基于乙二胺四乙酸酐和丁二胺的pH敏感水凝胶的合成与表征

以乙二胺四乙酸酐(EDTAD)和丁二胺(BDA)为原料,通过酸酐的N-酰化开环反应制备侧链含羧基的直链聚合物(pEDTAD-BDA);然后以二环己基碳二亚胺(DCC)活化pEDTAD-BDA中的羧基,以BDA为交联剂,制得单体间连接全部为酰胺键、侧链只含羧基的交联网络聚合物BDA-crosslinked-EDTAh-BDA。采用氢核磁共振(1H-NMR)、碳核磁共振(13C-NMR)和茚三酮显色法对pEDTAD-BDA的结构和数均分子量进行了表征。pH敏感性测试表明,BDA-crosslinked-pEDTAD-BDA在pH=12介质中的溶胀率约为pH=3和pH=7介质中溶胀率的5倍,表现出敏锐的pH响应性。该网络聚合物可望成为一种集完全可降解性、良好生物相容性和pH敏感性于一身的医用水凝胶材料。     

高效液相色谱法测定注射用二乙酰氨乙酸乙二胺含量的方法确认

目的：对高效液相色谱法测定注射用二乙酰氨乙酸乙二胺含量方法的专属性和准确性进行确认。方法：以十八烷基硅烷键合硅胶为填充剂;以0．4％庚烷磺酸钠的0．02mol／L磷酸二氢钾溶液（用磷酸调节pH值至3．O）为流动相。检测波长为200rim。结果：该方法专属性好,平均加样回收率为99．27％。结论：高效液相色谱法能够对注射用二乙酰氨乙酸乙二胺的含量进行准确的检验,有效地控制其质量。     

药品溶解度的研究与探讨

溶解度与药品研发的关系     

甲壳素-硅酸四乙酯膜的制备和性能

采用N,N-二甲基乙酰胺(DMAC)和无水氯化锂(LiCl)溶解甲壳素,以丙酮为非溶剂通过液致相分离法制备甲壳素膜,利用硅酸四乙酯对甲壳素膜进行改性,选用扫描电子显微镜、能谱仪、傅里叶变换红外光谱仪对膜性能进行表征,并研究了甲壳素-硅酸四乙酯膜对牛血清蛋白(BSA)的过滤特性。结果表明, 5%LiCl/DMAC溶剂可以快速溶解甲壳素,纯甲壳素膜的收缩程度非常剧烈,而甲壳素-硅酸四乙酯膜收缩程度较小并具有较好的拉伸强度,对BSA有一定的截留效果,铸膜液中甲壳素的浓度对BSA的截留率有较大影响。当铸膜液中甲壳素浓度从1%增加到1.8%时,对BSA的截留率从23.6%增加到了75%。     

富勒烯乙二胺铅盐的制备及研究

以富勒烯和乙二胺为原料合成富勒烯乙二胺,富勒烯乙二胺再与硝酸铅反应得到富勒烯乙二胺铅盐。通过单因素方法探讨了反应物物料比、反应温度以及反应时间对富勒烯乙二胺铅盐中铅含量的影响,获得最佳工艺条件为:富勒烯乙二胺和硝酸铅的摩尔比为1∶15,反应时间为2.0h,反应温度为35℃,所得富勒烯乙二胺铅盐中铅含量为49.4%。同时采用FT-IR、1 H NMR、XPS及AAS等测试手段对产物结构进行了表征。采用差热和热重分析法对富勒烯乙二胺铅盐的热稳定性进行了研究,结果表明,在空气气氛下,分解峰值温度为310℃,表明产物热稳定性良好。     

酚酞基聚醚砜溶解度参数的测定

采用浊度滴定法测定和基团贡献法估算了酚酞基聚醚砜的溶解度参数。基团贡献法估算与浊度滴定法测定的结果相吻合。测得酚酞基聚醚砜的溶解度参数为20.76J1/2mL-1/2,这对研究其溶液性质和应用有重要的意义。     

