Retinal drug delivery for next-generation therapies
Enabling scalable, targeted delivery for cell and gene therapies
Cell and gene therapies are reshaping ophthalmology, but many existing delivery techniques are not designed to meet the scale, precision and clinical demands these advanced therapies require.
Our ocular drug delivery team explores how retinal delivery is evolving, where current approaches fall short, and what next-generation delivery systems may need to enable broader clinical adoption.
The retinal delivery bottleneck
As ophthalmic pipelines shift toward biologics, cell and gene therapies targeting the back of the eye, existing retinal delivery approaches are being pushed to their limits. Larger molecules, procedural complexity, and scalability challenges are exposing the limitations of current techniques.
Report: Why today's retinal delivery tools won't scale
The move toward high-volume retinal therapies will require more than incremental improvements to existing delivery methods. Our report explores why current approaches are unlikely to meet future demand and what this means for next-generation device development. Read the report
Guide: Anatomy, drugs and delivery approaches
Our team has created a visual map showing how drug class, molecular size, and target location influence ocular delivery strategy - helping teams assess the opportunities and limitations of different front- and back-of-eye approaches. View the sheet
Device considerations for intravitreal delivery
Intravitreal delivery has become the standard for many posterior segment therapies, offering efficient access to the back of the eye while driving demand for improved usability, dosing frequency, and patient experience. As demand grows for longer-lasting therapies and improved patient experience, device performance becomes critical to success.
Our Ocular Drug Delivery team explores four often-overlooked engineering challenges that can significantly impact reliability, manufacturability, and usability. Drawing on experience across multiple IVT inserter programmes, it highlights the trade-offs that shape effective device design.
Insight: Four key design challenges for successful IVT devices
Designing for suprachoroidal delivery
Suprachoroidal (SCS) delivery offers an alternative route for targeting therapies to the choroid and retina while limiting systemic exposure. However, it also introduces therapy-specific challenges and procedural risks.
Low-viscosity formulations can spread across the globe following injection into the anterior choroid, enabling broad retinal coverage with relatively simple delivery tools. High-viscosity formulations, by contrast, tend to remain localised at the injection site, requiring more sophisticated approaches to ensure accurate delivery where needed.
Experimental cannula-based SCS delivery systems positioned near the macula may help deliver high-viscosity formulations to the central retina, though they offer little advantage for low-viscosity therapies. Despite growing interest in this route of administration, there are currently no marketed purpose-designed tools for posterior SCS access.
SCS delivery also carries a risk of choroidal haemorrhage, which can be severe. Developing devices capable of achieving reliable delivery while minimising procedural risk therefore remains a significant engineering challenge.
Video: how smarter delivery approaches can unlock the full potential of the suprachoroidal space
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The realities of subretinal delivery
Subretinal delivery enables direct access to retinal tissue for advanced therapies such as cell and gene treatments, but introduces significant procedural, device, and scalability challenges that require new approaches to delivery. Today’s procedures remain highly skilled, time-intensive, and inherently risky.
Current delivery tools restrict subretinal therapy to a small number of expert surgeons and specialist centres, limiting broader patient access. Without a significant step change in procedural simplicity, speed, and cost, subretinal delivery is unlikely to become mainstream.
Advancing delivery tools will be critical to reducing complexity, improving consistency, and enabling wider adoption of these transformative therapies.
Video: simpler, safer sub-retinal delivery approaches that can scale beyond specialist surgery
Opportunities for topical delivery
Topical delivery remains the mainstay of ocular drug administration. It is a mature, relatively simple approach that continues to work well for many therapies - despite its apparent inefficiencies. Flooding a ~10 microlitre tear film, which refreshes within minutes, with a 40 microlitre eye drop may seem crude, yet it can still achieve effective therapeutic outcomes for a wide range of drugs.
At the same time, it is unsurprising that topical delivery can suffer from poor bioavailability and systemic side effects. Much of the administered dose is cleared from the eye within seconds, and almost all of it within minutes. Both perspectives are valid. Ultimately, successful topical delivery depends on matching drug pharmacokinetics and transport behaviour to the capabilities - and limitations - of the delivery route.
More advanced topical delivery technologies could help expand the range of compatible therapies. Improvements such as tighter dose control, horizontal delivery approaches, multi-dose preservative-free systems, and other innovations may help improve retention, reduce waste, and enable more effective ocular drug delivery.
Video: Expanding the potential of topical delivery
Our areas of focus:
Medical Devices & Drug Delivery
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We deliver across the entire life of a project, from opportunity discovery to production engineering. Discover how our interdisciplinary teams of experts collaborate to tackle the toughest product development challenges.
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Working seamlessly with our development teams, we take clients' products through prototype builds, clinical trials, pilot manufacture and more. Using TTP Manufacturing reduces uncertainty, risk and time to market for our clients.
Meet some of the team
Nathan Wilkinson
Matthew Parker
David Cottenden
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