Cationic Thiolated Poly(aspartamide) Polymer as a Potential Excipient for Artificial Tear Formulations.

Mária Budai-Szűcs,Andrea Facskó,Carla Caramella,Piroska Szabó-Révész,András Szilágyi,Maria Cristina Bonferoni,Gabriella Horvát,Judit Soós,Erzsébet Csányi,Benjámin Gyarmati,Barnabás Áron Szilágyi,Szilvia Berkó,Giuseppina Sandri

doi:10.1155/2016/2647264

Abstract

Dry eye disease is a relatively common ocular problem, which causes eye discomfort and visual disorders leading to a decrease in the quality of life. The aim of this study was to find a possible excipient for eye drop formulations, which is able to stabilize the tear film. A cationic thiolated polyaspartamide polymer, poly[(N-mercaptoethylaspartamide)-co-(N-(N′,N′-dimethylaminoethyl)aspartamide)] (ThioPASP-DME), was used as a potential vehicle. Besides satisfying the basic requirements, the chemical structure of ThioPASP-DME is similar to those of ocular mucins as it is a protein-like polymer bearing a considerable number of thiol groups. The solution of the polymer is therefore able to mimic the physiological properties of the mucins and it can interact with the mucus layer via disulphide bond formation. The resultant mucoadhesion provides a prolonged residence time and ensures protective effect for the corneal/conjunctival epithelium. ThioPASP-DME also has an antioxidant effect due to the presence of the thiol groups. The applicability of ThioPASP-DME as a potential excipient in eye drops was determined by means of ocular compatibility tests and through examinations of the interactions with the mucosal surface. The results indicate that ThioPASP-DME can serve as a potential eye drop excipient for the therapy of dry eye disease.

Highlights

Dry eye disease (DED) has been reported to afflict 7–33% of the population, thereby reducing their quality of life
The results indicate that ThioPASP-DME can serve as a potential eye drop excipient for the therapy of dry eye disease
In order to modify the pH of the polymer solution close to that of the tear film, the synthesis was extended with a neutralization step

Summary

Introduction

Dry eye disease (DED) has been reported to afflict 7–33% of the population, thereby reducing their quality of life. The mucins act as a lubricant during blinking, stabilize the preocular tear film to prevent desiccation of the epithelium, and form a barrier against pathogen penetrance [5]. In the event of enhanced calcium release, the granules swell, become detached from the cell surface, form large aggregates, and diffuse onto the epithelial surface. This leads to a lower degree of hydration of the mucus coverage, which contains dry spots, resulting in decreased tear film stability [4]

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