叶酸偶联壳聚糖纳米粒的制备

目的制备叶酸偶联的壳聚糖纳米粒。方法根据叶酸与壳聚糖的偶联比选择最佳工艺条件,通过叶酸活性酯与壳聚糖上的氨基反应,制得叶酸偶联的壳聚糖,再通过离子交联法制得叶酸偶联壳聚糖纳米粒,并测定纳米粒的粒径和表面电位。结果正交实验结果显示叶酸活性酯用量和反应温度是影响偶联比的主要因素,在叶酸活性酯与壳聚糖用量比为2∶1,反应温度50℃,反应时间2 h的条件下可得到偶联比大致为每个壳聚糖分子上偶联3个叶酸分子的叶酸偶联壳聚糖。所制得的纳米粒粒径316 nm,表面电位为(24.85±1.14)mV,透射电镜下观察其形态圆整。结论该方法可成功制备叶酸偶联壳聚糖纳米粒。     

相转移催化氧化合成邻硝基苯甲酸

研究了季铵盐A-1催化高锰酸钾氧化邻硝基甲苯合成邻硝基苯甲酸的反应,考察了不同相转移催化剂的催化活性、催化剂用量、反应温度、反应时间、高锰酸钾用量和反应体系酸碱性对反应的影响.在优化反应条件下,即以季铵盐A-1为相转移催化剂,高锰酸钾与邻硝基甲苯摩尔比为2.51,反应温度为95℃,反应时间为3h,在中性条件下进行反应,产物收率可达95%.实验表明,季铵盐A-1对于高锰酸钾氧化邻硝基甲苯合成邻硝基苯甲酸的反应,是一种优良的相转移催化剂.     

对异丙基甲苯的制备

本实验旨在探索合成对异丙基甲苯的反应条件，选择催化剂配比。反应温度及催化剂用量3个因素进行正交试验．以求最佳反应条件。     

合成2-羟基-4-苯基丁酸的工艺条件优化研究

目的探讨从原料苯甲醇和乳酸出发,在催化剂雷尼镍的作用下,得到2-羟基苯基丁酸的最优化反应条件。方法反应结果用高效液相色谱法检测,以反应收率为考察指标,采用正交实验法,反应温度（A）、反应时间（B）、催化剂用量（C）3个因素,每个因素选取3个水平进行实验,所制定的因素水平选用L9（34）来安排实验,最后确定最佳反应条件。结果各因素对反应收率的影响分别为A〉B〉C,在温度170℃下,反应时间3h,催化剂用量10%是合成2-羟基-4-苯基丁酸在高温反应步骤的最优化反应条件。结论最佳工艺条件是A2B3C1,即反应温度在170℃下,反应时间为3h,催化剂用量为10%时。     

尿囊素的合成新法研究

报道了以磷钼酸为催化剂合成尿囊素的研究成果,探讨了催化剂的用量、反应时间、过氧化氢与乙二醛物质的量的比、反应温度等因素的影响,确定了反应的最佳条件。讨论了催化剂的催化活性,合成产品用红外光谱仪鉴定。     

十二水合硫酸铁铵催化合成肉桂酸异戊酯

目的:从酸醇比、催化剂用量、回流时间、带水剂的用量等方面考察十二水合硫酸铁铵作为催化剂催化合成肉桂酸异戊酯的性能。方法:采用环己烷作为带水剂,十二水合硫酸铁铵作为催化剂,加热回流制取内桂酸异戊酯。结果:通过实验得到的该酯化反应的最佳条件为:酸醇摩尔比为1:8,催化剂的用量为10g,回流时间5h,反应控温在106℃～114℃,上述条件下,肉桂酸异戊酯的酯收率可达66.5%。结论:与其他催化剂相比,十二水合硫酸铁铵是合成肉桂酸异戊酯的又一良好催化剂,具有实际应用的价值。     

对甲苯磺酸催化合成苯甲酸薄荷酯

目的：用对甲苯磺酸做催化剂,苯甲酸和薄荷醇作为原料合成苯甲酸薄荷酯的反应条件进行研究。方法：考察反应时间、醇酸比、催化剂用量因素对合成苯甲酸薄荷酯的影响,得到合成酯的适宜条件。结果：最佳的反应条件：反应时间为8.0h,醇酸摩尔比为1.0：1.4,催化剂用量为反应物料总量的3%。以述条件下,苯甲酸薄荷酯产率可高达80.0%。结论：对甲苯磺酸为合成苯甲酸薄荷酯的良好催化剂,具有较高实际应用价值,酯收率较高,实验的合成工艺简单。     

