Objective: To evaluate the properties of calcium hydrogen phosphate as an absorbent

effect of calcium hydrogen phosphate with different powder properties on the adsorption and desorption characteristics of paeonol was investigated. Method: Taking paeonol as a model drug and two kinds of calcium hydrogen phosphate (SG-Ⅰ and SG-Ⅱ) with different powder properties as absorbents

the adsorption kinetics model and isothermal curve model of paeonol were used to match the adsorption process

the adsorption quantity and adsorption rate of paeonol

along with the specific surface area

pore volume

pore size and other powder parameters

were taken as indexes to compare the adsorption capacity of these two kinds of calcium hydrogen phosphate.And the dissolution of paeonol from the two kinds of adsorptive dispersions was investigated. Result: Both of adsorbing processes of paeonol by SG-Ⅰ and SG-Ⅱ were in accordance with the pseudo secondary kinetic model

and the adsorption rate parameter of SG-Ⅱ(15.832 g·g-1·h-1) was higher than that of SG-Ⅰ(8.183 g·g-1·h-1).Within the selected concentration range of paeonol

its adsorbing processes by SG-Ⅰ and SG-Ⅱ were in agreement with Freundlich adsorption isothermal model.The adsorption quantity of paeonol by SG-Ⅱ(0.926 g·g-1) was higher than that of SG-Ⅰ(0.508 g·g-1).In two kinds of dissolution media

the desorption processes of the two kinds of adsorptive dispersions were accorded with the pseudo secondary kinetic model.The desorption rate of paeonol was similar between the two kinds of adsorptive dispersions in the same solvent. Conclusion: The adsorption property of SG-Ⅱ with larger specific surface area

pore volume and pore diameter is better than that of SG-Ⅰ.The desorption properties of SG-Ⅰ and SG-Ⅱ are similar.