一种pH敏感性智能水凝胶的合成与表征

以乙二胺四乙酸酐(EDTAh)和丁二胺(BDA)为原料,通过高温溶液聚合形成含多元环状酰亚胺的共聚物(pEDTAh-BDA-Imide),最后以丁二胺为交联剂,与pEDTAh-BDA-Imide中的酰亚胺发生N-酰化开环反应,生成了侧链含氨基的网络聚合物(BDA-crosslinked-EDTAh-BDA)。该网络聚合物可望成为一种集完全可降解、pH敏感性和生物相容性于一体的新型药物释放水凝胶。采用红外光谱和核磁共振对各共聚物进行了结构表征,采用扫描电镜(SEM)表征了水凝胶的表面形貌。pH敏感性测试表明,BDA-crosslinked-EDTAh-BDA表现出明显的pH响应性。     

桐油酰二乙醇胺的制备与表征

利用桐油和二乙醇胺间的转酰胺基作用制备了桐油酰二乙醇胺,并提出了一种提纯该产物的方法;同时,运用红外光谱和紫外光谱研究了所得桐油酰二乙醇胺的结构。研究结果显示:纯化后产物的红外吸收谱带符合桐油酰二乙醇胺分子结构中羟基、酰胺基和共轭双键的特征吸收谱带;桐油酰二乙醇胺和桐油具有相似的紫外吸收谱带,在200～270 nm和283～315 nm处均有强吸收谱带,但受酰胺基和羟基助色团的影响,桐油酰二乙醇胺的紫外吸收谱带呈现出了一定的红移。     

乙二胺改性聚乳酸溶液的性质

乙二胺改性聚乳酸(EMPLA)是一种具有支化结构的新型生物材料。文中采用GPC-MALLS技术对其在四氢呋喃(THF)中的分子量、分子量分布、半径、支化及其这些量之间的相互关系进行了分析与研究,结果表明:乙二胺改性聚乳酸在四氢呋喃中的折光指数增量dn/dc值为0.052 mL/g,第二维利系数A2为3.905e-3 mol mL/g2,重均分子量-Mw为5.753e 4,重均均方根旋转半径Rw为4.5 nm,-Mw与Rw的关系式为:Rw=0.608×-Mw0.316,通过与线性聚乳酸(PDLLA)的比较,能够得到具有与PDLLA相同分子量的EMPLA有较小的均方根旋转半径的结论,并能够推出EMPLA在四氢呋喃溶液中的分子构象为球形。     

溶解度参数预测共混物的相容性

用三维溶解度参数方法预测聚合物共混物的相容性。考虑了分子间色散、极性与氢键相互作用对均聚物 /均聚物、均聚物 /共聚物相容性的影响。对于共聚物 ,可以调节共聚组成来改变溶解度参数 ,使两个聚合物在三维空间的距离缩短 ,以提高共聚物与均聚物的相容性。通过计算值和实验结果的比较 ,揭示共混物相容性的趋向     

Solubilization and determination of solution thermodynamic properties of itraconazole in different solvents at different temperatures

The solubility of itraconazole (ITRA) in thirteen pure solvents including water, dimethyl sulphoxide, acetonitrile, methanol, 1,4-butanediol, ethanol, isopropyl alcohol, n-butanol, octanol, ethyl acetate, toluene, benzene, 1,4-dioxane were estimated at the temperatures ranging from 293.15?K to 318.15?K under atmospheric pressure (0.1?MPa). The results reflected that the solubility of ITRA was a function of temperature and was increased with a rise in temperature in each solvent. Moreover, the solubility in polar solvents was less and found to be increased in non-polar solvents. Furthermore, the results of solubilization were correlated by the Van’t Hoff equation, the modified Apelblat equation, the Buchowski???Ksiazaczak λh equation, and the polynomial empirical equation. The polynomial empirical equation proved to be more accurate and suitable for the correlation of solubilities of ITRA in studied solvents at various temperatures. Besides, theoretical ideal solubilities, activity coefficients, and thermodynamic properties of the solution process including standard molar enthalpy, entropy, Gibbs free energy, and excess enthalpy were calculated from the experimental solubility data. These thermodynamic parameters indicated that the solubilization process was not spontaneous, endothermic, and enthalpy driven. Such thermodynamic based solubility data of ITRA will be of immense help in solubilization, synthesis, process development, preformualtion, and dosage form development in pharmaceuticals.     

