摘要:

A radioreceptor assay using the opioid delta receptor-preferring ligand D-2ala, D-5leu leucine enkephalin (3H-DADL) and the broader-specificity ligand3H-etorphine was used to measure five HPLC-purified neuropeptide fractions derived from the peptide-rich fraction of tissue homogenates of nine anatomical regions of the canine brain. The receptoractive peptides studied were methionine enkephalin, alpha-neo-endorphin, dynorphin 1-8, methionine enkephalin-Arg-Phe, and leucine enkephalin. These peptides derive from two larger precursors: proenkephalin A, which contains methionine enkephalin, leucine enkephalin, methionine enkephalin-Arg-Phe; and proenkephalin B, which contains alpha-neo-endorphin and dynorphin 1-8. Receptoractive peptides were measured in the peptide-rich fraction derived from homogenates of canine hypothalamus, pituitary, caudate nucleus, amygdala, hippocampus, mid-brain, thalamus, pons-medulla, and cortex.

ISSN:0003-2719    

DOI:10.1080/00032718508062908

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A comparison of an enzymeless direct electrochemical oxidation procedure at a platinum electrode for the determination of uric acid, and an enzyme sensor with immobilized urate: oxygen oxidoreductase (uricase), was performed in flow stream systems. The uricase enzyme electrode is based on the H2O2oxidation current. Both amperometric methods were related to the wall-known photometric uricase-catalase-procedure (UCM) as a reference method. The measured values of both methods are of the first derivatives of current change (dI/dt) due to the electrochemical or electrochemical enzymatic reaction, respectively. The analytical quality of the measurements is characterized by: precision s% within run < 2% day to day < 5% accuracy acceptable (control materials) correlation to reference method r >0.93 analysis rate 80 samples/hr

ISSN:0003-2719    

DOI:10.1080/00032718508062909

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Fluorescence spectral properties of pseudouridine, an important biological indicator, have been measured for the first time in this study. The fluorescence quantum yield is maximal in aqueous solution with pH values above 9 with spectral properties characteristic of 5 alkyl substituted uracil derivatives. Chromatographic analysis shows the fluorescence is associated only with the pseudouridine peak. The concentration dependence of fluorescence is linear from 4 to 45 micromolar at pH 11.5. The excitation maximum is about 295 nm and the emission is broad with a maximum at about 390 nm. Addition of pseudouridine to urine extracts gives a linear increase in fluorescence with increasing pseudouridine concentration.

ISSN:0003-2719    

DOI:10.1080/00032718508062910

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Two spectrophotometric methods have been described for the determination of α -tocopherol acetate (vitamin E) in soft capsules. The first method applies the orthogonal function method under least squares. The quadratic coefficients calculated over the wavelength range 277 - 304 nm at 4-nm intervals in chloroform were reproducible and independent of ethyl oleate concentration. The second method applies the second derivative (D2) to correct for irrelevant absorbance due to ethyl oleate The peak trough amplitude at 271 - 287 nm was in linear correlation to the concentration of vitamin E. The recoveries obtained using the proposed methods agreed with those obtained using the official proceduce.

ISSN:0003-2719    

DOI:10.1080/00032718508062911

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A simple fluorescence assay for liposome stability is described. A fluorogenic enzyme substrate. 4-methylumbelliferyl-β-D-glucuronide, is encapsulated in liposomes. In the presence ofE. Coliβ-glucuronidase, any of the substrate that has been released into the medium is converted to 4-methylum-belliferone, which is monitored fluorimetrically. The method offers several advantages over current methods, including high gain, extremely low leakage, and facile quantitation. The use of the assay as part of a prototype immunoassay is decribed.

ISSN:0003-2719    

DOI:10.1080/00032718508062912

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A new and sensitive spectrophotometric method has been developed for the determination of tetracyclines either in a pure form or in Pharmaceuticals, by a molybdenum blue method. The procedure is based on the observation that, in sulphuric acid medium, tetracyclines reduce ammonium molybdate to molybdenum blue, the absorbance of which is proportional to the amount of antibiotic present. The variables affecting development of the color have been investigated and the conditions optimized. Beer's law is obeyed for up to 20 μg/ml of tetracycline HCl and oxytetracycline HCl, 28 μg/ml of demeclocycline HCl, 18 μg/ml of chlortetracycline HCl, 32 μg/ml of doxycycline HCl and 40 μ/ml of rolitetracycline. Molar absorptivities (1 mol−1cm−1) and Sandell's sensitivities (μ cm−2per 0.001 absorbance unit) are, respectively: tetracycline HCl 4.9×104and 0.0098, oxytetracycline HCl 5.4×104and 0.0092, demeclocycline HCl 1.6×104and 0.0313, chlortetracycline HCl 5.5×104and 0.0094, doxycycline HCl 3.4×104and 0.0141, rolitetracycline 2.7×104and 0.0195.

ISSN:0003-2719    

DOI:10.1080/00032718508062913

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A new procedure for determination of Bromohexine is described. The method consists of extracting an ion pair between the Bromhexine and the inorganic complex Co(SCN)24and measuring Co in the organic phase by AAS at 240. 7 nm. The optimal experimental conditions: pH, concentration of Co(SCN)24, shaking time, phase ratio, number of extractions and the linear range of calibration are studied.

ISSN:0003-2719    

DOI:10.1080/00032718508062914

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

An inexpensive step-gradient elution of the above nonsteroidal anti-inflammatory drugs (NSAIDs) using HPLC is described. The method involves: ion pairing the acid NSAIDs with tetrabutylammonium hydroxide (TBA) at pH 7.2, a stepwise change between two mobile phases differing only in solvent strength, and a “dilute and shoot” plasma sample preparation.

ISSN:0003-2719    

DOI:10.1080/00032718508062915

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The neutral [Cu(II) - streptomycin .4 H2O] complex is prepared and characterized by elemental analysis, TGA, IR, electronic and ESR spectra. The bonding between Cu(II) and streptomycin is found to take place through a Cu-O bond. The indirect estimation of streptomycin sulfate by atomic absorption spectroscopy is affected by the addition of an excess of cupric ions in slightly alkaline medium; the unreacted copper is separated as insoluble carbonate. The concentration of streptomycin in its product with copper is then indirectly determined from a pre-drawn caliberation curve for standard copper sulfate solutions.

ISSN:0003-2719    

DOI:10.1080/00032718508062916

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A reverse phase high performance liquid chromatography assay used for quantitative analysis of tamoxifen, 4-hydroxytamoxifen, and N-desmethyltamoxifen extracted from human plasma was developed. Plasma samples were spiked with an internal standard, nafoxidine, extracted with 2% butanol in hexane, and activated to fluorescence by exposure to high intensity short-wave ultraviolet (254 nm) light. Aliquots of extracted plasma were then injected onto a C18 reverse phase column and eluted isocratically with a mobile phase of water and triethylamine in methanol. Fluorescence of activated tamoxifen and its metabolites was measured at 266 nm. Peak height ratios were used to quantitate tamoxifen and its metabolites from extracted human plasma specimens.

ISSN:0003-2719    

DOI:10.1080/00032718508062917

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor