ABSTRACT
Some halogenated derivatives; namely, dibromohydantoin [DBH], N- bromosuccinimide [NBS] and N-chlorosuccinimide [NCS] are used for the titrimetric determination of five pharmaceutical compounds, that is, hydrochlorothiazide, theophylline, phenylephrine hydrochloride, antazoline hydrochloride and metronidazole. Phenylephrine hydrochloride and antazoline hydrochloride reacted, directly and indirectly, with DBH, NBS and NCS in the molar ratios 1: 1, 1: 2 and 1: 2; 1: 1, 1: 2 and 1: 2 respectively in the direct procedure. The molar ratios in the indirect procedure were 2: 3, 1: 3 and 1: 3, 1: 2, 1: 4 and 1: 3 for phenylephrine hydrochloride and antazoline hydrochloride, respectively. As for theophylline, hydrochlorothiazide and metronidazole they reacted only indirectly with DBH, NBS and NCS in the molar ratios, 1: 1, 1: 3 and 1: 1, 1: 1, 1: 2 and 1: 1, 1: 1 and 1: 2, respectively. NCS alone did not react, directly or indirectly, except after the addition of potassium bromide. The suggested titrimetric procedures are applied to bulk powders and to pharmaceutical formulations
ABSTRACT
Ten sulfonamides are determined by interaction with NCS or DBH together with metol and measurement of the purplered color produced at 520 nm. These sulfonamides are: sulfacetamide sodium, sulfamethoxazole, sulfaguanidine, sulfadimidine, sulfamethoxypyridazine, sulfamethoxydiazine, sulfaphenazole, sulfathiazole, phthalylsulfathiazole and succinylsulfathiazole. NBS is also used in conjuction with metol with the last five sulfonamides, not determined before by this procedure. The reaction is explained as involving oxidation of metol with NCS or DBH to p-N- methybenzoquinoneimine, followed by the formation of a purple red complex with the sulfonamide