Longest acting insulin is
**Core Concept**
Insulins are classified based on their duration of action and onset of action. Long-acting insulins are designed to provide a steady release of glucose-lowering activity over a prolonged period, typically 24 hours or more, without a pronounced peak in activity.
**Why the Correct Answer is Right**
The correct answer is **Glargine**. Glargine, a long-acting insulin analog, is formulated with a unique crystal structure that slows down its absorption from the subcutaneous tissue, resulting in a flat, basal insulin profile with minimal peak activity. This allows for 24-hour glucose control with once-daily dosing.
**Why Each Wrong Option is Incorrect**
* **Option A:** NPH (Neutral Protamine Hagedorn) insulin is an intermediate-acting insulin, not a long-acting insulin. It has a peak activity within 4-12 hours and a duration of action of around 12-18 hours.
* **Option B:** Ultralente insulin is a long-acting insulin, but it is not as commonly used as Glargine due to its variable absorption and peak activity. Its duration of action is also shorter than Glargine.
* **Option C:** Detemir insulin is another long-acting insulin analog, but it has a slightly shorter duration of action compared to Glargine and a more pronounced peak activity.
**Clinical Pearl / High-Yield Fact**
When selecting a long-acting insulin, consider the patient's lifestyle and glucose control needs. Glargine is a popular choice for patients with type 2 diabetes due to its flat profile and once-daily dosing.
**Correct Answer:** D. Glargine