A simple and rapid calorimetric method for the determination of 10 sulphonamides as single entities and sulphamethoxazole in combination with trimethoprim without prior separation was developed. The method is based on the reaction of sulphonamide with phenothiazine and N-bromosuccinimide at pH 6 to produce a blue coloured product after acidification. The chromogen for all the sulphonamides was ...

Identification, especially of drugs, plays an important role in pharmaceutical analysis. Thin-layer chromatography (TLC) has been widely applied in this field, but sometimes its resolving power leaves something to be desired. Barbiturates, steroids, sulphonamides and local anaesthetics, for example, represent classes where an abundance of closely similar derivatives are available. Separations a...

Being impermeable to folic acid, many bacteria must rely on their ability to synthesise folate from PABA, Pteridine, and glutamate in contrast the mammalian in cells cannot synthesise folic acid and must obtain preformed folate as a vitamin in their diet. The sulphonamides are structurally similar to PABA, the sulphonamides competitively inhibit dihydropteroate synthetase, the enzyme that catal...