Ultrasound-Enhanced Ciclopirox Delivery for Treatment of Onychomycosis

Utility of devices for onychomycosis: a review

Onychomycosis is difficult to treat due to long treatment durations, poor efficacy rates of treatments, high relapse rates, and safety issues when using systemic antifungal agents. Device-based treatments are targeted to specific regions of the nail, have favorable safely profiles, and do not interfere with systemic agents. They may be an effective alternative therapy for onychomycosis especially with increasing reports of squalene epoxidase gene mutations and potential resistance to terbinafine therapy. In this review, we discuss four devices used as antifungal treatments and three devices used as penetration enhancers for topical agents. Lasers, photodynamic therapy, microwaves, and non-thermal plasma have the capacity to inactivate fungal pathogens demonstrated through in vivo studies. Efficacy rates for these devices, however, remain relatively low pointing toward the need to further optimize device or usage parameters. Ultrasound, nail drilling, and iontophoresis aid in improving the permeability of topical agents through the nail and have been investigated as adjunctive therapies. Due to the paucity in clinical data, their efficacy in treating onychomycosis has not yet been established. While the results of clinical studies point toward the potential utility of devices for onychomycosis, further large-scale randomized clinical trials following regulatory guidelines are required to confirm current results.

Strategies for the enhancement of nail plate permeation of drugs to treat onychomycosis

Onychomycosis is caused by dermatophytes, non-dermatophytes and yeasts. It has a global prevalence of 5.5%, requires long treatment periods, and has high relapse rates following therapy. Oral antifungals are generally the most common treatment. While effective, they have limitations such as drug-drug interactions, hepatotoxicity and adverse side effects; thus, they cannot be used in several populations. Topical antifungals do not have the safety limitations but are typically not as effective. The primary challenge of topical treatment is the permeation of drug molecules across the nail plate barrier, which is a highly cross-linked keratin network. The use of drugs and formulations with favourable characteristics such as small size, absence of lipophilicity, hydrophilic nature, hydrating properties and appropriate pH can greatly improve permeation. Here, we review physical, nanoparticle-based, formulation-based, mechanical and chemical drug delivery strategies to improve the permeation of drugs across the nail plate.

Low-Intensity Continuous Ultrasound Therapies—A Systematic Review of Current State-of-the-Art and Future Perspectives

Therapeutic ultrasound has been studied for over seven decades for different medical applications. The versatility of ultrasound applications are highly dependent on the frequency, intensity, duration, duty cycle, power, wavelength, and form. In this review article, we will focus on low-intensity continuous ultrasound (LICUS). LICUS has been well-studied for numerous clinical disorders, including tissue regeneration, pain management, neuromodulation, thrombosis, and cancer treatment. PubMed and Google Scholar databases were used to conduct a comprehensive review of all research studying the application of LICUS in pre-clinical and clinical studies. The review includes articles that specify intensity and duty cycle (continuous). Any studies that did not identify these parameters or used high-intensity and pulsed ultrasound were not included in the review. The literature review shows the vast implication of LICUS in many medical fields at the pre-clinical and clinical levels. Its applications depend on variables such as frequency, intensity, duration, and type of medical disorder. Overall, these studies show that LICUS has significant promise, but conflicting data remain regarding the parameters used, and further studies are required to fully realize the potential benefits of LICUS.

Comparative Study of Traditional Ablative CO2 Laser-Assisted Topical Antifungal with only Topical Antifungal for Treating Onychomycosis: A Multicenter Study

BACKGROUND

The predominance of onychomycosis has been increasing recently. New medications and treatment modalities are being researched for better saturation of the antifungal agents through the nail plate topically because of the low resilience of some patients for the oral antifungal agents. Treatment of onychomycosis, mainly moderate to severe, can be very challenging, expensive, and time consuming.

OBJECTIVE

The objective of this clinical trial is to compare the efficacy and safety of a manually operated ablative CO₂ laser combined with a topical antifungal agent in patients with onychomycosis.

STUDY DESIGN

We conducted an open-label controlled prospective study of 160 eligible patients randomized into control and treatment groups with a 1:1 allocation in the department of dermatology in five different hospitals in Shanghai. It was a 6-month study where both groups were treated with a topical antifungal agent, with the treatment group also receiving ablation by the traditional CO₂ laser once a month for the first 3 months.

RESULTS

The clinical efficacy and mycological cure rate were significantly higher (p < 0.001) for the treatment group. Three (3.75%) patients from the control group and 18 (25%) patients from the treatment group achieved complete nail clearance along with negative potassium hydroxide and negative culture (primary endpoint) results at 24 weeks. Mycological clearance with at least moderate nail clearance (secondary endpoint) for the treatment group was also significantly higher (p < 0.001) for the laser treatment group. The laser treatment was mildly painful but tolerable by the patients. No drug interactions for both groups were encountered.

CONCLUSIONS

The ablative CO₂ laser is a primitive yet effective modality to be considered for the delivery of topical antifungal agents for the management of mild-to-severe onychomycosis. The laser has good tolerance in patients and is a common equipment found in most dermatology units even those without the latest medical technology.