[Validation of triiodothyronine sodium analysis method]

To validate the ultraviolet spectrophotometry analytical method for triiodothyronine sodium in order to use this method in the quality control process of a diluted powder of said active principle for the manufacturing of 25 mcg capsules.

An ultraviolet spectrophotometry analysis is performed on triiodothyronine sodium to obtain its spectrum. Subsequently, a mother solution of triiodothyronine sodium is made, from which 5 different-concentration dilutions are prepared in order to obtain a calibration line allowing the study of the method's linearity. Then 3 of these 5 dilutions are selected for repeatability and reproducibility studies. Two pattern solutions with differing concentrations are prepared for the accuracy study. Three different-concentration dilutions are prepared from each of them. The absorbencies of controls for both pattern solutions are measured to compare results obtained.

A scan is performed between 350 and 200 nm, and an experimental peak of 319 nm is obtained. The method proves linear for the considered range of concentrations (r(2) = 0.9985). Variation coefficients are around 2%, thus indicating good repeatability and reproducibility. The mean percentage of recovery in known-concentration samples does not significantly differ from the theoretical 100%.

The studied analytical method is adequately reliable to result in a foreseen result within defined intervals.