Long acting insulin:

Ans. C. GlargineRef: Essentials of Medical Pharmacology by KD Tripathi 7thled, p263ExplanationLente insulin is a combination of 30% semilente (amorphous) and 70% ultralente (crystalline) insulin zinc suspension.# One of the problems with regular insulin is it peaks 2 to 3 hours after administration and sustains over 6 to 8 hours, which does not mimic the physiological insulin response. This leads to postprandial hyperglycemia and intermittent hypoglycemia. To overcome this, long-acting 'modified' or 'retard' preparations of insulin were developed.# Retard preparations, are obtained by making insulin insoluble either by:# Complexing it with protamine (isophane) or# By precipitating it with excess zinc and increasing the particle size (ultralente, semilente, lente).Insulin-zinc suspensionIsophane (Neutral Protamine Hagedorn or NPH) insulinTwo types of insulin-zinc suspensions have been produced* Protamine is added in a quantity just sufficient to complex all insulin molecules* Neither of the two is present in free form* On S.C. injection, the complex dissociates slowly to yield an intermediate duration of action* Mostly used in combination with regular insulin (70:30 or 50:50)1. Ultralente # Large particles # Crystalline # Long-acting # Insoluble in water2. Semilente# Smaller particles# Amorphous# Short acting* Lente = ultralente + semilente in the ratio of 7:3 (It can be remembered like this: 70% bigger particle and 30% smaller particle)# Therefore lente insulin which is 70% ultralente + 30% semilente can be written in different ways as follows:# 70 % large particle + 30% small particle# 70 % crystalline + 30% amorphous (Answer)# 70 % long acting + 30% short acting# Apart from the above mentioned retard preparations, recently other insulin analogs like rapidly acting (lispro, aspart, glulisine) peakless and long-acting (glargine and detemir) have become available.TypeExampleRapid actingLisproAspartGlulisineShort actingRegular (soluble) insulinIntermediate actingLenteNPH or isophaneLong actingInsulin glargineInsulin detemir