Bioactivity analysis of the Ta (V) doped SiO2–CaO–Na2O–P2O5 ceramics prepared by solid state sintering method

The main objective of the study was to control the degradation rate of material at a higher degradation rate improving the chemical stability of the material. Ta is known to have good chemical resistance, biocompatibility and show no adverse biological response. In the present study, SiO2–Na2O–CaO–P2O5 bioceramics with different Ta2O5 contents was prepared by solid state sintering method at 1000 °C. The as-sintered ceramics were subjected to immersion studies in stimulated body fluid (SBF) for 21 days under static condition and characterized by XRD, FTIR, SEM, and AAS. The findings of the research indicate that the addition of Ta2O5 controlled degradability, and all samples showed sufficient bioactivity.     

浅谈蔷薇属植物对改善干旱地区生态环境功能的作用

文章介绍了蔷薇的原植物种类,重点分析了蔷薇植物在干旱地区对生态环境的改善等方面所具备的独特性能.蔷薇的原植物种类,并对蔷薇化学成分及经济价值进行了综述.     

野蔷薇根挥发油超声-微波协同提取工艺优化及GC-MS分析

研究野蔷薇根挥发油超声-微波协同提取的最佳工艺和挥发油的化学成分.在单因素试验的基础上,采用Box-Behnken设计对野蔷薇根挥发油超声波协同微波提取工艺中的液料比、微波时间和微波功率3因素的最优化组合进行了定量研究,建立并分析了各因素与得率关系的数学模型,并通过气相色谱-质谱联用技术对其成分进行了分析.最佳的工艺条件为液料比9.88 m L/g,提取时间156 s和微波功率276 W,经试验验证此条件下得率为3.88%,与理论计算值3.82%基本一致.说明回归模型能较好地预测野蔷薇根挥发油的提取得率.从野蔷薇根挥发油中共分离出104个峰,鉴定出49个化学成分,采用峰面积归一化法确定了各成分的相对含量.     

Effects of drug-polymer dispersions on solubility and <Emphasis Type="Italic">in vitro</Emphasis> diffusion of artemisinin across a polydimethylsiloxane membrane

Artemisinin(ART) is a sesquiterpene lactone with an endo-peroxide bridge that is thought to be responsible for its antimalarial activity.It has low oral bioavailability because of aqueous insolubility,which leads to local toxicity at the site of aggregation.The present work focused on increasing its solubility and evaluating its permeation across a model membrane to mimic transdermal delivery that bypasses the hepatic metabolism.For this purpose,physical mixtures(PM),solid dispersions(SD) and lyophilized dispersions(LD) with different drug-polymer ratios(1:0.5,1:1,1:2,1:4 and 1:9) were prepared using the hydrophilic polymer polyvinylpyrrolidone(PVP).Drug-polymer dispersions were characterized using X-ray diffraction(XRD) and Fourier transform infrared spectroscopy(FTIR).Solubility was measured in three solvents:de-ionized water,phosphate buffered saline(PBS) and methanol.The toluene-water partition coefficient was evaluated and compared with the literature and calculated logP values.In vitro diffusion of ART was studied across a polydimethylsiloxane membrane from a saturated solution of drug-polymer dispersions.XRD patterns showed a gradual decrease in crystallinity of ART with increasing polymer concentration,while FTIR confirmed no interactions between ART and PVP.Solubility was increased up to 4-,5-and 8-fold for LD in water,PBS and methanol,respectively.The logP for toluene-water was 2.65 ± 0.3,which is in good agreement with literature and calculated logP values.Permeation was enhanced,which is attributed to the decrease in crystallinity and increase in wettability of the drug.The ART flux was significantly higher than that of pure ART(0.12 ± 0.01) with increasing PVP concentration for SD and LD formulations.In conclusion,drug-polymer dispersions with PVP improve the pharmaceutical properties of ART in the order LD>SD>PM.