Drug Delivery and Translational Research Update

Special Issue on Ocular Drug Delivery

The issue contains articles by recognized global experts and researchers in the field of ophthalmic drug delivery, covering a broad spectrum of drug delivery topics including current challenges faced with regard to the ocular barriers presented and establishment of suitable models to drive future technology success. The issue is co-edited by Ilva Rupenthal, senior lecturer and director of the Buchanan Ocular Therapeutics Unit at the University of Auckland, New Zealand, and Michael O’Rourke, president of Scotia Vision Consultants, with a track record of launching several products in the market. The total download for the articles published in the issue has already reached over 3,200. The issue is also been highlighted in several media outlets (https://springerlink.altmetric.com/details/13414566/news). See the table of contents at http://link.springer.com/journal/13346/6/6/page/1. DDTR is an official journal of the CRS, and members get free access to the articles published in the journal as a membership benefit.

As an example of this stellar special issue, I would like to highlight two articles—the first a review article and the second a research article. Incidentally, these two are also the most downloaded articles thus far.

Human Corneal Cell Culture Models for Drug Toxicity Studies

Seppo Rönkkö, Kati-Sisko Vellonen, Kristiina Järvinen, Elisa Toropainen, and Arto Urtti Drug Deliv. Transl. Res. 6: 660-675 (2016)

This review gives an overview to the properties of the corneal cell culture models used in ocular toxicity testing. In vivo toxicity and absorption studies of topical ocular drugs are problematic, because these studies involve invasive tissue sampling and toxic effects in animal models. Therefore, different human corneal models ranging from simple monolayer cultures to three-dimensional models have been developed for toxicological prediction with in vitro models. Each system has its own set of advantages and disadvantages. Use of non-corneal cells, inadequate characterization of gene-expression profiles, and accumulation of genomic aberrations in human corneal models are typical drawbacks that decrease their reliability and predictive power. In the future, further improvements are needed for verifying comparable expression profiles and cellular properties of human corneal models with their in vivo counterparts. A rapidly expanding stem cell technology combined with tissue engineering may give future opportunities to develop new tools in drug toxicity studies. One approach may be the production of artificial miniature corneas. In addition, there is also a need to use large-scale profiling approaches such as genomics, transcriptomics, proteomics, and metabolomics for understanding of the ocular toxicity.

Rapidly Dissolving Polymeric Microneedles for Minimally Invasive Intraocular Drug Delivery

Raghu Raj Singh Thakur, Ismaiel A. Tekko, Farhan Al-Shammari, Ahlam A. Ali, Helen McCarthy, and Ryan F. Donnelly Drug Deliv. Transl. Res. 6: 800-815 (2016)

In this study, authors have developed dissolving microneedles (MNs) fabricated using polyvinylpyrrolidone polymer to enhance ocular drug delivery of macromolecules. In vitro studies showed significant enhancement of macromolecule permeation when MNs were used, across both the corneal and scleral tissues, in comparison to topically applied aqueous solutions. Confocal images showed that the macromolecules formed depots within the tissues, which led to sustained permeation. The material used in the fabrication of the MNs was found to be biocompatible with retinal cells (i.e., ARPE-19). Overall, this study reported the design and fabrication of minimally invasive rapidly dissolving polymeric MN arrays that were able to deliver high-molecular-weight molecules to the eye via the intrastromal or intrascleral route.

2017 DDTR Outstanding Research Paper Award

Consider submitting your best research/clinical paper for the 2017 DDTR Outstanding Research Paper Award. For consideration, the paper has to be published during the calendar year 2017. Criteria such as translation nature of research, overall impact, innovation, and significance of the study are considered in the selection process. The award is jointly sponsored by Springer-Nature and CRS. The corresponding author will be recognized at the 2018 CRS Annual Meeting & Exposition. Visit the CRS website for further details (www.controlledreleasesociety.org/about/Awards/Pages/DDTROustandingPaper.aspx).

DDTR to Continue Accepting Manuscripts with Negative Data

As announced in 2014, DDTR will continue to consider manuscripts reporting negative data, as long as the research is based on a strong rationale or hypothesis. Negative data from one study could provide a rationale or new approach/paradigm to pursue. Also, it would not waste the precious resources in duplicating the same/similar experiments that did not work. Such manuscripts will undergo the standard, rigorous review process as per the journal policy, but the reviewers will be alerted to the nature of the manuscripts. Authors are strongly encouraged to discuss the possible reasons why experiments failed and what alternative approaches or changes to the hypothesis or experimental design might be made.