Recent perspectives on the delivery of biologics to back of the eye

ABSTRACT

Introduction: Biologics are generally macromolecules, large in size with poor stability in biological environments. Delivery of biologics to tissues at the back of the eye remains a challenge. To overcome these challenges and treat posterior ocular diseases, several novel approaches have been developed. Nanotechnology-based delivery systems, like drug encapsulation technology, macromolecule implants and gene delivery are under investigation. We provide an overview of emerging technologies for biologics delivery to back of the eye tissues. Moreover, new biologic drugs currently in clinical trials for ocular neovascular diseases have been discussed.

Areas covered: Anatomy of the eye, posterior segment disease and diagnosis, barriers to biologic delivery, ocular pharmacokinetic, novel biologic delivery system

Expert opinion: Anti-VEGF therapy represents a significant advance in developing biologics for the treatment of ocular neovascular diseases. Various strategies for biologic delivery to posterior ocular tissues are under development with some in early or late stages of clinical trials. Despite significant progress in the delivery of biologics, there is unmet need to develop sustained delivery of biologics with nearly zero-order release kinetics to the back of the eye tissues. In addition, elevated intraocular pressure associated with frequent intravitreal injections of macromolecules is another concern that needs to be addressed.

KEYWORDS:

• Barriers
• biologics delivery
• back of the eye
• implants
• nanomicelles
• nanoparticles
• ocular delivery
• peptide
• protein
• pharmacokinetics

Article highlights

• Back of the eye diseases such as AMD, DME and DR are vision threatening diseases, normally diagnosed in elderly population.

• Treatment of posterior ocular diseases is challenging due to ocular barriers as well as physicochemical properties of therapeutic agents.

• Biologics also known as macromolecules have recently gained attention as therapeutic agents used to treat back of the eye diseases. These molecules have shown remarkable results relative to small molecule drugs and other treatments.

• Small number of biologics have been approved and several are in the pipeline for treatment of back of the eye diseases.

• With increase in number of biologics in pipeline; an ideal delivery system, one that will ensure stability of the molecule, sustained release, patient compliance and affordable needs to be developed.

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Declaration of interest

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Additional information

Funding

The authors were supported by grants from the U.S. Department of Health and Human Services, National Institutes of Health, National Eye Institute (R01-EY-09171, R01-EY-10569).