ABSTRACT
Enteric-soluble soft capsule is a kind of new preparation that does not disintegrate in the stomach ，but releases rapidly in the intestinal tract to play a pharmacodynamic role. It has the unique advantages of improving drug stability ，reducing drug irritation ，delivering drugs directionally to the intestinal tract ，and prolonging drug action time. In this paper ，the decomposition and release mechanism ，application advantages ，classification of enteric-soluble coating materials and preparation methods of enteric-soluble soft capsule are sorted and summarized ，in order to provide reference for further development of this type of preparation.
ABSTRACT
Objective:To compare the durability of resin-based root-surface coating material and all-in-one self-etching adhesive on root surface in vitro.Methods:Human extracted premolars or molars with intact roots were selected.The cementum was removed using a periodontal scaler to expose root dentin. The root surface was coated with an acid-resistant nail varnish,leaving a window of 3 mm ×3 mm on the exposed dentin.The window was covered with either PRG Barrier Coat (PRG)or Clearfil S3 Bond (CS3).After water aging for 14 d,specimens were immersed in acid buffer at pH 4.5 for 4 d and the demineralization buffer was changed every 24 h.Then the specimen was split longitudinally through the center of the ‘window’and the cross-sectional surface was observed with scanning electron microscope (SEM).After fixed and dehydrated,the prepared samples were coated with platinum.The coating mate-rial,root dentin and the interface was observed by scanning electron microscope (SEM).The thickness of the coating material was measured on the SEMimages.Regarding toothbrush wear test,coronal dentin-disks were prepared and covered with PRG and CS3,respectively.After storage in water for 24 h,the specimen was subjected to the toothbrush wear tester for 100,200,300,500,700,1 500 brushing cy-cles.A slurry of fluoride toothpaste (1 ∶2 ratio of toothpaste and deionized water by weight)was used and the brushing load was 300 N.The surface microstructure of remaining coating material was analyzed using SEM.The wear depths were determined by a profilometer.Statistical analysis was performed with SPSS 20.0 by one-way ANOVA.The level of significance was at 0.05.Results:Application of PRG Barrier Coat produced a coating layer of (47.1 ±27.3)μm,while CS3 presented a thin film of (5.7 ± 2.1)μm in thickness.The exposed dentin was hermetically sealed and no obvious gap was observed at the interface in both PRG and CS3 groups.There was no dentin demineralization observed in both groups after water aging.The wear depths of PRG and CS3 increased along with the numbers of brushing cycles. PRG wore at a significant lower pace than CS3 did (P <0.05).Conclusion:PRG coating resin had similar performances as CS3 on protecting root dentin from demineralization after water aging.What’s more,PRG demonstrated a higher toothbrush wear resistance than CS3.We concluded that PRG Barrier Coat contained S-PRG filler may be an effective coating material for protecting exposed root from both chemical and mechanical challenges.Further studies should be carried out to evaluate the long-term reli-ability of the rootsurface coating materials under the clinical setting.
ABSTRACT
Levan was used as agent in the synthesis of new colon-specific polymeric matrix together with Eudragit® FS 30 D. Eudragit® FS 30 D films incorporated with levan were made by casting process and characterized to: water vapour transmission, sweeling index, differential scanning calorimetry and thermogravimetric. The levan increased the films permeability (p < 0.001) however did not influenced in the sweeling index of the formulations (p > 0.05). The thermal analyses of the films indicated a glass transition temperature approximate at 47°C and thermal decomposition at 400°C. The results indicated that there is potential for using such site-specificity blend as pharmaceutical coating material.
Levana foi utilizada na síntese de novo material polimérico cólon-específico conjuntamente com o Eudragit® FS 30 D. Filmes de Eudragit® FS 30 D aditivados de levana foram feitos pelo método de "casting process" e caracterizados quanto à transmissão de vapor de água, índice de intumescimento, calorimetria diferencial de varredura e termogravimetria. A levana aumentou a permeabilidade dos filmes (p < 0,001), entretanto não influenciou no índice de intumescimento das formulações (p > 0,05). As análises térmicas dos filmes indicaram uma temperatura de transição vítrea aproximada de 47°C e temperatura de decomposição de 400°C. Os resultados indicaram que há potencial de uso desta nova blenda sítio-específica como material de revestimento farmacêutico.
Subject(s)
ColonABSTRACT
PURPOSE: To investigate the effect of coating material in RF coil, which is one of main parts in MRI machine, on the Q-factor and SNR(signal-to-noise ratio) in MR images. MATERIALS AND METHODS: RF coils with inner diameter of 1.7 mm were made by using copper wires coated with polyester, polyurethane, polyimide, polyamideimide, and polyester-imide, and by using copper wires in which coating materials had been removed. Q-factors of the RF coils were measured by network analyzer, and SNR values in the spin-echo MR images obtained by 600 MHz (14.1 T, Bruker DMX600) micro-imaging system for the coated and uncoated cases. RESULTS: The measured SNRs were almost same for the RF coils with coat-removed copper wires, however SNRs and Q-factors were different for the coated cases depending on the coating material. They were maximized in the polyurethane-coated case in which the SNR was >30% greater than polyester-coated case. CONCLUSION: We made solenoid-type RF coils which were easily used for MR micro-imaging in Bruker MRI probe. There was a significant coating-material dependence in the measured Q values and SNRs for the home-made RF coils. The study demonstrated that the choice of coating material of RF coil may be a critical factor in the MRI sensitivity based on SNR value.