Sustained Release of Ocular Drugs

Improved Patient Compliance can Avoid Vision Loss

Lowering the pressure in the eye is currently the only way to stop or slow down the loss of vision in glaucoma. While many excellent pressure lowering drugs are currently available, their effectiveness is often hampered by inconsistent use by patients. Also, eye drops typically reduce pressure most effectively right after application with a subsequent gradual increase in pressure in the hours afterwards.

We are hoping to address these problems through the development of a slow release formulation of pressure lowering medications. The chosen drugs are embedded in biodegradable microspheres that are injected into the conjunctiva of the eye. The beads will dissolve over the next months, slowly releasing the glaucoma drugs at a steady pace. The advantages of this strategy are:

• Convenient for patients – one injection every three months
• Consistent delivery of drug – no more forgetting the drops and no peaks and valleys of drug levels during the day
• Use of proven drugs and microspheres made from the FDA approved material poly(lactic-co-glycolic acid) (PLGA).

In order to prove that this method of drug delivery is efficient and safe, we tested the beads in a mouse model with elevated intraocular pressure and glaucoma. In these animals PLGA microspheres worked as well as traditional twice-daily drops. Importantly we were able to detect Timolol in the aqueous humor of these animals that are effective in reducing intraocular pressure in humans. In addition, we will also examine the eyes to ascertain that no undesired side effects (e.g. irritation or inflammation) develop.

We are currently continuing these studies to determine whether a clinical trial in glaucoma patients is advisable.