Drug-Loaded Nanoparticles Embedded in a Biomembrane Provide a Dual-Release Mechanism for Drug Delivery to the Eye

Topical delivery by eye drops, which accounts for ∼90% of all ophthalmic formulations, is inefficient for drug delivery to the posterior segment. Only 5% of the drug applied as drops reaches the target, whereas the rest is lost through tear drainage. A number of conditions such as glaucoma and proliferative retinopathy need sustained drug release to be therapeutically effective. The purpose of this study was to develop a novel dual-release drug delivery system to meet this requirement. Our system consists of lidocaine-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles suspended within a thin collagen membrane. This system provides constant contact with the cornea, and the nanoparticles supply a continuous release of medication, resulting in more drug reaching the target. This system provides dual release of the drug, from both the nanoparticles and the membrane. The nanoparticles loaded into the membrane did not have a significant effect on light transmittance through the membrane compared with a commercial contact lens. The membranes containing nanoparticles showed a lesser burst release of 16.2% of the initial lidocaine loading than the free nanoparticles with a burst release of 41.8% of the initial lidocaine loading. The membrane containing nanoparticles showed a slow and continuous release of lidocaine of up to 23.4% of the initial loading after 7 days compared with 64% for the free nanoparticles. The dual-release membrane system shows promise for a new drug delivery method to the eye with limited burst release and sustained delivery.