Strategies for delivering local anesthetics to the skin: focus on liposomes, solid lipid nanoparticles, hydrogels and patches.
BACKGROUND
Dermal and transdermal drug delivery systems offer the possibility to control the release of the drug for an extended period of time. In particular, skin-delivery of local anesthetics (LA) is one of the most important strategies to increase the local drug concentration and to reduce systemic adverse reactions.


METHODS
During the development phase of new formulations for skin-delivery of LA one should consider a set of desirable features such providing suitable adhesion, easy application/removal and also to be biocompatible, biodegradable and non-toxic. This review emphasizes the main strategies for skin-delivery of LA considering those features in relation to the composition of the delivery systems described. The topics highlight the relationships between physico-chemical studies and pharmaceutical applications for liposomes and solid lipid nanoparticles as well as the formulation and clinical applications for hydrogels and patches.


CONCLUSIONS
The development of LA skin-delivery systems using hydrogels and different permeation enhancers, liposomes or lipid nanoparticles (as isolated carrier systems or as their dispersion in a gel-base) and patches have been explored as alternatives to commercial formulations, modifying the release rate of LA, increasing bioadhesive properties and reducing toxicity, resulting in an improved therapeutic efficacy. This review should provide to the reader a special emphasis on four delivery-systems, comprising the group of liposomes and lipid nanoparticles, hydrogels and patches technologies looking forward their application for skin anesthesia.
ABC Federal University, Natural and Human Science Center , Av dos Estados 5001 Bloco A, Torre 3, Sala 624-3, Santo André, 09210-580 , Brazil draraujo2008@gmail.com, daniele.araujo@ufabc.edu.br.
Daniele R
DR
de Araújo
Deyse C
DC
da Silva
Raquel M
RM
Barbosa
Michelle
M
Franz-Montan
Cíntia M S
CM
Cereda
Cristina
C
Padula
Patrizia
P
Santi
Eneida
E
de Paula
D000279:Administration, Cutaneous; D000772:Anesthesia, Local / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000737:chemistry; D000818:Animals; D002626:Chemistry, Pharmaceutical; D016503:Drug Delivery Systems; D005782:Gels / Q000737:chemistry; D006801:Humans; D020100:Hydrogels / Q000008:administration & dosage; D008055:Lipids / Q000008:administration & dosage / Q000737:chemistry; D053758:Nanoparticles / Q000008:administration & dosage; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000737:chemistry; D012867:Skin
D000779:Anesthetics, Local; D005782:Gels; D020100:Hydrogels; D008055:Lipids; D004364:Pharmaceutical Preparations