Successfully improving ocular drug delivery using the cationic nanoemulsion, novasorb

Advances in ophthalmic therapeutic delivery: A comprehensive overview of present and future directions

Ophthalmic treatment demands precision and consistency in delivering therapeutic agents over extended periods to address many conditions, from common eye disorders to complex diseases. This diversity necessitates a range of delivery strategies, each tailored to specific needs. We delve into various delivery cargos that are pivotal in ophthalmic care. These cargos encompass biodegradable implants that gradually release medication, nonbiodegradable implants for sustained drug delivery, refillable tools allowing flexibility in treatment, hydrogels capable of retaining substances while maintaining ocular comfort, and advanced nanotechnology devices that precisely target eye tissues. Within each cargo category, we explore cutting-edge research-level approaches and FDA-approved methods, providing a thorough overview of the current state of ophthalmic drug delivery. In particular, our focus on nanotechnology reveals the promising potential for gene delivery, cell therapy administration, and the implantation of active devices directly into the retina. These advancements hold the key to more effective, personalized, and minimally- invasive ophthalmic treatments, revolutionizing the field of eye care.

Development of antifungal fibrous ocular insert using freeze-drying technique

Candida species is one of the pathogenic fungi of the eye responsible for keratitis that frequently causes vision impairment and blindness. Effective treatment requires long-term use of antifungal drugs, which is opposed by the defensive mechanisms of the eye and inadequate corneal penetration. The objective of this study was to develop a carrier for prolonged ocular application of fluconazole (FLZ) to treat keratitis. FLZ was encapsulated into chitosan fibrous matrices (F1-F4) using different chitosan concentrations (0.02, 0.1, 0.5, and 1%w/v, respectively) by freeze-drying as a single-step technique. Studying the morphology and surface properties of the inserts revealed a porous matrix with fibrous features with a large surface area. Thermal stability and chemical compatibility were confirmed by DSC/TGA/DTA and FT-IR, respectively. Loading capacity (LC) and entrapment efficiency (EE) were determined. According to the in vitro release study, F4 (0.11 mg mg-1 LC and 87.53% EE) was selected as the optimum insert because it had the most sustained release, with 15.85% burst release followed by 75.62% release within 12 h. Ex vivo corneal permeation study revealed a 1.2-fold increase in FLZ permeation from F4 compared to FLZ aqueous solution. Also, in the in vivo pharmacokinetic study in rabbits, F4 increased the AUC0-8 of FLZ by 9.3-fold and its concentration in aqueous humor was maintained above the MIC through the experimentation time. Studies on cytotoxicity (MTT assay) provide evidence for the safety and biocompatibility of F4. Therefore, the freeze-dried FLZ-loaded chitosan fibrous insert could be a promising candidate for treating ocular keratitis.

Efficacy and Safety of a Preservative-Free Latanoprost Cationic Emulsion in Patients with Open-Angle Glaucoma and Concurrent Ocular Surface Disease: A Randomized Phase 2 Study

Purpose: To compare intraocular pressure (IOP), ocular surface disease (OSD) parameters, and safety in patients with open-angle glaucoma (OAG)/ocular hypertension (OH) and concurrent OSD treated with preservative-free latanoprost 0.005% cationic emulsion (PF-latanoprost-E) or travoprost-Z 0.004% ophthalmical solution containing a soft preservative system. Methods: Patients with OAG/OH and OSD were randomized to treatment with PF-latanoprost-E or travoprost-Z nightly for 3 months. Outcomes included mean diurnal IOP reduction; OSD endpoints, including symptom improvement, tear break-up time (TBUT), and corneal fluorescein staining (CFS) score; and safety after 1 and 3 months. Results: A total of 105 patients were randomized, 51 to PF-latanoprost-E and 54 to travoprost-Z. IOP reductions (LS mean differences) at 3 months were numerically greater in the PF-latanoprost-E than in the travoprost-Z group at 8AM (7.2 versus 6.0 mmHg), 10AM (6.7 versus 5.9 mmHg), and 4PM (6.0 versus 5.4 mmHg). LS mean changes in IOP from baseline in both groups at 1 and 3 months, however, were comparable. Mean ± SD CFS scores on the Ora scale at month 3 showed significantly greater reductions in the PF-latanoprost-E than in the travoprost-Z group (-1.07 ± 1.863 versus -0.16 ± 2.553 P = 0.0461). The mean TBUT at month 3 showed similar improvements in both groups (1.1 versus 1.0 s, P > 0.05). OSD symptoms improved but did not differ significantly in the two groups. Overall safety was comparable in both groups. Conclusion: PF-latanoprost-E effectively and safely lowered IOP and improved OSD parameters in patients with OAG/OH. These findings provide evidence for the beneficial effects of this new formulation of latanoprost in glaucoma patients with OSD.

Polymers and their engineered analogues for ocular drug delivery: Enhancing therapeutic precision

Ocular drug delivery is constrained by anatomical and physiological barriers, necessitating innovative solutions for effective therapy. Natural polymers like hyaluronic acid, chitosan, and gelatin, alongside synthetic counterparts such as PLGA and PEG, have gained prominence for their biocompatibility and controlled release profiles. Recent strides in polymer conjugation strategies have enabled targeted delivery through ligand integration, facilitating tissue specificity and cellular uptake. This versatility accommodates combined drug delivery, addressing diverse anterior (e.g., glaucoma, dry eye) and posterior segment (e.g., macular degeneration, diabetic retinopathy) afflictions. The review encompasses an in-depth exploration of each natural and synthetic polymer, detailing their individual advantages and disadvantages for ocular drug delivery. By transcending ocular barriers and refining therapeutic precision, these innovations promise to reshape the management of anterior and posterior segment eye diseases.

Combination of PEGylation and Cationization on Phospholipid-Coated Cyclosporine Nanosuspensions for Enhanced Ocular Drug Delivery

Strong precorneal clearance mechanisms including reflex blink, constant tear drainage, and rapid mucus turnover constitute great challenges for eye drops for effective drug delivery to the ocular epithelium. In this study, cyclosporine A (CsA) for the treatment of dry eye disease (DED) was selected as the model drug. Two strategies, PEGylation for mucus penetration and cationization for potent cellular uptake, were combined to construct a novel CsA nanosuspension (NS@lipid-PEG/CKC) by coating nanoscale drug particles with a mixture of lipids, DSPE-PEG2000, and a cationic surfactant, cetalkonium chloride (CKC). NS@lipid-PEG/CKC with the mean size ∼173 nm and positive zeta potential ∼+40 mV showed promoted mucus penetration, good cytocompatibility, more cellular uptake, and prolonged precorneal retention without obvious ocular irritation. More importantly, NS@lipid-PEG/CKC recovered tear production and goblet cell density more efficiently than the commercial cationic nanoemulsion on a dry eye disease rat model. All results indicated that a combination of PEGylation and cationization might provide a promising strategy to coordinate mucus penetration and cellular uptake for enhanced drug delivery to the ocular epithelium for nanomedicine-based eye drops.

Recent Advances in Nanotechnology for the Treatment of Dry Eye Disease

Dry eye disease (DED) incidence is continuously growing, positioning it to become an emergent health issue over the next few years. Several topical treatments are commonly used to treat DED; however, reports indicate that only a minor proportion of drug bioavailability is achieved by the majority of eye drops available on the market. In this context, enhancing drug ability to overcome ocular barriers and prolonging its residence time on the ocular surface represent a new challenge in the field of ocular carrier systems. Therefore, research has focused on the development of multi-functional nanosystems, such as nanoemulsions, liposomes, dendrimers, hydrogels, and other nanosized carriers. These systems are designed to improve topical drug bioavailability and efficacy and, at the same time, require fewer daily administrations, with potentially reduced side effects. This review summarizes the different nanotechnologies developed, their role in DED, and the nanotechnology-based eyedrops currently approved for DED treatment.

Efficacy of a Cationic Emulsion of Cyclosporine in Moderate Vernal Keratoconjunctivitis

PURPOSE

The aim of this study was to demonstrate the efficacy of cyclosporine A 0.1% cationic emulsion (CsA CE) eye drops 4 times a day in pediatric patients affected by a moderate form of vernal keratoconjunctivitis (VKC).

