Colorimetric and Bromometric Determination of Pirbuterol Hydrochloride

Abstract

Two proposed methods are reported for the quantitation of pirbuterol hydrochloride, namely, (i) colorimetric and (ii) titrimetric methods. The colorimetric method is based on coupling betweem diazotized sulphanilamide and pirbuterol hydrochloride. Under the optimum conditions studied, the coupling product exhibits a maximum at 440 nm. Linear relation between absorbance, A, and concentration of pirbuterol hydrochloride is in the range 5–40 μgml^?1. The mean percentage obtained for capsules (Exirel^R ?15 mg) was 100.8 ± 0.7 whereas mean percentage recovery obtained for the authentic drug was 100.5 ± 0.8.

The titrimetric procedure involves bromination of authentic pirbuterol in acid medium and residual titration of excess bromine. The stoichiometry of the reaction was investigated and infra-red analysis, of the bromoderivative was carried out. When applied to capsules the bromometric method gave mean percentage of 100.18 ± 2.25.     

对氯苯肼盐酸盐的合成工艺

对氯苯肼盐酸盐;工业合成;对氯苯肼盐酸盐的合成工艺     

An efficient and one-pot green synthesis of novel 6-oxo-7-aryl-6,7-dihydrochromeno pyrano[2,3-b]pyridine derivatives

A simple and efficient protocol has been developed for the construction of novel 6-oxo-7-aryl-6,7-dihydrochromenopyrano[2,3-b]pyridine derivatives using one-pot, three-component cyclocondensation of 4-hydroxycoumarin, various aromatic aldehydes and 2-aminoprop-1-ene-1,1,3-tricarbonitrile using 10?mol % guanidine hydrochloride as the organocatalyst under solvent-free conditions at 90?°C for the first time. The significant features of this protocol are operational simplicity, provide good to high yields, avoidance of toxic solvents, straightforward work-up, no column chromatographic purification and atom-economy which is considered to be relatively environmentally benign.     

Synthesis of a new Pt(II) complex containing valganciclovir drug and calf-thymus DNA interaction study using multispectroscopic methods

A new complex, [Pt(valcyte)(DMSO)Cl]Cl, in which valcyte (trade name) served as valganciclovir hydrochloride drug ([2-[(2-amino-6-oxo-3H-purin-9-yl)methoxy]-3-hydroxypropyl](2S)-2-amino-3-methylbutanoate), was synthesized and characterized by different physicochemical methods. Binding interaction of this complex with calf-thymus DNA (ct-DNA) has been investigated by multispectroscopic techniques. The complex displays significant binding properties with ct-DNA. The results of fluorescence and UV–vis absorption spectroscopy indicated that this complex interacted with ct-DNA in a groove-binding mode, and the binding constant was 3.8 × 10⁴ M^?1. Furthermore, the complex induced detectable changes in the CD spectrum of ct-DNA and slightly changed its viscosity which verified the groove-binding mode. Finally, all results indicated that Pt(II) complex interact with DNA via groove-binding mode.     

超高效液相色谱-串联质谱法测定人血浆中盐酸氨溴索及其制剂的生物等效性评价

采用超高效液相色谱-串联质谱（UHPLC-MS/MS）技术,建立了快速、简单、灵敏的测定人血浆中盐酸氨溴索含量的方法,并用于盐酸氨溴索人体生物等效性预试验研究。取50 μL血浆样品,采用蛋白沉淀法处理,以盐酸氨溴索-d5为内标。采用Waters XBridge BEH C18色谱柱（50 mm×2.1 mm,2.5 μm）,以0.1%（v/v）甲酸水-含0.1%（v/v）甲酸的甲醇为流动相,在0.4 mL/min流速下进行梯度洗脱。采用电喷雾电离（ESI）源以正离子模式进行MRM检测。结果显示,盐酸氨溴索在2~400 ng/mL范围内线性关系良好,相关系数（r）为0.998,准确度为97.1%~108.7%,精密度为1.0%~5.6%。将该方法用于6名健康受试者口服盐酸氨溴索受试制剂和参比制剂30 mg后血药浓度的测定,结果显示二者相对生物利用度为（102.3±14.8）%,血药浓度-时间曲线下面积（AUC_0-t、AUC_0-∞）和最大血药浓度（C_max）的90%置信区间均在80.0%~125.0%范围内,两种制剂生物等效。     

D-氨基葡萄糖与Sm^3＋和Eu^3＋离子配合物的合成和表征

D-氨基葡萄糖(2氨-基-2脱-氧-D葡-萄糖,简称GLCN)是甲壳素或壳聚糖的最终水解产物。由于其分子内含有多个反应中心(-OH,-NH2),且无毒、水溶性好,易与多种金属离子配位,而用于贵金属回收、工业废水处理等生态和环境保护方面;由于其与金属离子形成的配合物水溶性好、低毒、甚至无     

