Retinal Diseases: The Next Frontier in Pharmacodelivery

Abstract

The future continuous growth of the global older population augments the burden of retinal diseases worldwide. Retinal characteristics isolating and protecting the sensitive neuro-retina from the rest of the ocular tissues challenge drug delivery and promote research and development toward new horizons. In this review, we wish to describe the unmet medical needs, discuss the novel modes of delivery, and disclose to the reader a spectrum of older-to-novel drug delivery technologies, innovations, and the frontier of pharmacodelivery to the retina. Treating the main retinal diseases in the everlasting war against blindness and its associated morbidity has been growing steadily over the last two decades. Implants, new angiogenesis inhibitor agents, micro- and nano-carriers, and the anchored port delivery system are becoming new tools in this war. The revolution and evolution of new delivery methods might be just a few steps ahead, yet its assimilation in our daily clinical work may take time, due to medical, economical, and regulatory elements that need to be met in order to allow successful development and market utilization of new technologies. Therefore, further work is warranted, as detailed in this Pharmaceutics Special Issue.

Acorus Tatarinowii Schott Increases the Permeability of Blood-Retinal Barrier: Evidence From an in Vitro Study

“…Thus, BRB modulation can increase the efficacy of various therapies. The inner BRB is similar to the canonical barrier of the CNS [13], and SCP was previously reported to increase the permeability of blood-brain barrier [9]. In this research, we successfully developed an in vitro model of inner BRB.…”

Ocular Delivery of Therapeutic Proteins: A Review

“…In another study, sustained release in the vitreous and retina–choroid from intravitreal injections of liposomal oligonucleotides showed a protective effect against enzymatic degradation [ 229 ]. Significant improvement in mean residence time of bevacizumab after intravitreal injection of liposomes [ 230 ] and sustained release of bevacizumab from the liposomes were observed for up to 42 days after intravitreal injection [ 221 ]. Significantly reduced inflammation with prolonged protection of peptides of up to 14 days in vivo after intravitreal injection of vasoactive intestinal peptide-containing liposomes was also observed [ 225 ].…”

“…With the aim of achieving sustained release in the vitreous and providing a long-term therapeutic effect from the polymeric network, intraocular implants are gaining popularity as drug delivery systems. Though it is an intrusive procedure, implants have shown several benefits such as bypassing the blood retinal barrier, avoiding burst release, reduction of the dose, and delivering therapeutics with a constant rate directly at the ocular site [ 230 ]. Nonbiodegradable and biodegradable implants are available in the market (see Table 3 and Figure 4 ) and can have a tunable delivery rate by changing the type and composition of the polymers or the delivery form, i.e., solid, semisolid, or a particulate-based system [ 270 , 271 , 272 ].…”

Anti-inflammatory IL-8 Regulation via an Advanced Drug Delivery System at the Oral Mucosa

“…Several therapeutic avenues concentrate on the development of novel drug delivery systems (DDSs) with increased efficacy and bioavailability of topically applied drug formulations. In dermatology, many of those DDSs are currently under investigation for topical treatment of inflammatory skin diseases. − In the field of ophthalmology, DDS applications are partly already in clinical use. , …”

“…11−13 In the field of ophthalmology, DDS applications are partly already in clinical use. 14,15 In oral medicine, there is a significant need for topical drug formulations to increase bioavailability in oral mucosal tissues. Therefore, there are several approaches investigating the use of nanoparticles as drug delivery systems for the treatment of periodontal diseases.…”