Microspheres for Eye Medication Delivery

Microspheres for Eye Medication Delivery

Posted under Eye Health

For those who are receiving regular eye injections to treat their retinal disease, the dread and anticipation of having a needle put into one’s eye can be worse than the actual procedure.  While some patients breeze through this treatment many others experience eye pain, eye swelling, allergic reactions, eye floaters, ocular hypertension and sometimes eye infections.  Getting to and from the eye doctor can also be a challenge for those who have transportation problems and the cost of frequent injections can place a burden on many families.  Several research initiatives are seeking to provide an alternative delivery system.  However, there are several challenges related to eye medications actually reaching or getting to the back of the eye.


“Ocular drug delivery is one of the most challenging fields of pharmaceutical research.” writes Irene Bravo-Osuna, PhD, from the Department of Pharmacy and Pharmaceutical Technology at Complutense University in Madrid, Spain.  The delivery process has to “overcome the static (different layers of cornea, sclera, and retina, including blood aqueous and blood-retinal barriers) and dynamic barriers (choroidal and conjunctival blood flow, lymphatic clearance, and tear dilution) of the eye.”


At this time medications delivered through eye drops cannot reach the back of the eye or in concentrated amounts to be therapeutic.  However, several researchers and research companies are looking at other ways to deliver “sight saving” medications.  They recognize the many challenges of intravitreal injections and are seeking a solution to get anti-VEGF and other eye medications to the back of the eye in a way that would eliminate or reduce the number of intravitreal injections and provide more targeted and compliant medication management.


One new method that is being researched is the delivery of eye medication through biodegradable microspheres. Microspheres are microcapsules filled with medication that provide sustained and controlled delivery. There are several benefits to this new intraocular drug delivery systems (IDDS).


  1. The microsphere can contain more than one drug for combined therapy such as anti-VEGF medication and intraocular corticosteroids
  2.  The microsphere can be personalized to the patient and to their eye condition.
  3.  The medication can be delivered in a sustained release delivery system so that the drug(s) are released over a set period of time providing more controlled and optimized treatment.
  4.  Biodegradable microspheres decompose and disappear after the drugs have been delivered so there is no need to remove it.
  5. Less frequent eye injections and trips to the eye doctor would be needed.
  6. Patients would experience less discomfort and side effects with improved compliance due to a more comfortable delivery system

The potential of using biodegradable microspheres in retinal diseases and other intraocular pathologies  Progress in Retinal & Eye Research Volume 42, September 2014, Pages 27-43


An intraocular delivery system that required less or no eye injections at all will be a welcome relief for those who know the the burden of continued, regular visits to their eye doctor to treat their retinal disease.


Leslie Degner, RN, BSN