Abstract
Purpose: :
To develop and determine viability of a novel, sustained release, refillable intraocular, drug delivery device which acts as a reservoir and delivery agent for potential multi drug use.
Methods: :
The capsule drug ring (CDR) prototypes were manufactured using a CO2 VLS 3.60 (Versa Laser). The primary structural components for the device were made of Carbothane, a thermoplastic aliphatic polycarbonate-based polyether urethane. The device has been optimized using Avastin® and dexamethasone as the drugs of interest. Each component of the device has been evaluated for in vitro biocompatibility by testing for lens epithelial cell (B-3) migration and proliferation with Avastin® and dexamethasone, measuring Lipopolysaccharide (LPS) levels, and testing for the presence of pro-inflammatory cytokines (i.e. MIP-1β, MIP-1α, MCP-1, IL-1β, TNF, TGF-β1) after in vitro culture with macrophages (J774A.1) and fibroblasts (L-929).
Results: :
The design of the device was intended to maximize the volume available in the capsular bag without interfering with or impairing vision. The device was designed to be a circular ring shape and had a drug reservoir of 40µL. Prototype CDR designs have been manufactured. Two valves have been included in the design such that the reservoir would be refillable and also have potential for multi-drug delivery. The kinetics of drug release from the device have been shown to be near zero order. After manufacture, LPS was detected at levels below 0.0303 EU/mL. As each component of the device was specifically chosen because they are established medical grade biomaterials it was not unexpected that the device would be within acceptable biocompatibility limits.
Conclusions: :
The results show the successful manufacture of the CDR from established medical grade biomaterials. The drugs Avastin® and dexamethasone were used as drugs of interest to show that the device works as designed and delivers the drug in a desirable way. The in vitro biocompatibility of the completed CDR and of the component materials was also assessed through a variety of tests and evaluation. The CDR shows great potential as an implantable ocular device for drug delivery.
Keywords: age-related macular degeneration • cataract • drug toxicity/drug effects