An alternative choice of lidocaine-loaded liposomes: lidocaine-loaded lipid–polymer hybrid nanoparticles for local anesthetic therapy

The skin permeation enhancement of local anesthetics by newer innovative nanotechnologies has been an appealing field recently. However, which nanocarrier is better for drug loading and has better stability? Therefore, the aim of our study was to compare two kinds of nanocarriers: liposomes and lipid-polymer hybrid nanoparticles (LPNs) for lidocaine (LA) delivery.LA-loaded liposomes (LA-LPs) and LPNs (LA-LPNs) were prepared. Two kinds of nanocarriers were characterized in terms of particle size, zeta potential, drug encapsulation efficiency (EE), drug release, and stability. Their in vitro skin permeation was studied using a Franz diffusion cell mounted with depilated mouse skin in vitro. In vivo local anesthetic effects of LA containing formulations were evaluated by tail flick latency (TFL) test using a tail-flick measuring device.Compared with LA-LPs, LA-LPNs showed significantly better in vitro skin permeation ability and in vivo local anesthetic effects.The results demonstrated that LPNs could improve the efficacy of drugs to higher levels than LPs and free drugs, thus could serve as an effective drug system for LA loading for local anesthetic therapy.