METHODS

This was a prospective study of pediatric patients, aged 5-16 years, with an active moderate form of VKC who were poor responders to topical antihistamines treatment and were treated 4 times a day with CsA CE. The clinical signs were graded for analysis as follows: hyperemia, tarsal papillae, and limbal papillae.

RESULTS

Twenty-eight patients (22 males and 6 females) with a minimum follow-up period of 3 months were included in the analysis. Statistical analysis excluded tarsal papillae because of the very low baseline value. The clinical score of hyperemia and limbal papillae improved from the first evaluation and was maintained over the follow-up. No side effects were noted.

CONCLUSION

CsA CE has been proposed as a treatment for severe forms of VKC. This study has shown that administration 4 times a day is also effective in the treatment of moderate forms of VKC in children.

Review of clinical outcomes of a cationic emulsion tear substitute in patients with dry eye disease

First-line options for the treatment of dry eye disease (DED) rely on artificial tears (ATs), among which cationic emulsion (CE)-based ATs have been developed in order to mimic the healthy tear film for an improved restoration of the ocular surface homeostasis. In this review, we describe the outcomes reported in several studies, assessing the mode of action, ocular tolerance and clinical performance of a CE-based AT. Pilot studies have revealed that CE-based ATs can increase the volume and stability of the tear film while limiting its evaporation rate. Larger studies have demonstrated that CE-based ATs play a significant role in the improvement of both objective and subjective DED parameters, including superior efficacy on DED symptoms compared to several other available AT formulation types. Concomitantly, CE-based ATs have been shown to help patients to prevent or recover from corneal defects associated with refractive surgery. These positive outcomes on ocular surface epithelia are likely due to the combination of unique rheological behaviour and intrinsic anti-inflammatory properties. Based on all clinical findings, CE-based ATs represent a valuable treatment option for patients with various etiologies of DED including evaporative forms and would deserve evaluation of benefits in other surgical intervention types triggering DED.

[The place of ciclosporin A cationic emulsion 0.1% in the therapy of xerophthalmia]

Dry eye disease (DED) is pathogenetically based on inflammation of the ocular surface. A step-by-step approach to DED treatment involves early initiation of anti-inflammatory therapy, including instillation of cyclosporine A (CsA). However, recommendations for the use of topical CsA in clinical practice are limited. This article presents an expert consensus on practical recommendations for the management of patients with DED, including indications, time of initiation and duration of CsA therapy, comparison of CsA forms currently registered in the Russian Federation, as well as issues of patient education.

An Updated Review on Nanoemulsion: Factory for Food and Drug Delivery

BACKGROUND

A nanoemulsion is a colloidal system of small droplets dispersed in another liquid. It has attracted considerable attention due to its unique properties and various applications. Throughout this review, we provide an overview of nanoemulsions and how they can be applied to various applications such as drug delivery, food applications, and pesticide formulations.

OBJECTIVE

This updated review aims to comprehensively overview nanoemulsions and their applications as a versatile platform for drug delivery, food applications, and pesticide formulations.

METHODS

Research relevant scientific literature across various databases, including PubMed, Scopus, and Web of Science. Suitable keywords for this purpose include "nanoemulsion," "drug delivery," and "food applications." Ensure the search criteria include recent publications to ensure current knowledge is included.

RESULTS

Several benefits have been demonstrated in the delivery of drugs using nanoemulsions, including improved solubility, increased bioavailability, and controlled delivery. Nanoemulsions have improved some bioactive compounds in food applications, including vitamins and antioxidants. At the same time, pesticide formulations based on nanoemulsions have also improved solubility, shelf life, and effectiveness.

CONCLUSION

The versatility of nanoemulsions makes them ideal for drug delivery, food, and pesticide formulation applications. These products are highly soluble, bioavailable, and targeted, providing significant advantages. More research and development are required to implement nanoemulsion-based products on a commercial scale.

Comparative Study of Latanoprost Drug Delivery Systems for Glaucoma Treatment and Their Interaction with the Tear Film Lipid Layer Models

This study investigates the interaction of two approved and one newly developed latanoprost formulation with in vitro and in silico models of the tear film and tear film lipid layer (TFLL). Latanoprost, a prostaglandin analogue used for intraocular elevated pressure treatment, is topically delivered by nanocarriers within aqueous solutions or emulsions. The study focuses on the impact of these carriers on drug interactions with the tear film and their effect on the TFLL. Three different types of latanoprost carriers, micellar, nanoemulsion, and polymer-based, were compared, and each revealed distinct interaction patterns with the TFLL. Surface pressure kinetics demonstrated a rapid increase for the benzalkonium chloride formulation and a slow rise for the preservative-free variants. Visualization of the acellular in vitro TFLL model revealed different patterns of incorporation for each formulation, indicating unique interaction mechanisms. Molecular dynamics simulations further revealed different mechanisms of drug release in the TFLL between micellar and nanoemulsion formulations. In-depth examination highlighted the role of triglyceride molecules in replenishing the nonpolar layer of the TFLL, which suggests potential improvements in ocular surface compatibility by adjusting the quality and concentration of the oily phase. These findings suggest the potential for optimizing latanoprost formulations by tuning the oily phase-to-surfactant ratio and selecting suitable surfactants.

The Effect of High-Pressure Homogenization Conditions on the Physicochemical Properties and Stability of Designed Fluconazole-Loaded Ocular Nanoemulsions

The growing interest in high-energy emulsification is a result of its scalability, which is important from an industrial perspective and allows for a more reproducible and efficient production of pharmaceutical formulations. The aim of this study was to evaluate the effect of composition, mainly a fixed surfactant/cosurfactant (Smix) ratio, their concentration, and the parameters of high-pressure homogenization (HPH) processing on the quality and stability of ophthalmic fluconazole-loaded nanoemulsions. After a physicochemical analysis of nanoemulsions containing 20% w/w of oil, as optimal conditions for the HPH process, three cycles at a pressure of 1000 bar were established, obtaining formulations with an average droplet diameter size in the range of 80.63-129.68 nm and PDI values below 0.25. While it was expected that an increasing cosurfactant concentration decreased the droplet size, in the case of formulations containing Tween 20 and 10% w/w of cosurfactants, "over-processing" was observed, identified by the droplet size and polydispersity index increase. Consecutively, the selected formulations were evaluated for in vitro drug release in Franz's cell, antifungal activity, and 30-day stability using NMR spectroscopy. An antifungal activity test showed no significant difference in the antifungal activity between optimal fluconazole-loaded nanoemulsions and a 0.3% aqueous drug solution, but previously, research showed that prepared formulations were characterized by a higher viscosity and satisfactory prolonged release compared to a control. In a 30-day stability study, it was observed that higher HLB values of the used surfactants decreased the stability of the formulations in the following order: Kolliphor EL, Tween 80, Tween 20. The NMR spectra confirmed that Kolliphor EL-based formulations ensured the higher stability of the nanoemulsion composition in comparison to Tween 80 and a better stabilizing effect of propylene glycol as a cosurfactant in comparison to PEG 200. Therefore, the optimization of HPH technology should be focused on the selection of Smix and the Smix:oil ratio in order to prepare stable formulations of high quality.

