Objective: To investigate in vitro dissolution of five active ingredients in water-honeyed pills and dispensing granules of Erzhi Wan

and to compare dissolution behavior of five ingredients in these two preparations. Method: In vitro dissolution of Erzhi Wan was studied in formulations of water-honeyed pills and dispensing granules in different media (water

30% ethanol

0.1 mol·L-1 HCl

PBS with pH of 4.5 and 6.8) by following the 2010 edition of Chinese Pharmacopoeia through the second method (the paddle method)

rotation speed was set 75 r·min-1.UPLC was developed and validated to detect simultaneously in vitro dissolution of five active ingredients (salidroside

specnuezhenide

nuezhenoside

luteolin

oleanolic acid).Different parameters were employed to evaluate dissolution characteristics of these two preparations. Result: In different dissolution media

dissolution behavior of five ingredients in these two preparations had great difference.Salidroside

specnuezhenide and nuezhenoside in dispensing granules could dissolve fast and had high dissolution percentages (>85%) in each medium.Luteolin and oleanolic acid in water-honeyed pills dissolved very little (<30%) only in PBS with pH 6.8.Form difference factor of f1 and similarity factor of f2

the same ingredient in these two preparations had different dissolution behavior. Conclusion: Compared with water-honeyed pills

active ingredients in dispensing granules have a higher cumulative dissolution

and in the same medium

medicinal ingredient can be dissolved more.Dispensing granules has great advantage in the aspect of in vitro dissolution.This developed method can be applied for quality control of Erzhi Wan preparations.