Please confirm that an ethics committee approval has been applied for or granted: Not relevant

Background and Aims Chronic pain affect over a third of the global population aged 25 and older. Regardless of its etiology, it adversely impacts all aspects of life, leading to decreased productivity and diminished overall well-being. The available systemic treatments are effective but exhibit significant adverse reactions with long-term use. Conversely, local treatments demonstrate limited duration of effectiveness, necessitating frequent reapplication. Lidocaine is recognized as an effective local anesthetic; however, it also possesses an analgesic effect with a central mechanism that remains poorly understood. Additionally, Cannabidiol has demonstrated analgesic properties through both local application and systemic use.

Methods To combine the proven effectiveness of both substances, we developed beta-cyclodextrin encapsulated nanoparticles containing lidocaine and CBD. These nanoparticles were incorporated into a gel base for local application. The formulation was tested in vitro using a Franz Cell system and synthetic membranes. The diffusion medium was analyzed to quantify the amounts of both substances that passed through the membranes at 1, 2, and 24 hours using ultraviolet-visible (UV-VIS) spectrophotometry.

Results The results showed that lidocaine diffused through the membranes primarily within the first two hours, whereas CBD exhibited a significant diffusion rate between 2 and 24 hours.

Conclusions With just one topical application, the developed formulation could produce long-lasting analgesic effects for up to 24 hours. This formulation has the potential to act as an alternative for a controlled-release transdermal device, a topical product requiring frequent administration, or a systemic pain reliever.