Microscopic and Biopharmaceutical Evaluation of Emulsion and Self-Emulsifying Oil with Cyclosporine

Among the currently available commercial eye drops with cyclosporine A (Cs) there is a lack of long-acting dosage forms and products with a concentration of the drug substance higher than 0.1%, although Cs is widely used in ophthalmology. The aim of the research was to conduct the microscopic and biopharmaceutical evaluation of two formulations, an emulsion (EM) and a self-emulsifying oil (SEO), both with 0.5% of Cs, proposed for use in eye drops, and the comparison of both. SEO eye drops with Cs or any other drug substance are currently not available as marketed products, and the highest concentration of Cs in the ocular emulsion is only 0.1%. The microscopic evaluation of the emulsion and the SEO after emulsification with water was carried out using a high-resolution digital microscopy. The properties of both preparations were compared using the high dynamic range function or optical shadow effect mode. Images in the 3D composition mode were also recorded. The in vivo study of the Cs formulations was performed on male albino rabbits. The eye tolerance of the preparations was assessed using the ocular irritation test, which is a modified Draize test. Placebo carriers (without the drug substance) were also subjected to irritation testing. The concentration of Cs in the tissues (cornea and conjunctiva) and fluids (tear fluid and aqueous humor) of the rabbit eye was determined after multiple instillations of Cs-EM or Cs-SEO. The tested preparations were compared using the digital microscopy technique, which highlights the features of the formulations and eliminates the risk of unnoticeable properties that are difficult to observe in classical optical microscopy. Both tested Cs-loaded formulations are classified as practically non-irritating. There were also no significant differences when testing the placebo carriers. After a topical administration, Cs was widely distributed in all tissues (e.g., in cornea 1.3 ng/mg and 1.0 ng/mg) and fluids of the eye (e.g., in tear fluid 11.6 µg/mL and 4.3 µg/mL), after the administration of Cs-SEO and Cs-EM, respectively. The obtained results allow us to recognize both tested formulations, the emulsion and the self-emulsifying oil with 0.5% Cs content, as carriers safe for ophthalmic use and effective in delivering the drug substance to the structures of the eye.

NOVATIVE: A Phase II/III, Multicenter, Double-masked, Randomized Study of Cyclosporine A 0.05% and 0.1% Ophthalmic Cationic Emulsion Versus Vehicle in Patients with Vernal Keratoconjunctivitis

PURPOSE

This study evaluates the efficacy and tolerability of cyclosporine A cationic emulsion (CsA-CE) in patients ≥4 years of age with moderate-to-severe vernal keratoconjunctivitis (VKC).

METHODS

This Phase II/III, multicenter, double-masked, dose-ranging study had 2 treatment periods: a 4-week, randomized, vehicle-controlled period in which patients received 0.05% CsA-CE, 0.1% CsA-CE, or vehicle eye drops 4 times daily (period 1) and a 3-month period in which patients received 0.05% CsA-CE or 0.1% CsA-CE 2 or 4 times daily (period 2). The primary efficacy end point was rating of subjective symptoms at day 28 in period 1 per the BenEzra scale.

FINDINGS

All groups showed improvement in subjective VKC symptoms at day 28, without a statistically significant difference between 0.05% or 0.1% CsA-CE vs vehicle. Both CsA-CE doses produced statistically significant improvements in corneal fluorescein staining scores vs vehicle at day 28; improvements were evident as early as week 1 and continued through month 1. Progressive reduction in subjective itching was evident after week 1 and continued through month 1. Treatment for an additional 3 months further improved subjective symptoms and objective signs of VKC in both CsA-CE groups. Improvement was most notable with 0.1% CsA-CE in patients with severe keratitis. The safety and tolerability profile is favorable.

IMPLICATIONS

Although treatment with 0.05% and 0.1% CsA-CE showed clinical efficacy in alleviating keratitis and itching as early as week 1, with sustained benefit through 1 month, the primary efficacy end point was not met. These findings informed the design of the Phase III trial of 0.1% CsA-CE (Vernal Keratoconjunctivitis Study).

CLINICALTRIALS

gov identifier: NCT00328653.

Cationic nanoemulsion vs. 0.15% sodium hyaluronate artificial tears in the healing process following modern surface keratorefractive surgery

PURPOSE

The aim of this study was to investigate the influence of artificial tears containing either cationic nanoemulsion (CCN) or sodium hyaluronate artificial tears (SH) on early postoperative healing after modern surface refractive surgery.

MATERIALS AND METHODS

In this multicenter, prospective, double-masked, parallel-group (1:1), comparative study, 129 patients (n = 255 eyes) were randomized to receive CCN (n = 128) or SH (n = 127) as an adjuvant treatment after either transepithelial photorefractive keratectomy (transPRK) or Epi-Bowman keratectomy (EBK). The patients' perspectives were gathered using the Ocular Surface Disease Index (OSDI) questionnaire, and uncorrected (UCVA), and corrected (BCVA) visual acuity were assessed before and one week and one month after the procedure. In addition, corneal epithelization and subjective assessment of visual blur and eye irritation on drop instillation were assessed at one week postoperatively.

RESULTS

No statistically significant differences were found between two groups in age, spherical equivalent refractive error, UCVA, BCVA or OSDI scores before the procedure. There was also no difference between groups in UCVA one week and one month after the procedure. However, statistically significantly lower OSDI scores were found one week and one month after the procedure in the CCN group. Moreover, blurred vision after use of the eye drops was observed less frequently in the CCN group than in the SH group.

CONCLUSIONS

The CCN and SH groups had similar postoperative UCVA. However the significantly lower OSDI scores and less frequently blurred vision after application of the eye drops in the CCN group suggest better subjective outcomes in this group.

Management of vernal keratoconjunctivitis: Navigating a changing treatment landscape

Vernal keratoconjunctivitis (VKC) is a chronic, progressive, and potentially sight-threatening form of ocular inflammatory disease that primarily affects children and young adults. Prevalence varies by region, ranging from <2 per 10,000 in the United States to as high as 1,100 per 10,000 in parts of Africa. The rarity of VKC in developed countries can make differential diagnosis challenging, and treatment is often delayed until the disease is advanced, and symptoms are significantly impacting patients' quality of life. Although once viewed primarily as an immunoglobulin E-mediated condition, approximately 50% of patients with VKC do not exhibit allergic sensitization. It is now recognized that the immunopathology of VKC involves multiple inflammatory pathways that lead to the signs, symptoms, and conjunctival eosinophilic and fibroproliferative lesions that are a hallmark of the disease. We examine the evolution of our understanding of the immunopathology of VKC, the expanding VKC treatment armamentarium, the clinical implications of emerging treatment approaches, and future directions for VKC research and practice.

Technological Advances in a Therapy of Primary Open-Angle Glaucoma: Insights into Current Nanotechnologies

Glaucoma is a leading cause of irreversible blindness and is characterized by increased intraocular pressure (IOP) and progressive optic nerve damage. The current therapeutic approaches for glaucoma management, such as eye drops and oral medications, face challenges including poor bioavailability, low patient compliance, and limited efficacy. In recent years, nanotechnology has emerged as a promising approach to overcome these limitations and revolutionize glaucoma treatment. In this narrative review, we present an overview of the novel nanotechnologies employed in the treatment of primary open-angle glaucoma. Various nanosystems, including liposomes, niosomes, nanoparticles, and other nanostructured carriers, have been developed to enhance the delivery and bioavailability of antiglaucoma drugs. They offer advantages such as a high drug loading capacity, sustained release, improved corneal permeability, and targeted drug delivery to the ocular tissues. The application of nanotechnologies in glaucoma treatment represents a transformative approach that addresses the limitations of conventional therapies. However, further research is needed to optimize the formulations, evaluate long-term safety, and implement these nanotechnologies into clinical practice. With continued advancements in nanotechnology, the future holds great potential for improving the management and outcomes of glaucoma, ultimately preserving vision and improving the lives of millions affected by this debilitating disease.

A new era in posterior segment ocular drug delivery: Translation of systemic, cell-targeted, dendrimer-based therapies

Vision impairment and loss due to posterior segment ocular disorders, including age-related macular degeneration and diabetic retinopathy, are a rapidly growing cause of disability globally. Current treatments consist primarily of intravitreal injections aimed at preventing disease progression and characterized by high cost and repeated clinic visits. Nanotechnology provides a promising platform for drug delivery to the eye, with potential to overcome anatomical and physiological barriers to provide safe, effective, and sustained treatment modalities. However, there are few nanomedicines approved for posterior segment disorders, and fewer that target specific cells or that are compatible with systemic administration. Targeting cell types that mediate these disorders via systemic administration may unlock transformative opportunities for nanomedicine and significantly improve patient access, acceptability, and outcomes. We highlight the development of hydroxyl polyamidoamine dendrimer-based therapeutics that demonstrate ligand-free cell targeting via systemic administration and are under clinical investigation for treatment of wet age-related macular degeneration.

Recent advances in drug treatments for dry eye disease

INTRODUCTION

Dry eye disease (DED) is a common ocular condition with a significant impact on patients' quality of life. Conventional treatments include behavioral changes, tear substitutes, and anti-inflammatory agents; however, recent advances in the understanding of DED pathogenesis have opened the way to the development of novel treatment strategies able to target several pathways involved in the onset and persistence of DED.

