[Quality control of mixtures for pediatric parenteral nutrition: Validation of sodium and potassium assay method]

Control of electrolyte concentration in mixtures for parenteral nutrition (MPN) for newborns is crucial before the release of the final product. We aimed to assess the validation of the electrolytes assay in MPN.

Electrolytes assay was performed with Ilyte Analyzer^®. Validation of method was realized in accordance with ICH (International Conference on Harmonization) guideline Q2(R1) and the commission report of the French society of pharmaceutical science and technology. Linearity test solutions were prepared in triplicate using five levels of concentrations for sodium and potassium (60-140% of theoretical concentrations). Accuracy of the method was deducted from the same results of linearity. The intermediate precision was ensured by dosing the main electrolyte in six MPN, during three successive days.

Linearity was assessed with correlation coefficients greater than 0.996 for both electrolytes. A non-significant result of comparison test of the intercept with zero (Student test) was obtained. A highly significant result of the test of existence of slopes (Fisher test) proved a linear regression for the 2 electrolytes (P<0.1%). Inter-day precision values were 2.68% and 2.65% respectively for sodium and potassium.

The validation of sodium and potassium assay method was successfully performed with Ilyte Analyzer^® allowing routine quality control in MPN.