Mixtard 50 Penfill is a biphasic insulin formulation containing 50% soluble human insulin and 50% isophane insulin (NPH), each at a concentration of 100 IU/ml. This combination provides both rapid and intermediate-acting insulin effects, making it suitable for managing blood glucose levels in individuals with type 1 and type 2 diabetes mellitus. The insulin is produced using recombinant DNA technology, ensuring it is structurally identical to natural human insulin. Mixtard 50 Penfill is administered subcutaneously and is available in a 3 ml cartridge designed for use with insulin pens. It is indicated for the treatment of diabetes, particularly when blood glucose levels cannot be controlled by diet and oral medications alone. The onset of action is within 30 minutes, with peak effects occurring between 2 to 8 hours, and a duration of action up to 24 hours. Patients should follow their healthcare provider's instructions regarding dosage and administration. Common side effects may include hypoglycemia (low blood sugar), allergic reactions, and injection site reactions. Proper storage and handling are essential to maintain the efficacy of the insulin.