Physicochemical characterization of a DMPC-based nanoemulsion for dry eye and compatibility test with soft contact lenses in vitro

Nanomedicines for Dry Eye Syndrome: Targeting Oxidative Stress with Modern Nanomaterial Strategies

Dry eye syndrome (DES) is a dynamic, chronic disease of the ocular surface and ocular appendages caused by inflammation. The most common symptoms include redness, itching, and blurred vision, resulting from dysfunction of the meibomian glands and impaired tear-film production. Factors contributing to the development of DES include environmental elements, such as UV radiation, and internal elements, such as hormonal imbalances. These factors increase oxidative stress, which exacerbates inflammation on the surface of the eye and accelerates the development of DES. In recent years, the incidence of DES has risen, leading to a greater need to develop effective treatments. Current treatments for dry eye are limited and primarily focus on alleviating individual symptoms, such as reducing inflammation of the ocular surface. However, it is crucial to understand the pathomechanism of the disease and tailor treatment to address the underlying causes to achieve the best possible therapeutic outcomes. Therefore, in this review, we analyzed the impact of oxidative stress on the development of DES to gain a better understanding of its pathomechanism and examined recently developed nanosystems that allow drugs to be delivered directly to the disease site.

Efficacy and Safety of an Ophthalmic DMPC-Based Nanoemulsion in Patients with Dry Eye Disease: A Phase I/II Randomized Clinical Trial

Purpose

The goals of this study were to evaluate the safety and efficacy of an ophthalmic 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-based nanoemulsion (Nanodrop®) in patients with dry eye disease (DED).

Methods

This was a randomized phase I/II multicentric, prospective, double-blind clinical trial. Patients (phase I: n = 25 and phase II: n = 101) were assigned to receive either PRO-176 (Nanodrop®) or Systane Balance® (control) for 29 days. Once the visits of the first 25 subjects were completed, if there were less than 20% of unexpected adverse events (AEs), related to PRO-176, recruitment was continued until the sample was completed for noninferiority (efficacy) analysis (phase II, n = 126). Efficacy endpoints were the ocular surface disease index (OSDI), tear break-up time (TBUT), epithelial defects, best corrected visual acuity (BCVA), and the incidence of expected AE.

Results

For the phase I portion of the study, there were no differences between groups regarding the incidence of AE. All related-AE symptoms in both groups were mild and expected. For the phase II subset, there was a significant reduction in OSDI scores at day 29 and noninferiority between treatments was confirmed (p=0.650, CI 95% [-8.7, 5.5]). Similar improvement was observed for TBUT although no significant intergroup differences were found (p=0.518, CI 95% [-0.08, 1.6]). There were no significant differences between treatments for epithelial staining or safety parameters.

Conclusions

Topical application of PRO-176 is as safe and effective as the controls. Both groups were clinically similar in terms of efficacy and safety. The results support the hypothesis that ophthalmic DMPC-based nanoemulsion may improve clinical parameters and symptoms in patients with DED. This trial is registered with NCT04111965.

A novel osmoprotective liposomal formulation from synthetic phospholipids to reduce in vitro hyperosmolar stress in dry eye treatments

Dry eye disease (DED) is a worldwide, multifactorial disease mainly caused by a deficit in tear production or increased tear evaporation with an increase in tear osmolarity and inflammation. This causes discomfort and there is a therapeutic need to restore the homeostasis of the ocular surface. The aim of the present work was to develop a biodegradable and biocompatible liposomal formulation from the synthetic phospholipids 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) that is able to reduce the effects of hypertonic stress by helping to restore the lipid layer of the tear film. Liposomes were made using the lipid film hydration method with synthetic phospholipids (10 mg/mL) with and without 0.2% HPMC. They were characterised in terms of size, osmolarity, pH, surface tension, and viscosity. Additionally, the in vitro toxicity of the formulation at 1 and 4 h in human corneal epithelial cells (hTERT-HCECs) and human conjunctival cells (IM-HConEpiC) was determined. Furthermore, osmoprotective activity was tested in a corneal model of hyperosmolar stress. In vivo acute tolerance testing was also carried out in albino New Zealand rabbits by topical application of the ophthalmic formulations every 30 min for 6 h. All the assayed formulations showed suitable physicochemical characteristics for ocular surface administration. The liposomal formulations were well-tolerated in cell cultures and showed osmoprotective activity in a hyperosmolar model. No alterations or discomfort were reported when they were topically administered in rabbits. According to the results, the osmoprotective liposomal formulations developed in this work are promising candidates for the treatment of DED.