A systematic approach to the formulation of anti-onychomycotic nail patches

Abstract

Nail patches have a potential role as drug carriers for the topical treatment of nail diseases such as onychomycosis, a common condition. Our aim was therefore to develop a systematic and novel approach to the formulation of a simple drug-in-adhesive ungual patch. Twelve pressure-sensitive adhesives (PSAs), four backing membranes, two release liners and three drugs were screened for pharmaceutical and mechanical properties. From this initial screening, two PSAs, two drugs, one backing membrane and one release liner were selected for further investigation. Patches were prepared by solvent-casting and characterised. The patches had good uniformity of thickness and of drug content, and showed minimal drug crystallisation during six months of storage. Meanwhile, the drug stability in the patch upon storage and patch adhesion to the nail was influenced by the nature of the drug, the PSA and the backing membrane. The reported methodology paves the way for a systematic formulation of ungual nail patches to add to the armamentarium of nail medicines. Further, from this work, the best patch formulation has been identified.

The effect of various primers improving adhesiveness of gel polish hybrids on pH, TOWL and overall nail plates condition

“…The use of acetone also has an effect on TOWL. Spruit found that the TOWL is higher for thinner nail plates, decreases after applying nail polish and increases after using different solvents (eg, acetone) . In our studies, the minimum TOWL value of the nail plate with an applied gel polish hybrid was 2.9 g/m 2 /h, maximum 33.2 g/m 2 /h (median 13.5), while after removing the hybrid the minimum value was 1.9 g/m 2 /h maximum 45.7 g/m 2 /h (median 15.3).…”

“…Therefore, in the case of application of a gel polish hybrid, which can nourish the plate, it may be worth using keratin, vitamin or protein bases. Additionally, Gunt et al show (by incubating nail plates at different humidities) that in vitro, nail hydration actually increased the diffusivity of water and antifungal ketoconazole in the nail, which corresponds to the registered test results. It may be observed that the application of one layer of a nail polish reduced TOWL (because the loss of water from the surface of the nail was distorted by the nail polish coating), and its subsequent removal resulted in the return of TOWL to the baseline values .…”

Printing Drugs onto Nails for Effective Treatment of Onychomycosis

“…The concentration of the drug in the liquid ink was determined using High-Performance Liquid Chromatography-UV (HPLC-UV), using a Hewlett Packard 1260 Series HPLC system (Agilent Technologies, Stockport, UK). The method used was adapted from a previously reported procedure [50]. The stationary phase was a Luna C18 Column, 150 × 4.6 µm (Agilent Technologies, Stockport, UK), and the mobile phase was a combination of aqueous solution and Acetonitrile at a ratio of 65:35 v/v.…”

“…Hence, improved topical treatment is essential. Current research is ongoing into different drug carriers and topical formulations [45][46][47][48][49], including nail patches [50], UV-curable gels [51][52][53], lacquers [54][55][56], films [57,58] and solutions [59][60][61]. However, many of these applications do not allow for the user to precisely control the dose, or to easily apply multiple drugs.…”

What can GP data tell us about the treatment of onychomycosis in the UK?

“…7,8 Their treatment is however extremely challenging. The condition is chronic and recurrence (relapse following treatment and reinfection) is common, leading to onychomycosis being called stubborn, 9 and much research on ungual drug delivery and the development of more effective medicines, for example Rizi et al (2018). 10 Oral antifungals are the mainstay of therapy with success rates of about 60%-70%, 11 followed by topical antifungals for mild and superficial infections and when oral antifungals are contra-indicated.…”