UV-curable gel formulations: Potential drug carriers for the topical treatment of nail diseases.

Laxmi Valji Kerai, Stephen Hilton, Sudaxshina Murdan

Index: Int. J. Pharm. 492 , 177-90, (2015)

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Abstract

Nail diseases are common, cause significant distress and treatments are far from successful. Our aim was to investigate the potential of UV-curable gels - currently used as cosmetics - as topical drug carriers for their treatment. These formulations have a long residence on the nail, which is expected to increase patient compliance and the success of topical therapy. The gels are composed of the diurethane dimethacrylate, ethyl methacrylate, 2-hydroxy-2-methylpropiophenone, an antifungal drug (amorolfine HCl or terbinafine HCl) and an organic liquid (ethanol or NMP) as drug solvent. Following its application to a substrate and exposure to a UVA lamp for 2 min, the gel polymerises and forms a smooth, glossy and amorphous film, with negligible levels of residual monomers. No drug-polymer interactions were found and drug loading did not affect the film's properties, such as thickness, crystallinity and transition temperatures. In contrast, the organic solvent did influence the film's properties; NMP-containing films had lower glass transition temperatures, adhesion and water resistance than ethanol-based ones. Water-resistance being a desired property, ethanol-based formulations were investigated further for stability, drug release and ungual permeation. The films were stable under accelerated stability testing conditions. Compared to terbinafine, amorolfine was released to a greater extent, had a higher ungual flux, but a lower concentration in the nailplate. However, both drugs were present at considerably high levels in the nail when their MICs are taken into account. We thus conclude that UV-curable gels are promising candidates as topical nail medicines.Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.