摘要:

The behaviour of sodium salts of two heterocyclic sulphonamide derivatives (Sulphadimidine and sulphadiazine) in non-aqueous titrimetry was studied. Accordingly a simple and accurate procedure for their determination, based on their titration in acetic anhydride-acetic acid solvent system (5:1) with acetous perchloric acid solution is proposed. Results obtained agreed with those of a pharmacopoeial method.

ISSN:0003-2719    

DOI:10.1080/00032718508064482

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Due to the limited supply of blank synovial fluid, the usual practice of preparing a calibration curve for the biological sample of measurement is not practical for synovial fluid drug level determination. The linearity and correlation of peak height ratio between plasma and synovial fluid samples were investigated in this study. Excellent linear relationship is obtained from the calibration curves for both biological samples. In addition, excellent correlation of peak height ratios between plasma and synovial fluid indicates that the plasma calibration curve can be used in lieu of a synovial fluid calibration curve (slope 0.9154; intercept not statistically different than zero; and r-0.999 with N=13). According to this linear relationship, synovial fluid levels can be calculated based on the concentration as determined from the plasma calibration curve and divided by 0.9154. The extraction efficiences were comparable when diclofenac was spiked into human plasma or synovial fluid samples but the extraction of internal standard is better from synovial fluid than from plasma. The results are in good agreement with those observed in correlation between plasma and synovial fluid. Linearity and sensitivity of diclofenac in synovial fluid were determined in this study, but precision, accuracy and specificity were not determined due to the difficulty to obtain blank synovial fluid. Nevertheless, the same assay has been applied to plasma where all parameters have been well established and it is reasonable to assume the same results would have been obtained from synovial fluid samples.

ISSN:0003-2719    

DOI:10.1080/00032718508064483

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A selective and sensitive spectrophotometric and atomic absorption spectrophotometric method is developed for the determination of traces of mercury with N-phenylcinnamohydroxamic acid (PCHA) in the environment. Mercury is extracted into a chloroform solution of PCHA at pH 8.5-10.0 and determined by AAS. The mercury hydroxamate binary complex is yellow in colour having a maximum absorbance at 390 nm and molar absorptivity 4.3 × 1031 mol−1cm−1, sandell sensitivity 0.0466 μg/cm2. The ternary system using 1-(2-pyridylazo)-2-naphthol has molar absorptivity 8.82 × 1031 mol−1cm−1at 550nm, sandell sensitivity 0.0228 μ/cm2. Beer's law is obeyed in the concentration range of 2.37-38.0 ppm and 0.80-19.5 ppm of mercury for binary and ternary system, respectively. The extraction of Hg-PCHA binary system is studied with a liquid cation exchanger, bis-(2-ethyl hexyl) phosphoric acid (HDEHP) and found to have better selectivity than Hg-PCHA-PAN system. The molar absorptivity of the Hg-PCHA-HDEHP system is 8.82 × 1031 mol−1cm−1at 390 nm and Beer's law is obeyed in the concentration range of 0.47-20 ppm of mercury.

ISSN:0003-2719    

DOI:10.1080/00032718508064484

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The structure of the derivative formed during the reaction of 1,3-dimethyluric acid, the major metabolite of theophylline in humans, with iodopropane was elucidated. GC-MS analysis indicated the presence of a single dipropylated product even though three positional isomers are possible. The stability of the product was lower than anticipated since one of the alkyl groups added was readily removed by acid hydrolysis. Carbon-13 NMR proved to be the most useful technique for establishing the positions of alkylation. Assignment of carbon-13 resonances were consistent with placement of propyl groups onN-7 and on the oxygen atC-8. The structure of the product was assigned as 1,3-dimethyl-7-(1-propyl)-8-(1-propyloxy)xanthine. ThisO-alkylated structure is unusual since most heterocycles that can exist as lactim-lactam tautomers alkylate primarily on ring nitrogens.

