Preparation and evaluation of DEET-ethylcellulose microsphere / 第二军医大学学报

ABSTRACT

Objective:To prepare DEET-ethylcellulose microsphere(DEET-EC) and observe its properties to retard volatilization of DEET. Methods: DEET-EC was prepared with solvent evaporation method. DEET was dissolved in CH 2Cl 2 with EC served as dispersed phase and 1% PVA water solution as continuous phase. The dispersed phase was added into the continuous phase with stirring rate at 1 000 r/min. The stirring rate was changed into 600 r/min after 30 min, and was kept until CH 2Cl 2 was entirely volatilized. After being watered, precipitated and lyophilized for 12 h, DEET-EC was derived, and the shape was observed with electron microscope. The particle size distribution was detected in 500 microspheres with optical microscope. HPLC method was established to determine the embedding ratio and loaded ratio of DEET-EC microsphere. Chromatograph conditions: Diamonsil ODS column (150 mm?4.6 mm), CH 3OH∶H 2O=65∶35 as mobile phase at 1 ml/min, the detected wavelength 210 nm. Results: The DEET-EC was egg-white and had spherical shape. Almost 90% of the MS distributed in 30-70 ?m, while ( ar ) and ( v ) were 49.6 ?m and 51.2 ?m, respectively. The loading ratio was 18.7% and the embedding ratio was 56.1%(n=6). Conclusion: The solvent evaporation method is convenient and simple to prepare DEET-EC microsphere.