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Micro-patterned drug delivery device for light-activated drug release.

Raiyan T Zaman¹, Ashwini Gopal, Kathryn Starr

¹Stanford University School of Medicine, Stanford, California 94305, USA. rtzaman@stanford.edu

Lasers in Surgery and Medicine

|December 1, 2011

Summary

This study demonstrates a novel micro-patterned drug delivery device for ocular applications. The device showed excellent stability and controlled dye release via mechanical or laser methods, with a 13-day half-life and minimal inflammation.

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Area of Science:

Biomaterials Science
Ophthalmology
Drug Delivery Systems

Background:

Development of micro-patterned drug delivery devices for sustained ocular drug release.
Evaluation of long-term stability and controlled release mechanisms.

Purpose of the Study:

Fabricate and assess a micro-patterned drug delivery device for ocular use.
Investigate dye release using mechanical puncture and laser photodisruption.
Determine the long-term stability and retention of the released marker dye.

Main Methods:

Fabrication of a transparent, biocompatible polymer device with two reservoirs containing sodium fluorescein dye.
Implantation in rabbit eyes, followed by topical glycerol application to reduce light scattering.
Dye release induced by a 28-gauge needle or an ophthalmic Nd:YAG laser.
Fluorescence spectrophotometry for dye half-life measurement and histological analysis of surrounding tissues.

Main Results:

No leakage of sodium fluorescein dye observed post-implantation.
Ablation threshold for device perforation determined to be 6-10 mJ, creating 100-500 µm holes.
Measured dye half-life in the vitreous chamber was 13 days.
Histology revealed minimal immune and foreign body responses, including mild inflammation.

Conclusions:

The micro-patterned drug delivery device exhibits minimal inflammatory response and retains its contents effectively.
Controlled release of marker dye was achieved through mechanical or laser-induced disruption.
The device demonstrates potential for controlled drug delivery in treating ocular diseases with a long retention time.