Philippe Daull

Successfully improving ocular drug delivery using the cationic nanoemulsion, novasorb.

Topical ophthalmic delivery of active ingredients can be achieved using cationic nanoemulsions. In the last decade, Novagali Pharma has successfully developed and marketed Novasorb, an advanced pharmaceutical technology for the treatment of ophthalmic diseases. This paper describes the main steps in the development of cationic nanoemulsions from formulation to evaluation in clinical trials. A major challenge of the formulation work was the selection of a cationic agent with an acceptable safety profile that would ensure a sufficient ocular surface retention time. Then, toxicity and pharmacokinetic studies were performed showing that the cationic emulsions were safe and well tolerated. Even in the absence of an active ingredient, cationic emulsions were observed in preclinical studies to have an inherent benefit on the ocular surface. Moreover, clinical trials demonstrated the efficacy and safety of cationic emulsions loaded with cyclosporine A in patients with dry eye disease. Ongoing studies evaluating latanoprost emulsion in patients with ocular surface disease and glaucoma suggest that the beneficial effects on reducing ocular surface damage may also extend to this patient population. The culmination of these efforts has been the marketing of Cationorm, a preservative-free cationic emulsion indicated for the symptomatic treatment of dry eye.

Benefits of cetalkonium chloride cationic oil-in-water nanoemulsions for topical ophthalmic drug delivery.

Topical ocular administration is the most convenient route of administration of drugs for the treatment of eye diseases. However, the bioavailability of drugs following eye instillations of eye drops is very low. Over the past 20 years, extensive efforts have been put into research to improve drug bioavailability without compromising treatment compliance and patients quality of life.

Distribution of Cyclosporine A in Ocular Tissues After Topical Administration of Cyclosporine A Cationic Emulsions to Pigmented Rabbits

Purpose: The aim of this study was to compare the ocular and systemic distribution of cyclosporine A (CsA) in rabbits after the instillation of preservative-free CsA cationic and anionic emulsions. Methods: For the single-dose pharmacokinetic (PK) study, rabbits were instilled with 50 &mgr;L of the test material. For the multiple-dose PK study, rabbits were instilled twice daily with Restasis or once daily with NOVA22007 for 10 days. At each time point, the cornea, conjunctiva, and whole blood were harvested for CsA quantification. Ocular and systemic distribution were determined after 4 times daily instillations with 50 &mgr;L of 3H-CsA cationic and anionic emulsions for 7 days. Restasis was used as a reference in all studies. Results: Single-dose PK data demonstrated that NOVA22007 0.1% and 0.05% delivered higher CsA concentrations to the cornea than Restasis [concentration maximum (Cmax): 2692, 1372, and 748 ng/g, respectively] and have a better exposition (area under the curve). Conjunctival Cmax values were 1914, 696, and 849 ng/g and area under the curve values were 3984, 2796, and 2515 ng/g·h, for either dose of the cationic emulsions and Restasis, respectively. The multiple-dose PK and the 3H-CsA distribution data demonstrated that the systemic distribution after repeated instillations was low and comparable for all emulsions. Conclusions: These data demonstrate that the CsA cationic emulsions were more effective than Restasis at delivering CsA to target tissues, thus confirming the potential advantage of cationic emulsions over anionic emulsions as vehicle for ocular drug delivery for the treatment of ocular surface diseases.

In Vitro and In Vivo Evaluation of a Preservative-Free Cationic Emulsion of Latanoprost in Corneal Wound Healing Models

