Abstract
Purpose :
The composition of tear fluid and the mechanical rubbing produced by the eye lids are important factors that may influence ocular drug delivery. The aim of this study was to evaluate and compare the release of moxifloxacin from a variety of daily disposable (DD) contact lenses (CLs) under various conditions using a novel in vitro eye model.
Methods :
Four commercially available DD conventional hydrogel (CH) CLs (nelfilcon A, omafilcon A, etafilcon A, ocufilcon B) and three silicone hydrogel (SH) CLs (somofilcon A, narafilcon A, delefilcon A) were evaluated. These lenses (n=3 for each lens type) were incubated in moxifloxacin (1mg/mL) for 24 h. The release of the drug was measured using a novel in vitro model in three experimental conditions: (1) phosphate buffered saline (PBS) (2) artificial tear solution (ATS) containing a variety of proteins & lipids and (3) ATS with mechanical rubbing produced by the device. The flow rate was set to 2.1 µL/min (3 mL/24h). The drug was detected using fluorescence spectrophotometry at excitation and emission wavelengths of 296 nm and 471 nm respectively.
Results :
Overall, CH CLs had a higher drug release than SH CLs (p<0.05) under all conditions. Typically, a higher drug release was observed in PBS than ATS (p<0.05). For CH, drug release was found to be higher in ATS with rubbing than PBS or ATS (p<0.05). For most lens types, ATS with rubbing produced higher drug release than ATS alone (p<0.05). Total drug release in PBS varied between 27.9±4.0 - 111.3±12.9 µg/lens, in ATS drug release ranged between 7.0±3.2 - 96.2±4.4 µg/lens, and in ATS with rubbing the drug release ranged between 18.1±4.3 - 164.3±15.5 µg/lens. Generally, the release kinetics for all conditions were sustained over the 24 h testing period, and no burst release was observed (p<0.05).
Conclusions :
The release of drugs from a CL into ATS is lower when compared to release into PBS. When mechanical rubbing is introduced, the amount of drugs released is increased. These results suggests that drug release from a CL can be significantly influenced by these parameters, and thus sophisticated in vitro models are necessary to adequately model on-eye drug release.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.