Canine Diabetes Wiki
Novo Semilente MC
Semilente by Novo Nordisk
U40 Zinc
Action in dogs:
  • onset within 45 minutes,
  • peak 2-4h,
  • duration 4-6h
Line: Novo
Also known as: Semitard, [1] pork semilente, semilente pork
Similar to: Insulinum semilente CHO
Use and Handling:
Shelf Life: 36 months Type: cloudy
When Opened: 6 weeks room temp.
In Pen: N/A
Notes: Protect from light and heat
Do Not Freeze,
Do not use if product does not re-suspend
Do not use intravenously [2]
Do not mix with non Lente-type insulins
Lente insuline

Novo Nordisk Semilente MC 40- Porcine (Pork) Insulin-German Packaging. This is semilente pork insulin (Insulin vom Schwein) in U40 strength. Novo discontinued this insulin and Polfa Tarchomin (Poland) began producing a similar insulin, Insulinum semilente CHO, in U80 strength. [3]

This was one of the last "plain" semilente [4] insulins marketed. Novo Nordisk distributed it in Germany, but not in places like the US, Canada and the UK. Semilente insulin [5] has an activity pattern similar to that of R/Neutral.

The MC (stands for Monocomponent) designation seen in the insulin's name means it is of animal origin and highly purified. In some markets, Novo Nordisk "coded" their insulin in this manner: MC was insulin of animal origin, while HM was of r-DNA/GE/GM origin. In the past, the MC designation could mean it was made of beef, of pork, or a blend of both, as it was a way of distinguishing highly purified beef and pork insulins. Seeing it prior to its discontinuance means the insulin was of pure porcine origin, as Novo discontinued its bovine insulins some time ago.

What Semilente Is Not[]

No Lente-type insulin regardless of species can contain any NPH/isophane insulin [6] or any R/Neutral insulin. [7][8]

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. [9][10]

The zinc suspension of Lente-type insulin binds R/Neutral, causing the short-acting insulin to slow, losing its short-acting effect. [11][12]

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.[13]

Combining Lente Family Insulins[]

None of the Lente family of insulins (semilente, Lente, Ultralente) can be combined with [9] 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. [9][14]

Keeping the phenol preservatives in mind, all protamine-suspended insulin mixes would be "off limits" regarding same syringe mixing with any Lente-type insulins. [14]

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. [8][16][17][14]

Mixing semilente with either NPH/isophane or PZI will alter the semilente insulin because of the phenol preservatives present in either of them.

Novo Nordisk has discontinued this insulin.[18] Polfa Tarchomin of Poland has recently started producing their own brand of pork semilente insulin which should be available in the UK & Europe.


  1. Montgomery, DAD. Modern Insulin and Insulin Therapy. Royal Victoria Hospital-Belfast.
  2. Maddison, Jill E.,Page, Stephen W.,Church, David B. (2008). Small Animal Clinical Pharmacology. Saunders Ltd..
  3. Insulinium semilente ChO. Diabetes News de.
  4. Definition of Semilente Insulin. Merck Manual.
  5. Dumitriu, Severian (2001). Polymeric Biomaterials, Revised and Expanded 1104. CRC Press.
  6. Combining Lente-type Insulins with Phenol-Preserved Insulins. National Federation for the Blind.
  7. Lente Zinc Suspension Causes Loss Of R/Neutral Short-Acting Effect.
  8. 8.0 8.1 Huffman DM, Garber AJ. (1991). Availability of Soluble (R/Neutral) Insulin in Mixed Preparations With Crystalline (Lente) & Ultralente GE Insulin. Clinical Therapeutics. Cite error: Invalid <ref> tag; name "Huffman" defined multiple times with different content
  9. 9.0 9.1 9.2 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 Cite error: Invalid <ref> tag; name "Bad" defined multiple times with different content
  10. 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.
  11. Deckert, T. (1980). Intermediate-Acting Insulin Preparations: NPH (Isophane) & Lente. Diabetes Care.
    Note--in 1980, there were no r-DNA/GE/GM insulins
  12. Resource Guide. American Diabetes Association (2005).
  13. Hanas, Ragnar (1999). Insulin-Dependent Diabetes-Page 10. ChildrenWithDiabetes.
  14. 14.0 14.1 14.2 Insulin Therapy-Mixing Precautions. Cite error: Invalid <ref> tag; name "Rx" defined multiple times with different content
  15. Insulin Producers vs Doctors Re:Combining R/Neutral & Lente-type Insulins.
  16. 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.
  17. 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.
  18. Novo Nordisk Discontinues Animal Insulin Worldwide. Forum Insulin Schweiz.

More information[]