Water/oil type microemulsion systems containing lidocaine hydrochloride: in vitro and in vivo evaluation.
The purpose of this study was to develop a water/oil microemulsion containing lidocaine hydrochloride (4%) and to compare its local anaesthetic efficacy with commercial products. A pseudoternary diagram (Km:1/1 or 1/2) was constructed using lecithin/ethanol/oil/water. The droplet size, viscosity and release of the microemulsions were evaluated. Tail flick tests were conducted for in vivo effectiveness; the initiation time of effect, maximum effect, time to reach maximum effect, and relative efficacy were evaluated. The drug caused a significant increase in droplet size. The use of olive oil resulted in a decrease in the solubilisation parameter, as well as a reduction in the release. The droplet size and viscosity of the microemulsion composed of Miglyol/lecithin/ethanol/water/drug (Km:1/2) was lower than other microemulsions (8.38 nm, 6.9 mPa), and its release rate (1.61 mg/h) was higher. This system had a faster and more efficient anaesthetic effect than the other microemulsions and commercial products. Results indicate that a water/oil type microemulsion (Miglyol/lecithin/ethanol/water) has promising potential to increase the local anaesthetic effect.
Department of Medical Pharmacology, Gülhane Military Academy of Medicine (GATA) , Ankara , Turkey and.
Ahmet
A
Dogrul
Seyda Akkus
SA
Arslan
Figen
F
Tirnaksiz
D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000494:pharmacology*; D000818:Animals; D004655:Emulsions / Q000737:chemistry*; D008012:Lidocaine / Q000008:administration & dosage* / Q000494:pharmacology*; D051379:Mice; D000069463:Olive Oil; D014677:Pharmaceutical Vehicles / Q000737:chemistry*; D044367:Phase Transition; D010938:Plant Oils / Q000737:chemistry; D014783:Viscosity
D000779:Anesthetics, Local; D004655:Emulsions; D000069463:Olive Oil; D014677:Pharmaceutical Vehicles; D010938:Plant Oils; D008012:Lidocaine
Local anaesthetic activity; miglyol 818; olive oil; tail flick test