Precision Ocular Drug Delivery Via Aerosol Ring Vortices.

PURPOSE: Despite being the most prominent dosage form for topical ocular delivery, eye-drops have several well-recognized drawbacks. Addressing these limitations, in this work we introduce a novel method to accurately deliver ophthalmic medications to the surface of the eye at relatively low volume and low velocity. By aerosolizing a medicament and dispensing it in the form of a toroidal vortex, commonly known as a "smoke ring", several major drawbacks associated with topical drug delivery can be avoided.

METHODS: A device capable of emitting a toroidal vortex was developed such that actuation force and aerosol loading could be modulated. Different solution formulations were tested for deposited dose on an in vitro eye.

RESULTS: It was found that the dose delivered to the surface of an in vitro eye was directly proportional to the velocity and the size of the droplets emitted from the device. With a dilute solution formulation (0.05% fluorescein sodium), doses could be reproducibly deposited by actuating the device at different velocities (from ~5 ng to ~18 ng per actuation). While a more concentrated solution of 0.5% fluorescein sodium, between 20 ng and 160 ng could be deposited depending on selected actuation velocity. And with the highest concentration, 5% fluorescein sodium, 1.15 +/- 0.075 μg was deposited. It was also shown that the amount of drug deposited onto the eye surface could be modulated by modulating the chamber fill time.

CONCLUSION: Precise toroidal vortex based aerosol delivery may facilitate optimized administration of medicines to the surface of the eye.