A Note on the Current Status of the Trans-ungual Delivery of Poorly Soluble Drugs at a Glance: Formulation Perspective

The Trans ungual drug delivery (TUDD) system involves the delivery of drugs through the hard keratinized nail plate. Topical treatment is ideal for treating nail diseases because it has localized effects, resulting in fewer systemic side effects and perhaps better adherence. Conventional formulations have failed to promote nail adhesion and medication absorption due to the nail's highly keratinized hydrophilic nature, which obstructs drug absorption. Systemic therapy has several side effects and a high rate of recurrence, whereas surgery is painful and invasive. As a result, there is a definite need to design an efficient TUDD system that allows antifungals to penetrate the nail and reach the infection site at a sufficient concentration and for a longer period of action to eliminate the infection. The system also avoids the oral toxicity of drugs. Several techniques, including physical, chemical, and mechanical, are employed to increase medication penetration over the nail plate. To increase nail adherence, therapeutic action, and bioavailability, several innovative formulation techniques are being researched, including the use of penetration enhancers in traditional dosage forms (gel, solution), novel dosage forms such as films, nail lacquer, and nanotechnology.