Solubility measurement,Hansen solubility parameters and solution thermodynamics of gemfibrozil in different pharmaceutically used solvents

Gemfibrozil (GEM) is cholesterol-lowering agent which is being proposed as poorly water soluble drug (PWSD). Temperature based solubility values of GEM are not yet available in literature or any pharmacopoeia/monograph. Hence, the present studies were carried out to determine the solubility of PWSD GEM (as mole fraction) in various pharmaceutically used solvents such as water (H₂O), methanol (MeOH), ethanol (EtOH), isopropanol (IPA), 1-butanol (1-BuOH), 2-butanol (2-BuOH), ethylene glycol (EG), propylene glycol (PG), polyethylene glycol-400 (PEG-400), ethyl acetate (EA), dimethyl sulfoxide (DMSO) and Transcutol^® (THP) at the temperatures ranging from T?=?298.2 K–318.2?K under atmospheric pressure P?=?0.1?MPa. Equilibrium/experimental solubilities of GEM were recorded by applying a saturation shake flask methodology and regressed using ‘van’t Hoff and Apelblat models’. Hansen solubility parameters for GEM and various pharmaceutically used solvents were estimated using HSPiP software. The solid states of GEM (both in pure and equilibrated states) were studied by ‘Differential Scanning Calorimetry’ which confirmed no transformation of GEM after equilibrium. Experimental solubilities of GEM in mole fraction were observed maximum in THP (1.81?×?10^?1) followed by DMSO, PEG-400, EA, 1-BuOH, 2-BuOH, IPA, EtOH, PG, MeOH, EG and H₂O (3.24?×?10^?6) at T?=?318.2 K and similar tendencies were also recorded at T?=?298.2 K, T?=?303.2 K, T?=?308.2 K and T?=?313.2 K. ‘Apparent thermodynamic analysis’ on experimental solubilities furnished ‘endothermic and entropy-driven dissolution’ of GEM in each pharmaceutically used solvent.     

Measurement and the effect of different solvents on thin polymericfilm surface resistance

A method of measuring the thin polymeric film surface resistance has been developed. The method uses an arrangement of concentric cylindrical electrodes for the measurements and has been studied analytically and experimentally. The effect of different solvents on the thin polymeric film surface resistance as well as the use of the method are examined. The mathematical modeling of the cylindrical electrode measuring system fitted the experimental results     

Measurement and the effect of different solvents on thin polymer film surface resistance

A method of measuring the surface resistance of thin polymer films has been developed. The method uses a concentric cylindrical electrode arrangement for the measurements and has been studied analytically and experimentally. The effect of different solvents on the thin polymer film surface resistance is examined as well using the method.     

Measurement of radio signal parameters based on spline approximation of the interference correlation function

On the basis of a spline-parabolic approximation for the envelope of a correlation function of Gaussian interference, an analytical expression is obtained for the required likelihood function that is a basis for constructing an evaluation algorithm for unknown radio signal parameters. __________ Translated from Izmeritel’naya Tekhnika, No. 12, pp. 9–10, December, 2007.     

