| abstract |
A crystalline polymorphic form of 2- [4- [2 - [[(1S, 2R) -2-hydroxy-2- (4-hydroxyphenyl) -1-methylethyl] amino] ethyl] phenoxy] acetic acid having X-ray powder diffraction is disclosed analysis of intense diffraction peaks (diffraction angle: 2.theta.. + -. 0.1.degree.) at 10.8, 19.1, 19.3, 19.8, 20.6 and 27.0.degree. having significant stimulatory effects on .beta..sub.2.n. and .beta..sub.3.n.-adrenoreceptor, wherein said form of the compound is useful as a pain relieving agent and promoting the removal of calculi in urolithiasis and the like . Said crystalline polymorphic form may be prepared, for example, by hydrolysis of 2- [4- [2 - [[(1S, 2R) -2-hydroxy-2- (4-hydroxyphenyl) -1-methylethyl] amino] ethyl] phenoxy] acetate phosphate with sodium hydroxide followed by the addition of an aqueous phosphoric acid solution at 40 ° C and then by the addition of a mixed solvent containing water and methanol or by adding methanol to the resulting compound and stirring the suspension for 30 minutes to several hours at 40 ° C to reflux. flow. |