The synthesized piperazium salt of KMUPs disclosed in the present invention is characterized by presented pharmaceutics having functions to improve 5-HT function and eNOS expression of KMUPS in lung diseases, such as proliferation, obliteration, pulmonary artery hypertension. The pharmaceutical composition for inhibiting monocrotaline (MCT)-induced proliferation of pulmonary artery includes an effective amount of a complex salt of formula (I):wherein R2 and R4 are each selected independently from the group consisting of a C1˜C5 alkoxy group, a hydrogen, a nitro group, and a halogen atom RX contains a carboxylic group donated from one selected from a group consisting of a Statin, a Co-polymer, a poly-γ-polyglutamic acid (γ-PGA) derivative and sodium CMC and −RX substituent is an anion of the carboxylic group carrying a negative charge and a pharmaceutically accepted carrier.
