Doctoral Defence in Pharmaceutical Sciences – Ismael Abo Horan

On Wednesday, 19 August, Ismael Abo Horan will defend his doctoral thesis in pharmaceutical sciences at the Faculty of Pharmaceutical Sciences, University of Iceland. The thesis is entitled: Self-assembled nanocarriers technology: Drug delivery to the posterior segment of the eye.

The opponents are Dr René Holm, Professor at the University of Southern Denmark in Odense, and Dr Sveinn Hákon Harðarson, Associate Professor at the Faculty of Medicine, University of Iceland.

The supervisor and principal advisor was Hákon Hrafn Sigurðsson, Professor. In addition to him, the doctoral committee consisted of Carmen Alvarez-Lorenzo, Professor, Paolo Gasco, and Sara Nicoli, Professor.

Berglind Eva Benediktsdóttir, Associate Professor and Dean of the Faculty of Pharmaceutical Sciences, will chair the ceremony, which will take place in Veröld – Auðarsalur and begin at 9:00 a.m.

Please notice this is a closed ceremony.

Abstract

Diseases of the posterior segment of the eye, including age-related macular degeneration and diabetic retinopathy, are major causes of irreversible vision loss worldwide and place a substantial burden on patients and healthcare systems. Treatments for many of these diseases rely on intravitreal injections, creating a pressing need for effective, non-invasive topical alternatives. However, drug delivery from the ocular surface to the retina is limited by poor aqueous drug solubility, rapid precorneal clearance, multiple ocular barriers, and the complex anatomy of the eye.

Statins are of interest for the treatment of retinal diseases because of their anti-inflammatory and other pleiotropic effects. However, their poor aqueous solubility limits their use in ocular formulations. This thesis investigated self-assembled nanocarrier strategies to solubilise and stabilise simvastatin and atorvastatin and improve their potential delivery to the posterior segment. The work progressed from cyclodextrin complexation studies to the development of nanoemulsion- and microemulsion-based systems and included an ex vivo model for evaluating posterior ocular drug delivery.

Overall, the results demonstrate the successful development of statin-loaded systems for posterior ocular delivery. The work showed that formulation design strongly influenced drug stability, solubilisation, retention, release, viscosity, and distribution within ocular tissues. Cyclodextrin-based systems improved statin solubility but were limited by the instability of the lactone form, whereas lipid-based nanoemulsion and microemulsion systems offered alternative approaches for preserving this form. Among the formulations investigated, the self-emulsifying microemulsion preconcentrate emerged as the most promising platform. It formed nanosized droplets upon dilution, improved the stability of the lactone form, and supported the delivery of statins to posterior ocular tissues in the ex vivo model.

About the doctoral candidate

Ismael Abo Horan was born in Daraa, Syria, on 1 November 1992. He received a BSc degree in pharmacy from Damascus University in 2016 and a master’s degree in nanoscience and nanotechnology from the University of Barcelona, Spain, in 2021.

Ismael began his doctoral studies at the Faculty of Pharmaceutical Sciences, University of Iceland, in June 2022, supported by a fellowship through the ORBITAL project, part of the Marie Skłodowska-Curie Innovation and Training Network funded by the European Union. His doctoral research subsequently received additional funding from Rannís, the Icelandic Centre for Research.

Ismael’s parents are Yassin Abo Horan and Yousra Alshabani. His wife, Alaa Abo Horan, is a paediatrician. They have two children, Karam and Omar.