ABSTRACT
Objective: To prepare poly-n-butylcyanoacrylate (PBCA) nanoparticles entrapped a Chinese medicine monomer of bufalin. Methods: Alcohol polymerization method was adopted to prepare bufalin PBCA nanoparticles and the preparation process was optimized by single factor experiment and orthogonal test design, while size distribution, morphology, encapsulation efficiency (EE), drug loading and hemolytic of the prepared nanoparticles were systemly analyzed. Results: The obtained nanoparticles were regular in shape with average particle size of (151.2 ± 6.1) nm, as well as a poly-dispersity index of 0.133 ± 0.024. The Zeta potential and EE of bufalin PBCA nanoparticles were (-7.09 ± 0.58) mV and (70.812 ± 6.139)%, respectively. Drug loading of PBCA nanoparticles is (1.990 ± 0.291)%. Moreover, less hemolysis and improved safety were appeared in the formulation group, comparing with the bulk drug group. Conclusion: Alcohol polymerization method, a method to prepare PBCA nanoparticles which exhibites good physical and chemical properties, can effectively reduce the exposure time of the Chinese medicine monomer in the acidic media. It may provide a new idea for the preparation of nanocarrier of easily hydrolyzed monomer.
ABSTRACT
O objetivo do presente estudo é comparar e avaliar a microdureza Vickers de um compósito restaurador microhíbrido ativado por dois tipos de unidades polimerizadoras e armazenados em água destilada. Trinta espécimes foram feitos com resina Charisma B1, para cada um dos regimes de polimerização: fotopolimerização por luz halógena, fotopolimerização por LED e fotopolimerização mais ciclo adicional em autoclave. Foram feitas duas leituras de microdureza Vickers por corpo de prova em 1 dia, 7 dias e 14 dias de imersões. O ciclo adicional de polimerização mostrou uma tendência de aumentar os valores de microdureza dos compósitos restauradores, não mostrando diferenças estatisticamente significantes entre LED e Luz Halógena (p > 0,05).
The purpose of this study is to evaluate and compare the Vickers microhardness of one microhybrid composite polymerized with different sources and stored in distilled water for up to 14 days. Thirty samples have been prepared with Charisma composite, shade B1, for each polymerization method: halogen light photopolymerization, LED photopolymerization, photopolymerization plus post-cured cycles in autoclave. Two readings of Vichers micro hardness have been done in each sample on 24h, 7days and 14 days of storage. The post curing method tended to improve the microhardness, but it was not statistically different from halogen or LED curing methods (p > 0.05). After 7 days, the hardness values were higher than the first day, but statistically not different to 14 days (p < 0.05). Post-cured samples in autoclave had an improved mean value, however, without differing from those of the LED and halogen.