Purpose: Cationic emulsions (CEs), developed as vehicles for lipophilic drugs, have been shown to be safe and effective for the treatment of dry eye. The aim of this study was to investigate the effects of a preservative-free latanoprost 0.005% CE (latanoprost-CE) in in vitro and in vivo models of corneal wound healing. Methods: An in vitro wound was made by scraping through a confluent layer of human corneal epithelial cells. Cytotoxicity, cell migration, and proliferation were analyzed after an exposure to phosphate-buffered saline, CE, latanoprost-CE, 0.02% benzalkonium chloride (0.02%BAK), and Xalatan (0.02%BAKlatanoprost). In vivo, the recovery and integrity of corneal wound healing were assessed in rat eyes instilled twice a day for 5 days with the above treatments after deepithelialization of the superior cornea. Results: In vitro wound distances decreased at 2 and 24 hours for human corneal epithelial cells exposed to CE, latanoprost-CE, and phosphate-buffered saline, whereas they progressively increased for 0.02%BAK-treated and 0.02%BAKlatanoprost-treated cells. The greater wound closure was associated with a higher number of Ki67-positive cells. In CE- and latanoprost-CE-treated rats, reepithelialization of the cornea was enhanced, restoring normal appearance and function. In contrast, 0.02%BAK or 0.02%BAKlatanoprost delayed corneal healing, induced inflammation, and decreased MUC5-AC expression. Conclusions: Both models effectively evaluated the cytotoxicity and dynamic recovery of corneal wound healing, and their correlation supports the potential of the in vitro model as a reliable alternative to in vivo ocular toxicity tests. Both models demonstrated that in the face of corneal injury, CEs favored corneal healing, whereas BAK was deleterious.

A preliminary evaluation of dexamethasone palmitate emulsion: a novel intravitreal sustained delivery of corticosteroid for treatment of macular edema.

PURPOSEnDexamethasone palmitate (DXP) is a lipophilic prodrug of dexamethasone (DXM), a potent corticosteroid used to treat a variety of ophthalmic diseases. The aim of the study was to characterize the sustained release capacity (in rabbit), efficacy (in rat and rabbit), and safety (in rabbit, cat, and minipig) of intravitreal (IVT) DXP emulsions in preclinical models.nnnMETHODSnOil-in-water emulsions of DXP were administered by IVT injections in rats, rabbits, cats, or minipigs. Efficacy was assessed in rabbits by the inhibition of VEGF-induced vascular leakage and in rats by inhibition of laser-induced choroidal neovascularization. Concentrations of DXP and DXM in aqueous humor, vitreous, retina, choroid, and blood were determined to characterize the ocular and systemic pharmacokinetic (PK) profile. Complete ophthalmic examinations (indirect ophthalmoscopy, slit-lamp biomacroscopy, electroretinography, tonometry) were performed to assess the ocular safety of IVT DXP doses up to 2,600 μg in minipig, followed by histopathologic examinations. A validated feline model of DXM-induced elevated intraocular pressure (IOP) was used to assess the ocular hypertensive impact (i.e., the safety) of an IVT injection of DXP emulsion.nnnRESULTSnRat and rabbit efficacy data demonstrated that IVT injections of DXP emulsions were effective. Rabbit PK data demonstrated that following a single 1,280 μg IVT injection resulted in sustained DXM levels in the retina and choroid (1,179.6 and 577.7 ng/g with a half-life of 189 and 103 days, respectively) sufficient to inhibit VEGF-induced vascular hyper-permeability for up to 9 months. No adverse ocular findings were observed in the rabbit at the 1,280 μg DXP dose. Plasma levels of DXP and DXM were close to the lower limit of quantification (0.5 ng/mL). In minipigs, no systemic effects were observed at a dose up to 2,600 μg DXP. In steroid responsive cats, IVT DXP emulsions increased IOP to a lesser extent than triamcinolone acetonide with a more rapid return to basal levels and no evidence of cataract formation.nnnCONCLUSIONSnIVT injections of DXP emulsions were well tolerated and shown to be efficacious for the sustained release of the drug, with the potential to control vascular leakage up to 9 months following a single IVT injection. These data suggest that IVT injections of DXP emulsions could be a safe and effective alternative IVT drug delivery vehicle for corticosteroid to treat back of the eye diseases complicated by macular edema.

Efficacy of a new topical cationic emulsion of cyclosporine A on dry eye clinical signs in an experimental mouse model of dry eye.

