Canine Diabetes Wiki
Betasint Porcine Lente
Lente by Beta Laboratorios
U40, U80, U100 Zinc
Action in dogs:
  • onset onset <1 hour,
  • peak gentle peak 4-8h,
  • duration 12h [1]
Line: Betasint
Also known as: Pork Lente
Similar to: Caninsulin U 40, Vetsulin U 40
Lente CHO U 80, Iletin II Lente U 100
Monotard Pork U 100
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, [2]  Re-suspend
Do not use if product does not re-suspend [3]
Do not use intravenously [4][5]
Intramuscular use not advised,
Store Upright between 2-8C

Betasint logo. Bovine insulin was successfully extracted in January 1987-porcine followed in June of the same year.

Betasint Porcine Lente [6][7] is an intermediate-acting Pork insulin made by Beta Laboratorios. Polfa Tarchomin produces a U80 pork Lente insulin called Lente CHO. The insulin in its U40 strength is identical to Caninsulin and Vetsulin.

Monotard Pork was a U100, 100% porcine insulin made by Novo Nordisk. It was an intermediate-acting, lente [8]-type.

Eli Lilly also made a comparable pork lente insulin, Iletin II Lente. [9][10]

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.[11] 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.[12]

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. [13] or any R/Neutral insulin[14]

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. [13][15]

The zinc suspension of Lente-type insulin binds R/Neutral, causing the short-acting insulin to slow, losing its short-acting effect. [16][15][17]

Combining Lente Family Insulins[]

Insulin manufacturers [18] 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. [19][20][21][22]

None of the Lente family of insulins (semilente, Lente, Ultralente) can be combined with [13] 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. [22]

Keeping the phenol preservatives in mind, all protamine-suspended insulin mixes would be "off limits" regarding same syringe mixing with any Lente-type insulins. [22]

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.


  1. Ruchinsky, Renee, et. al. (2010). Diabetes Management Guidelines for Dogs and Cats-page 7. American Animal Hospital Association (AAHA).
  2. Can I Still Use a Vial of Caninsulin if it Freezes?-FAQ. Intervet.
  3. What Should Caninsulin Look Like?-FAQ. Intervet.
  4. Maddison, Jill E.,Page, Stephen W.,Church, David B. (2008). Small Animal Clinical Pharmacology. Saunders Ltd..
  5. Caninsulin. Intervet UK.
  6. Betasint Porcine Lente. Beta Laboratorios.
  7. Google Translation of Betasint Porcine Lente page.
  8. Definition of Lente Insulin. Merck Manual.
  9. Copy of Iletin II Lente Patient Information Leaflet. Eli Lilly.
  10. Iletin II Lente Discontinuation Material. Eli Lilly (2003).
  11. Dumitriu, Severian (2001). Polymeric Biomaterials, Revised and Expanded 1104. CRC Press.
  12. Greco, Deborah (2010). Treating Diabetes Mellitus in Dogs and Cats. Western Veterinary Conference.
  13. 13.0 13.1 13.2 Combining Lente-type Insulins with Phenol-Preserved Insulins. National Federation for the Blind. Cite error: Invalid <ref> tag; name "Bad" defined multiple times with different content Cite error: Invalid <ref> tag; name "Bad" defined multiple times with different content
  14. Lente Zinc Suspension Causes Loss Of R/Neutral Short-Acting Effect.
  15. 15.0 15.1 Havlik I, Galasko G, Alberts E, Furman KI, Seftel HC. (1988). Solubility Changes on Mixing Short- and Long-acting Insulin Preparations. South African Medical Journal. Cite error: Invalid <ref> tag; name "Mixing" defined multiple times with different content
  16. Deckert, T. (1980). Intermediate-Acting Insulin Preparations: NPH (Isophane) & Lente. Diabetes Care.
    Note--in 1980, there were no r-DNA/GE/GM insulins
  17. Resource Guide. American Diabetes Association (2005).
  18. Insulin Producers vs Doctors Re:Combining R/Neutral & Lente-type Insulins.
  19. Huffman DM, Garber AJ. (1991). Availability of Soluble (R/Neutral) Insulin in Mixed Preparations of Crystalline (Lente) & Ultralente GE Insulins. -Clinical Therapeutics.
  20. 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.
  21. 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.
  22. 22.0 22.1 22.2 Insulin Therapy-Mixing Precautions.
  23. Iletin I Lente-Beef/Pork Insulin Shown at Right.
  24. Carton Image-Iletin II Lente.

More Information[]

Related Pages
Caninsulin 10764 420 00002841 101 Insulinum Lente 400px Lentetap
Iletin II Lente
Lente CHO
Monotard Pork