AREAS COVERED

Literature search was conducted on PubMed and Scopus around the term 'dry eye disease' and others involving its pathophysiology and therapeutic strategy. The primary focus was on recent drugs approved by FDA or under investigation in phase 3 clinical trials. Google and ClinicalTrials.gov were used for obtaining information about the status of FDA approval and ongoing clinical trials.

EXPERT OPINION

Due to its multifaced pathogenesis, DED management is often challenging, and patients' needs are frequently unmet. Recently, several novel treatments have been either FDA-approved or studied in late-phase trials. These novel drugs target-specific biological components of the ocular surface and reduce inflammation and ocular pain. Additionally, new drug delivery systems allow for increased bioavailability, improve effective dosing, and minimize ocular side effects. These advances in drug therapies show real promise for better management of DED patients.

Ultrasound-Mediated Ocular Drug Delivery: From Physics and Instrumentation to Future Directions

Drug delivery to the anterior and posterior segments of the eye is impeded by anatomical and physiological barriers. Increasingly, the bioeffects produced by ultrasound are being proven effective for mitigating the impact of these barriers on ocular drug delivery, though there does not appear to be a consensus on the most appropriate system configuration and operating parameters for this application. In this review, the fundamental aspects of ultrasound physics most pertinent to drug delivery are presented; the primary phenomena responsible for increased drug delivery efficacy under ultrasound sonication are discussed; an overview of common ocular drug administration routes and the associated ocular barriers is also given before reviewing the current state of the art of ultrasound-mediated ocular drug delivery and its potential future directions.

Topical cyclosporine A cationic ophthalmic emulsion in paediatric vernal keratoconjunctivitis: pooled analysis of randomised NOVATIVE and VEKTIS trials

BACKGROUND/OBJECTIVES

Cyclosporine A cationic ophthalmic emulsion (CsA CE) was evaluated in paediatric and adolescent patients with vernal keratoconjunctivitis (VKC) in the NOVATIVE (NCT00328653) and VEKTIS (NCT01751126) trials. The similarity of these studies permitted pooled assessment of the effect of CsA CE on corneal damage as well as safety and tolerability.

SUBJECTS/METHODS

Pooled outcomes were assessed for the first 28 days of treatment. In NOVATIVE, 118 patients were randomised to 4 times daily (QID) CsA CE 0.05%, 0.1%, or vehicle eye drops. In VEKTIS, 169 patients were randomised to CsA CE 0.1% QID or twice daily (BID) or vehicle. For these analyses, treatment groups comprised: (1) pooled CsA CE 0.1% QID arms (high-dose; n = 96); (2) pooled CsA CE 0.05% QID arm from NOVATIVE and CsA CE 0.1% BID data from VEKTIS (low-dose; n = 93); and (3) pooled vehicle QID arms (vehicle; n = 98).

RESULTS

Changes from baseline to day 28 (mean ± standard deviation) in corneal fluorescein staining (CFS) scores for CsA CE high-dose, low-dose, and vehicle groups were -1.6 ± 1.47 (95% CI: -0.9, -0.1; p = 0.0124 vs vehicle), -1.7 ± 1.39 (95% CI: -1.1, -0.3; p = 0.0015 vs vehicle), and -1.0 ± 1.55, respectively. Adverse events (AEs) of any type were reported in 37.5%, 34.4%, and 37.8% of the high-dose, low-dose, and vehicle groups, respectively. Most were mild or moderate in severity.

CONCLUSIONS

CsA CE significantly decreased corneal damage and was safe and well tolerated in patients with VKC. These data support CSA CE as a treatment option for the management of VKC.

Nanotechnology-based ocular drug delivery systems: recent advances and future prospects

Ocular drug delivery has constantly challenged ophthalmologists and drug delivery scientists due to various anatomical and physiological barriers. Static and dynamic ocular barriers prevent the entry of exogenous substances and impede therapeutic agents' active absorption. This review elaborates on the anatomy of the eye and the associated constraints. Followed by an illustration of some common ocular diseases, including glaucoma and their current clinical therapies, emphasizing the significance of drug therapy in treating ocular diseases. Subsequently, advances in ocular drug delivery modalities, especially nanotechnology-based ocular drug delivery systems, are recommended, and some typical research is highlighted. Based on the related research, systematic and comprehensive characterizations of the nanocarriers are summarized, hoping to assist with future research. Besides, we summarize the nanotechnology-based ophthalmic drugs currently on the market or still in clinical trials and the recent patents of nanocarriers. Finally, inspired by current trends and therapeutic concepts, we provide an insight into the challenges faced by novel ocular drug delivery systems and further put forward directions for future research. We hope this review can provide inspiration and motivation for better design and development of novel ophthalmic formulations.

Recent Advances of Ocular Drug Delivery Systems: Prominence of Ocular Implants for Chronic Eye Diseases

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

Trans-corneal drug delivery strategies in the treatment of ocular diseases

The cornea is a remarkable tissue that possesses specialized structures designed to safeguard the eye against foreign objects. However, its unique properties also make it challenging to deliver drugs in a non-invasive manner. This review highlights recent advancements in achieving highly efficient drug transport across the cornea, focusing on nanomaterials. We have classified these strategies into three main categories based on their mechanisms and have analyzed their success and limitations in a systematic manner. The purpose of this review is to examine potential general principles that could improve drug penetration through the cornea and other natural barriers in the eye. We hope it will inspire the development of more effective drug delivery systems that can better treat ocular diseases.

Clinical Outcomes of Topical 0.1% Ciclosporin Cationic Emulsion Used on Label in Children with Vernal Keratoconjunctivitis

INTRODUCTION

The purpose of this short article is to report the clinical outcomes of topical 0.1% ciclosporin cationic emulsion (CsA-CE) used on label in children with vernal keratoconjunctivitis (VKC).

METHODS

In this prospective, non-comparative, observational study children affected by active severe VKC were treated for at least 12 months with topical 0.1% CsA-CE. The drug was instilled in both eyes 4 times daily. Data collected from medical charts for the baseline visit (T0) and 1-year follow-up visit (T1) included symptomatic score (0-15), clinical score (0-15), side effects, rescue therapy (need and total number of courses with 0.1% dexamethasone 4 times daily for 5 days), ocular complications and tolerability (visual analog scale [0-100]).

RESULTS

Data from 25 children (20 boys, 5 girls; mean [± standard deviation] age 8.40 ± 2.54 years) were included in the study. Of the 25 patients, 23 (92%) used 0.1% CsA-CE eye drops as per label recommendations, including four patients who had prematurely stopped using topical galenic CsA due to side effects. Symptomatic and clinical scores decreased significantly after treatment, with the mean symptomatic score decreasing from 9.76 ± 1.27 at T0 to 3.80 ± 1.08 at T1, and the mean clinical score decreasing from 9.20 ± 1.32 at T0 to 3.44 ± 1.00 at T1; both P < 0.0001). Five patients (20%) required at least one course of rescue medication (mean 3.4 ± 4.8 courses/year). No patients experienced ocular complications during the study, and treatment tolerability was very high (mean score 89.40 ± 5.46).

CONCLUSION

Our findings confirm that topical CsA-CE is an effective on-label option for children with VKC in the real-life setting. In our pediatric patient population, CsA-CE provided good clinical outcomes with a limited need for rescue medication, and it was well tolerated by almost all patients, including those who were intolerant to galenic formulations.

