerability profile and, hence, may be a viable alternative to topical antibiotic drops for the treatment of bacterial conjunctivitis.