Pure sodium salt of clavulanic acid

摘要

The invention provides the compound (2R,5R,Z)-3-(2-hydroxyethylidene)-7-oxo-4-oxa-1-azabicyclo-[3,2,0]hept ane-2-carboxylic acid and its salts in purified form and pharmaceutical compositions containing them and a process for the purification of such compounds by conversion in aqueous media to the lithium salt of the above acid and precipitation thereof.