Targeted Drug Delivery to the Eye Enabled by Microneedles

Abstract

Drug delivery targeted to specific tissues within the eye represents an important advance over conventional methods of topical and injectable delivery that have poor specificity for particular ocular tissues requiring therapy. This level of intraocular targeting can be achieved using microneedles, which are solid and hollow needles of micron dimensions. Microneedles can selectively target intraocular tissues by delivering drug formulations within the cornea, sclera, and suprachoroidal space in a minimally invasive manner. Intrastromal delivery in the cornea, intrascleral delivery, and suprachoroidal delivery using microneedles have been shown to deliver small molecules and macromolecules, as well as nanoparticles and microparticles. Delivery strategies have employed a variety of microneedle designs including coated microneedles that administer solid formulations and hollow microneedles for injection of liquid formulations. The work reported in this chapter highlights the capabilities of microneedles to provide targeted delivery to the eye in a minimally invasive way through in vitro and in vivo animal studies.

Targeted Delivery of Antiglaucoma Drugs to the Supraciliary Space Using Microneedles

“…The cannulas were shortened to approximately 700 to 800 lm in length, and the bevel at the orifice was shaped using a laser (Resonetics Maestro, Nashua, NH, USA), as described previously. 37,38 The microneedles were electropolished using an E399 electropolisher (ESMA, South Holland, IL, USA) and cleaned with deionized water. Sulprostone (Cayman Chemical, Ann Arbor, MI, USA) and 0.15% brimonidine tartrate ophthalmic solution (Alphagan P; Allergan, Irvine, CA, USA) were diluted in Hanks' balanced salt solution (HBSS; Cellgro, Manassas, VA, USA).…”

Microneedles for drug and vaccine delivery

“…Drug delivery to the eye, especially via the suprachoroidal space, has received recent attention [11]. As an extension of micropipette techniques, microneedles have been used to deliver molecules into cells and their nuclei, among other laboratory applications [12–13].…”

Formulation to target delivery to the ciliary body and choroid via the suprachoroidal space of the eye using microneedles

“…Using conventional formulations, the particles injected into the SCS spread over a portion of the SCS [18, 19, 21, 22], but are not well targeted either to localize anteriorly adjacent to pharmacological sites of action in the ciliary body or to spread posteriorly across the whole choroidal surface adjacent to pharmacological sites of action in the choroid and/or retina.…”