Dexamethasone-loaded keratin films for ocular surface reconstruction

Rebekka Schwab,Stephan Reichl

doi:10.1007/s10856-021-06638-z

Rebekka Schwab, Stephan Reichl

Open Access

https://doi.org/10.1007/s10856-021-06638-z

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Abstract

Amniotic membrane (AM) is often applied as a substitute material during ocular surface reconstruction. However, since AM has several disadvantages, alternative materials must be considered for this application. Keratin films made from human hair (KFs) have previously been presented as a promising option; they exhibited suitable characteristics and satisfactory biocompatibility in an in vivo rabbit model. Nevertheless, dexamethasone (DEX) eye drops are necessary after surgery to suppress inflammation. Since eye drops must be administered frequently, this might result in poor patient compliance, and the release of DEX at the transplant site would be clinically beneficial. Therefore, we aimed to incorporate DEX into KFs without hindering the positive film characteristics. Drug-loaded KFs were generated either by suspension technique or by the addition of solubilizing agents. The resulting specimens were analyzed regarding appearance, loading capacity, transparency, mechanical characteristics, swelling behavior and in vitro release. Furthermore, biocompatibility was assessed in vitro by determining the cell viability, seeding efficiency and growth behavior of corneal epithelial cells. The amount of incorporated DEX influenced the transparency and biomechanical properties of the films, but even highly loaded films showed properties similar to those of AM. The suspension technique was identified as the best incorporation approach regarding chemical stability and prolonged DEX release. Moreover, suspended DEX in the films did not negatively impact cell seeding efficiencies, and the cell-growth behaviors on the specimens with moderate DEX loads were satisfactory. This suggest that these films could comprise a suitable alternative material with additional anti-inflammatory activity for ocular surface reconstruction.Graphical

Highlights

Serious ocular surface disorders, such as membrane pemphigoid, Stevens-Johnson syndrome, severe dry eye, injuries, and chronic inflammation of the eye, are major hazards to the patient’s vision and can cause corneal blindness
Films fabricated from keratin dialysates with solubilized or suspended active pharmaceutical ingredient (API) showed lower transparency levels (Fig. 1C–H)
The transparencies of loaded Keratin films made from human hair (KFs) with equal amounts of DEX were higher for KFs manufactured from dialysate suspensions than for those manufactured from dialysates with solubilized DEX

Summary

Introduction

Serious ocular surface disorders, such as membrane pemphigoid, Stevens-Johnson syndrome, severe dry eye, injuries, and chronic inflammation of the eye, are major hazards to the patient’s vision and can cause corneal blindness. Since only limited pharmacological options are available to treat this clinical need, reconstruction of the ocular surface is often necessary to maintain eyesight. Human donor material in the form of corneal transplantation is utilized for this purpose [1, 2]. Journal of Materials Science: Materials in Medicine (2022) 33:29 supplies make it necessary to search for additional materials, and the amniotic membrane (AM) has been established as an alternative for the treatment of corneal epithelial defects or replacement of the conjunctiva [3]. The amnion membrane is the inner layer of the maternal placenta and amniotic sac that closely covers the fetus during formation in the womb. Since the amnion membrane is a human material, some challenges must be considered to enable application of such membranes. The material transparency and biomechanical strength are limited [8–11]

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