[Study and evaluation of preparation of silybin PLGA microspheres by stainless steel membrane emulsification technique].

OBJECTIVE: The aim of the present study was to prepare uniform-sized silybin loaded poly (lactic-co-glycolic acid) (PLGA) microspheres in study of silybin with stainless steel membrane. METHOD: Silybin PLGA microspheres were prepared by stainless steel membrane emulsification. The preparation conditions were optimized by single-factor test and orthogonal experiment, and evaluating the mean diameters, the particle size distribution, drug loading, entrapment efficiency and morphology of microsphere. RESULT: Prepared microspheres were round and surface was smooth. The mean diameter was (4.961 +/- 0.56) microm. The span was (1.75 +/- 0.18). The entrapment efficiency was (54.997 +/- 4.05)% and the average drug loading was (23.6 +/- 1.70)%. CONCLUSION: The stainless steel membrane emulsification can be used to prepare the silybin PLGA microspheres. The mean diameters of the silybin PLGA microspheres can be controlled in certain level. Stainless steel membrane emulsification has great potentiality exploitation and utilization.

Effects of light curing modes and ethanol-wet bonding on dentin bonding properties.

OBJECTIVE: This study explored the effects of different light curing modes and ethanol-wet bonding on dentin bonding strength and durability. METHODS: A total of 54 molars were randomly divided into three groups: Single Bond 2, Gluma Comfort Bond, and N-Bond. Based on the three light-curing modes and presence or absence of ethanol pretreatment, the samples were assigned to six subgroups: high-light mode, ethanol pretreatment+high-light mode, soft-start mode, ethanol pretreatment+soft-start mode, standard mode, and ethanol pretreatment+standard mode. All samples were bonded with resin based on the experimental groups. After 24 h and 6 months of water storage, a universal testing machine was used to measure microtensile bond strength. Scanning electron microscopy (SEM) was applied to observe mixed layer morphology. RESULTS: The 24-h and 6-month microtensile bond strengths of the ethanol pretreatment groups were significantly higher than those of the non-ethanol pretreatment groups at the same light modes (P<0.05). With or without ethanol pretreatment, the microtensile bond strengths of the high-light modes were significantly lower than those of the soft-start modes and standard modes (P<0.05). The microtensile bond strengths of samples from the 6-month water storage group significantly decreased compared with those of samples from the 24-h water storage group (P<0.05). The soft-start groups and standard groups formed better mixed layers than the high-light mode groups, whereas the ethanol pretreatment groups formed more uniform mixed layers than those without ethanol pretreatment. CONCLUSIONS: Ethanol-wet bonding technique, soft-start, and standard modes could improve dentin bonding properties.