Effect of ablative laser on in vitro transungual delivery

Fractional CO2 laser in the treatment of nail psoriasis: how can it help?

Treating nail psoriasis is often a time-consuming challenge with an unsecure outcome. Response to the treatment is variable and relapses are common. Systemic treatments have multiple systemic side effects and lack of the patient compliance makes intra-lesional therapies not the best choice for treatment of nail psoriasis. We aimed to evaluate and compare the efficacy and side effects of methotrexate versus calcipotriol plus betamethasone two-compound formula when applied topically to psoriatic nails after fractional CO2 laser. This comparative pilot study included 20 patients with nail psoriasis. One side was treated with fractional CO2 laser followed by the application of topical methotrexate (Group A) and the other side with fractional CO2 laser followed by topical (Calcipotriol 0.05 mg/gm + Betamethasone 0.5 mg/gm) (Group B). 4 sessions were done, once every 2 weeks. There was a high statistical significant decrease in total NAPSI score in group A at 1(P = 0.000) and 2 months (P = 0.000). There was a high statistical significant decrease in total NAPSI score in group B at 1(P = 0.001) and 2 months (P = 0.001). There was no statistical significant difference regarding total NAPSI score between both group A and B at 0 (P = 0.271), 1(P = 0.513) and 2 months (P = 0.647). Combined fractional CO2 laser with either topical MTX or topical betamethasone plus calcipotriol two-compound formula is effective treatment for nail psoriasis.

Laser microporation facilitates topical drug delivery: a comprehensive review about preclinical development and clinical application

INTRODUCTION

Topical drug delivery is highly attractive and yet faces tissue barrier challenges. Different physical and chemical methods have been explored to facilitate topical drug delivery.

AREAS COVERED

Ablative fractional laser (AFL) has been widely explored by the scientific community and dermatologists to facilitate topical drug delivery since its advent less than two decades ago. This review introduces the major efforts in exploration of AFL to facilitate transdermal, transungual, and transocular drug delivery in preclinical and clinical settings.

EXPERT OPINION

Most of the preclinical and clinical studies find AFL to be safe and highly effective to facilitate topical drug delivery with little restriction on physicochemical properties of drugs. Clinical studies support AFL to enhance drug efficacy, shorten treatment time, reduce pain, improve cosmetic outcomes, reduce systemic drug exposure, and improve safety. Considering most of the clinical trials so far involved a small sample size and were in early phase, future trials will benefit from enrolling a large group of patients for thorough evaluation of the safety and efficacy of AFL-assisted topical drug delivery. The manufacturing of small and less costly AFL devices will also facilitate the translation of AFL-assisted topical drug delivery.

Fractional CO2 laser ablation leads to enhanced permeation of a fluorescent dye in healthy and mycotic nails-An imaging investigation of laser-tissue effects and their impact on ungual drug delivery

Purpose

Conventional oral antifungal therapies for onychomycosis (OM) often do not achieve complete cure and may be associated with adverse effects, medical interactions, and compliance issues restricting their use in a large group of patients. Topical treatment can bypass the systemic side effects but is limited by the physical barrier of the nail plate. Ablative fractional laser (AFL) treatment can be used to improve the penetration of topical drugs into the nail. This study visualized the effects of laser ablation of nail tissue and assessed their impact on the biodistribution of a fluorescent dye in healthy and fungal nail tissue.

Methods

For the qualitative assessment of CO₂ AFL effects on healthy nail tissue, scanning electron microscopy (SEM), coherent anti‐Stokes Raman scattering microscopy (CARS‐M), and widefield fluorescence microscopy (WFM) were used. To quantitate the effect of laser‐pretreatment on the delivery of a fluorescent dye, ATTO‐647N, into healthy and fungal nail tissue, ablation depth, nail plate thickness, and ATTO‐647N fluorescence intensity in three nail plate layers were measured using WFM. A total of 30 nail clippings (healthy n = 18, fungal n = 12) were collected. An aqueous ATTO‐647N solution was directly applied to the dorsal surface of 24 nail samples (healthy n = 12, fungal n = 12) and incubated for 4 hours, of which half (healthy n = 6, fungal n = 6) had been pretreated with AFL (30 mJ/mb, 15% density, 300 Hz, pulse duration <1 ms).