Use of a Cationic Emulsion of Latanoprost to Treat Glaucoma Patients with Ocular Surface Disease: A Preclinical Review

Prostaglandin analogue topical medications are one of the most effective therapeutic approaches for the chronic management of glaucoma and ocular hypertension, through the reduction of elevated intra ocular pressure (IOP). While many of the first generations of anti-glaucoma eye drops were preserved with benzalkonium chloride, their repeated use may induce chronic ocular surface toxicity that leads to ocular surface disease (OSD) signs and symptoms. As a result, soft-preservatives and preservative-free formulations have been developed with the goal to avoid the long-term iatrogenic toxicity of the preservative agents. In addition, it has been suggested that OSD and its associated inflammation may negatively impact the efficacy of the IOP-lowering medications, including treatment adherence and compliance. Hence, it may be particularly interesting that glaucoma medications can concomitantly protect and "heal" the ocular surface and its environment while lowering elevated IOP, for the greater benefit of glaucoma patients. The objective of the present review is to briefly present the preclinical data of the cationic oil-in-water emulsion of latanoprost (latanoprost-CE) to shed some light on its mechanisms of action. It overall supports the following hypothesis: the restoration of a healthy ocular surface environment and treatment of the OSD signs and symptoms will allow for an improved elevated IOP reduction and glaucoma management. This would be achieved with a once daily dosing regimen to preserve glaucoma patients' vision, ocular surface, and quality-of-life and wellness.

Influence of BAKs on Tear Film Lipid Layer: in vitro and in silico models

Benzalkonium chloride (BAK) compounds are commonly used in topical ophthalmic products as preservatives and stabilizers. BAK mixtures containing several compounds with different alkyl chain lengths are typically used. However, in chronic eye conditions, such as dry eye disease and glaucoma, the accumulation of adverse effects of BAKs was observed. Hence, preservative-free eye drops formulations are preferred. On the other hand, selected long-chain BAKs, particularly cetalkonium chloride, exhibit therapeutic functions, promoting epithelium wound healing and tear film stability. Nevertheless, the mechanism of BAKs influence on the tear film is not fully understood. By employing in vitro experimental and in silico simulation techniques, we elucidate the action of BAKs and demonstrate that long-chain BAKs accumulate in the lipid layer of the tear film model, stabilizing it in a concentration-dependent fashion. In contrast, short-chain BAKs interacting with the lipid layer compromise the tear film model stability. These findings are relevant for topical ophthalmic drug formulation and delivery in the context of selecting proper BAK species and understanding the dose dependency for tear film stability.

A latanoprost cationic emulsion (STN1013001) vs. other latanoprost formulations (Latanoprost) in open angle glaucoma/ocular hypertension and ocular surface disease: an Italian cost-utility analysis

BACKGROUND

STN1013001 is an innovative latanoprost cationic emulsion for open-angle glaucoma/ocular hypertension (OAG/OHT) and ocular surface disease (OSD).

METHODS AND FINDINGS

A 5-year, 7 health states, 1-year cycle early Markov model-supported cost-utility analysis (CUA) of STN1013001 vs. other latanoprost formulations (Latanoprost) followed the Italian National Health Service (INHS) perspective.One-way, probabilistic and scenario sensitivity analyses tested the uncertainty of the baseline results. Value of information analysis (VOIA) investigated the potential cost-effectiveness of collecting further evidence.

RESULTS

Over 5 years, the Markov model-supported CUA predicts STN1013001 to be potentially highly cost-effective vs. Latanoprost (+€57.60 cost at €2020 values; +0.089 Quality-Adjusted Life Years).The Incremental Cost-Utility Ratio (€647.65) falls well below the lower limit of the acceptability range proposed for Italy (€25,000-€40,000).Sensitivity analyses confirmed the robustness of the baseline findings. VOIA highlighted that further information might only be cost-effective for OAG/OHT utilities and OSD-related disutility.

CONCLUSION

STN1013001 is potentially highly cost-effective and strongly dominant vs. Latanoprost for OAG/OHT+OSD patients from the INHS perspective. These findings should be re-assessed using the data from the ongoing Phase III trial (NCT04133311) comparing the efficacy and safety of STN1013001 vs. Latanoprost and with future real-world CUAs upon the availability of STN1013001 on the Italian market.

Cellulose Acetate Phthalate-Based pH-Responsive Cyclosporine A-Loaded Contact Lens for the Treatment of Dry Eye

Cyclosporine A (CsA) as an eye drop is an effective treatment for dry eye. However, it has potential side effects and a short ocular residence time. To overcome these obstacles, we developed a cellulose acetate phthalate-based pH-responsive contact lens (CL) loaded with CsA (CsA-CL). The CsA was continuously released from the CsA-CL at physiological conditions (37 °C, pH 7.4) without an initial burst. CsA was well-contained in the selected storage condition (4 °C, pH 5.4) for as long as 90 days. In safety assays, cytotoxicity, ocular irritation, visible light transmittance, and oxygen permeability were in a normal range. CsA concentrations in the conjunctiva, cornea, and lens increased over time until 12 h. When comparing the therapeutic efficacy between the normal control, experimental dry eye (EDE), and treatment groups (CsA eye drop, naïve CL, and CsA-CL groups), the tear volume, TBUT, corneal fluorescein staining at 7 and 14 days, conjunctival goblet cell density, and corneal apoptotic cell counts at 14 days improved in all treatment groups compared to EDE, with a significantly better result in the CsA-CL group compared with other groups (all p < 0.05). The CsA-CL could be an effective, stable, and safe option for inflammatory dry eye.

A Multicenter, Randomized, Double-Blind Evaluation of the Efficacy of TJO-087 Versus 0.05% Cyclosporine A in Moderate to Severe Dry Eye

Purpose: To compare the efficacy and ocular tolerability of a 0.08% nanoemulsion cyclosporine A (CsA) (TJO-087) once daily versus a conventional 0.05% emulsion CsA twice daily in dry eye disease. Methods: 178 patients with dry eye disease were randomly assigned to one of two groups: the TJO-087 or CsA0.05% group. Changes in the Ocular Surface Disease Index (OSDI), tear film break-up time (TBUT), corneal and conjunctival staining scores, and Schirmer test scores from baseline to the 32-week visit were compared between both groups. To evaluate ocular tolerability of the study formulations, 7 symptoms (stinging/burning, itching, blurred vision, sandiness/grittiness, dryness, light sensitivity, and pain or soreness) were evaluated (the higher the score, the lower the tolerability) at each follow-up visit. Results: A total of 155 eyes of 155 patients were enrolled. The TJO-087 and CsA0.05% groups showed significant improvement in OSDI, TBUT, ocular surface staining, and Schirmer test scores at 32 weeks from baseline. There was no difference in the extent of improvement in all efficacy parameters. There were no differences in the ocular tolerability scores between the 2 groups at all visits, except that the itching score was higher in the TJO-087 group than in the CsA0.05% group at week 8. Conclusions: Using topical 0.08% CsA once daily is an effective therapeutic option for improving the symptoms and signs in dry eye disease, with a tolerability comparable with that of conventional 0.05% CsA. This trial was registered at the US National Library of Medicine ClinicalTrials.gov (http://clinicaltrial.gov) as NCT05245604 (registration date: 19/06/2020).

The influence of a mineral oil cationic nanoemulsion or perfluorohexyloctane on the tear film lipid layer and higher order aberrations

PURPOSE

To prospectively assess the effect of a single and regular application of either a cationic nanoemulsion of mineral oil (CN) or perfluorohexyloctane (F6H8) on the lipid layer of the tear film and higher order aberrations (HOA) in patients with Dry Eye Disease (DED).

METHODS

Fifty-seven patients with a lipid layer thickness (LLT) ≤ 75 interferometric colour units (ICU) were included in the study. In group A (20 patients) the effect of a single drop of F6H8 or CN on HOA and LLT was assessed immediately after application and up to two hours later. For long term effects (Group B) 37 patients applied CN or F6H8 five times a day for 12 weeks. Measurement of LLT, HOA, non-invasive-tear-break-up-time (NIBUT) and meibography were assessed prior to as well as at 4 weeks and 12 weeks after initiation of treatment. Our study is registered in the "German Clinical Trials Register" under the trial number: DRKS00028696.

RESULTS

CN led to an increase of the LLT from 46.8 ± 16.9 ICU to 76.3 ± 23.5 ICU (p = 0.021) and to an increase of HOA from 0.43 ± 0.06 μm to 0.48 ± 0.08 μm immediately after application (p = 0.027). There was no correlation between the increase of LLT and HOA (r = -0.04; p = 0.90). In group B an increase of LLT was observed in the F6H8 group from 45.8 ± 8.8 ICU at baseline to 66.7 ± 19.5 ICU at 12 weeks (p = 0.002). No changes of HOA were measured throughout the observation period in group B. After 12 weeks CN increased NIBUT from 9.9 ± 5.3 seconds to 15.5 ± 5.6 seconds (p = 0.04). F6H8 increased NIBUT from 12.4 ± 5.9 seconds to 16.9 ± 4.7 seconds (p = 0.02) after 12 weeks.