不同底质海底窄带混响信号空间相关半径研究

海底混响是主动声呐的主要干扰之一,分析海底混响信号的空间相关特性是抗海底混响技术研究的基础。本文依据混响信号的空间相关特性,从理论上解释海底混响信号空间相关半径的定义,利用实验数据研究了在不同海底底质情况下混响信号空间相关半径变化规律以及不同底质混响信号强度的变化。研究表明不均匀海底底质情况下,散射体颗粒增大,混响信号空间相关半径减小且底质较硬时混响信号较强。     

Prediction of anthracene solubilities in binary alcohol+alcohol solvent mixtures using alcohol-specific mobile order theory stability constants

Experimental solubilities are reported for anthracene dissolved in six binary mixtures containing 2-methyl-1-pentanol with 1-propanol, 2-propanol, 1-butanol, 2-butanol 2-methyl-1-propanol, and 1-octanol at 25°C. Results of these measurements, along with previously published solubility data for anthracene in binary alcohol + alcohol solvent mixtures, are used to test the limitations and applications of expressions derived from mobile order theory and the Kretschmer-Wiebe association model. Alcohol-specific mobile order theory association constants are calculated from vapor-liquid equilibrium data for binary alkane + alcohol solvent mixtures and used in the solubility predictions. For the 57 systems considered, both models provided very accurate predictions of the anthracene solubilities, with an overall average absolute deviation between measured and calculated values being 1.7 and 1.2% for mobile order theory and the Kretschmer-Wiebe association model, respectively.     

Prediction of solubility of long-chain hydrocarbons in various solvents using UNIFAC

The UNIFAC group contribution model has been widely used in the prediction of phase equilibria of various fluid mixtures. We have applied the method to predict the solubility of various long-chain hydrocarbon solids in a number of solvents of industrial importance. The calculated solubilities are compared with measured values and also with the predictions of the regular solution theory of Hildebrand and Scatchard. Some disagreements were found between the measured solubilities and the predicted values of both theories. Overall the UNIFAC scheme appears to be superior to the regular solution theory.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

Thermodynamic solubility and solvation behavior of ferulic acid in different (PEG-400 + water) binary solvent mixtures

This work was carried out to determine solubility, solution thermodynamics, solvation behavior, and molecular interactions of a natural compound ferulic acid (FLA) in different ‘[polyethylene glycol-400 (PEG-400) + water]’ binary solvent mixtures at ‘T?=?298.2 K to 318.2?K’ and ‘p?=?0.1?MPa.’ The mole fraction solubilities (x_e) of FLA were determined by liquid chromatographic technique using a static equilibrium technique. The obtained solubility data of FLA were regressed using ‘Van’t Hoff, Apelblat, Yalkowsky-Roseman and Jouyban-Acree models.’ The solubility of FLA (expressed in mole fraction) was enhanced with elevation in absolute temperature in each ‘PEG-400?+?water’ binary solvent mixture evaluated. The maximum x_e values of FLA were recorded in neat PEG-400 (1.94?×?10^?1) at ‘T?=?318.2 K.’ While, the minimum one was obtained in neat water (4.90?×?10^?5) at ‘T?=?298.2 K.’ The molecular interactions between FLA-PEG-400 and FLA-water were obtained by determination of activity coefficients of FLA in different ‘PEG-400?+?water’ binary solvent mixtures. The physical data of activity coefficients recorded in this work suggested strong molecular interactions in FLA-PEG-400 in comparison with FLA-water. ‘Apparent thermodynamic analysis’ suggested an ‘endothermic and entropy-driven dissolution’ of FLA in each ‘PEG-400?+?water’ binary solvent mixture investigated.     

Measurement of discontinuous displacement/strain using mesh-based digital image correlation

In this study, a method for evaluating discontinuous displacement and strain distributions using digital image correlation (DIC) is proposed. A finite element mesh-based DIC method is used for measuring displacements while taking into account displacement and strain discontinuities. Smoothed displacements are thus obtained, and strains are computed from the measured displacements using the finite element mesh again. Discontinuous strains can be obtained by the proposed method using a split finite element mesh. The effectiveness of this method is validated by applying it to measure the displacement and strain in a triaxially woven fabric composite containing numerous free boundaries, to measure displacements around a crack and the displacement and strain around the interface between dissimilar materials. Results show that the discontinuous displacement and strain distributions can be measured by the proposed method. The proposed method is expected to be applicable for the experimental evaluations of various structures and members, including displacement and strain discontinuities such as free boundaries, cracks, and interfaces.