苦丁茶中熊果酸的分离纯化研究

 目的研究苦丁茶(Ilex kudingcha C.J.Tseng)中熊果酸的分离纯化,建立分离纯化工艺条件,以利于苦丁茶资源的开发利用。方法以熊果酸浸出率为考核指标,采用正交实验法考察诸因素对浸出率的影响。乙醇提取液经沉淀富集和大孔树脂柱色谱纯化得到熊果酸,采用HPLC分析检测。结果优化的提取条件为:在85℃水浴中,以体积分数90％乙醇水溶液为提取溶剂。固液比为1:14,提取2次,每次提取2.5h,熊果酸的浸出率可达到1.44％。D₈树脂分离富集的最优条件:样品溶液熊果酸浓度1～2 mg·mL^-1,样品溶液pH=6.0～7.0,吸附1h,洗脱剂pH=11.0,依次用水、4倍体积30％乙醇、4倍体积90％乙醇以2～3mL·min^-1的流速洗脱,收集90％乙醇洗脱液,熊果酸回收率为97.82％,纯度为95.0％。结论 该工艺产品纯度高,收率高,可实现工业化。     

中心组合设计优化法筛选独一味分散片制备工艺

 目的　中心组合设计法优化独一味分散片制备处方。方法　采用粉末直接压片,以分散片崩解时间、木犀草苷溶出的t₈₀及分散片混悬后的混悬系数为考察指标,应用中心多点等距设计法及效应面优化法对独一味分散片处方进行筛选,通过对自变量各水平的多元线性回归及二项式拟合,选取较佳工艺,并进行预测分析。结果　考察指标与各因素间具有较好的相关性,优化后独一味分散片处方为12％PVPP为崩解剂、14％预胶化淀粉为溶胀剂、3％微粉硅胶为润滑剂和助流剂、45％MCC为填充剂。优化条件下制备的分散片崩解时间为20.6s,木犀草苷溶出的t₈₀为1.68 min,分散片混悬后的混悬系数为0.068 9。结论 中心组合设计法具有应用简便、预测性好等优点,筛选的处方可以在最适宜的范围内制备一定硬度且具有可被接受口味的速释分散片。     

D301树脂吸附丹参有效成分的研究

目的 :考察利用大孔树脂D301,富集丹参水提取液中有效成分丹参素及原儿茶醛 ,去除杂质 ,降低出膏率 ,提高膏中有效成分含量。方法 :以丹参素 ,原儿茶醛为指标 ,HPLC检测分离前后有效成分的含量变化。结果 :D301树脂能够有效的吸附丹参素和原儿茶醛。结论 :采用D301树脂可以作为改进分离纯化工艺 ,去除杂质 ,提高粗提物中有效成分含量。     

D140大孔树脂分离纯化淫羊藿黄酮的研究

目的:研究大孔树脂提取淫羊藿黄酮的工艺.方法:以淫羊藿苷含量为指标,用不同浓度的乙醇进行洗脱,对D140大孔树脂吸附剂提取淫羊藿总黄酮的工艺进行了筛选,并对树脂的使用次数进行了考察.结果:当乙醇浓度为80％时可以洗脱完全,大孔树脂使用次数10次以上.结论:提取淫羊藿总黄酮的含量大于60％,而且工艺简便,树脂再生容易,提取方法可取.     

大孔吸附树脂对白藜芦醇苷静态吸附性能的研究

目的 研究白藜芦醇苷在大孔吸附树脂上的静态吸附。方法 考察了吸附温度、吸附液pH值、洗脱液浓度对静态吸附性能的影响。结果与结纶 吸附温度增加,吸附液pH提高,都可以导致降低白藜芦醇苷在树脂上的吸附性能。     

Biocompatibility evaluation of dicalcium phosphate/calcium sulfate/poly (amino acid) composite for orthopedic tissue engineering in vitro and in vivo