Dry eye disease (DED) is a complex, multifactorial pathology characterized by corneal epithelium lesions and inflammation. The aim of the present study was to evaluate the efficacy of a cationic emulsion of cyclosporine A (CsA) in a mouse model that mimics severe dry eye. Eight to 12-week-old female C57BL/6N mice with tail patches of scopolamine were housed in controlled environment chambers to induce dry eye. At day three, following dry eye confirmation by corneal fluorescein staining (CFS, score 0-15) and phenol red thread (PRT) lacrimation test, the mice (nxa0=xa010/gp) were either treated 3 times a day in both eyes with drug-free cationic emulsion, a 0.1% CsA cationic emulsion, or 1% methylprednisolone (positive control), or non-treated. Aqueous tear production and CFS scores were evaluated at baseline and throughout the treatment period. The lacrimation test confirmed the scopolamine-induced decrease in aqueous production by the lacrimal gland. A reduction of 59% in induced-CFS was observed following topical treatment with 0.1% CsA. The beneficial effect of the cationic emulsion vehicle itself on keratitis was also clearly evidenced by its better performance over 1% methylprednisolone, -36%, vs. -28% on the CFS scores, respectively. This study indicates that the cationic emulsion of CsA (0.1%) was a very effective formulation for the management of corneal epithelium lesions in a severe DED mouse model. In addition, it performed better than a potent glucocorticosteroid (1% methylprednisolone). This cationic emulsion of CsA (0.1%), combining CsA and a tear film oriented therapy (TFOT), i.e. with vehicle properties that mechanically stabilize the tear film, represents a promising new treatment strategy for the management of the signs of dry eye.

Comparison of the Anti-Inflammatory Effects of Artificial Tears in a Rat Model of Corneal Scraping

Abstract Purpose: Artificial tears (ATs) are used routinely to alleviate the symptoms of mild to moderate dry eye. Preservative-free cationic emulsions (eg, Cationorm®) are an innovative approach for the management of signs and symptoms of dry eye. The aim of the present exploratory experiment was to evaluate the efficacy of this cetalkonium chloride (CKC)-containing cationic emulsion on debrided cornea and to characterize its effects on scraping-induced inflammation. Methods: Four ATs were assessed in a rat model of corneal scraping. The upper part of the corneal epithelium was scraped before a 5-day treatment, followed by clinical evaluations and fluorescein staining to evaluate cornea recovery. The anti-inflammatory efficacy of the ATs was assessed in vivo and in vitro. Results: In vivo confocal microscopy (IVCM) revealed a trend toward better corneal clinical signs (lower IVCM scores) for the animals treated with the unpreserved ATs. Benzalkonium chloride treatment decreased goblet cell count by 37.5%. While the soft-preserved Systane Balance® and Optive® and the preservative-free Vismed® had no effect on the goblet cell count, Cationorm increased this count by almost 40%. Interestingly, inflammatory cell infiltration in the stroma was at its lowest following treatment with the preservative-free Cationorm. Cationorm is also the only AT decreasing IL6- and IL8-stimulated secretion by 59% and 74%, respectively. Conclusion: By restoring an adequately hydrated ocular surface environment, the different ATs promote corneal epithelium healing. These data position Cationorm as a promising AT for the management of signs and symptoms of dry eye in patients with mild to moderate dry eye disease presenting chronic subclinical levels of ocular inflammation.

Development of a Cationic Nanoemulsion Platform (Novasorb®) for Ocular Delivery

The ocular mucosa is among the most complex mucosa of the body. To be crossed by drugs, drug delivery systems need to have special features and at the same time preserve the eye environment and ocular surface integrity while promoting drug absorption and efficacy. The cationic emulsion-based technology was designed to extend ocular surface residence time and improve the therapeutic benefits of pharmacological treatments. Novasorb technology development is described from formulation work to the clinics. Particular attention was paid to the choice of the cationic agent and key component of the emulsions. Preclinical pharmacokinetics and toxicity evaluation have demonstrated that the cationic emulsions are safe and effective drug-delivery vehicles. Clinical trials proved the efficacy and safety of the cationic emulsions in the treatment of dry eye disease and glaucoma. This development illustrates that natural eye protection mechanisms can be diverted from their original function and used as a mean to promote ocular drug penetration.

