First Direct Isolation of Stable α-Form Crystals of Mirabegron, a Selective β3–Adrenoceptor Agonist

Abstract

An efficient and scalable method for the direct isolation of stable α-form crystals of mirabegron (1) is developed. The developed method negates transformation of metastable β-form crystals into α-form crystals thereby overcome the limitations of reported methods and avoids additional processing steps during its manufacture. The developed method directly provides stable α-form crystals of Mirabegron (1) with yield of around 84 % and purity of >99.77% by HPLC in a single step.