正交实验法优选舒通胶囊的提取纯化工艺

［摘要］目的探讨舒通胶囊的提取工艺。方法采用天然絮凝剂壳聚糖对舒通胶囊进行精制,运用正交实验设计,选用L16（45）表,考察中药浸膏浓度、壳聚糖浓度、反应温度、pH值和反应时间等实验影响因素,以总黄酮含量和絮凝沉淀量为指标,判别其优化提纯效果。结果最佳提纯工艺参数为：药液浸膏浓度1：1,壳聚糖用量20%,反应液pH值6,反应时间10 min,反应温度30 ℃。根据此工艺参数纯化后,中药提取液的出膏率可由原来的48%降为15%。结论壳聚糖能对通便胶囊的提取工艺起到纯化作用。     

对甲苯磺酸催化合成肉桂酸异戊酯

目的:以对甲苯磺酸为催化剂对肉桂酸与异戊醇的液相酯化反应进行研究。方法:考察了醇酸比、反应时间、带水剂用量等因素对合成肉桂酸异戊酯的影响,得到合成该酯的较适宜条件。结果:最佳反应条件为n(醇):n(酸)=5:1,催化剂用量为肉桂酸用量的20%,反应时间2h,反应温度110～118℃,酯收率可达76.6%。结论:对甲苯磺酸是合成肉桂酸异戊酯的良好催化剂,具有实际应用价值,该实验合成工艺简单,酯收率较高。     

DL-对羟基苯甘氨酸的制备研究

目的研究一步法催化合成DL-对羟基苯甘氨酸的合成条件。方法对原料配比、反应时间、反应温度、催化剂用量四个因素进行考察,得到最佳反应条件。结果所得较佳工艺条件为：乙醛酸∶苯酚：氨基磺酸为1∶1.2∶1.3（摩尔）,反应时间为8h,反应温度为70℃,催化剂用量为乙醛酸的2%,产品收率达70%以上。结论 DL-对羟基苯甘氨酸的制备研究方法可行。     

Nitrosation of quaternary ammonium compounds in vivo in the Wistar rat

Animals dosed orally with nitrite (1.5 X 10(-3) mol/kg) and nonyl dimethylbenzylammonium bromide (2.9 X 10(-4) mol/kg) exhibit liver damage within two hours; cetyl trimethylammonium bromide plus nitrite was not significantly hepatotoxic. Both nonyl dimethylbenzyl ammonium bromide and cetyl trimethylammonium bromide were demethylated by rat-liver microsomal preparations; substrate concentrations of 1 mM or more were inhibitory. Bile from rats given i.p. doses of cetyl trimethylammonium bromide, nonyl dimethylbenzylammonium bromide or dodecyl dimethylbenzylammonium bromide contains only metabolites, no unchanged compounds were detected.     

Nitrosation of quaternary ammonium compounds in vivo in the Wistar rat

1. Animals dosed orally with nitrite (1.5 × 10^?3 mol/kg) and nonyl dimethylbenzylammonium bromide (2.9 × 10^?4 mol/kg) exhibit liver damage within two hours; cetyl trimethylammonium bromide plus nitrite was not significantly hepatotoxic.

2. Both nonyl dimethylbenzyl ammonium bromide and cetyl trimethylammonium bromide were demethylated by rat-liver microsomal preparations; substrate concentrations of 1 mM or more were inhibitory.

3. Bile from rats given i.p. doses of cetyl trimethylammonium bromide, nonyl dimethylbenzylammonium bromide or dodecyl dimethylbenzylammonium bromide contains only metabolites, no unchanged compounds were detected.     

Effect of cetyl trimethyl ammonium bromide on the heat-induced denaturation and protein-protein interactions of arachin at pH 3.6

The effect of a cationic detergent, cetyl trimethyl ammonium bromide, on the heat-induced denaturation and protein-protein interactions of arachin at pH 3.6 was studied by gel melting temperature, turbidity, electrophoresis, u.v. difference and fluorescence spectral measurements. Cetyl trimethyl ammonium bromide decreased the heat-induced protein-protein interactions as shown by the melting temperature, turbidity and electrophoretic measurements. Turbidity and electrophoretic measurements also showed that the detergent induces dissociation of the protein before and after heating it at higher detergent concentration (above 1 times 10^-3 M). U.v. difference and fluorescence spectral measurements suggested that the detergent induces unfolding of arachin at room temperature and this increases markedly after heating the protein in the detergent. The promotive effect of cetyl trimethyl ammonium bromide on the heat-induced denaturation and its preventive effect on the protein-protein interactions of arachin under the experimental conditions may arise out of the binding of the detergent to protein by primarily hydrophobic interactions.     

