多肽在金纳米粒子表面偶联反应效率研究

通过1-(3-二甲氨基丙基)-3-乙基碳二亚胺(EDC)与N-羟基琥珀酰亚胺(NHS)活化反应将多肽偶联到金纳米粒子表面,采用荧光光谱研究其形成的酰胺键的反应偶联效率.考察了实验条件,包括缓冲液的种类(HEPES、Tris-HCl、硼酸、PBS缓冲液)、pH值(pH 6.5~9.0)、缓冲液浓度(10, 25, 40和50 mmol/L)、NHS和EDC的浓度(NHS 0.2~1.0 mol/L,EDC 0.01~0.5 mol/L)及二者比例(0,0.5,1.0,2.0和2.5)、偶联反应时间(4, 8, 12, 24和36 h)等对偶联效率的影响,筛选出最佳实验条件.实验结果表明, 25 mmol/L 4-羟乙基哌嗪乙磺酸(HEPES)缓冲液(pH 7.0), NHS/EDC浓度为0.4 mol/L/0.2 mol/L和24 h的反应时间为EDC-NHS活化反应将多肽偶联到金纳米粒子上的最佳实验条件.本研究结果可为相关研究提供技术参考.     

Sulfated polyborate catalyzed expeditious and efficient three-component synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones

A rapid and highly efficient methodology for the synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones has been developed using sulfated polyborate as a catalyst. The multicomponent reaction of an aromatic/heterocyclic aldehyde, hydroxylamine hydrochloride, and ethyl acetoacetate under a solvent free condition at 80 °C is described. This protocol has promising features for the reaction response such as shorter reaction time, easy work-up, ease of separation of pure product with high yields and simplicity in the experimental procedure. The products have been obtained in high yields (80–90%) and convenient reaction time (15–30 min). The method is operationally simple and eco-friendly.     

A fluorescent polymer dots positive readout fluorescent quenching lateral flow sensor for ractopamine rapid detection

A fluorescent polymer dots positive readout and sensitive lateral flow assay (LFA) based on fluorescent quenching has been developed to detect ractopamine (Rac), a chemical residue in food, harmful to human health. Compared with traditional LFA strips, these fluorescent quenching LFA (FQLFA) strips provide a positive correlation method that allows users to obtain results from a weak fluorescent signal. The immunoassay strip scheme is based on the fact that fluorescent polymer dots (FPDs) in close proximity to gold nanoparticles (AuNPs) represent a strong fluorescent quenching. We show that the FQLFA strips can be used as a source to quantitatively analyze Rac in phosphate buffers (PB), swine urine and muscle tissue samples. The lowest detection limitation of the FQLFA was 0.16 ng mL⁻¹. Our results indicated that this novel scheme was more suitable for rapid detection of small molecules.     

盐酸克伦特罗在纳米ZnO和多壁碳纳米管修饰玻碳电极上的电化学行为

制备了纳米ZnO与多壁碳纳米管(MWNTs)复合修饰玻碳电极(ZnO-MWNTs/GCE),考察了盐酸克伦特罗(CLB)在该修饰电极上的电化学行为。实验结果表明:纳米ZnO与MWNTs显著增强了修饰电极对盐酸克伦特罗的伏安响应,增加了电极的有效表面积,改善了电极的导电性和电催化活性。在2~30μmol·L-1和30~500μmol·L-1浓度范围内,CLB在所制备的修饰电极上的电流响应与其浓度线性关系良好,且该电极具有较好的重现性和稳定性。     

Nano engineered biodegradable capsules for the encapsulation and kinetic release studies of ciprofloxacin hydrochloride

Polyelectrolyte based nano and micro capsules have been extensively studied as promising drug carrier in recent years. Natural degradable capsules have received great deal of attention due to their fascinating structural and morphological characteristics, biocompatibility, sustained and targeted-release capabilities. In this work, chitosan - dextran sulphate nano capsules were prepared via Layer-by-Layer (L-b-L) technique using sacrificial template for drug delivery applications. The loading and in vitro release studies were performed using ciprofloxacin hydrochloride as a model drug. The release media used in the study are plain water and Phosphate Buffered Saline (PBS). The optimum drug load was 389 ​μg, at a loading pH of 2.1 and a temperature of 25 ​°C for 50 ​min encapsulation time. The drug loaded capsules exhibited a slow and sustained release up to 24 ​h and the maximum release rate was obtained at pH 1.2 in water and pH 7.4 in PBS. Least amount of drug release occurred at pH 5.0 in both the release media. The amounts of drug release in water at pH 1.2, pH 5.0 and pH 7.4 are 309 ​μg, 163 ​μg and 251 ​μg respectively where as the corresponding values in the case of PBS (at pH 1.2, pH 5.0 and pH 7.4) are 236 ​μg, 198 ​μg and 251 ​μg respectively. Two different models namely, Ritger - Peppas and Higuchi models were chosen to study the release kinetics behaviour of ciprofloxacin hydrochloride. The prepared bio-degradable capsules had potential as drug carrier for targeting antibacterial drugs with diverse functionality.     

