Comparison study of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres

To compare two microspheres of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin loaded theophylline as pulmonary sustained drug delivery carriers, the characteristics and ciliotoxicity were studied. The drug loadings of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres were 21.09% and 21.42%, and the encapsulation efficiencies were 91.40% and 92.80%. The distributions of 50% (d _0.5) of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres were 4.89 and 5.83 μm, respectively. Both microspheres showed spherical shape with smooth or wrinkled surfaces. FT-IR of chitosan/β-cyclodextrin microspheres demonstrated that theophylline had formed hydrogen bonds with chitosan and β-cyclodextrin, while for the carboxymethyl chitosan/β-cyclodextrin microspheres theophylline had interaction with carboxymethyl chitosan. The moisture absorption showed that an equilibrium was reached within 24 h. The two microspheres possessed better adaptability. In vitro release of theophylline from chitosan/β-cyclodextrin microspheres was slower than that from carboxymethyl chitosan/β-cyclodextrin microspheres at pH 6.8. Biography: LI Ruobao(1968–), male, Associate professor, research direction: foundation research of respiratory system.     

茶碱对美味侧耳胞外多酚氧化酶和纤维素酶活性的影响

本文以美味侧耳为实验菌研究了茶碱对胞外多酚氧化酶和纤维素酶活性的影响.多酚氧化酶活性测定是用邻甲氧基苯酚为底物,用分光光度法测定.纤维素酶活性测定是以微晶纤维素和 CMC 为底物,用 DNS 法测定还原糖生成量.结果表明:当棉子壳培养基中茶碱浓度为0.5～2ppm 时,酶活提高极为显著,这一结果与茶碱促进菌丝生长和子实体形成的效应相吻合.     

特异选择性分子烙印固定相形成的条件

探讨了形成非共价型分子烙印固定相的必要条件，以咖啡因和茶碱为例从分子结构的角度加以说明，并用实验证明。     

富硒茶对小肠电活动与小肠运动的影响

咖啡和茶是人类饮用最广泛的两大饮料．近年来，关于各种茶的抗癌研究非常活跃［１，２］．本实验以小肠电和环肌张力、纵肌张力为指标，用同步记录的方法观察了咖啡因、茶碱和亚硒酸钠对豚鼠离体小肠电活动和小肠张力的影响，旨在从消化生理角度分析咖啡、茶和富硒茶对人...     

紫外-可见光度法测定茶碱缓释片中茶碱的研究

在H2BO3-Na2B4O7缓冲溶液中,甲酚红同茶碱会发生诱导荷移反应,使其吸收光谱发生变化.以十二烷基磺酸钠作增敏剂,常温下显色20 min,茶碱与甲酚红形成2︰1型络合物,其λmax=570 nm,摩尔吸光系数κ=5.56×105L/(mol.cm),茶碱浓度在0.10~8.00μg/mL范围内符合比尔定律,线性回归方程为A=0.064 36C 0.058 50,相关系数R=0.999 1,根据信噪比确定的检测限(S/N=3,n=3)为0.172μg/mL.该方法简单易行,准确度、灵敏度高,适用于快速、大批量地分析茶碱缓释片中的茶碱.     

利用太赫兹光谱定量分析固体混合物

为测定固体混合物中感兴趣成分的含量,研究基于太赫兹吸收光谱拟合的定量检测方法。以无水茶碱和乳糖一水合物组成的混合物为例,在样品组成已知的条件下,采用经典最小二乘回归建立校正模型,二者浓度预测的平均误差分别为5.39%和6.91%。当假设乳糖为未知干扰物时,采用Lorentzian线型与多项式叠加拟合吸收峰,并通过拟合得到的峰强度预测茶碱的浓度,平均误差为6.64%。结果表明,根据太赫兹光谱包含的特征信息能够对混合物中的感兴趣成分进行准确的定量分析,因而太赫兹技术在质量监控领域具有潜在的应用前景。     

Effects of gastric secretagogues on tissue glycerol in the isolated amphibian gastric mucosa

Summary Histamine and theophylline, two gastric secretagogues, significantly increased tissue glycerol content by 121 and 66%, respectively, in the isolated toad gastric mucosa. This is new evidence in favor of the hypothesis that gastric segretagogues may act via lipid mobilization.This investigation was supported by Consejo de Desarrollo Científico y humanístico de la Universidad del Zulia, Maracaibo, Venezuela.     

自模式曲线分辨红外光度法用于咖啡碱—茶碱混合物的不分离定量测定

本文研究了自模式曲线分辩红外光度法及其在多组分结构相似混合物同时定量测定中的应用.测定不同配比(10:1至1:10)咖啡碱—茶碱混合物组分,平均回收率分别为99.2±3.6%与99.1±2.8%,测定雀巢咖啡中咖啡碱的结果为3.37±0.093%.     

萃取法回收母液中的茶碱

提出了以２－乙基己醇或仲辛醇萃取回收母液中茶碱的工艺流程。讨论了ｐＨ值，温度和Ｎａ２ＳＯ４含量对萃取的影响。１５℃，ｐＨ＝６．７时，２－乙基己醇萃取母液中茶碱的分配比为０．７，ｐＨ≥８时分配比迅速下降。温度升高或Ｎａ２ＳＯ４浓度增高均促使分配比增大。负载２－乙基己醇可用ＮａＯＨ溶液反萃取，反萃取为不均相化学反应过程，ＮａＯＨ用量和动力学因素是使反萃取完全的重要条件。     

1,3-二甲基黄嘌呤与锌(Ⅱ)、镉(Ⅱ)、汞(Ⅱ)配合物的合成及性质研究

合成了茶碱与ｄ１０组态金属离子的固态配合物，并对配合物进行了红外、热稳定性、紫外光谱、荧光光谱、微观结构的表征研究，以揭示金属离子和生物碱形成配合物的配位点，从而可确定所形成配合物的结构