Determination of peroxide value in microsphere suspending agents by automatic potentiometric titration
Objective To establish a potentiometric titration method for the determination of peroxide value in suspending agents for microsphere injection.Methods The pH of suspending agents was adjusted with phosphoric acid,and after shaking reaction with saturated potassium iodide solution,iodine titration solution(0.005 mol/L)was added,titrated with sodium thiosulfate titration solution(0.001 mol/L),and the peroxide value was determined with potentiometric titrator.Results The method was durable(RSD=2.23%)in the range of pH 4.0-5.0,with good precision(RSD=1.49%),the recovery rate was 88.46%-114.10%,and the accuracy was high.The suspending agents peroxide content of four batches were 2.75-3.98 μmol/100 ml.Conclusion This method is environmentally friendly and highly sensitive,and is suitable for the determination of peroxide value in liquid pharmaceutical preparations with extremely low peroxide value,such as microsphere suspending agents.