DEVELOPMENT AND VALIDATION OF A SENSITIVE LC–MS METHOD FOR THE DETERMINATION OF FOUR POTENTIAL IMPURITIES (LAS-I, LAS-II AND THEIR REGIOISOMERS) IN LASMIDITAN DRUG SUBSTANCE AT PPM LEVELS. int. J. Eng. Res. Sci. Tech. 2026;22(4(S):109-116. doi:10.62643/ijerst.2026.v22.n4(s).4807