Development of an enzyme-linked immunosorbent assay (ELISA)-like fluorescence assay to investigate the interactions of glycosaminoglycans to cells

Sulfated glycosaminoglycans were labeled with biotin to study their interaction with cells in culture. Thus, heparin, heparan sulfate, chondroitin 4-sulfate, chondroitin 6-sulfate and dermatan sulfate were labeled using biotin-hydrazide, under different conditions. The structural characteristics of the biotinylated products were determined by chemical (molar ratios of hexosamine, uronic acid, sulfate and biotin) and enzymatic methods (susceptibility to degradation by chondroitinases and heparitinases). The binding of biotinylated glycosaminoglycans was investigated both in endothelial and smooth muscle cells in culture, using a novel time resolved fluorometric method based on interaction of europium-labeled streptavidin with the biotin covalently linked to the compounds. The interactions of glycosaminoglycans were saturable and number of binding sites could be obtained for each individual compound. The apparent dissociation constant varied among the different glycosaminoglycans and between the two cell lines. The interactions of the biotinylated glycosaminoglycans with the cells were also evaluated using confocal microscopy. We propose a convenient and reliable method for the preparation of biotinylated glycosaminoglycans, as well as a sensitive non-competitive fluorescence-based assay for studies of the interactions and binding of these compounds to cells in culture.     

Colorimetric and Polarographic Methods of Analysis for Prenalterol Hydrochloride

Abstract

Two proposed methods have been described for the determination of prenalterol hydrochloride in acetate buffer (pH=4.1) as authentic material and in tablets form using a (i) colorimetric method based on reduction of ferric iron by prenalterol hydrochloride and subsequent measurement at 511 nm of the red color obtained by the treatment of the resultant ferrous iron with 1, 10-orthophenanthroline, (ii) a differential pulse polarographic method based on nitrosation with 0.1 M NaNO₂/dil. HC1 and consequent recording of the differential pulse polarogram. The differential polarogram was obtained under constant amplitude pulses of 50 mV (DP 50) superimposed on a linearly increasing DC-voltage ramp. The peak height (h), of the polarogram was measured at the peak potential of -0.2V on the dropping mercury electrode (DME) versus Ag/AgCl reference electrode. The linearity ranges observed are 0.6μgfml to 6.0μg/ml and 2μg/ml to 12μg/ml, respectively. The mean percentage recoveries for an authentic sample are 99.5±1.4 and 100.5±0.7, respectively. When applied to tablets claimed to contain 10 mg each, the mean percentages obtained are 99.7±2.3 and 100.6 ±1.5 respectively.     

盐酸吡格列酮的合成新方法研究

报道了治疗糖尿病药物盐酸吡格列酮的合成新方法.在六氢吡啶作用下,对羟基苯甲醛和2,4-噻唑烷二酮缩合生成5-[(4-羟苯基)亚甲基]-2,4-噻唑烷二酮,经钯炭催化氢化还原生成5-[(4-羟苯基)甲基]-2,4-噻唑烷二酮,再和氢氧化钾反应生成相应的钾盐,然后与5-乙基-2-羟乙基吡啶和甲基磺酰氯反应得到的磺酸酯作用生成吡格列酮,最后用盐酸酸化得到其盐酸盐.产品结构经1H NMR和IR确证.     

Flow Injection Chemiluminescence Method for Nalbuphine Hydrochloride in Pharmaceutical Formulations Using Tris(2,2'-bipyridyl)ruthenium(II) Chloride-diperiodatocuprate(III) Reaction

Asensitive and selective method employing chemiluminescence(CL) coupled with flow injection(FI) is reported for nalbuphine hydrochloride(NAL) assay in pharmaceutical formulations. The enhancement effect of NAL on the CL reaction between tris(2,2'-bipyridyl)ruthenium(II) chloride-diperiodatocuprate(III) {Ru[(bpy)₃]²⁺-Cu(III) complex} in acidic medium is used as analytical measurement. The optimal conditions of the CL reaction were sulfuric acid 1.0×10^-3 mol/L, Ru[(bpy)₃]²⁺ 7.5×10^-5 mol/L, Cu(III)/Ag(III) complexes 4.0×10^-4/5.0×10^-4 mol/L, sample loop volume of 120 μL and flow rate of 2.5 mL/min. The sensitivities of the method in terms of detection(S/N=3) and quantification(S/N=10) limits are 5×10^-4 and 0.001 ppm(1 ppm=1 mg/L), respectively. The linear response of the instrument in the form of CL intensity with respect to NAL concentration is over the range 0.001-15.0 ppm(R²=0.9999) with relative standard deviation from 0.8% to 3.2% and injection throughput of 120 injection/h. The applications of the method include the quantitative analysis of NAL in pharmaceutical injection samples. Variations and the average results of the proposed method are not signi-ficantly different from the results of a reported method by applying F- and paired student t-test. The most likely CL reaction mechanism is written in accordance with spectrophotometric and CL studies.