Development of novel microemulsion-based hydrogel for topical delivery of sinomenium

The objective of the present investigation was to develop and evaluate microemulsion-based hydrogel (MBH) for the topical delivery of sinomenium. The solubility of sinomenium in oils and surfactants was evaluated to identify components of the microemulsion, the pseudo-ternary phase diagrams were developed to identify the area of microemulsion existence and obtain the optimization Km (the weight ratio of surfactant to cosurfactant). The transdermal ability of various microemulsion formulations were evaluated in vitro using Franz diffusion cells fitted with rat skins and sinomenium was analyzed by HPLC. The permeation of microemulsions accorded with the Fick’s first diffusion law and the optimal formulation of the microemulsion was obtained. The MBH formulation containing 2 % sinomenium was prepared with Carbomer 940 as the gelling matrix. Stability test showed that MBH stored at 4°C and 25 °C for 3 months had no significant change in physicochemical properties. Pharmacokinetic study in vivo was conducted using rabbits, and the area under curve of plasma concentration-time (AUC0→∞) of MBH was 1.27 times greater than that of the hydrogel. These results indicated that MBH might be a promising vehicle for the transdermal delivery of sinomenium.Colegio de Farmacéuticos de la Provincia de Buenos Aire

A Nonlinear Microseismic Source Location Method Based on Simplex Method and Its Residual Analysis

Source location is one of the most valuable features of the microseismic technique due to its ability to delineate the unstable areas. In this paper, the precise formulas of the station residual and event residual are derived for the L1 norm statistical standard and the L2 norm statistical standard based on the residual analysis. Then, the error space for microseismic source location is proposed and analyzed. Based on the above research, a nonlinear microseismic source location method using the Simplex method is developed. This new method can search the microseismic source directly in the error space through four deformations of the simplex figures, and it is able to make use of both P-wave and S-wave velocities. Finally, the performance of the Simplex microseismic source location method is tested and verified by laboratory experiments. Test results show that the Simplex microseismic source location method can improve the accuracy and stability of the source location greatly when P-wave and S-wave velocities are involved simultaneously and correctly. The results also demonstrate that the L1 norm statistical standard always provides more accurate and reliable solutions than the L2 norm statistical standard when there are some major but isolated errors in the input data. However, none of the optimization methods are able to function when the errors in the input data are systematic and extreme, which indicates that an early detection and correction of these errors is of primary importance for microseismic source location