Application of lipid nanoparticles to ocular drug delivery

ABSTRACT

Introduction: Although eye drops are widely used as drug delivery systems for the anterior segment of the eye, they are also associated with poor drug bioavailability due to transient contact time and rapid washout by tearing. Moreover, effective drug delivery to the posterior segment of the eye is challenging, and alternative routes of administration (periocular and intravitreal) are generally needed, the blood–retinal barrier being the major obstacle to systemic drug delivery.

Areas covered: Nanotechnology, and especially lipid nanoparticles, can improve the therapeutic efficiency, compliance and safety of ocular drugs, administered via different routes, to both the anterior and posterior segment of the eye. This review highlights the main ocular barriers to drug delivery, as well as the most common eye diseases suitable for pharmacological treatment in which lipid nanoparticles have proved efficacious as alternative delivery systems.

Expert opinion: Lipid-based nanocarriers are among the most biocompatible and versatile means for ocular delivery. Mucoadhesion with consequent increase in pre-corneal retention time, and enhanced permeation due to cellular uptake by corneal epithelial cells, are the essential goals for topical lipid nanoparticle delivery. Gene delivery to the retina has shown very promising results after intravitreal administration of lipid nanoparticles as non-viral vectors.

KEYWORDS:

• Solid lipid nanoparticles
• nanostructured lipid carrier
• eye
• drug delivery

Article highlights

• The main advantages of lipid nanoparticles over alternative carriers are: low toxicity, good long-term stability, economic and solvent free production techniques, easy production at large scale, possibility to be autoclaved or sterilized

• Lipid nanoparticles are potential alternatives to ocular administration mainly due to their capacity for increasing the residence time and bioavailability of the drugs

• The main issue addressed by lipid nanoparticles for ocular topical route is overcoming the corneal barriers and increasing corneal retention

• Optimized lipid nanoparticles formulations to the retina should aim to controlled drug release and reduced administration frequency

• Lipid nanoparticles have shown promising results as non-viral vectors for ocular gene therapy.

This box summarizes key points contained in the article.

Acknowledgments

Thanks are due to Mr Adrian Belton for kindly revising the English version of the manuscript.

Declaration of interest

This work has been supported by the Basque Government’s Department of Education, Universities and Investigation (IT-341-10) and by the Spanish Ministry of Economy and Competitiveness (SAF2014-53092-R). The authors would also thank Ricerca Locale 2015 (Italian MIUR) for funding. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.