[Determination of acid-base amphoteric dissociation constant of 2-methyl-5 (4)-nitroimidazole by UV-spectrophotometry].

[Determination of acid-base amphoteric dissociation constant of 2-methyl-5 (4)-nitroimidazole by UV-spectrophotometry].

Hua xi yi ke da xue xue bao = Journal of West China University of Medical Sciences = Huaxi yike daxue xuebao (2002-09-06)

S Yang

PMID12212306

ABSTRACT

The 2-methyl-5(4)-nitromidazole(BH) is an ampholyte with acid and base. It is an intermediate of metronidazole. The amphoteric dissociation constant of BH determined by equimolar UV-spectrophotometry. The acidic dissociation constant pKa is 9.64 +/- 0.04 and the basic dissociation constant pKb is 12.98 +/- 0.02.

MATERIALS

Product Number

Brand

Product Description

32542

Supelco

Menidazole, VETRANAL^®, analytical standard

136255

Sigma-Aldrich

2-Methyl-4(5)-nitroimidazole, 99%

PHR1195

Supelco

Tinidazole Related Compound A, Pharmaceutical Secondary Standard; Certified Reference Material

Y0000087

Metronidazole impurity A, European Pharmacopoeia (EP) Reference Standard