ISSN:0003-2719    

DOI:10.1080/00032718508064485

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The official compendial USP method for the determination of Diphenoxylate HCI (DPHCI) and Atropine Sulphate (ATSO4) involves extensive sample manipulation followed by non-aqueous titration for (DPHCI) and gas chromatography for (ATSO4). Furthermore, the assay for individual tablets (content uniformity) is not specific. The proposed HPLC methodology offers substantial improvement in sensitivity, specificity and speed. The method provides simultaneous separation with minimum sample manipulation. The total elution time is less than ten minutes. The accuracy of the method was validated by comparing the results with those obtained by applying the USP XX method on commercial tablets. The specificity of the method was confirmed by the results of content uniformity of DPHCI which were more accurate than those obtained by the USP method.

ISSN:0003-2719    

DOI:10.1080/00032718508064486

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Adsorptive/extractive accumulation of 1,2,3,4-tetrahydrocarbazole at a carbon paste electrode is used to improve the subsequent voltammetric measurement with respect to sensitivity and selectivity. By simply immersing the electrode in the 1,2,3,4-tetrahydrocarbazole solution for a given period of time, and then transferring it to a blank solution, high degree of selectivity is achieved. After 10 min preconcentration, a detection limit near 1.4×10-8M 1,2,3,4-tetrahydrocarbazole is obtained. Cyclic voltammetry is used to aid understanding the nature of the accumulation process. Applicability to measurements of other indole alkaloids and to analysis of urine samples is illustrated.

ISSN:0003-2719    

DOI:10.1080/00032718508064487

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The anodic oxidation of melphalan was studied on a glassy carbon disk electrode, either stationary or rotated, using a d.c. and a differential pulse potential program. The conditions have been found for a differential pulse voltammetric determination of the substance, with a detection limit of 1 × 10−6mol 1−1

ISSN:0003-2719    

DOI:10.1080/00032718508064488

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The mixture of captopril (antihypertensive) and bendroflumethiazide (diuretic) was assayed using conductimetric and amperometric methods. Each method was applied for the analysis of laboratory-made sample mixtures in authentic and dosage forms. For captopril, the amperometric and conductimetric methods gave mean percent recoveries of 100.2 ± 1.2 and 99.6 ± 1.2, respectively. These results have shown good agreement when compared with other methods in the literature. When applied to bendroflumethiazide the conductimetric method gave percent recovery of 98.5 ± 1.6 which agreed closely with the spectrophotometric pharmacopoeial method.

ISSN:0003-2719    

DOI:10.1080/00032718508064489

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The development of a polymer electrode using reticulated vitreous carbon (RVC) as a support material is described. A conducting layer of (poly)carbazole or (poly)thiophene is el eletrochemically plated onto a RVC surface and the system is applied to the study of the electrochemistry of certain tricyclic drugs. An electrochemical response is seen for amitriptyline, nortriptyline and protriptyline all of which were previously reported to be electrochemically inactive while iminostilbene, imipramine and carbamazepine demonstrate similar electrochemical behaviour at both polymer and conventional carbon electrodes. The advantages of such electrodes and their use as working electrodes in hydrodynammic electrochemical detectors is presented.

ISSN:0003-2719    

DOI:10.1080/00032718508064490

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Pentafluorophenyldimethylsilylchloride (flophemesyl chloride, FICI) has recently been used for derivatizations of alcohols, leading to significant improvements in detectability by gas chromatography (GC)-photoionization detection (PID) and electron capture detection (ECD). This off-line reaction has now been applied to a number of related alcohol derivatives, naturally occurring bioorganics such as cholesterol, androsterone, and similar sterols and steroids. Standard GC-ECD-PID analytical parameters have been determined, such as detection limits, calibration plots, ECD and PID relative response factors (RRF), ECD/PID relative response factor ratios, etc. for underivatized and derivatized substrates. Packed and capillary column GC conditions have been used with a 10.2 eV PID lamp. Application of the optimized derivatization-GC-ECD-PID method is reported for bioorganics in biological media. The overall results demonstrate the immediate applicability of such an approach for a number of alcohol derivatives, especially those having biological properties.

ISSN:0003-2719    

DOI:10.1080/00032718508064491

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor