Transungual permeation: current insights

In Silico Drug Screening Based Development of Novel Formulations for Onychomycosis Management

Onychomycosis is a prominent fungal infection that causes discoloration, thickening, and mutilation leading to the separation of the nail from the nail bed. Treatment modalities for onychomycosis may include oral, topical, or combination therapy with antifungals and at times may require chemical or surgical intervention. The burden of side effects of antifungals is enormous, and therefore using molecular docking-based drug selection in context with the target keratin protein would ensure better disease management. Ciclopirox, Amorolfine HCl, Efinaconazole, Tioconazole, and Tavaborole were submitted for assessment, revealing that Amorolfine HCl is the best fit. Consequently, two formulations (Nail lacquer and nanoemulgel) were developed from Amorolfine HCl to validate the in silico screening outcomes. The formulations were further fortified with over-the-counter ingredients vis-a-vis with vitamin E in nail lacquer and undecylenic acid in nanoemulgel for their prominent roles in improving nail health. Both the formulations were systematically designed, optimized, and characterized. Amorolfine HCl containing nanoemulgel (NEG) was developed using undecylenic acid as an oil phase and thioglycolic acid as a penetration enhancer. The quality parameters evaluated were particle size, the zeta potential for nanoemulsion (NE) (78.04 ± 4.724 nm and −0.7mV, respectively), in vitro cumulative drug release (96.74% for NE and 88.54% for NEG), and transungual permeation (about 73.49% for NEG and 54.81% for NE). Nail lacquer was evaluated for the drying time, non-volatile content, and blush test. In vitro cumulative drug release of the developed nail lacquer and comparator marketed formulations were around 81.5% and 75%, respectively. Similarly, the transungual drug permeation was 6.32 μg/cm² and 5.89 μg/cm², respectively, in 24 h. The in silico guided preparation of both formulations containing Amorolfine HCl and over the counter ingredients is amenable for therapeutic use against onychomycosis and will be evaluated in the in vivo model.

Mechanistic Insights of Formulation Approaches for the Treatment of Nail Infection: Conventional and Novel Drug Delivery Approaches

Onychomycosis is a chronic disorder that is difficult to manage and hard to eradicate with perilous trends to relapse. Due to increased prevalence of HIV, use of immunosuppressant drugs and lifestyle-related factors, population affected with fungal infection of nail (Onychomycosis) happens to increase extensively in last two decades. Modalities available for the treatment of onychomycosis include systemically administered antifungals, mechanical procedures, and topical drug therapy. But the efficacy of the most of approaches to deliver drug at targeted site, i.e., deep-seated infected nail bed is limited due to compact and highly keratinized nail structure. A series of advanced formulation approaches, such as transfersomes, liposomes, nano/micro emulsion, nail lacquers etc., have been attempted to improve the drug penetration into nail plate more efficiently. The manuscript reviews these formulation approaches with their possible mechanisms by which they improve the drug penetration.Comparative analysis of available treatment modalities for onychomycosis has been provided with pros and cons of each alternatives. Additionally, ongoing research about the application of biological materials such as modified cationic antimicrobial peptides (AMPs), plant-derived proteins, and synthetic antimicrobial peptidomimetics have also been explored.

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.