In vitro cytocompatibility of ternary biocomposite of dicalcium phosphate (DCP) and calcium sulfate (CS) containing 40 wt% poly (amino acid) (PAA) was evaluated using L929 ?broblasts and MG-63 osteoblast-like cells. Thereafter, the biocompatibility of biocomposite in vivo was investigated using an implantation in muscle and bone model. In vitro L929 and MG-63 cell culture experiments showed that the composite and PAA polymer were noncytotoxic and allowed cells to adhere and proliferate. The scanning electron microscope (SEM) confirmed that two kinds of cells maintained their phenotype on all of samples surfaces. Moreover, the DCP/CS/PAA composite showed higher cellular viability than that of PAA; meanwhile, the cell proliferation and ALP activity were much higher when DCP/CS had added into PAA. After implanted in muscle of rabbits for 12 weeks, the histological evaluation indicated that the composite exhibited excellent biocompatibility and no inflammatory responses were found. When implanted into bone defects of femoral condyle of rabbits, the composite was combined directly with the host bone tissue without fibrous capsule tissue, which shown good biocompatibility and osteoconductivity. Thus, this novel composite may have potential application in the clinical setting.     

Balancing mechanical strength with bioactivity in chitosan–calcium phosphate 3D microsphere scaffolds for bone tissue engineering: air- vs. freeze-drying processes

The objective of this study was to evaluate the potential benefit of 3D composite scaffolds composed of chitosan and calcium phosphate for bone tissue engineering. Additionally, incorporation of mechanically weak lyophilized microspheres within those air-dried (AD) was considered for enhanced bioactivity. AD microsphere, alone, and air- and freeze-dried microsphere (FDAD) 3D scaffolds were evaluated in vitro using a 28-day osteogenic culture model with the Saos-2 cell line. Mechanical testing, quantitative microscopy, and lysozyme-driven enzymatic degradation of the scaffolds were also studied. FDAD scaffold showed a higher concentration (p?<?0.01) in cells per scaffold mass vs. AD constructs. Collagen was ～31% greater (p?<?0.01) on FDAD compared to AD scaffolds not evident in microscopy of microsphere surfaces. Alternatively, AD scaffolds demonstrated a superior threefold increase in compressive strength over FDAD (12 vs. 4?MPa) with minimal degradation. Inclusion of FD spheres within the FDAD scaffolds allowed increased cellular activity through improved seeding, proliferation, and extracellular matrix production (as collagen), although mechanical strength was sacrificed through introduction of the less stiff, porous FD spheres.     

Influence of various irradiation processes on the mechanical properties and polymerisation kinetics of bulk-fill resin based composites

ObjectivesTo assess the effect of irradiation time and distance of the light tip on the micro-mechanical properties and polymerisation kinetics of two bulk-fill resin-based composites at simulated clinically relevant filling depth.MethodsMicro-mechanical properties (Vickers hardness (HV), depth of cure (DOC) and indentation modulus (E)) and polymerisation kinetics (real-time increase of degree of cure (DC)) of two bulk-fill resin-based composites (Tetric EvoCeram^® Bulk Fill, Ivoclar Vivadent and x-tra base, Voco) were assessed at varying depth (0.1–6 mm in 100 μm steps for E and HV and 0.1, 2, 4 and 6 mm for DC), irradiation time (10, 20 or 40 s, Elipar Freelight2) and distances from the light tip (0 and 7 mm). Curing unit's irradiance was monitored in 1 mm steps at distances up to 10 mm away from the light tip on a laboratory-grade spectrometer.ResultsMultivariate analysis (α = 0.05), Student's t-test and Pearson correlation analysis were considered. The influence of material on the measured mechanical properties was significant (η² = 0.080 for E and 0.256 for HV), while the parameters irradiation time, distance from the light tip and depth emphasise a stronger influence on Tetric EvoCeram^® Bulk Fill. The polymerisation kinetics could be described by an exponential sum function, distinguishing between the gel and the glass phase. The above mentioned parameters strongly influenced the start of polymerisation (gel phase), and were of less importance for the glass phase.ConclusionsBoth materials enable at least 4 mm thick increments to be cured in one step under clinically relevant curing conditions.Clinical significanceThe susceptibility to variation in irradiance was material dependent, thus properties measured under clinically simulated curing conditions might vary to a different extent from those measured under ideal curing conditions.