CONCLUSION

CN leads to a short-term increase in LLT and HOA, but only immediately after application. In contrast F6H8 does lead to an increase of LLT after regular long-term use but has no effect on HOA. The regular application of lipid-based products does not seem to decrease the quality of vision as measured in HOA. Instead, CN and F6H8, both are able to stabilize the tear film after regular application.

[Modern possibilities of pathogenetically oriented therapy for dry eye syndrome]

In recent years, anti-inflammatory therapy has become a significant part of the complex approach to treatment of patients with dry eye syndrome (DES), with cyclosporine preparations becoming increasingly important in the structure of the therapy. Taking into account the immunosuppressive effect of cyclosporine A, which is realized through hindering the activation of T-lymphocytes in the tissues of the ocular surface, its topical application in DES has a pronounced pathogenetic focus. Numerous clinical studies have shown that instillations of cyclosporine into the conjunctival cavity contribute to an increase in total tear production, as well as recovery of the density of goblet cells in the conjunctiva of DES patients. The positive effect of cyclosporine A instillations has been convincingly demonstrated in the complex therapy of patients with vernal and atopic corneal conjunctivitis, Thygeson's superficial punctate keratitis, autoimmune keratitis, meibomian gland dysfunction, etc. However, one significant problem associated with cyclosporine A instillations is the irritating effect of the drug. That prompted the development of a drug that is safe and tolerable during instillations into the conjunctival cavity - preservative-free 0.1% cyclosporine A labelled Ikervis (Santen, Japan). The drug carrier is artificial tear Cationorm (Santen), which has an advantage of stabilizing the tear film and protecting the ocular surface from the irritating effect of cyclosporine. According to numerous clinical studies, Ikervis instillations can improve the effectiveness of complex therapy in patients with DES (especially secondary to Sjögren syndrome, Stevens-Johnson syndrome, graft-versus-host disease), with allergic diseases of the cornea and conjunctiva (spring, atopic corneal conjunctivitis), with corneal transplant disease, and other similar conditions. The high efficacy and safety of Ikervis constitute the reason to recommend it for wide clinical use.

Nanoemulsion applications in photodynamic therapy

Nanoemulsion, or nanoscaled-size emulsions, is a thermodynamically stable system formed by blending two immiscible liquids, blended with an emulsifying agent to produce a single phase. Nanoemulsion science has advanced rapidly in recent years, and it has opened up new opportunities in a variety of fields, including pharmaceuticals, biotechnology, food, and cosmetics. Nanoemulsion has been recognized as a potential drug delivery technology for various drugs, such as photosensitizing agents (PS). In photodynamic therapy (PDT), PSs produce cytotoxic reactive oxygen species under specific light irradiation, which oxidize the surrounding tissues. Over the past decades, the idea of PS-loaded nanoemulsions has received researchers' attention due to their ability to overcome several limitations of common PSs, such as limited permeability, non-specific phototoxicity, hydrophobicity, low bioavailability, and self-aggregation tendency. This review aims to provide fundamental knowledge of nanoemulsion formulations and the principles of PDT. It also discusses nanoemulsion-based PDT strategies and examines nanoemulsion advantages for PDT, highlighting future possibilities for nanoemulsion use.

Diagnosis, Management, and Treatment of Vernal Keratoconjunctivitis in Asia: Recommendations From the Management of Vernal Keratoconjunctivitis in Asia Expert Working Group

Vernal keratoconjunctivitis (VKC) is an underdiagnosed and underrecognized ocular surface disease with limited epidemiological data in Asia. It is more prevalent in warm, dry, and windy climates, and often has a substantial impact on a patient's quality of life. In rare cases, VKC can be associated with vision loss, either through corticosteroid overuse or inadequate treatment of persistent inflammation. As a potentially severe and complex disease, there is variability with how VKC is managed across Asia and among the various allergic eye diseases. Diagnosis and treatment of patients with VKC is a challenge for many ophthalmologists, since no precise diagnostic criteria have been established, the pathogenesis of the disease is unclear, and anti-allergic treatments are often ineffective in patients with moderate or severe disease. In addition, the choice of treatment and management strategies used for patients varies greatly from country to country and physician to physician. This may be because of a lack of well-defined, standardized guidelines. In response, the Management of Vernal Keratoconjunctivitis in Asia (MOVIA) Expert Working Group (13 experts) completed a consensus program to evaluate, review, and develop best-practice recommendations for the assessment, diagnosis, and management of VKC in Asia. The expert-led recommendations are summarized in this article and based on the currently available evidence alongside the clinical expertise of ophthalmologists from across Asia with specialism and interest in the ocular surface, VKC, and pediatric ophthalmology.

Customized cationic nanoemulsions loading triamcinolone acetonide for corneal neovascularization secondary to inflammatory processes

Customized cationic oil-in-water nanoemulsions (NEs) have been produced to improve the bioavailability of poorly water-soluble drugs, such as triamcinolone acetonide (TA). TA is a synthetic glucocorticoid with anti-inflammatory and antiangiogenic therapeutic properties and it is widely used as an effective treatment in ocular disorders. In this work, TA-NEs were characterized using two different custom-made cationic surfactants, showing a high positive surface charge favouring corneal penetration and a particle size below 300 nm. Both TA-NE formulations demonstrated to be stable at 4 °C during the first months of storage. Furthermore, TA-NEs were able to produce antiangiogenic effects in chicken membranes. The TA-NEs safety profile was evaluated using in vitro and in vivo ocular tolerance tests. Out of the two formulations, the one showing no irritant effects was screened in vivo demonstrating capacity to ameliorate ocular inflammation in New Zealand rabbits significantly, specially to reduce the risk of ocular inflammation processes, with antiangiogenic activity, and can therefore be exploited as a suitable formulation to avoid inflammatory reactions upon ocular surgical procedures, such as cataracts.

Ketoconazole-Loaded Cationic Nanoemulsion: In Vitro-Ex Vivo-In Vivo Evaluations to Control Cutaneous Fungal Infections

An attempt has been made to optimize ketoconazole (KTZ)-loaded cationic nanoemulsion for topical delivery followed by in vitro, ex vivo, and in vivo evaluations. Central composite design suggested a total of 13 outcomes at 3 factors and 2 levels against 6 responses. Formulations were characterized for globular size, polydispersity index, pH, ζ potential, % entrapment efficiency (% EE), and drug content. Moreover, the optimized KTZ-CNM13 was compared against drug suspension (KTZ-SUS), commercial cream, and anionic nanoemulsion for in vitro drug release, ex vivo permeation, in vitro hemolysis, antifungal assay, in vivo dermal irritancy, and long-term stability. KTZ-CNM13 was found to have a low size (239 nm), an optimal ζ potential (+22.7 mV), a high % EE (89.1%), a spherical shape, a high drug content (98.9%), and a high numerical desirability value (1.0). In vitro drug release behavior of KTZ from KTZ-CNM13 was 7.54- and 1.71-folds higher than those of KTZ-ANM13 and KTZ-SUS, respectively, at 24 h. The permeation rate values were ordered as KTZ-CNM13 > KTZ-ANM13 > KTZ-MKT > KTZ-SUP due to various studied factors. High values of zone of inhibition for KTZ-CNM13 were observed against Candida albicans, Candida glabrata, Candida tropicalis, and Candida krusei as compared to KTZ-SUS. In vitro hemolysis and in vivo irritation studied confirmed the safety concern of the nanoemulsion at the explored composition. Long-term stability result revealed a stable product at the explored temperature for a year. Conclusively, cationic nanoemulsion is a promising approach to deliver KTZ for high permeation and therapeutic efficacy.

