A passive MEMS drug delivery pump for treatment of ocular diseases

Abstract

An implantable manually-actuated drug delivery device, consisting of a refillable drug reservoir, flexible cannula, check valve, and suture tabs, was investigated as a new approach for delivering pharmaceuticals to treat chronic ocular diseases. Devices are fabricated by molding and bonding three structured layers of polydimethylsiloxane. A 30 gauge non-coring needle was used to refill the reservoir; this size maximized the number of repeated refills while minimizing damage to the reservoir. The check valve cracking pressure was 76 +/- 8.5 mmHg (mean +/- SE, n = 4); the valve sustained > 2000 mmHg of reverse pressure without leakage. Constant delivery at 1.57 +/- 0.2 microL/sec and 0.61 +/- 0.2 microL/sec (mean +/- SE, n = 4) under 500 mmHg and 250 mmHg of applied pressure, respectively, was obtained in benchtop experiments. The valve closing time constant was 10.2 s for 500 mmHg and 14.2 s for 250 mmHg. Assembled devices were successfully demonstrated in benchtop, ex vivo, and in vivo experiments.

Recent Advances in Ocular Drug Delivery Systems

“…A microelectromechanical systems (MEMS) drug delivery device is investigated for the treatment of chronic and refractory ocular diseases [10,161]. MEMS device can be re-filled with the drug solution, giving long-term drug therapy which avoids repeated surgeries.…”

Corticosteroids and Anti-Complement Therapy in Retinal Diseases

“…Genetically engineered human RPE cells are encapsulated in this implant to secrete ciliary neurotrophic factor. The company is currently conducting clinical trials in patients with early-stage retinitis pigmentosa and Usher syndrome types 2 and 3 (Normand et al 2005;NeurotechUSA;Lo et al 2009;RoweRendleman et al 2014). 4.3.5 Refillable Devices While the above-described slow-release systems need to be readministered after their intended duration of release, an alternative approach to minimize surgical placement of implants is to use refillable systems and reinject drug as required ).…”

“…4.3.5 Refillable Devices While the above-described slow-release systems need to be readministered after their intended duration of release, an alternative approach to minimize surgical placement of implants is to use refillable systems and reinject drug as required ). Lo et al (2009) developed a surgically implantable system to be placed under the conjunctiva and release a specified amount of drug following mechanical activation by a patient's finger (Lo et al 2009). Since it is a refillable system, it only requires implantation once and allows for continual treatment of chronic diseases.…”

Towards soft robotic devices for site-specific drug delivery

“…It is implanted in the space surrounding the eye, towards the back of the eye. This is proposed as an alternative to a manually operated drug release system to treat chronic ocular diseases [27].…”