Insulin preparations, based on their duration of action, are categorized as short-acting and long-acting.

Short-acting regular insulin forms hexamers, slowing its absorption, and is given 30-45 minutes before a meal. In contrast, short-acting insulin analogs like lispro, aspart, and glulisine are injected just before meals. They dissociate into monomers, resulting in quicker absorption and rapid action.

An intermediate-acting NPH contains an insulin suspension complexed with zinc and protamine, which, upon administration, dissolves gradually, prolonging its action up to 10-20 hours.

In comparison, long-acting analogs, such as glargine, detemir, and degludec, provide extended insulin coverage and lower hypoglycemia risk.

Typically, pens or needle-free jet injectors subcutaneously inject an insulin preparation.

Also, continuous subcutaneous insulin infusion pumps deliver only short-acting insulins, improving glucose control overnight, between meals, and during exercise.

Additionally, intravenous infusions of regular insulin regulate glucose in diabetic ketoacidosis patients and during perioperative procedures.