Design of Topical Moxifloxacin Mucoadhesive Nanoemulsion for the Management of Ocular Bacterial Infections

Ocular bacterial infections can lead to serious visual disability without proper treatment. Moxifloxacin (MOX) has been approved by the US Food and Drug Administration as a monotherapy for ocular bacterial infections and is available commercially as an ophthalmic solution (0.5% w/v). However, precorneal retention, drainage, and low bioavailability remain the foremost challenges associated with current commercial eyedrops. With this study, we aimed to design a MOX-loaded nanoemulsion (NE; MOX-NE) with mucoadhesive agents (MOX-NEM) to sustain MOX release, as well as to overcome the potential drawbacks of the current commercial ophthalmic formulation. MOX-NE and MOX-NEM formulations were prepared by hot homogenization coupled with probe sonication technique and subsequently characterized. The lead formulations were further evaluated for in vitro release, ex vivo transcorneal permeation, sterilization, and antimicrobial efficacy studies. Commercial MOX ophthalmic solution was used as a control. The lead formulations showed the desired physicochemical properties and viscosity. All lead formulations showed sustained release profiles a period of more than 12 h. Filtered and autoclaved lead formulations were stable for one month (the last time point tested) under refrigeration and at room temperature. Ex vivo transcorneal permeation studies revealed a 2.1-fold improvement in MOX permeation of the lead MOX-NE formulation compared with Vigamox^® eyedrops. However, MOX-NEM formulations showed similar flux and permeability coefficients to those of Vigamox^® eyedrops. The lead formulations showed similar in vitro antibacterial activity as the commercial eyedrops and crude drug solution. Therefore, MOX-NE and MOX-NEM formulations could serve as effective delivery vehicles for MOX and could improve treatment outcomes in different ocular bacterial infections.

Recent developments in industrial applications of nanoemulsions

Nanotechnology is being utilized in various industries to increase the quality, safety, shelf-life, and functional performance of commercial products. Nanoemulsions are thermodynamically unstable colloidal dispersions that consist of at least two immiscible liquids (typically oil and water), as well as various stabilizers (including emulsifiers, texture modifiers, ripening inhibitors, and weighting agents). They have unique properties that make them particularly suitable for some applications, including their small droplet size, high surface area, good physical stability, rapid digestibility, and high bioavailability. This article reviews recent developments in the formulation, fabrication, functional performance, and gastrointestinal fate of nanoemulsions suitable for use in the pharmaceutical, cosmetic, nutraceutical, and food industries, as well as providing an overview of regulatory and health concerns. Nanoemulsion-based delivery systems can enhance the water-dispersibility, stability, and bioavailability of hydrophobic bioactive compounds. Nevertheless, they must be carefully formulated to obtain the required functional attributes. In particular, the concentration, size, charge, and physical properties of the nano-droplets must be taken into consideration for each specific application. Before launching a nanoscale product onto the market, determination of physicochemical characteristics of nanoparticles and their potential health and environmental risks should be evaluated. In addition, legal, consumer, and economic factors must also be considered when creating these systems.

Selective Pharmacologic Therapies for Dry Eye Disease Treatment: Efficacy, Tolerability, and Safety Data Review from Preclinical Studies and Pivotal Trials

Keratoconjunctivitis sicca, also known as dry eye disease (DED), is a prevalent, multifactorial disease associated with compromised ocular lubrication, ocular surface inflammation and damage, and ocular symptoms. Several anti-inflammatory, topical ophthalmic therapies are available to treat clinical signs and symptoms of DED in the USA and Europe. Cyclosporine A (CsA)-based formulations include an ophthalmic emulsion of 0.05% CsA (CsA 0.05%), a cationic emulsion (CE) of CsA 0.1% (CsA CE), and an aqueous nanomicellar formulation of 0.09% CsA (OTX-101). Lifitegrast is a 5% ophthalmic solution of a lymphocyte function-associated antigen 1 antagonist that is believed to target T cell activation and recruitment to inhibit ocular inflammation. Here we provide a comprehensive review summarising preclinical studies and pivotal trial data for these treatments to provide a complete understanding of their efficacy and safety profile. Overall, data in the evaluated studies show a favourable risk-benefit profile for the use of targeted topical anti-inflammatory pharmacologic treatments in patients with DED. Pivotal trials for CsA 0.05%, CsA CE, OTX-101, and lifitegrast clearly demonstrate treatment efficacy compared to vehicle across treatments with no serious ocular treatment-emergent adverse events (TEAEs). Patients using ophthalmic treatments reported ocular TEAEs more frequently than those treated with vehicle; however, relatively few TEAEs led to treatment discontinuation. The specific signs and symptoms of DED that improve with treatment vary with the treatment prescribed. Long-term and direct comparative studies between treatments are needed to further understand treatment differences in efficacy and safety profiles.

Emerging trends and promises of nanoemulsions in therapeutics of infectious diseases

Infectious diseases are prevalent and have contributed to high morbidity rates by creating havoc like the COVID-19, 1918 influenza and Black Death (the plague) pandemics. Antimicrobial resistance, adverse effects, the emergence of co-infections and the high cost of antimicrobial therapies are major threats to the health of people worldwide while impacting overall healthcare and socioeconomic development. One of the most common ways to address this issue lies in improving existing antimicrobial drug-delivery systems. Nanoemulsions and their modified forms have been successfully employed for the delivery of antimicrobials to treat infectious diseases. In this article, the authors comprehensively reviewed how nanoemulsion-based formulation systems are shifting the paradigm for therapeutics and diagnosis of infectious diseases.

Current trends in pharmaceutical treatment of Dry Eye Disease: A review

Dry eye disease (DED), keratoconjunctivitis sicca or dysfunctional tear syndrome, is the most prevalent ophthalmic disease which affects a substantial segment of people worldwide with increasing frequency. It is considered a multifactorial disease of the ocular surface and tear film, characterized by a variation of signs and symptoms. The symptoms range from mild to severe itching, burning, irritation, eye fatigue, and ocular inflammation that may lead to potential damage to the cornea, conjunctiva and even vision loss. Correspondingly, depending on the different manifestations and pathophysiology, the treatment must be tailored specifically to each patient by targeting the specific mechanisms implicated in their disease. Currently, there are several medical products and techniques available or under investigation for the treatment of DED. The present article focused on the pathophysiology of DED, the new diagnostic approach and the recently developed drug delivery systems or devices reducing the progress of the disease and treating the causes.

Management Strategies for Evaporative Dry Eye Disease and Future Perspective

Dry eye disease (DED) is a common disorder that remains challenging from a clinical perspective. Unstable or deficient tear film is a major factor contributing to DED and the inability to resolve the loss of tear film homeostasis that accompanies DED can result in a vicious circle of inflammation and treatment-refractory disease. Recently recognized as a multifactorial disease, the main etiological subtypes of DED are aqueous-deficient and evaporative which exist on a continuum, although evaporative dry eye (EDE) is the more frequent classification. Although attaining greater recognition in recent years, there is currently no consensus and no clear recommendation on how to manage EDE. Clarity on the early diagnosis and treatment of EDE may facilitate the avoidance of progression to chronic inflammation, permanent damage to the ocular surface, and treatment-refractory disease. The purpose of this review was to identify current best practice for management of EDE in order to help clinicians in providing accurate diagnosis and optimized treatment. We summarize recent literature considering the role of the lipid layer on tear film stability, the importance of its composition and of its dynamic behavior, and the link between its malfunction and the insurgence and maintenance of tear film-related diseases. We have provided an assessment of the best management of lipid-deficient EDE based upon an understanding of disease pathophysiology, while indicating the flow of current treatments and possible future evolution of treatment approaches. Lipid containing eye drops may be considered as a step closer to natural tears from artificial aqueous tears because they more closely mimic the aqueous and lipid layers and may be used in combination with other management approaches. As a next step, we recommend working with a wider expert group to develop full guidelines to enable patient-centered management of EDE. Key pointsDry eye is a multifactorial disease of variable presentation with the tendency to become a chronic disease for which it is essential to identify and treat the main pathogenic mechanisms involved and tailor the treatment to the individual patient.Early intervention is needed to prevent the vicious cycle of DED and may require a multi-faceted management approach.EDE is not just a problem of MGD but can be the result of anything affecting blinking, mucin spreading, aqueous layer volume and content.Lipid-containing eye drops may provide significant relief of symptoms by improving the lipid layer and its spreading ability and, as such, are an appropriate component of the overall management of lipid-deficient EDE; natural lipid-containing eye drops should be the preferred treatment.

