Objective: To provide reference for rational amount of dilution solvent for precise dispensing of non-integral power injection in pharmacy intravenous admixture services (PIVAS). Methods: By simulating the actual process of drug dilution and using accurate measurement methods

the rational amount of dilution solvent was obtained through statistical analysis. Results: The amount of dilution solvent for 55 kinds of powder commonly used in our hospital was summarized. The following rules were obtained: the liquid volume of powder injection drugs with dose <0.40 g increased by 0 after dispensing; the liquid volume of powder injection drugs with dose from 0.40 to 0.60 g increased by 0.3 mL after dispensing; the liquid volume of powder injection drugs with dose from 1.00 to 1.20 g increased by 0.6 mL after dispensing

the liquid volume of powder injection drugs with dose from 1.50 to 2.25 g increased by 1.0 mL after dispensing. Conclusion: The precise dilution of powder injection has a certain rule. By introducing relative error analysis

a more rational amount of dilution solvent can be obtained

which is conducive to the precise dispensing in PIVAS of the children’s hospital.