Ocular Drug Delivery Systems and Nanoparticle Applications

Ocular drug delivery remains a formidable challenge owing to the eye’s unique anatomical and physiological barriers. Conventional topical formulations suffer from rapid tear turnover, nasolacrimal drainage and limited corneal permeability, resulting in low drug bioavailability. Systemic administration achieves poor ocular penetration, while intravitreal injection, although effective for posterior-segment diseases, is invasive and carries risks of infection and patient discomfort. Nanoparticle-based carriers—including liposomes, polymeric nanoparticles, peptide-drug conjugates and stimuli-responsive hydrogels—have emerged to overcome these hurdles. By encapsulating therapeutics within biodegradable matrices such as poly(lactic-co-glycolic acid) (PLGA) or chitosan, these systems enhance ocular surface retention or vitreous residence, provide sustained release and enable targeted delivery to anterior or posterior segments. Innovations in mucoadhesive polymers and depots that bind endogenous pigments extend dosing intervals, while non-invasive modalities such as ultrasound offer additional pathways to disrupt ocular barriers transiently. These advances hold particular promise for chronic conditions—glaucoma, age-related macular degeneration and diabetic retinopathy—where prolonged, controlled therapy is essential. With an ageing global population and rising prevalence of retinal disorders, refining nanoparticle platforms is critical to improving clinical outcomes, reducing treatment burden and enhancing patient adherence.

Research from Nature Portfolio

Recent studies have exploited machine learning to design multifunctional peptide-drug conjugates that form sustained-release depots in the eye. By engineering peptides with high affinity for ocular melanin, researchers created nanoscale conjugates of ocular hypotensive agents that localise within the uveal tract. In rabbit models, a single intracameral administration of these constructs maintained therapeutic intraocular pressure reduction for up to 18 days, representing a nearly 17-fold increase in cumulative effect compared with free drug injections. This approach exemplifies how data-driven peptide engineering can produce next-generation depots that reduce injection frequency and improve patient compliance in chronic eye diseases.

Ocular Drug Delivery Systems and Nanoparticle Applications publication trend

The graph below shows the total number of articles in ocular drug delivery systems and nanoparticle applications across all publications each year (not limited to Nature Index journals).

Technical terms

Nanoparticle: A carrier particle with dimensions below 100 nm used to transport and release drugs in a controlled fashion.

Intravitreal injection: Direct administration of therapeutics into the vitreous humour to achieve high local drug concentration.

Bioavailability: The fraction of administered drug that reaches the target ocular tissues in an active form.

Mucoadhesion: The interaction between drug carriers and the mucin layer of the ocular surface to prolong residence time.

Sustained release: A delivery profile in which the drug is released at a predetermined rate over an extended period.

References

1. Intravitreal therapeutic nanoparticles for age-related macular degeneration: Design principles, progress and opportunities. Advances in Colloid and Interface Science (2024).
2. Machine learning-driven multifunctional peptide engineering for sustained ocular drug delivery. Nature Communications (2023).
3. A systematic review of ultrasound-mediated drug delivery to the eye and critical insights to facilitate a timely path to the clinic. Theranostics (2023).
4. Ocular Drug Delivery Barriers—Role of Nanocarriers in the Treatment of Anterior Segment Ocular Diseases. Pharmaceutics (2018).
5. Drug Delivery to the Posterior Segment of the Eye: Biopharmaceutic and Pharmacokinetic Considerations. Pharmaceutics (2020).
6. Chitosan Nanoparticles as a Mucoadhesive Drug Delivery System for Ocular Administration. Marine Drugs (2017).
7. Ocular Drug Delivery: Role of Degradable Polymeric Nanocarriers for Ophthalmic Application. International Journal of Molecular Sciences (2018).
8. Hydrogel Biomaterials for Application in Ocular Drug Delivery. Frontiers in Bioengineering and Biotechnology (2020).