The invention relates to a controlled release pharmaceutical formulation for oral administration which comprises discrete units comprising acrivastine or a salt thereof coated with a mixture containing:
a) a copolymer or polymer containing repeating monomer units selected from alkyl esters of acrylic and methacrylic acids and
b) ethyl cellulose,
 and a process for preparing such formulations.  
                            本发明涉及一种用于口服的控释药物制剂,该制剂包括由
阿伐斯汀或其盐组成的离散单元,其上涂有一种混合物,该混合物含有:
a) 共聚物或聚合物,含有选自
丙烯酸和
甲基丙烯酸烷基酯的重复单体单元,以及
b) 
乙基纤维素、
 以及制备此类制剂的工艺。