Pharmaceuticals sulphonamides

Other methods have involved compleximetric titration, nephelom-etry, potentiometric titration, and gravimetric methods. In 1981, a paper by Mayanna and Jayaram11 outlined the determination of caffeine in a wide variety of products including pharmaceuticals and food products using sodium N-chloro-p-toluene-sulphonamide (chloramine-T) in a titri-metric procedure. 

A plethora of weakly acidic pharmaceutical substances may be titrated effectively by making use of a suitable non-aqueous solvent with a sharp end-point. The wide spectrum of such organic compounds include anhydrides, acids, amino acids, acid halides, enols (viz., barbiturates), xanthines, sulphonamides, phenols, imides and lastly the organic salts of inorganic acids. 

This section is devoted mainly to the derivatization and GC of thiols, sulphonic acids and related compounds. The GC of other sulphur compounds (sulphones, sulphonamides, etc.) is also mentioned in other sections, e.g., Pharmaceuticals, Insecticides. 

The pharmaceutical uses of sulphonamides have ensured that they have been well-studied by NMR spectroscopy. Proton NMR spectra have been reported, but in recent years systematic studies have been particularly evident for 13C and other nucleus NMR (Section III.B). 

Many sulphonamides are important compounds in the pharmaceutical and other branches of the chemical industry. In fact, sulphonamides were among the first synthetic antibacterial agents that were found to be effective in humans. An excellent account of the uses, manufacture and properties of sulphonamides has been published431. 

Garcia-Alvarez-Coque, M.C. Simo-Alfonso, E.F. Ramis-Ramos, G. Esteve-Romero, J.S. High-performance micellar liquid chromatography determination of sulphonamides in pharmaceuticals after azodye precolumn derivatization. J.Pharm.Biomed.Anal., 1995, 13, 237-245... 

The modem pharmaceutical industry dates back to the discovery of the sulphonamide drags in 1935. The industry has grown since 1950 typically at 7-15% per year, and over 95% of drags available originated after that date. An astonishing series of innovations has increased life... 

Sulphonamides in pharmaceutical preparations and urine were determined indirectly using flame AAS by continuous precipitation with copper or silver, as proposed by Montero et al.[22]. The copper method exhibited a better selectivity, and only this was used for determinations in urine. The precipitate, formed by injecting one of the cations into a carrier containing the sample, was collected on an on-line filter, and the peak absorbance of the residual metal in the stream passing through the filter was measured. The decrease in peak height compared to a blank was then related to the sulphonamide... 

Moniero et al.[24] developed an indirect AAS method for the determination of local anaesthetics (lidocaine. tetracaine and procaine hydrochlorides) in pharmaceutical preparations using FI on-line precipitation-dissolution. A cobalt solution is injected into a carrier stream containing the sample, and the precipitate formed is retained on an online stainless steel filter. The determinations were made by measuring the residual cobalt concentration in a similar way as for the indirect determination of sulphonamides (cf. Sec. 9.4.2). A sampling frequency of 100 h was achieved with a precision of 0.6% r.s.d.. 

Interest in the new drugs was considerable at ICI, in keeping with its new-found interest in diversified research. In 1936, ICI had created a Medicinals Chemicals Division as a subsection of its dyestuffs research department. The division drew on expertise in coal tar dye chemistry, as did sulphonamide studies, since the reactions used to produce dye intermediates were almost the same as those used to prepare many pharmaceutical products. This enabled ICI to make substantial contributions during World War II, again drawing on earlier German discoveries, notably the antimalarials Atebrin (Mepacrine), and Plasmoquin," ... 

Many sulphonamides can be extracted with acetone from pharmaceutical preparations. 

Several successful applications of fused-core columns for the analysis of emerging contaminants in environmental samples are described in the literature, including the analysis of pharmaceuticals and their metabolites in wastewater [13], personal care products (PCPs antimicrobials, preservatives), benzotriazole UV stabilizers and organophosphorus compounds in fish tissue [14], sulphonamide antibiotics in fish [15],... 

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