Project/scholarship details


Nowadays, most ophthalmic drug formulations are applied as eyedrops. Although this administration form is easy to use and well accepted by patients, it requires frequent applications, leads to significant drug losses (> 95%) and may cause undesirable side effects, due to the rapid drug absorption into the bloodstream. The development of more efficient drug delivery systems, that enhance the ocular bioavailability of the drugs, has been subject of an increasing interest in the last years and is regarded as a major advance in ophthalmic therapeutics. Among the several studied possibilities, soft contact lenses (SCLs) have deserved special attention due to their high degree of comfort, biocompatibility and prolonged contact with the eye. Drug soaked SCLs demonstrated to be more efficient than eyedrops, but still lead to short release times and are not commercially available. In order to enhance their drug loading capacity and to achieve a controlled drug release, various methods have been explored. These methods may be extended to other ophthalmic lenses - the intraocular lenses (IOLs) - due to the similarity of the constituent materials and functionality. The main objective of this project is to develop new efficient systems for the treatment of ocular diseases and post-surgical infections, based on the surface coating or modification of drug-loaded ophthalmic lens materials. Commercial SCLs, IOLs and newly synthesized lens hydrogel materials will be loaded with model drugs (e.g. fluoroquinolones, cefuroxime). Their surface will be modified/coated to create drug diffusion barriers which lead to a sustained release for an extended period of time. Tested methods will include crosslinking of the surfaces, coatings with layer-by-layer polyelectrolytes and/or with liposomes, and adsorption/grafting of specific molecules. These methods are particularly welcomed both by clinicians and industry, since they may be used in commercial lenses whose properties and production are already optimized. For the first time, the in vitro drug release kinetics will be investigated considering the tribomechanical effect inherent to eyelid sliding: a homemade apparatus allowing for simulation of tear flow and blinking will be used. Physical-chemical characterization of the hydrogels will be done to evaluate the changes caused by the surface modifications. Numerical modelling will be used to aid in the optimization of the novel delivery systems. In vitro and in vivo (with animals) biological tests will be also carried out. To achieve these purposes, an international multidisciplinary team of researchers from several universities (Instituto Superior de Ciências da Saúde Egas Moniz - PT, University of Coimbra - PT, University of Iceland - IS) and hospitals (Instituto de Oftalmologia Dr. Gama Pinto - PT) will work in straight collaboration with industry (PhysIOL - BE, an experienced IOL manufacturer, and Altakitin - PT, which produces raw materials for medical applications, like chitosan). The project has the support of Bausch+Lomb UK (see anex), which will supply commercial SCLs. The collaboration of the companies is fundamental for the definition of new research routes with economic viability and may have repercussions on technology transfer and on the future funding for the research centers. The participation of ophthalmologists will be crucial for the discussion of the clinical relevance of the project outcomes and preparation of a pre-clinical validation plan. The development of a new concept for drug-delivering ophthalmic lens, besides being beneficial for improving the peoples’ life quality, comfort and working ability at long term, would lead to savings for healthcare system. Collaboration between partners would enhance their cooperation potential, expertise and competitiveness at European and global level.

  • Funder

    FCT - Fundação para a Ciência e a Tecnologia, I.P.

  • Funder's country

    Portugal

  • Funding program

    3599-PPCDT

  • Funding amount

    60,000.00 €

  • Start date

    Wed Jan 01 00:00:00 WET 2014

  • End date

    Sat Dec 31 00:00:00 WET 2016

  • Date awarded

    Mon Mar 03 00:00:00 WET 2014

Documents


In vitro controlled drug release from contact lenses materials under physiologi...

Paradiso, P.; Mata, J.; Moutinho, M. G.; Fernandes, A. I.; Colaço, R.; Saramago, B.; Serro, A. P.

Poster presented at the 9th World Meeting on Pharmaceutics, Biopharmaceutics and Pharmaceutical Technology. Lisbon, 31 March-3 April 2014.


The effect of albumin and cholesterol on the biotribological behavior of hydrog...

Silva, D.; Fernandes, A. C.; Nunes, T. G.; Colaço, R.; Serro, A. P.

