This work describes the development of poly-ε-caprolactone nanocapsules (PCL-NC) and solid lipid nanoparticles (SLN) aiming delivery for articaine (ATC), in order to improve its chemical stability in semi-solid preparations looking forward their use for skin delivery. The nanoparticles were characterized by size, polydispersity index, and pH. Cellular viability was evaluated using the MTT test and the in vitro release kinetics was determined using a two-compartment model. The hydrogels with nanoparticle suspensions were characterized considering their rheological aspects and in vitro permeation across artificial membranes. Colloidal stability was satisfactory, since the formulations did not present major alterations during 120 days. High ATC encapsulation was achieved (78% for PCL-NC and 65% for SLN). The release profile of PCL-NC-ATC was slower, compared to the free molecule and SLN-ATC. MTT experiments showed the nanosystems were capable to increase cellular viability compared with free ATC. The hydrogels showed good consistency, homogeneity, and stability and presented pseudoplastic behavior with thixotropy, improving drug efficacy in clinical applications. The gel based on PCL-NC showed faster onset of activity and flux of 35.68 ± 1.98 μg/cm2/h, which then continued for up to 8 h. This study opens up prospects for employment of nanoparticulate systems for modified release of ATC.

Topical anesthetics are widely applied in order to relieve the discomfort and anxiety caused by needle insertion and other painful superficial interventions at the oral cavity. So far, there are no commercially available effective topical anesthetic formulations for that purpose, and the most of developments are related to hydrophilic and low mucoadhesive forms. Therefore, we have prepared different hybrid nanofilms composed of biopolymer matrices (chitosan, pectin, and chitosan-pectin) blended with nanostructured lipid carriers (NLC) loading the eutectic mixture of 5% lidocaineprilocaine (LDC-PLC), in order to fulfill this gap in the market. These dual systems were processed as hybrid nanofilms by the solvent/casting method, and its mucoadhesive, structural and mechanical properties were detailed. The most appropriate hybrid nanofilm combined the advantages of both pectin (PCT) and NLC components. The resultant material presented sustained LDC-PLC release profile for more than 8 h; permeation across porcine buccal mucosa almost twice higher than control and non-cytotoxicity against 3T3 and HACAT cell lines. Then, the in vivo efficacy of PCT/ NLC formulation was compared to biopolymer film and commercial drug, exhibiting the longestlasting anesthetic effect (> 7 h), assessed by tail flick test in mice. These pectin-based hybrid nanofilms open perspectives for clinical trials and applications beyond Dentistry.

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