1H-purine-2,6-dione, 3,7-dihydro-7-(2-((2-hydroxy-1-methyl-2-phenylethyl)amino)ethyl)-1,3-dimethyl-, monohydrochloride, (R-(R*,S*))-, mixt. with 7-(2-((2-(3,4-dihydroxyphenyl)-2-hydroxyethyl)amino)ethyl)-3,7-dihydro-1,3-dimethyl-1H-purine-2,6-dione monohydrochloride