Crystalline microparticles consisting of a phenylalkylamino beta2-adrenergic agonist coated with a C12-C20 fatty acid to be used for the preparation of pharmaceutical aerosol formulations in form of suspension in a liquefied propellant gas or powder formulations.經以C12-C20脂肪酸包覆的苯基烷基胺基β2-腎上腺素激性致效劑所組成的結晶微粒可用於呈懸浮於液化推進劑氣體的懸浮液或粉末配方形式之醫藥噴霧劑配方的製備。