[DEFINITION]:（3R,4S,5S,6R,7R,9R,11S,12R,13S,14R）-4-[（2，6，-Dideoxy-3-C-L-ribo-hexopyranosyl）oxy]-14-ethyl-7，12，methyl-3-O-methyl- α -13-trihydroxy-10-[(E)-[(2-methoxyethoxy)methoxy]imino]-3,5,7,9,11,13,-hetamethyl-6-[[3,4,6-tr-deoxy-3-(dimethylamino)—D-xylo-hexopyranosyl]oxy]oxacyclotetradecan-2-one(erythromycin9-CE)-[0-[(2-methoxyethoxy)methyl]oxime]).

[CHARACTERS]:Appearace：white,crystalline powder.

Solubilily：very slightly soluble in water,freely soluble in acetone,in alcohol and in methylene chloride.It is slightly soluble in dilute hydrochloric acid. It shows polymorphism.

[FUNCTION]:·Roxithromycin is indicated for use in the treatment of mild to moderate infections of the ear ,nose and throat ,reapiratory tract,in the skin structure and genito–urinary tract caused by susceptible strains of organisms listed below.

·Pharyngitis,tonsillitis,sinusitis and otitis media,due to Group A beta-haemolyetic Streptococci and Steptococcus pneumoniae.

·Pnenmonia and acute bronchitis due to streptococcue pneumoniae.

·Atypical pneumonia due to Mycoplasma pneumoiae pyoderma and erysipelas due to staphylococcus aureus and Group A betehaemolytic streptococci.

·Non­gonococcal urethritis in man, due to chlamydia trachomatis and ureaplasma urealyticum.