Canine Diabetes Wiki
Beef Lentard
Lente by Novo Nordisk
U100 Zinc
Action in dogs:
  • onset 2-5h,
  • peak 12-24h,
  • duration: maximum 36h
Line: Novo
Also known as: Beef Lente
Similar to: Betasint Bovine Lente
Hypurin Bovine Lente, Insuvet Lente, Iletin Lente
Use and Handling:
Shelf Life: 24 months Type: cloudy
When Opened: 28 days room temp.
In Pen: N/A
Notes: Protect from light and heat
Do Not Freeze, Re-suspend
Do not use if product does not re-suspend
Do not use intravenously [1]
Intramuscular use not advised,
Store between 2-8C
See Insuvet Lente, Hypurin Bovine Lente or
Betasint Bovine Lente for current handling information for beef lente insulin.
Lilly human insulins1992charts

Lilly insulin products-1992. This insulin is shown as Iletin II Lente.

Note that some countries have the brand name in U40 strength.

Novo Nordisk's old product, similar to Lilly's Iletin Lente [2]--a 100% bovine lente insulin which is intermediate-acting.

Current equivalents are: Hypurin Bovine Lente [3][4] by CP Pharma, Betasint Bovine Lente by Beta Laboratorios.[5]

It shared the Lente composition [6] definition of being a suspension of crystalline (ultralente) and amorphous (semilente) insulin in a ratio of 7 crystalline parts to 3 amorphous parts.[7]

Why Lente doesn't equal 70/30[]

Lente-70 30

Direct comparison of insulin activity profiles for Lente and 70/30 insulins. The early strong action from the non-suspended R/neutral/normal insulin is seen at the "bump" from hours 0-6.

Let's look at the differences in the two insulins. Lente is comprised of 70 % long-acting Ultralente insulin and 30% short-acting Semilente insulin. So proportions of a long-acting and short-acting insulin are being combined to produce a intermediate-acting insulin. Both Ultralente and Semilente insulin are suspended by adding zinc and the size of their respective insulin crystals. The largest insulin crystals are those of Ultralente, while Semilente contains the smallest, or microcrystals. Simply put, you're combining a long insulin and a short insulin to make an intermediate-acting one.[8] 70/30 insulin starts with 70% NPH/isophane insulin, an intermediate-acting insulin which is suspended by protamine. To that, 30% R/neutral/normal insulin, which is short-acting and soluble, meaning there is no suspension; nothing is added to this insulin to delay its action. In this case, you are taking an intermediate-acting insulin with a suspension and adding to it a short-acting one with no suspension to create an intermediate-acting insulin.

So we have an insulin (Lente), made up of a long-acting and short-acting insulin, both with zinc suspensions, and a mixed insulin (70/30), made from an intermediate-acting protamine suspended insulin and a short-acting one without any suspension. Because of these differences, the insulin action profile for these two insulins is going to be quite different, even though both insulins are classed as intermediate-acting.

What Lente Is Not[]

No Lente-type insulin regardless of species can contain any NPH/isophane insulin [9] or any R/Neutral insulin. [10]

Both are chemically impossible: the phenol preservative present in NPH/isophane alters the action of Lente-type insulins, creating a mixture with an approximate action of R/Neutral. [11]

The zinc suspension of Lente-type insulin binds R/Neutral, causing the short-acting insulin to slow, losing its short-acting effect. [12][13]

Before the invention of VetPen, Lente-type insulins could not be dispensed in pen or cartridge form because the glass ball formerly used to mix the insulin in these devices shattered the Lente crystals.[14]

Combining Lente Family Insulins[]

Insulin manufacturers [15] indicate that R/neutral and semilente, Lente, ultralente insulins are able to be combined in the same syringe, but only just before injection. In pre-filled syringes, the zinc suspension of the Lente-type insulins binds the R/neutral, causing it to lose its short-acting effect. Various studies have documented this, and some doctors advise against using R/neutral in the same syringe with the Lente family of insulins. [16][17][18][19]

