ABSTRACT
OBJECTIVE：To prepare Brevisc apine（BRE） nanocrystals，and to evaluate its quality. METHODS ：BRE nanocrystal suspensions were prepared by media milling method. The diameter and amount of grinding beads ，grinding time ，type and ratio of stabilizer ，BRE ratio were investigated to screen the optimal technology and formulation with particle size and polydispersity index （PDI） as evaluation indexes. Using morphology ，color，particle size and PDI of BRE nanocrystals as evaluation index ，different lyoprotectants （50％ mannitol，5％ glucose，5％ lactose）and without lyoprotectant were investigated to screen the optimal lyoprotectant. Particle size analyzer ，scanning electron microscope （SEM），X-Ray diffraction （XRPD）， differential scanning calorimeter （DSC）were used to evaluate the quality of BRE nanocrystals which was prepared with the optimal technology and formulation. RESULTS ：The optimal technology and formulation of BRE nanocrystals included that particle size of 0.6 mm zirconia beads with the amount of 450 g，grinding time of 1 h，stabilizer of 15％ Tween-80，BRE ratio of 25％，without lyoprotectant. Prepared BRE nanocrystals were yellow powder with loose texture and uniform color. The average particle size of BRE nanocrystals was （283.10±3.08）nm，average PDI was （0.212±0.021）and average Zeta potential was （－38.48±0.39）mV. BRE nanocrystals were rod-like crystals ，uniform in distribution and had no change in crystalline state. Accumulative dissolution of BRE nanocrystals were （90.37±1.22）％ within 20 min. Under the condition of （40±2）℃ temperature and （75±5）％ relative humidity，BRE nanocrystals remained stable after being kept away from light for 3 months. CONCLUSIONS ：Established preparation method of BRE nanocrystals is simple and feasible. Prepared BRE nanocrystals show good stablility and dissolution.
ABSTRACT
Objective:To prepare capsaicin liposomes and study the feasibility by in vitro percutaneous penetration test. Meth-ods:Capsaicin liposomes were prepared by a film-ultrasonic method. The best formula was screened by orthogonal test based on single factor studies with the entrapment efficiency as the index. The improved Franz diffusion cells were used to study the transdermal pene-tration of capsaicin suspensions, capsaicin liposomes and capsaicin ointments, and the cumulative penetration amount through the isola-ted rat skin was compared. Results:The optimal formula of capsaicin liposomes were as follows:the ratio of capsaicin to lipids was 1∶5;the amount of Tween-80 was 100 mg;the amount of vitamin E was 50 mg;10 ml dichloromethane was used as the solvent. The op-timal pH value of the external phase was 6. 5 with the volume of 10 ml. The ultrasonic time was 8 min. The order of 12-hour cumulative penetration amount was capsaicin liposomes>capsaicin-PBS suspensions>capsaicin ointments. Capsaicin liposomes had the highest 12-hour cumulative penetration amount and showed obvious sustained-release property. Conclusion:Capsaicin liposomes have high en-trapment efficiency, good percutaneous penetration and sustained-release property, and the preparation technology is simple.