Emergence of nail lacquers as potential transungual delivery system in the management of onchomycosis

ABSTRACT

Introduction: Onchomycosis is the most common nail fungal disease afflicting toes and fingers with a high recurrence rate. The disease is caused by various types of fungi ranging from dermatophyte to non-dermatophyte, making it difficult to eradicate.

Areas covered: The present article focuses on the emergence of nail lacquers as prospective transungual delivery systems for the treatment of mild-to-moderate onchomycosis. Updates regarding emerging nail lacquers, research progress in terms of clinical studies and patents for better understanding of the disease are provided. Finally, the characterization techniques for the assessment of drug concentration in different layers of nail are reviewed.

Expert opinion: The conventional topical delivery systems have failed to improve nail adhesion and drug absorption due to the highly keratinized hydrophilic structure of nail which obstructs the passage of drugs. The surgical therapy systems are painful and invasive while systemic therapy produces serious side effects and a high degree of relapse. These issues have led to the advent of nail lacquers. Nail lacquers have an immense potential to improve nail adhesion as well as bioavailability. However, the nail barrier is still a challenge in imparting complete cure. Several novel approaches are being developed in order to offer better therapeutic action.

KEYWORDS:

• Nail lacquers
• nail
• onchomycosis
• topical
• transungual drug delivery

Article highlights

• The article provides preliminary information on pathophysiology of onchomycosis and structure of nail.

• The currently available therapeutic strategies for the management of the disease include systemic, topical, surgical nail avulsion, chemical treatment or a combination of these.

• Transungual delivery is an effective approach in the treatment of onchomycosis where the drug penetration is influenced by compact structure of nail.

• Nail lacquers based on novel formulation approaches are being focused upon to improve the delivery of active ingredients in a more economical way.

• The article lists the latest in vitro characterization techniques for nail lacquers.

This box summarizes key points contained in the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.