Results

Imaging revealed a three‐layered nail structure, an AFL‐induced porous ablation crater, and changes in autofluorescence. While intact fungal samples showed a 106% higher ATTO‐647N signal intensity than healthy controls, microporation led to a significantly increased fluorophore permeation in all samples (p < 0.0001). AFL processing of nail tissue enhanced topical delivery of ATTO‐647N in all layers, (average increase: healthy +108%, fungal +33%), most pronounced in the top nail layer (healthy +122%, fungal +68%). While proportionally deeper ablation craters correlated moderately with higher fluorescence intensities in healthy nail tissue, fungal samples showed no significant relationship.

Conclusion

Fractional CO₂ laser microporation is a simple way of enhancing the passive delivery of topically applied ATTO‐647N. Although the impaired nail plate barrier in OM leads to greater diffusion of the aqueous solution, AFL can increase the permeability of both structurally deficient and intact nails.

Transdermal Delivery of Therapeutic Compounds With Nanotechnological Approaches in Psoriasis

Psoriasis is a chronic, immune-mediated skin disorder involving hyperproliferation of the keratinocytes in the epidermis. As complex as its pathophysiology, the optimal treatment for psoriasis remains unsatisfactorily addressed. Though systemic administration of biological agents has made an impressive stride in moderate-to-severe psoriasis, a considerable portion of psoriatic conditions were left unresolved, mainly due to adverse effects from systemic drug administration or insufficient drug delivery across a highly packed stratum corneum via topical therapies. Along with the advances in nanotechnologies, the incorporation of nanomaterials as topical drug carriers opens an obvious prospect for the development of antipsoriatic topicals. Hence, this review aims to distinguish the benefits and weaknesses of individual nanostructures when applied as topical antipsoriatics in preclinical psoriatic models. In view of specific features of each nanostructure, we propose that a proper combination of distinctive nanomaterials according to the physicochemical properties of loaded drugs and clinical features of psoriatic patients is becoming a promising option that potentially drives the translation of nanomaterials from bench to bedside with improved transdermal drug delivery and consequently therapeutic effects.

Efficacy of combined fractional carbon dioxide laser and topical tazarotene in nail psoriasis treatment: A randomized intrapatient left-to-right study

BACKGROUND

Treatment of nail psoriasis is disappointing; due to poor penetrability of topical therapies and variable efficacy of systemic therapies. Fractional carbon dioxide laser (FCL) may enhance penetration of topical therapy for nail psoriasis.

OBJECTIVE

To evaluate the efficacy and safety of FCL plus topical tazarotene versus tazarotene monotherapy in the treatment of nail psoriasis.

METHODS

Twenty-seven patients with bilateral fingernail psoriasis randomly received 3 sessions of FCL at four-week interval plus once-daily tazarotene 0.1% gel for one hand, and once-daily tazarotene 0.1% gel only for 3 months on the other hand. The primary outcome was modified Nail Psoriasis Severity Index (mNAPSI) at 3 and 6 months compared to baseline, and the secondary outcomes included dermoscopic examination and patient global assessment. Adverse events were reported.

RESULTS

The total, nail matrix, and nail bed mNAPSI scores were significantly improved at 3 and 6 months by both regimens, but they decreased more after FCL/tazarotene combination (p = 0.001, p = 0.023, and p = 0.001, respectively). Combination therapy showed faster improvement of nail matrix signs and greater efficacy for nail bed signs. The dermoscopic features of the nail plate were the most responsive after both treatments. The combined therapy was more effective in improving the dermoscopic nail bed features. Patient's global assessment scores were significantly higher after the combined therapy. Both treatments were well tolerated.

CONCLUSION

Fractional CO₂  laser is an effective and well-tolerated treatment for nail psoriasis; it improves the outcomes of topical tazarotene especially in nail bed lesions.

Onychomycosis: Current Understanding and Strategies for Enhancing Drug Delivery into Human Nail Tissue

BACKGROUND

Onychomycosis is by far the most common finger or toe nail fungal infectious disease caused by dermatophytes, non-dermatophytic molds or yeast. It accounts for 50% of the total nail disorders, and affects patients physically, socially, and psychologically and can seriously influence their quality of life.