None of the Lente family of insulins (semilente, Lente, Ultralente) can be combined with [11] NPH/isophane insulins. The phenol preservatives present in NPH-type insulins alters the Lente-types to the point where they become a close approximation of R/neutral, with regard to action. [19]

Keeping the phenol preservatives in mind, all protamine-suspended insulin mixes would be "off limits" regarding same syringe mixing with any Lente-type insulins. [19]

The following are lente type zinc suspension insulins but since they are produced for use in animals, they are not found in BNF, but in its sister veterinary formulary.

These fall into the category of intermediate-length insulins.

Lilly also produced an 85% bovine, 15% porcine insulin under the same Iletin trade name in the same various types. The blended beef/pork Iletin I was produced until 1999 [22].


  1. Maddison, Jill E.,Page, Stephen W.,Church, David B. (2008). Small Animal Clinical Pharmacology. Saunders Ltd..
  2. Discontinuation of Lilly's Iletin I beef/pork line of insulins; Iletin I Lente is at right.. Eli Lilly.
  3. Hypurin Bovine Lente Patient Information. NetDoctor UK.
  4. Hypurin Bovine Lente. Wockhardt UK.
  5. Prescribing Bovine Insulin.
  6. Scientific Discussion-Monotard. EMEA.
  7. Dumitriu, Severian (2001). Polymeric Biomaterials, Revised and Expanded 1104. CRC Press.
  8. Greco, Deborah (2010). Treating Diabetes Mellitus in Dogs and Cats. Western Veterinary Conference.
  9. Combining Lente-type Insulins with Phenol-Preserved Insulins. National Federation for the Blind.
  10. Lente Zinc Suspension Causes Loss Of R/Neutral Short-Acting Effect.
  11. 11.0 11.1 Lente-Type Insulins & NPH/Isophane Insulins-A Bad Combination. National Federation for the Blind. Cite error: Invalid <ref> tag; name "Bad" defined multiple times with different content
  12. Deckert, T. (1980). Intermediate-Acting Insulin Preparations: NPH (Isophane) & Lente. Diabetes Care-1980.
    Note--in 1980, there were no r-DNA/GE/GM insulins
  13. Resource Guide. American Diabetes Association (2005).
  14. Hanas, Ragnar (1999). Insulin-Dependent Diabetes-Page 10. ChildrenWithDiabetes.
  15. Insulin Producers vs Doctors Re:Combining R/Neutral & Lente-type Insulins.
  16. Huffman DM, Garber AJ. (1991). Availability of Soluble (R/Neutral) Insulin in Mixed Preparations of Crystalline (Lente) & Ultralente GE Insulins. Clinical Therapeutics.
  17. Bilo HJ, Heine RJ, Sikkenk AC, van der Meer J, van der Veen EA. (1987). Absorption Kinetics & Action Profiles-Single Subcutaneous Administration of Human Soluble (R/Neutral) & Lente Insulin. Diabetes Care.
  18. Heine RJ, Sikkenk AC, Eizenga WH, van der Veen EA. (1983). Delayed Onset of Action of Soluble (R/Neutral) Insulin After Premixing With Lente Insulin. Diabetes Research & Clinical Practice.
  19. 19.0 19.1 19.2 Insulin Therapy-Mixing Precautions. Cite error: Invalid <ref> tag; name "Rx" defined multiple times with different content Cite error: Invalid <ref> tag; name "Rx" defined multiple times with different content
  20. Iletin I Lente-Beef/Pork Insulin Shown at Right.
  21. Carton Image-Iletin II Lente.
  22. Norsworthy, Gary (July 1999). Lilly Discontinues Beef-Pork Insulin. Veterinary Forum.

Related pages
Lilly human insulins1992charts
Cp wockhardt bovine insulins
87 main
Iletin Lente
Hypurin Bovine Lente
Insuvet Lente