Release of Fluconazole from Contact Lenses Using a Novel In Vitro Eye Model

PURPOSE: Rapid drug release followed by a plateau phase is a common observation with drug delivery from contact lenses (CLs) when evaluated in a vial. The aim of this study was to compare the release of fluconazole from seven commercially available daily disposable CLs using a conventional vial-based method with a novel in vitro eye model. METHODS: An eye model was created using two 3-dimensional printed molds, which were filled with polydimethylsiloxane to obtain an inexpensive model that would mimic the eyeball and eyelid. The model was integrated with a microfluidic syringe pump, and the flow-through was collected in a 12-well microliter plate. Four commercial daily disposable conventional hydrogels (nelfilcon A, omafilcon A, etafilcon A, ocufilcon B) and three silicone hydrogels (somofilcon A, narafilcon A, delefilcon A) were evaluated. These CLs were incubated with fluconazole for 24 h. The drug release was measured in a vial containing 4.8 mL of phosphate-buffered saline and in the polydimethylsiloxane eye model with a 4.8-mL tear flow across 24 h. RESULTS: Overall, conventional hydrogel CLs had a higher uptake and release of fluconazole than silicone hydrogel CLs (p < 0.05). A higher drug release was observed in the vial condition compared with the eye model (p < 0.001). In the vial system, the drugs were rapidly released from the CL within the first 2 h, followed by a plateau phase. In contrast, drug release in the eye model under low tear volume was sustained and did not reach a plateau across 24 h (p < 0.05). CONCLUSIONS: Rapid drug release results from using a vial as the release system. Under low tear volume at physiological tear flow, commercial CLs can maintain a sustained drug release profile for up to 24 h. However, eyes with fungal keratitis may have increased tearing, which would significantly accelerate drug release.