Aim: To develop a validated and rapid reverse phase High Performance Liquid Chromatography (HPLC) analytical method for the assay of DTZ that could then be utilised to determine the stability of gastrografin®.
Methods: A published HPLC method for meglumine amidotrizoate injection was adapted and validated for the stability studies. These were carried out in accordance with ICH guidelines.
Results: The HPLC method was validated for specificity (no elution peak with placebo), linearity (r2=0.999), accuracy (≤5%) and precision (≤3%). Gastrografin® exposed to 25ºC and 60% relative humidity remained stable for 30 days with no physical change to the solution. Gastrografin® stored under identical conditions and exposed to 1.2 million lux hours of light remained stable for 7 days. Gastrografin® stored at 4ºC underwent crystallisation; this was readily reversed by agitation and had no discernible effect on 30-day drug stability.
Conclusion: Gastrografin® remains stable and active for a minimum of 30 days under standard storage conditions (25ºC, 60% humidity, no light) after re-packaging.