STABILITY OF INSULIN: A REVIEW ON THE IMPACT OF THE STORAGE CONDITIONS

Insulin, a life-saving hormone used in the treatment of diabetes, is exceptionally sensitive to various environmental factors. Its structural integrity and therapeutic efficacy can be significantly compromised by improper storage and handling. As a protein-based drug, insulin is susceptible to both physical and chemical degradation, which can result in reduced potency, increased immunogenicity, and potentially adverse patient outcomes. Understanding and mitigating these risks is essential for ensuring insulin remains safe and effective from the point of manufacture to patient administration. Several environmental factors influence insulin stability, with temperature being the most critical. Insulin must typically be stored between 2°C and 8°C to maintain its effectiveness. Exposure to temperatures outside this range, especially prolonged heat, can denature the protein, causing it to lose its functional conformation. Freezing insulin is equally detrimental, as it can lead to the formation of aggregates or fibrils that are not only inactive but may also provoke immune reactions. Light exposure, particularly ultraviolet (UV) light, can also induce chemical degradation through oxidation of amino acid residues, affecting the molecule's structure and activity. In addition, insulin’s stability is pH-dependent; extreme pH conditions can cause hydrolysis or deamidation, altering the molecule's charge and solubility.