摘要:

The results of investigations of active silicas do not permit an unambiguous description of their structure, which is different for each kind of this material. Aerogels, xerogels or the so called precipitated silicas have different physical properties, due to the application of empirically established conditions of precipitation or condensation of polysilicic acids.

ISSN:0038-7010    

DOI:10.1080/00387017908069143

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A PMR analytical method is developed for the quantitation of Clofibrate (ethyl 2-(ρ-chlorophenoxy)-2-methylpropionate) as a drug entity and in capsule dosage form. Standard deviations of ± 1. 07% and ± 1. 34% were obtained for the pure drug and capsules, respectively. The results obtained comply with official standards required by different pharmacopeias. The PMR spectrum, in addition, provides a very specific mean for identification of Clofibrate. The procedure proved to be simple, rapid, accurate and precise.

ISSN:0038-7010    

DOI:10.1080/00387017908069144

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A new method, involving the application of PMR spectrometry for the assay of tolazoline and its tablets, is proposed. The PMR spectrum of tolazoline has two well-defined singlets. The proposed method involves: 1) The extraction of tolazoline from alkaline medium with carbon tetrachloride containing hexamethyl-cyclotrisilazane as internal standard. 2) Comparing the integral of one of the singlets of tolazoline to that of the sharp singlet of hexamethylcyclotrisilazane.

ISSN:0038-7010    

DOI:10.1080/00387017908069145

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A new method is developed using PMR for the assay of chloramphenicol and its pharmaceutical forms. The method is rapid, accurate, precise and helps in confirming the identity and purity of the drug. The principle of the method involves comparing the integral of the well-defined doublet system of chloramphenicol spectrum (positioned at 7.6 δ and 7.5 δ) to that of the sharp singlet (positioned at 6.25 δ) of maleic acid which is used as internal standard.

ISSN:0038-7010    

DOI:10.1080/00387017908069146

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The conformational equilibrium of trans-2,3-dihydroxytetraline was studied by the1H-NMR method, on the basis of the methin protons signal width measurements. The metylene and methin protons of the alicyclic tetralene-diol ring represent the AB CC' A'B' system /Fig. 1,2/. The spectrum data are time averages of the values corresponding to the diaxial /a,a/ and diequatorial /e,e/ conformations and depend upon their ratio. The methin protons /C C'/ signal width /J, the distance measured between outer strong peaks, or at the 1/4 signal height/ equals JAC+ JBC+ JA'C+ JB'C1.Itis also represented by the equation J = nJaa + /1-n/Jee, where Jaa and Jee are the signal widths in the diaxial and diequatorial forms respectively, and n is the molar fraction of the diaxial form.

ISSN:0038-7010    

DOI:10.1080/00387017908069147

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A number of acid salts of simple dicarboxylic acids crystallize with their molecules linked into infinite chains by “very short” hydrogen bonds. In this type of H-bond two oxygen atoms, belonging to adjacent molecules are related by a centre of symmetry or by other symmetry element, and the proton lies on the symmetry elemept. These structures have been referred to as Type A2structures and present a characteristic i.r. spectrum of Hadzi's type1. Examples of salts showing this behaviour are given by the potassium hydrogen ma-lonate (KHM)2, potassium hydrogen succinate (KHS)3and potassium hydrogen glutarate (KHG)4, whose crystal structures have been studied by J.C. Speakman and his coworkers.

ISSN:0038-7010    

DOI:10.1080/00387017908069148

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A rapid and accurate PMR procedure is reported for the analysis of noscapine as a drug entity and in tablet dosage form. The method is precise with a standard deviation of ± 1. 44% and 1. 12% in the alkaloid and tablets respectively. The results of synthetic mixtures and tablets are comparable to those obtained by B. P. 1973 and NF. XIII procedures. In addition, the PMR spectrum furnishes a specific means of identification of noscapine.

ISSN:0038-7010    

DOI:10.1080/00387017908069149

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

An investigation is made of the axial distribution of thallium atoms in a unipolar arc dischrge depending on the interelectrode gap (of between 1 to 6 mm), the current intensity (of between 4 to 16 A), the lithium concentration (of between 0 to 8 per cent), and the position and polarity of the sample. With the aid of a time

ISSN:0038-7010    

DOI:10.1080/00387017908069150

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0038-7010    

DOI:10.1080/00387017908069142

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor