Insulin detemir achieves its prolonged duration of action through which pharmacokinetic property?

• A Covalent dimerisation of insulin molecules at the lysine B29 residue
• B Precipitation as microcrystals at the neutral pH of subcutaneous tissue
• C Binding to protamine to form an insoluble isophane complex
• D Formation of multi-hexamer dihexamers after acylation with myristic acid, with reversible albumin binding ✓

Explanation

Detemir has myristic acid (a C14 fatty acid) attached to lysine B29. This promotes self-association into dihexamers at the injection site and, more importantly, reversible binding to serum albumin, from which it is slowly released. Only about 2 percent circulates free, giving a smooth profile lasting up to 24 hours. Microcrystal precipitation at neutral pH is the mechanism of glargine, protamine complexation defines NPH, and covalent multihexamer chains describe degludec.

Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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