The uptake of cetyltrimethylammonium bromide by Escherichia coli

THE uptake of cetyltrimethylammonium bromide (CTAB) by bacteria has previously been examined by Salton (1951) and by McQuillen (1950). Both workers determined its concentration in solutions by titration with sodium cetyl sulphate using pinacyanol bromide as indicator, and reported that uptake was in the form of a typical adsorption isotherm with saturation of the cells at an uptake equivalent to several theoretical close packed monolayers. This communication reports on studies of the uptake of ¹⁴C-labelled CTAB by cells of Escherichia coli and the concurrent release of phosphorus compounds from their metabolic pool.     

Kinetics of the acid hydrolysis of diazepam, bromazepam, and flunitrazepam in aqueous and micellar systems

A kinetic study of the acid hydrolysis of aqueous diazepam, bromazepam, and flunitrazepam was carried out at 25 degrees C using a spectrophotometric method. For diazepam and flunitrazepam, the experimental pseudo first-order rate constant decreased as the acid concentration was increased. The contrary behavior was found in the case of bromazepam. A kinetic scheme that includes the hydrolysis reaction of both protonated and nonprotonated species of the drug can account for these results. Also, the kinetics of the acid hydrolysis of the same drugs in the presence of micellar aggregates [nonionic polyoxyethylene-23-dodecanol (Brij 35); cationic cetyl trymethyl ammonium bromide (CTAB); and anionic sodium decyl (SdeS), dodecyl (SDS), and tetradecyl (STS) sulfate] was studied at 25 degrees C. Negligible effects were observed in the cases of nonionic and cationic micelles. Anionic micelles produced an inhibitory effect in the reaction velocity. This effect increased as the hydrophobic nature of the surfactant increased. All these facts are interpreted quantitatively by means of a pseudophase model.     

酮洛芬的相转移催化氧化合成

2-(3-苄基苯基)丙醛和高锰酸钾在相转移催化剂度米芬作用下,以苯为有机相、氢氧化钠水溶液为水相氧化制得酮洛芬,收率69%,纯度99.5%.     

Airway effects of inhaled quaternary ammonium compounds in mice

Quaternary ammonium compounds (QAC) constitute a family of widely used chemical substances. The QAC benzalkonium chloride (BAC) has caused bronchoconstriction in human beings by poorly understood mechanisms and lung damage at high concentration as shown in a single rat study. This study evaluates acute airway effects in mice after inhalation of aerosols of the QACs, BAC, hexadecyl trimethyl ammonium bromide (HTA), cetyl pyridinium chloride (CPC) and dimethyl dioctadecyl ammonium bromide (DDA). The QACs gave rise to concentration-dependent decreases in the tidal volume (VT) and a concomitant increase in respiratory rate indicating pulmonary irritation. The potencies of the QAC to induce these effects were in the order: BAC > HTA = CPC > DDA. Furthermore, inhalation of BAC and CPC aerosols gave rise to pulmonary inflammation as apparent from bronchoalveolar lavage. Stimulation of nasal trigeminal nerve endings by QAC, which may serve as a warning signal, was absent.     

2,3,4-三甲氧基苯甲酸的合成

焦性没食子酸经碳酸二甲酯甲基化,再经Blanc氯甲基化反应制得2,3,4-三甲氧基氯苄,最后在氢氧化钠和溴化四丁铵催化下经高锰酸钾氧化得到2,3,4-三甲氧基苯甲酸,总收率约63%。     

Key production parameters for the development of solid lipid nanoparticles by high shear homogenization

In this work, we report the development and optimization of solid lipid nanoparticles (SLN) production by a simple, fast, and cost-effective high shear homogenization process. A screening of several solid lipids (Compritol 888 ATO, Precirol ATO 5, Cetyl Palmitate, Dynasan 118, Imwitor 900K, Stearic acid) has been carried out in combination with Poloxamer 188 as the selected surfactant, based on the mean particle size and polydispersity index. The improvement of the physical stability of the SLN dispersions was achieved by the use of a cationic lipid (cetyl trimethylammonium bromide) reaching zeta potential values above +60 mV. Combining the optimized speed and time of shear, monodispersed SLN (PdI < 0.25) under the nanometer range could be produced.     

Analysis of underivatized gentamicin by capillary electrophoresis with UV detection

A selective and rapid capillary zone electrophoresis method for determination of the multicomponent aminoglycoside antibiotic gentamicin is described. Baseline separation of gentamicin C1, C1a, C2, C2a and C2b components was achieved with a background electrolyte containing 0.35 mM cetyl trimethylammonium bromide, 3% methanol and 90 mM sodium pyrophosphate (pH 7.4) and detected directly with UV detection without derivatization. Quantitative analysis was performed and illustrated the potential use of capillary electrophoresis for the identification and quantitation of gentamicin components, but the application of this method is limited to a gentamicin concentration range of 2–6 mg/ml.