Safety and Tolerability of Overdosed Artificial Tears by Abraded Rabbit Corneas

Abstract Purpose: Preservative-free cationic emulsion-based artificial tear (AT) is an innovative eye drop based on the Novasorb® technology with cetalkonium chloride (CKC) as the cationic agent. The cationic emulsion Cationorm is designed for the management of mild-to-moderate dry eye disease (DED) patients that present cornea epithelium alterations. The aim of the present study was to evaluate the safety and tolerability of overdosed ATs by altered corneal epithelium in vivo and assess the usefulness of the ex vivo eye irritation test (EVEIT) as a predictive alternate toxicity test method. Methods: The experimental procedure, treatment duration, and instillation frequency closely mimic in vivo the ex vivo protocol described by Pinheiro et al. and discussed in the Discussion and Conclusion section of this article. Two to 3-month-old female New Zealand white rabbits, nu2009=u20096 per group, were treated with ATs (21 instillations/day over 3 days) following corneal abrasion. Corneal fluorescein staining, in vivo confocal microscopy (IVCM), and slit lamp examinations were performed to assess corneal epithelium recovery and the ocular tolerability of the overdosed ATs. Results: All abraded eyes experienced almost complete epithelium recovery within 3 days following treatments with Cationorm, Optive, Vismed, and Saline. Benzalkonium chloride (BAK, 0.02%) treatment resulted in 82.4% reepithelialization. IVCM data illustrated corneal epithelium normal recovery. Acute local tolerability of the overdosed ATs was confirmed using Draize and McDonald–Shadducks test scales. Conclusions: The different ATs were demonstrated to be well tolerated by abraded corneas in vivo, and the extreme overdosing regimen did not hamper the wound healing process of the rabbit eye in comparison to saline. These data did not confirm the ones obtained with the nonvalidated ex vivo eye irritation test.

Conjunctival Inflammatory Gene Expression Profiling in Dry Eye Disease: Correlations With HLA-DRA and HLA-DRB1

Purpose: In several multicenter clinical trials, HLA-DR was found to be a potential biomarker of dry eye disease (DED)s severity and prognosis. Given the fact that HLA-DR receptor is a heterodimer consisting in an alpha and a beta chain, we intended to investigate the correlation of inflammatory targets with the corresponding transcripts, HLA-DRA and HLA-DRB1, to characterize specific targets closely related to HLA-DR expressed in conjunctival cells from patients suffering from DED of various etiologies. Methods: A prospective study was conducted in 88 patients with different forms of DED. Ocular symptom scores, ocular-staining grades, tear breakup time (TBUT) and Schirmer test were evaluated. Superficial conjunctival cells were collected by impression cytology and total RNAs were extracted for analyses using the new NanoString® nCounter technology based on an inflammatory human code set containing 249 inflammatory genes. Results: Two hundred transcripts were reliably detected in conjunctival specimens at various levels ranging from 1 to 222,546 RNA copies. Overall, from the 88 samples, 21 target genes showed a highly significant correlation (R > 0.8) with HLA-DRA and HLA-DRB1, HLA-DRA and B1 presenting the highest correlation (R = 0.9). These selected targets belonged to eight family groups, namely interferon and interferon-stimulated genes, tumor necrosis factor superfamily and related factors, Toll-like receptors and related factors, complement system factors, chemokines/cytokines, the RIPK enzyme family, and transduction signals such as the STAT and MAPK families. Conclusions: We have identified a profile of 21 transcripts correlated with HLA-DR expression, suggesting closely regulated signaling pathways and possible direct or indirect interactions between them. The NanoString® nCounter technology in conjunctival imprints could constitute a reliable tool in the future for wider screening of inflammatory biomarkers in DED, usable in very small samples. Broader combinations of biomarkers associated with HLA-DR could be analyzed to develop new diagnostic approaches, identify tighter pathophysiological gene signatures and personalize DED therapies more efficiently.