荷移反应-离心光度法测定盐酸环丙沙星的研究

在水溶液中盐酸环丙沙星与荧光桃红形成多络合物,离心分离后,将络合物溶于乙醇溶液中进行光度测定,络合物的最大吸收波长为５４６ｎｍ,直 丙沙星的量浓度在０．５－６×１０＾－５ｍｏｌ／Ｌ符合比尔定律,ε＝２．７１×１０＾４。测定了片剂中盐酸环丙沙星的含量。     

盐酸普鲁卡因及其环糊精包结物的光谱研究

本文通过盐酸普鲁卡因的紫外光谱,确定了盐酸普鲁卡因两种型体（分子型体和离子型体）存在时的ｐＨ值,并研究了这两种型体加入β－环糊精、ＨＰ－β－环糊精和Ｍｅｔｈｙｌ－β－环糊精前后荧光强度的变化。     

反相高效液相色谱法同时测定片剂中的加替沙星与盐酸氨溴索

 A reversed-phase high performance liquid chromatography (HPLC) method was developed, validated, and used for the quantitative determination of gatifloxacin (GA) and ambroxol hydrochloride (AM), from its tablet dosage form. Chromatographic separation was performed on a HiQ Sil C18 column (250 mm×4.6 mm, 5 μm), with a mobile phase comprising of a mixture of 0.01 mol/L potassium dihydrogen orthophosphate buffer and acetonitrile (70∶30, v/v), and pH adjusted to 3 with orthophosphoric acid, at a flow rate of 1 mL/min, with detection at 247 nm. Separation was completed in less than 10 min. As per International Conference on Harmonisation (ICH) guidelines the method was validated for linearity, accuracy, precision, limit of quantitation, limit of detection, and robustness. Linearity of GA was found to be in the range of 10-60 μg/mL and that for AM was found to be 5-30 μg/mL. The correlation coefficients were 0.9996 and 0.9993 for GA and AM respectively. The results of the tablet analysis (n=5) were found to be 99.94% with ±0.25% standard deviation (SD) and 99.98% with±0.36% SD for GA and AM respectively. Percent recovery of GA was found to be 99.92%-100.02% and that of AM was 99.86%-100.16%. The assay experiment shows that the method is free from interference of excipients. This demonstrates that the developed HPLC method is simple, linear, precise, and accurate, and can be conveniently adopted for the routine quality control analysis of the tablet.     

Surface,micellar, and thermodynamic properties of antidepressant drug nortriptyline hydrochloride with TX‐114 in aqueous/urea solutions

This paper deals with a comprehensive study of the mixed micellization and adsorption behavior of mixed systems enclosing an amphiphilic antidepressant drug nortriptyline hydrochloride (NOT) and Triton X‐114 (TX‐114) (nonionic surfactant) in aqueous/urea (500 mmol·kg^?1 and 1000 mmol·kg^?1) solutions by tensiometric method. The NOT is used for the cure of depression. For comparison purpose cmc value of pure drug NOT was also evaluated by conductimetric technique. Different theoretical models like Clint, Rubingh, and Rosen were used to get information about the nature of interaction between the components in bulk and at the interface. Because of the occurrence of urea increase in the surface charge of the micelles was obtained resulting a delay of the micelles formation. The cmc values of the mixed systems of NOT and TX‐114 were found to be in between the cmc values of pure components, which signify nonideal mixed system having attractive interactions in the absence and presence of urea. Various parameters such as micellar mole fractions of TX‐114 (X₁^m, X₁^σ) in solution and at interface, interaction parameter (β^m/β^σ) in solution and at interface, and activity coefficient in solution and at interface were evaluated and discussed using Rubingh's and Rosen's models. Surface excess (Γ_max) increases that means minimum area per head group (A_min) decreases as mole fraction (α₁) of TX‐114 increases in the absence/presence of urea. Different thermodynamic parameters have been calculated and discussed. The ?G⁰_m values achieved are all negative both in the absence and occurrence of urea.     

流动注射化学发光测定环境雌激素双酚S

在碱性介质中,鲁米诺与还原剂盐酸羟胺反应产生化学发光,Co(Ⅱ)可催化此化学发光反应,而双酚S的存在能够明显抑制发光信号的强度,由此建立测定微量双酚S的流动注射化学发光分析方法.双酚S浓度在1.008×10-6～1.209 ×10-5mol·L-1范围内线的性回归方程为Y =550.83X+ 15 989.24(R=0.993 2).对样品浓度为1.0×10-6mol·L-1的标准溶液进行7次平行测定,相对标准偏差(RSD)为2.5;,检出限为1.0×10-6mol·L-1.应用该法测定环境样品中双酚S,简便、快速、准确.