Conditions for modifying intraocular lenses as drug carriers for methotrexate using poly (lactic-co-glycolic acid)

The intraocular lens (IOL) can be used as a slow-release drug carrier in cataract surgery to alleviate posterior capsular opacification (PCO). The following is a systematic development of an IOL using methotrexate and the solvent casting process with poly (lactic-co-glycolic acid) (PLGA) as a carrier polymer.

Different solvents for PLGA and methotrexate were tested for dissolution properties and possible damage to the IOL. The required biological concentration of methotrexate was determined in human capsular bags implanted with an IOL. To detect fibrosis, α-SMA, f-actin, and fibronectin were labelled by immunofluorescence staining. Cell proliferation and extracellular matrix contraction were observed in a lens epithelial cell line (FHL-124). Finally, the IOL was designed, and an ocular pharmacokinetic model was used to measure drug release.

Solvent mixtures were found to allow coating of the IOL with drug and PLGA without damaging it. PCO in the capsular bag model was inhibited above 1 μM methotrexate (p = 0.02). Proliferation in FHL-124 was significantly reduced above a concentration of 10 nM (p = 0.04) and matrix contraction at 100 nM (p = 0.02). The release profile showed a steady state within therapeutic range.

After determination of the required physicochemical manufacturing conditions, a drug releasing IOL was designed. A favourable release profile in an ocular pharmacokinetics model could be shown.