Thorsteinn received a M.S. Pharmacy (Pharmacist) degree from University of Copenhagen, Faculty of Pharmaceutical Sciences and M.S. and Ph.D. degrees from the Department of Pharmaceutical Chemistry at the University of Kansas. He is a Professor of Physical Pharmacy at the University of Iceland, Faculty of Pharmaceutical Sciences. His main research interest is pharmaceutical applications of cyclodextrins. Other research interests include marine lipids, prodrugs and soft drugs. Thorsteinn has authored or co-authored over 230 papers in peer-reviewed journals, 20 book chapters and 20 patents and patent applications.
He is an inventor and co-owner of two R&D companies: Oculis, an ophthalmic drug delivery company with eye drops in Phase I and Phase II/III, and Lipid Pharmaceutical that extracts biologically active compounds from marine lipids and has suppositories in couple of Phase II/III trials and a dermal preparation going into Phase I.