Nanomicelles-in-coaxial nanofibers with exit channels as a transdermal delivery platform for smoking cessation

Smoking is a life-threatening habit; that is why many nicotine-replacement therapies (NRTs), which include chewing gums, nicotine patches, lozenges, mouth sprays, inhalers and nasal sprays that are usually administered for 8-12 weeks, have been reported for smoking cessation. We report the fabrication of patches comprising nanomicelles-in-coaxial nanofibers (NFs) for the transdermal delivery of varenicline (VAR) tartrate, a partial agonist of the α4β2 receptor subtype, for smoking cessation. The cores of the fabricated coaxial NF structures are composed of polyethylene oxide, VAR-loaded Pluronic F127 nanomicelles (NPs) and free VAR, while the shell consists of a blend of cellulose acetate (CA) and polycaprolactone (PCL) in a ratio of 1 : 9 (w/w) that incorporates 50% (wt%) free VAR. The morphology and the coaxial structure of the NFs were investigated using TEM, SEM and fluorescent microscopy. The physicochemical and mechanical properties of the scaffolds were analyzed using FTIR, DSC, DLS, TGA and a universal testing machine. SEM micrographs depict NFs with a size ranging from 793.7 ± 518.9 to 324.5 ± 144.1 nm. In vitro release of VAR reaches almost 100% after 3, 9 and 28 days for free VAR, VAR-loaded NPs and the NPs-in-NFs patches, respectively, while the ex vivo release tested using albino rat skin, over a period of 60 days, showed up to 94% sustained release of VAR. Besides, skin permeation, in vivo release and plasma concentrations of VAR from the NF transdermal patches were monitored via cyclic voltammetric measurements during the course of treatment. DFT calculations as well as mathematical release kinetic models were performed in order to study the release mechanism. The cell viability of human skin fibroblast (HSF) cells in the case of plain and VAR-loaded NFs was 75.09 and 32.11%, respectively. The in vivo results showed that VAR was being continuously released from the transdermal patch over a period of 14 days. Besides, the treatment with VAR-loaded patches did not cause any severe conditions in the studied animal model. The new fabricated NPs-in-NFs transdermal patch for VAR tartrate delivery is considered as an effective, economic, safe and long-acting NRT for smoking cessation.