<a href=
http://vardenafil.top>achat levitra pro</a> to obtain a second mixture of 1 and 2 having a ratio of 1 to 2 of about 1 1; and iii cooling the mixture to form a crystalline solid and a first mother liquor; iv removing the first mother liquor from the crystalline solid; and v evaporating the first mother liquor to form a solid having a ratio of 1 to 2 that is greater than 1 1