Development and Validation of Two Analytical Methods Using High‐Performance Liquid Chromatography and Atomic Absorption Spectroscopy for the Analysis of Tunisian Marketed Pharmaceutical Product‐Based Insulin and Zinc: Application in Routine Stability

Given the widespread reliance on insulin among diabetic patients, ensuring its stability is an essential task not only for preserving its therapeutic efficacy but also for safeguarding patient health and safety. In addition, insulin storage practices were frequently misunderstood that may compromise drug potency. Moreover, there were discrepancies in the shelf lives of the different insulin products offered in Tunisia. Therefore, two analytical methods for the analysis of insulin using high-performance liquid chromatography coupled to ultraviolet detector (HPLC-UV) and zinc using atomic absorption spectroscopy (AAS) in Tunisian marketed pharmaceutical product-based insulin were employed. Then the stability of these products was assessed. The study showed good insulin stability at neutral pH exposed to daylight for at least 30 days at 25°C, whereas instability was revealed only in diluted solutions at pH 2. Our work highlights the necessity for a more comprehensive evaluation of insulin stability, particularly under conditions where consistent refrigeration is not feasible. Such an assessment is essential to inform practical storage guidelines and ensure therapeutic efficacy in resource-limited settings.