2026-10-11T13:57:52Z https://api.figshare.com/v2/oai

oai:figshare.com:article/32640051 2026-10-01T16:34:41Z portal_1172 item_type_8 month_year_10_2026

Sustained intrascleral drug delivery using hollow microneedles to target posterior segment eye diseases Shilpkala Shankar Gade (24169062) PUREID: 612262128 microneedles hollow microneedle electron discharge machine 3D printing thermoresponsive hydrogel chitosan poly(N-isopropylamide) in-vivo biodistribution Age-related macular degeneration (AMD) is a chronic eye disease causing central vision loss in older adults. It affects the macula, the central part of the retina responsible for detailed vision. The wet form of AMD involves abnormal blood vessel growth, leading to retinal damage. This thesis explores minimally invasive intrascleral drug delivery using hollow microneedles (HMNs) for management of AMD and developing sustained-release formulations. Current AMD treatments involve frequent intravitreal injections, which carry risks and are invasive. The research developed HMNs ranging from 200-1500 µm in height with various bevel angles for minimally invasive intrascleral drug delivery. A 3D-printed adapter guided injections and the distribution of different formulations was studied using microscopy and optical coherence tomography. To address the need for long-acting treatments, developed a thermoresponsive hydrogel by chitosan conjugated poly (N-isopropyl acrylamide) for controlled release of sunitinib (SUN), an anti-angiogenic drug. To reduce burst release, SUN-loaded PLGA nanoparticles were incorporated into the hydrogels, achieving sustained release over 3 months. In vitro and ex vivo studies demonstrated the safety and anti-angiogenic efficacy of the formulations. In vivo studies in rabbits showed significantly higher scleral drug retention with the nanoparticle-loaded hydrogels compared to SUN solution or hydrogel alone. This thesis demonstrates the potential of HMNs for minimally invasive intrascleral drug delivery and the promise of nanoparticle-loaded thermoresponsive hydrogels for long-term management of AMD and other chronic ocular diseases.<br><br><i>Thesis is embargoed until 31 December 2027</i>.<br><br> 2026-10-01T16:34:41Z Text Thesis 10.17034/32640051.v1 https://figshare.com/articles/thesis/Sustained_intrascleral_drug_delivery_using_hollow_microneedles_to_target_posterior_segment_eye_diseases/32640051 All Rights Reserved Open Access after 2027-12-31