A patient is prescribed a premixed insulin formulation containing 70% insulin aspart protamine and 30% insulin aspart. The protamine component in this mixture serves which purpose?

• A It acts as a preservative to prevent bacterial growth in the vial
• B It neutralizes the acidic pH of insulin aspart to reduce injection site pain
• C It accelerates the onset of insulin aspart by preventing hexamer formation
• D It binds to insulin aspart to form a slowly absorbed crystalline suspension, providing intermediate-acting basal coverage ✓

Explanation

In premixed biphasic insulins like NovoMix 30, protamine binds to insulin aspart to create a crystalline suspension that is absorbed slowly, providing intermediate-acting (basal) coverage. The 30% free insulin aspart provides rapid mealtime coverage. This combination offers both basal and prandial insulin in a single injection, improving convenience and adherence.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.