Evaluation of the Ability of a Novel Miconazole Formulation To Penetrate Nail by Using Three In Vitro Nail Models

How effective is topical miconazole or amorolfine for mild to moderately severe onychomycosis in primary care: the Onycho Trial - a randomised double-blind placebo-controlled trial

OBJECTIVES

To evaluate the efficacy of topical miconazole or amorolfine compared to placebo for mild to moderately severe onychomycosis.

DESIGN

Randomised, double-blind, placebo-controlled trial, with computer-generated treatment allocation at a 1:1:1 ratio.

SETTING

Primary care, recruitment from February 2020 to August 2022.

PARTICIPANTS

193 patients with suspected mild to moderately severe onychomycosis were recruited via general practices and from the general public, 111 of whom met the study criteria. The mean age of participants was 51 (SD 13.1), 51% were female and onychomycosis was moderately severe (mean OSI 12.1 (SD 8.0)).

INTERVENTIONS

Once-daily miconazole 20 mg/g or once-weekly amorolfine 5% nail lacquer solution was compared with placebo (denatonium benzoate solution).

MAIN OUTCOME MEASURES

Complete, clinical and mycological cure at 6 months. Secondary outcomes were clinical improvement, symptom burden, quality of life, adverse effects, compliance, patient-perceived improvement and treatment acceptability.

RESULTS

Based on intention-to-treat analysis, none of the participants receiving miconazole or amorolfine reached complete cure compared with two in the placebo group (OR not estimable (n.e.), p=0.493 and OR n.e., p=0.240, respectively). There was no evidence of a significant difference between groups regarding clinical cure (OR n.e., p=0.493 and OR 0.47, 95% CI 0.04 to 5.45, p=0.615) while miconazole and amorolfine were less effective than placebo at reaching both mycological cure (OR 0.25, 95% CI 0.06 to 0.98, p=0.037 and OR 0.23, 95% CI 0.06 to 0.92, p=0.029, respectively) and clinical improvement (OR 0.26, 95% CI 0.08 to 0.91, p=0.028 and OR 0.25, 95% CI 0.07 to 0.85, p=0.021, respectively). There was no evidence of a significant difference in disease burden, quality of life, adverse reactions, compliance, patient-perceived improvement or treatment acceptability.

CONCLUSIONS

Topical miconazole and amorolfine were not effective in achieving a complete, clinical or mycological cure of mild to moderately severe onychomycosis, nor did they significantly alleviate the severity or symptom burden. These treatments should, therefore, not be advised as monotherapy to treat onychomycosis.

TRIAL REGISTRATION NUMBER

WHO ICTRP NL8193.

Systematic Review on the Effectiveness of Essential and Carrier Oils as Skin Penetration Enhancers in Pharmaceutical Formulations

Oils, including essential oils and their constituents, are widely reported to have penetration enhancement activity and have been incorporated into a wide range of pharmaceutical formulations. This study sought to determine if there is an evidence base for the selection of appropriate oils for particular applications and compare their effectiveness across different formulation types. A systematic review of the data sources, consisting of Google Scholar, EMBASE, PubMed, Medline, and Scopus, was carried out and, following screening and quality assessment, 112 articles were included within the analysis. The research was classified according to the active pharmaceutical ingredient, dosage form, in vitro/in vivo study, carrier material(s), penetration enhancers as essential oils, and other chemical enhancers. The review identified four groups of oils used in the formulation of skin preparations; in order of popularity, these are terpene-type essential oils (63%), fatty acid-containing essential oils (29%) and, finally, 8% of essential oils comprising Vitamin E derivatives and miscellaneous essential oils. It was concluded that terpene essential oils may have benefits over the fatty acid-containing oils, and their incorporation into advanced pharmaceutical formulations such as nanoemulsions, microemulsions, vesicular systems, and transdermal patches makes them an attractive proposition to enhance drug permeation through the skin.

Improved Methods for Assessing Therapeutic Potential of Antifungal Agents against Dermatophytes and Their Application in the Development of NP213, a Novel Onychomycosis Therapy Candidate

Onychomycosis is a common, difficult-to-treat nail infection that is mainly caused by dermatophytes. Current therapies are not wholly effective and are associated with manifold side effects.

Onychomycosis is a common, difficult-to-treat nail infection that is mainly caused by dermatophytes. Current therapies are not wholly effective and are associated with manifold side effects. The development of treatments for onychomycosis is challenging because standard in vitro tests are not predictive of antifungal efficacy within the nail. We have developed a new antifungal agent, NP213, for the treatment of onychomycosis. NP213 is based on endogenous host defense peptides produced within the nail. We compared the in vitro activity of NP213 and existing antifungal agents using conventional antimicrobial susceptibility test (AST) systems and more physiologically relevant models based on the human nail. We observed that the standard in vitro AST methodologies failed to predict the efficacy of antifungal agents within the nail. To address that, we present a more physiologically relevant modified AST method. This method, alongside other standard in vitro assessments of activity (including mechanism-of-action and time-of-kill studies), better reflected the activity of NP213 and other antifungal agents within the nail than standard in vitro AST methods. NP213 is a rapidly acting, fungicidal peptide that is superior to existing antifungal agents in vitro. It penetrated the nail more effectively than other antifungals, as confirmed by using an optimized in vitro nail infection model. The data presented here support the current clinical development status of NP213 as a novel agent for treating onychomycosis. We propose that the modified tests developed and applied for NP213 characterization are the most relevant to use for screening any potential therapeutic candidates for onychomycosis.