OBJECTIVES

Oral antifungals are routinely used to treat the nail fungal disease; however oral therapy is associated with severe side effects and longer treatment times. In recent years, drug delivery directly into the nail or nail bed has gained attention and various topical products have been tested that can cure the disease when applied topically or transungually. Nevertheless, drug penetration into and through the nail is not straightforward and requires chemicals to improve its permeability or by applying physical stress to promote drug penetration into and through the nail. This lucid review presents an overview of various causes of onychomycosis, current therapeutic approaches, and efforts aimed at increasing the permeability of nails through various strategies such as chemical, physical and mechanical methods for permeation enhancement.

CONCLUSION

Various strategies have been proposed for the treatment of onychomycosis, however, much research into a more precise and effective therapy is still required.

Pulse-Dye Laser Followed by Betamethasone-Calcipotriol and Fractional Ablative CO2-Laser-Assisted Delivery for Nail Psoriasis

BACKGROUND

Nail psoriasis is a common and potentially debilitating condition for which no effective and safe nonsystemic therapy is currently available. Recently, laser-assisted drug delivery (LADD) is being increasingly used to facilitate transcutaneous penetration of topical treatments.

OBJECTIVES

We set to assess the efficacy and safety of combined pulse-dye laser and fractional CO2 laser-assisted betamethasonecalcipotriol gel delivery for the treatment of nail psoriasis.

MATERIAL AND METHODS

We conducted a prospective, intrapatient comparative study in a series of 22 patients with bilateral fingernail psoriasis. Nails on the randomized hand were treated with 3 monthly sessions of pulse-dye laser to the proximal and lateral nail folds followed by fractional ablative CO2 laser to the nail plate. Between treatments and one month following the last treatment, the participants applied betamethasone propionate-calcipotriol gel once daily to the nail plate. Clinical outcome was ascertained using nails photography, the Nail Psoriasis Severity Index (NAPSI) and patient satisfaction.

RESULTS

Seventeen completed the study. Three participants withdrew from the study because of treatment-associated pain. Treatment was associated with a statistically significant improvement of the NAPSI scale (p < .002). Patient satisfaction was high.

CONCLUSION

Combined PDL and fractional ablative CO2-LADD of betamethasone-calcipotriol gel should be considered for the treatment of nail psoriasis.

A novel technique to evaluate nail softening effects of different urea formulations

Urea has been incorporated into several topical ungual formulations to hydrate and soften the nail plate. In this study, we employed various characterization techniques (visual observation, scanning electron microscopy, measurement of thickness, transonychial water loss, nail electrical resistance, and mechanical study) to investigate the effect of urea concentration on the hydration of bovine hoof membranes - an in vitro model of infected human nails. We obtained inconsistent results in the thickness, transonychial water loss, nail electrical resistance, and scanning electron microscopy studies. In the mechanical study using a modified Texture Analyzer method, we reported an inverse and linear correlation between urea concentrations in the formulations and the force required to puncture the treated membrane (R² = 0.9582, n ≥ 8). As the urea concentration decreased from 4x to 2x, 1x, and 0x % w/w, the puncture force increased significantly from 0.47 ± 0.07 to 0.77 ± 0.07, 0.91 ± 0.09, and 1.33 ± 0.26 N, respectively (p < 0.05). Thus, urea provided a positive softening effect on the membranes and the puncture force could indicate the urea level in topical formulations. In this study, we provided a novel, efficient, and reliable tool to evaluate the hydration level and physical properties of bovine hoof membranes.

Potential of Naftifine Application for Transungual Delivery

Naftifine is used to treat fungal skin infections as it inhibits dermatophytes, which are the cause of onychomycosis. However, naftifine's ability to permeate the human nail barrier has not been investigated, thus, the antimycotic potential is not clearly established. This work aims to evaluate the effect of penetration enhancing factors on the accumulation of naftifine hydrochloride through human nail clippings. Naftifine polymeric nail lacquers with Eudragit RL100 were developed as a suitable delivery system. Low penetration of naftifine into nail has been determined as less than 10% of applied drug dose accumulated in the nail layers. Incorporation of thioglycolic acid into formulations resulted in increased accumulation of antifungal agent in the nail layers by 100% compared with a control group. Salicylic acid did not effect naftifine accumulation in the human nail. The permeation of naftifine through the nail increased by threefold when the thioglycolic acid-containing formulation was applied and the nail was pretreated with a fractional CO2 laser. Structural changes of the nail barrier, induced by fractional CO2 laser, were visualized by microscopy. The results suggest, that naftifine nail penetration could be significantly increased when physical and chemical enhancing factors are applied.

