[Preparation and electron microscopic observation of lidocaine microemulsion].
OBJECTIVE
To prepare and determine the proportion of the components of lidocaine microemulsion.


METHODS
Pseudoternary phase diagrams of the prepared lidocaine microemulsion with different Km (surfactant/cosurfactant) were generated to determine the optimal Km according to the size of the microemulsion area. The diameter and its distribution range, viscosity, electric conductivity and refractivity of lidocaine microemulsion drop was determined, and the appearance and system type of the microemulsion was observed using electron microscope. RESULTS; Maximum microemulsion area in the pseudoternary phase diagrams was obtained with the Km of 3, and the drop size of the microemulsion averaged 29.8+/-14.4 nm (with up to 98% of the drop size ranging between 15.1-45.5 nm and 2% between 77.9-261.3 nm). At 25 degrees C, the viscosity, electric conductivity and refractivity of the microemulsion was 25 mPa.S, 130 micros/cm and 1.473, respectively, and the lidocaine microemulsion was identified to belong to O/W type. The microemulsion drop appeared in spherical shape of heterogeneous sizes in a multi-disperse system.


CONCLUSIONS
The optimal proportion of the components in lidocaine microemulsion can be obtained by analyzing pseudoternary phase diagrams, and the drop size, distribution, shape and system type can be determined or observed through Maerwen Zetasizer combined with electron microscopic observation.
Zhu
Xiao-liang
XL
Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. zxl@fimmu.com
Chen
Zhi-liang
ZL
Li
Guo-feng
GF
Zeng
Kang
K
D045703:Emulsifying Agents / Q000138:chemical synthesis*; D004655:Emulsions; D008012:Lidocaine; D046529:Microscopy, Electron, Transmission; D013501:Surface-Active Agents / Q000737:chemistry
D045703:Emulsifying Agents; D004655:Emulsions; D013501:Surface-Active Agents; D008012:Lidocaine