The irritation/discomfort associated with the use of contact lenses (CLs) is often related to the eyelid-lens friction. Although the use of such devices is widespread, the information about the influence of the lacrimal fluid biomolecules on the tribological behavior of the CLs hydrogels is scarce. In this work, we investigated the effect of the presence of albumin and cholesterol in the lubricant medium, on th...


Effect of sterilization on chlorhexidine loaded soft contact lenses

Topete, Ana; Moutinho, Maria Guilhermina; Saramago, Benilde; Serro, Ana Paula

Poster presented at the First International Congress of CiiEM - From Basic Sciences to Clinical Research. 27-28 November 2015, Caparica, Portugal


Sterilization of ophthalmic drugs and intraocular lenses

Oliveira, Andreia; Moutinho, Guilhermina M.; Bozukova, Dimitriya; Saramago, Benilde; Serro, A. P.

Poster presented at the First International Congress of CiiEM - From Basic Sciences to Clinical Research. 27-28 November 2015, Egas Moniz, Caparica, Portugal


Diffusion-based design of multi-layered ophthalmic lenses for controlled drug r...

Pimenta, Andreia F. R.; Serro, Ana Paula; Paradiso, Patrizia; Saramago, Benilde; Colaço, Rogério

The study of ocular drug delivery systems has been one of the most covered topics in drug delivery research. One potential drug carrier solution is the use of materials that are already commercially available in ophthalmic lenses for the correction of refractive errors. In this study, we present a diffusion-based mathematical model in which the parameters can be adjusted based on experimental results obtained u...


Controlled release of antibiotics from vitamin E–loaded silicone-hydrogel conta...

Paradiso, Patrizia; Serro, Ana Paula; Saramago, Benilde; Colaço, Rogério; Chauhan, Anuj

Symptoms of bacterial and fungal keratitis are typically treated through the frequent application of antibiotic and antifungal eye drops. The high frequency of half hourly or hourly eye drop administration required to treat these indications is tedious and could reduce compliance. Here, we combine in vitro experiments with a mathematical model to develop therapeutic soft contact lenses to cure keratitis by exte...


Controlled drug release from hydrogels for contact lenses: drug partitioning an...

Pimenta, A.F.R.; Ascenso, J.; Fernandes, J.C.S.; Colaço, R.; Serro, A.P.; Saramago, B.

Optimization of drug delivery from drug loaded contact lenses assumes understanding the drug transport mechanisms through hydrogels which relies on the knowledge of drug partition and diffusion coefficients. We chose, as model systems, two materials used in contact lens, a poly-hydroxyethylmethacrylate (pHEMA) based hydrogel and a silicone based hydrogel, and three drugs with different sizes and charges: chlorh...


Simulation of the hydrodynamic conditions of the eye to better reproduce the dr...

Pimenta, A. F. R.; Valente, A.; Pereira, J. M. C.; Pereira, J. C. F.; Filipe, H. P.; Mata, J. L. G.; Colaço, R.; Saramago, B.; Serro, A. P.

Currently, most in vitro drug release studies for ophthalmic applications are carried out in static sink conditions. Although this procedure is simple and useful to make comparative studies, it does not describe adequately the drug release kinetics in the eye, considering the small tear volume and flow rates found in vivo. In this work, a microfluidic cell was designed and used to mimic the continuous, volumetr...


Diclofenac release from a silicon based contact lens material controlled by a c...

Filipe, Helena; Silva, Diana; Pinto, Luís F. V.; Henriques, José; Bozukova, Dimitriya; Saramago, Benilde; Serro, Ana Paula

Poster presented at the AAO 2016 (American Academy of Ophthalmology Annual Meeting). Chicago, 15-18 October 2016.


Effect of sterilization on drugs and lenses for ophthalmic applications

Topete, Ana; Oliveira, Andreia; Galante, Raquel; Bozukova, Dimitriya; Saramago, Benilde; Serro, A. P.

Poster presented at the 10th World Biomaterials Congress. Montreal, Canada, 17-22 May 2016

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