Formulation design and optimization of cationic-charged liposomes of brimonidine tartrate for effective ocular drug delivery by Design of Experiment (DoE) approach

OBJECTIVE

The present study was aimed to design and optimize brimonidine tartrate (BRT) loaded cationic-charged liposome formulation with enhanced trans-corneal drug permeation, prolonged corneal residence, and sustained drug release for effective ocular delivery.

METHODS

Design of experiment (DoE) based formulation optimization was done by 3-factor, 3-level Box-Behnken design selecting lipid, cholesterol, and drug content as independent variables and particle size (PS), PDI, zeta potential (ZP), entrapment efficiency (EE%), and cumulative % drug release (CDR) as response variables. The optimized formulation consisting of 79.2 mM lipid, 36.2 mM cholesterol, and 15.8 mg/ml drug was prepared by thin film hydration-sonication method using EPCS:DOTAP(1:1) as lipid component and characterized for all desired critical quality attributes (CQAs), drug release kinetics, TEM, DSC, XRD analysis, ex-vivo trans-corneal drug permeation, and physical stability studies.

RESULTS

The optimized liposome formulation exhibited experimentally observed responses close to predicted values having 150.4 nm (PS), 0.203 (PDI), 30.62 mV (ZP), and 55.17% (EE). The observed CDR(%) was 36.15% at 1h and 91.13% at 12h exhibiting sustained drug release profile and followed Higuchi drug release kinetics. The TEM, DSC, and XRD studies revealed spherical, nanosized, small unilamellar vesicles effectively entrapping BRT in liposomes. The ex-vivo permeation study across goat cornea recorded apparent permeability (P_app) 1.011 ± 0.07 cm.min^-1 and steady-state flux (J_ss) 17.63 ± 1.22 µg.cm^-2.min^-1 showing >2 fold enhanced drug permeation as compared to BRT solution.

CONCLUSION

The developed liposomal formulation possessed all recommended CQAs in optimal range with enhanced trans-corneal drug permeation and remained physically stable in 3 months stability study.

Cost-Utility Analysis of STN1013001, a Latanoprost Cationic Emulsion, versus Other Latanoprost Formulations (Latanoprost) in Open-Angle Glaucoma or Ocular Hypertension and Ocular Surface Disease in France

Purpose

To investigate the cost utility of STN1013001, a latanoprost cationic emulsion, versus Latanoprost in patients with open-angle glaucoma or ocular hypertension (OAG/OHT) and concomitant ocular surface disease (OSD) in France.

Methods

An early Markov model, including 7 health states and a 1-year cycle length, was developed to estimate the cost utility of STN1013001 versus Latanoprost from the French health system perspective over a 5-year time horizon. The model was populated with pooled data (treatment adherence, quality of life, disease progression, and resource utilization) collected, via a questionnaire, from a convenience sample of 5 French glaucoma specialists. Remaining data were retrieved from published sources. Half-cycle correction and 2.5% real social discount rate were applied to costs (in €2020), life years saved (LYS), and quality-adjusted life years (QALYs). The incremental cost-utility ratio (ICUR) was contrasted against the informal willingness-to-pay (WTP) range for incremental LYS or QALY gained (€30,000-€50,000) suggested for France. One-way and probabilistic sensitivity analyses tested the robustness of the baseline ICUR.

Results

Over a 5-year time horizon, STN1013001 resulted in an incremental 0.35 QALYs gained at an incremental cost of €7.39 compared to Latanoprost, resulting in an ICUR of €21.26. This is well below the lower limit of the unofficial WTP range proposed for France. Sensitivity analyses confirmed the robustness of the baseline results.

Conclusion

Once on the market, STN1013001 will provide the French health system with a cost-effective treatment versus Latanoprost for OAG/OHT + OSD patients. These results should be confirmed by future economic evaluations carried out alongside empirical trials.

Artificial Tears: Biological Role of Their Ingredients in the Management of Dry Eye Disease

Dry eye disease (DED) is the most common ocular surface disease, characterized by insufficient production and/or instability of the tear film. Tear substitutes are usually the first line of treatment for patients with DED. Despite the large variety of tear substitutes available on the market, few studies have been performed to compare their performance. There is a need to better understand the specific mechanical and pharmacological roles of each ingredient composing the different formulations. In this review, we describe the main categories of ingredients composing tear substitutes (e.g., viscosity-enhancing agents, electrolytes, osmo-protectants, antioxidants, lipids, surfactants and preservatives) as well as their effects on the ocular surface, and we provide insight into how certain components of tear substitutes may promote corneal wound healing, and/or counteract inflammation. Based on these considerations, we propose an approach to select the most appropriate tear substitute formulations according to the predominant etiological causes of DED.

Permeability, anti-inflammatory and anti-VEGF profiles of steroidal-loaded cationic nanoemulsions in retinal pigment epithelial cells under oxidative stress

Age-related macular degeneration (AMD) is defined as a degenerative, progressive and multifactorial disorder that affects the macula with a complex etiology. The retinal pigment epithelium is a monolayer of cells that has the function to separate the surface of the choroid from the neural retina that is involved in the signal transduction leading to vision. The blood-aqueous barrier and the blood retinal barrier limit the permeation of drugs into the retina and thereby reducing their efficacy. Triamcinolone acetonide (TA) is widely used as anti-inflammatory and immunomodulatory drug that promotes the inhibition of the inflammatory processes. The factors that stimulate or inhibit angiogenesis in AMD create a local balance that is responsible for the growth of sub-retinal neovascularization. In AMD, the main angiogenic stimulus is the vascular endothelial growth factor (VEGF). In this work, nanoemulsions with cationic surfactants (mono- and dicationic DABCO and quinuclidine) were produced to deliver TA, and were found to reduce the production of tumor necrosis factor alpha (TNF-α), which stimulates the choroidal neovascularization development by upregulating the VEGF production, and consequently decreased the VEGF levels. Our results support the potential use of mono- and dicationic DABCO and quinuclidine-based cationic nanoemulsions for the delivery of TA in the treatment of AMD.

Cost–Utility Analysis of a Latanoprost Cationic Emulsion (STN1013001) versus Other Latanoprost in the Treatment of Open-Angle Glaucoma or Ocular Hypertension and Concomitant Ocular Surface Disease in Germany

Purpose

This study aimed to estimate the cost–utility and economic value of STN1013001, a latanoprost cationic emulsion vs other latanoprost formulations (henceforth latanoprost) in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT) and concomitant ocular surface disease (OSD) in Germany.

Methods

An early 5-year Markov model-supported cost–utility analysis was performed to estimate costs, quality-adjusted life years (QALYs) and life-years saved (LYS) for STN1013001 vs latanoprost from the German health system perspective. The model included seven mutually exclusive health states and adopted a 1-year cycle length. The model was populated with pooled data derived, by means of a questionnaire, from a convenience sample of five German glaucoma specialists. Remaining data were derived from published sources. Data provided by the ophthalmologists included annual treatment adherence probabilities, utility values and resource utilization. The half-cycle correction as well as a discount rate of 3.0% per year were applied to costs (expressed in €2020), life-year saved (LYS) and QALYs. The incremental cost–utility ratio (ICUR) was contrasted against the informal willingness-to-pay (WTP) threshold for incremental LYS saved or QALY gained (€30,000) proposed for Germany. One-way and probabilistic sensitivity analyses (OWSA; PSA) tested the robustness of the base case ICUR.

Results

Over the 5-year time horizon, STN1013001 strongly dominates latanoprost as it is less costly (€1003.65 vs €1145.37; −12.37%) and produces more QALYs (2.612 vs 2.365; +10.44%) per notional patient. Baseline findings were robust against all the variations included in OWSA. PSA shows that STN1013001 has a 100% probability of being cost-effective vs Latanoprost at each WTP threshold for incremental QALY gained.

Conclusion

Once on the market, STN1013001 will provide a cost-effective and possibly strongly dominant therapy vs latanoprost for OAG/OHT+OSD patients from a German health system perspective. Future empirical research should confirm these findings.