Addition salts of azithromycin and citric acid and process for preparing them

摘要

Said addition salts have a molar ratio between azithromycin and citric acid such as to provide a pH comprised between 4.0 and 8.0 in a 10% aqueous solution. The process for preparing said salts comprises: a) dissolving azithromycin in a solvent or mixture of solvents; b) adding citric acid; and c) isolating the product obtained by crystallisation. The addition salts of azithromycin and citric acid are stable and soluble in aqueous medium, being useful antibacterial and antiprotozoan agents.