Treatment of Psoriasis: Novel Approaches to Topical Delivery

Topical treatment is the cornerstone for the management of mild to moderate psoriasis. Despite efforts in drug development, patient's satisfaction with the available topical treatments is limited. A strategy to improve safety, efficacy and comfort of topical treatment provides the development of new drug delivery and drug carrier systems. This review provides an overview of recent advances in this field with a focus on psoriasis. Laser-assisted drug delivery, foam formulations, nanoparticles, ethosomes, and niomes are considered. Hopefully, these new developments will improve topical drug therapy and patient satisfaction.

Potential of Chemical and Physical Enhancers for Transungual Delivery of Amorolfine Hydrochloride

Topical monotherapy of nail infection is limited by poor drug permeability into the human nail plate. Numerous substances and methods are applied to improve the antifungal agent delivery across the nail plate. This work aimed to evaluate the effect of chemical and physical enhancers on the accumulation and permeation of amorolfine hydrochloride through human nail clippings. Polymeric nail lacquers with Eudragit E100 were developed as a potentially suitable delivery system for amorolfine hydrochloride. Incorporating thioglycolic acid and urea into formulations provided increased accumulation of antifungal agent in nail layers of up to 100% and 57%, respectively. Structural changes of nail barrier, induced by fractional CO₂ laser, were visualized by microscopy. The permeation of amorolfine hydrochloride through the nail increased twofold when thioglycolic acid-containing formulation was applied and the nail was pretreated with a fractional CO₂ laser. The results suggest that this novel combination of enhancers has the potential to be an effective option for topical drug delivery through the nail, and increased the efficacy of treatment.

Effect on Nail Structure and Transungual Permeability of the Ethanol and Poloxamer Ratio from Cyclodextrin-Soluble Polypseudorotaxanes Based Nail Lacquer

Aqueous-based nail lacquers have shown potential in promoting the diffusion of drugs into the nail. In our laboratory, we have recently developed a transungual delivery system based on an aqueous dispersion of cyclodextrin-poloxamer soluble polypseudorotaxanes, supramolecular host−guest assemblies that improves the drug permeation into the nail. However, the high-water content and the rheological and adhesive properties of this lacquer negatively affect properties that play a fundamental role in the patients’ acceptance such as stickiness, nail film formation or drying rate, properties. In this work, we have optimized the composition of these lacquers to improve these properties whilst maintaining good drug permeation profiles. Incorporating ethanol into the vehicle and reducing the proportion of Poloxamer 407 (PL), provided a good strategy. The use of hydro-ethanolic mixtures (>50% ethanol) and the reduction of the poloxamer concentration significantly improved the lacquer drying speed by reducing the stickiness and promoting film formation on the nail surface. Additionally, in a surprising way, the use of hydro-ethanolic vehicles further enhanced the permeation of ciclopirox olamine and clobetasol propionate, used for the treatment of onychomycosis and nail psoriasis respectively, into the nail and hooves.

Electrically and Ultrasonically Enhanced Transdermal Delivery of Methotrexate

In this study, we used sonophoresis and iontophoresis to enhance the in vitro delivery of methotrexate through human cadaver skin. Iontophoresis was applied for 60 min at a 0.4 mA/sq·cm current density, while low-frequency sonophoresis was applied at a 20 kHz frequency (2 min application, and 6.9 W/sq·cm intensity). The treated skin was characterized by dye binding, transepidermal water loss, skin electrical resistance, and skin temperature measurement. Both sonophoresis and iontophoresis resulted in a significant reduction in skin electrical resistance as well as a marked increase in transepidermal water loss value (p < 0.05). Furthermore, the ultrasonic waves resulted in a significant increase in skin temperature (p < 0.05). In permeation studies, the use of iontophoresis led to a significantly higher drug permeability than the untreated group (n = 4, p < 0.05). The skin became markedly more permeable to methotrexate after the treatment by sonophoresis than by iontophoresis (p < 0.01). A synergistic effect for the combined application of sonophoresis and iontophoresis was also observed. Drug distribution in the skin layers revealed a significantly higher level of methotrexate in the sonicated skin than that in iontophoresis and untreated groups. Iontophoresis and low-frequency sonophoresis were found to enhance the transdermal and intradermal delivery of methotrexate in vitro.