Sustained delivery of timolol maleate from poly(lactic-co-glycolic acid)/poly(lactic acid) microspheres for over 3 months

Abstract

It is estimated that 2.2 million people have glaucoma in the US and 67 million people worldwide. The majority of cases are associated with elevated intraocular pressure (IOP) and decreasing IOP eliminates or greatly reduces degeneration in most cases, including cases in which the IOP is in the normal range but optic neuropathy occurs. Timolol maleate has the longest record of safety and efficacy to lower IOP and is administered via eye drops one or more times per day. Unfortunately, compliance is poor across patient populations leading to degeneration. Patients typically see their ophthalmologist once every 3–4 months. If one could administer a long-acting treatment while in the doctor's office, one might overcome the compliance issue and effectively preserve sight. The critical step is to develop a formulation for timolol maleate that leads to sustained delivery for greater than 90 days and would permit a different treatment paradigm, namely subconjunctival administration once every 3–4 months. By using a 50 : 50 blend of PLGA 502H and PLA, this study was able to fabricate microspheres that delivered timolol maleate continually over 107 days, well within the time frame needed to make subconjunctival administration feasible and permit a new approach to treating glaucoma and diseases of the eye more broadly.

• IOP reduction
• PLGA/PLA
• timolol maleate
• glaucoma
• subconjunctival delivery

Acknowledgements

An Early Career Award from the Wallace H. Coulter Foundation funded this work. J. P. B. acknowledges an NIH Neuroengineering Training Grant, NIH T90-DK070068.

Abstract

Corrigendum: Sustained delivery of timolol maleate from poly(latic-co-glycolic acid)/poly(lactic acid) microspheres for over 3 months

by James P. Bertram, Sandeep S. Suluja, Jodi Mckain, & Erin B. Lavik,Journal of Microencapsulation, Volume 26, Issue 1, 2009 (pp. 18–26).

The publishers were notified that the below Acknowledgements section was missed at the author correction stage by the authors when this article was first published online ahead of print publication. We have added the Acknowledgements section below:

We would to apologize for this error on behalf of the authors.

Acknowledgements

The authors would like to thank Dr. Markus Kuehn and Dr. Young Kwon for their help and insight in the design of the technology. Drs. Kuehn and Kwon were instrumental in determining the necessary release kinetics, loading, and sizing to facilitate delivery of the formulation.