Addition salts of acids esters crystalline 1- (2,2-dimethyl-propionyloxy) -etilicos of 3-cephem-4-carboxylic pure regarding the diastereoisomers.

The invention relates to SALES CRISTALINAS acid addition salts of the two diastereomers OF ESTER FROM 3 ARBOXILICO GENERAL II Mula where x equals the anion of an acid organic or inorganic, physiologically safe, OF ONE OR MORE BASES AND GROUP = NOH ARE NO POSITION, ASSETS Pharmaceutical AGAINST BACTERIAL INFECTIONS CEFAMICOS containing them, METHOD FOR PRODUCING DERIVATIVES CEFAMICOS and the use CEFAMICOS DERIVATIVES FOR COMBATING bacterial infections.