Canine Diabetes Wiki
Insuvet Lente
Lente by Pfizer Animal Health
U100 Zinc
Action in dogs:
  • onset 2-5h,
  • peak 12-24h,
  • duration: maximum 36h
Line: Insuvet
Also known as: Beef Lente
Similar to: Betasint Bovine Lente
Hypurin Bovine Lente, Iletin Lente, Beef Lentard
Use and Handling:
Shelf Life: 36 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

All Insuvet insulins have been discontinued by Pfizer Animal Health.[2][3] The insulins were made under contract by Wockhardt UK for both Pfizer and for Schering-Plough Animal Health, who owned the brand name earlier. Wockhardt makes the same insulins under their Hypurin brand name.[4]

Switching from Insuvet to Caninsulin

87 main

Insuvet Lente-U100 bovine lente insulin.

Pfizer Animal Health UK produced bovine insulins for veterinary use under the brand name Insuvet. [8] This is their U100, intermediate-acting lente.[9] [10] insulin [11][12][13]

Comparing Insuvet insulins with Hypurin insulins[]

Currently marketed Wockhardt Bovine insulins comparable with Insuvet insulins:

Hypurin Bovine Neutral [5] EMC UK product description.[14]

Insuvet Neutral VMD product description [15]

Hypurin Bovine Lente [6] EMC product description.[12]

Insuvet Lente VMD product description [16]

Hypurin Bovine Protamine Zinc [7] EMC UK product description.[17]

Insuvet Protamine Zinc VMD product description[18]

If you are in Canada, your vet may also be able to obtain manufactured beef insulin from the UK for you through Health Canada's Emergency Drug Release program. [19] With it, you are able to receive up to 6 months worth of insulin; a C$ 50.00 fee for the application is required. [20] If permitted, you would then be eligible to import PZI insulins such as Hypurin Bovine Protamine Zinc, as well as other bovine or porcine insulins.

The program is similar to Health Canada's Special Access Programme [21] for importing necessary drugs for people.

Wherever you are, the comparable CP Pharma Hypurin insulins should be able to be imported provided you follow the import rules and guidelines for your country of residence. CP Pharma will be glad to assist you if you contact them through their website link on the CP Pharma page.

Recently the US-FDA has dropped their paperwork requirements regarding the importation of non-US approved drugs for animal patients who need them. [22] While 100% bovine protamine zinc insulin is available in the US through compounding pharmacies, there is no source of bovine R/Neutral or bovine Lente. It would appear that the relaxed restrictions would make it easier and quicker for a veterinarian to obtain bovine insulins for a diabetic patient.

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.[23] 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.[24]

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 insulin 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 [25] or any R/Neutral insulin. [26][27]

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. [28][29]

The zinc suspension of Lente-type insulin binds R/Neutral, causing the short-acting insulin to slow, losing its short-acting effect. [30][31]

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.[32].

Technical details[]

The official NOAH (National Office of Animal Health) [33] description of Insuvet Lente is that it is a highly purified bovine Zinc suspension insulin as per British Pharmacopeia (BP). The "mixed" tag refers to the 30% semilente, 70% ultralente composition of all lente insulins. It is U100 and presented in 10ml vials. The insulin [12] has a shelf life of 3 years.

Usage and handling[]

Insuvet Lente [34] is classed as being a medium to long duration insulin given subcutaneously. Onset is 1-3 hours after injection, with a peak at 6-12 hours and a total duration of 18-28 hours.

Dosage information for Insuvet Lente [35] can be found here. To be given subcutaneously [36] only. Store at 2-8 C [37] at 2-8 C. Insuvet Lente requires rolling and should not be used if product does not re-suspend. Do not freeze. Vials are to be used within 28 days of their first use.

Comparable to CP Pharma's Hypurin Bovine Lente and Beta Laboratorios' Betasint Bovine Lente, but is only approved for veterinary use. It is also comparable to Lilly's discontinued Iletin Lente.

Combining Lente Family Insulins[]

None of the Lente family of insulins (semilente, Lente, Ultralente) can be combined with [38] 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. [39][40]

Keeping the phenol preservatives in mind, all protamine-suspended insulin mixes would be "off limits" regarding same syringe mixing with any Lente-type insulins. [40]

Insulin manufacturers [41] 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. [27][42][43][40]

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. Maddison, Jill E.,Page, Stephen W.,Church, David B. (2008). Small Animal Clinical Pharmacology. Saunders Ltd..
  2. No Further Supplies of Insuvet Insulins. UK.
  3. Pfizer insulin products currently unavailable. VetsOnline UK.
  4. SPAH Contracts CP/Wockhardt UK for Insuvet Insulins. Wockhardt.
  5. 5.0 5.1 Hypurin Bovine Neutral. Wockhardt UK. Cite error: Invalid <ref> tag; name "Neutral" defined multiple times with different content
  6. 6.0 6.1 Hypurin Bovine Lente. Wockhardt UK.
  7. 7.0 7.1 Hypurin Bovine Protamine Zinc. Wockhardt UK.
  8. Pfizer Animal Health Adds Former Schering-Plough Products to European Portfolio. Farming UK (2008).
  9. Insuvet Lente. Veterinary Medicines Directorate UK.
  10. Definition of Lente Insulin. Merck Manual.
  11. Hypurin Bovine Lente Patient Information. Net
  12. 12.0 12.1 12.2 Hypurin Bovine Lente. Wockhardt UK. Cite error: Invalid <ref> tag; name "LenteEMC" defined multiple times with different content Cite error: Invalid <ref> tag; name "LenteEMC" defined multiple times with different content
  13. Prescribing Bovine Insulin.
  14. Hypurin Bovine Neutral. EMC UK.
  15. Insuvet Neutral. VMD UK.
  16. Insuvet Lente. VMD UK.
  17. Hypurin Bovine Protamine Zinc. EMC UK.
  18. Insuvet Protamine Zinc. VMD UK.
  19. Health Canada-Veterinary: Emergency Drug Release Information. HealthCanada.
  20. Health Canada-Emergency Drug Release Form. HealthCanada.
  21. Health Canada-Special Access Programme. HealthCanada.
  22. FDA no longer issuing letters for importation of unapproved animal drugs. JAVMA News (15 October 2009).
  23. Dumitriu, Severian (2001). Polymeric Biomaterials, Revised and Expanded 1104. CRC Press.
  24. Greco, Deborah (2010). Treating Diabetes Mellitus in Dogs and Cats. Western Veterinary Conference.
  25. Combining Lente-type Insulins with Phenol-Preserved Insulins. National Federation for the Blind.
  26. Lente Zinc Suspension Causes Loss Of R/Neutral Short-Acting Effect.
  27. 27.0 27.1 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
  28. Lente-Type Insulins & NPH/Isophane Insulins-A Bad Combination. National Federation for the Blind.
  29. 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.
  30. Deckert, T. (1980). Intermediate-Acting Insulin Preparations: NPH (Isophane) & Lente. Diabetes Care.
    Note--in 1980, there were no r-DNA/GE/GM insulins
  31. Resource Guide. American Diabetes Association (2005).
  32. Hanas, Ragnar (1999). Insulin-Dependent Diabetes-Page 10. ChildrenWithDiabetes.
  33. Insuvet. NOAH Compendium UK.
  34. Insuvet Uses. NOAH Compendium.
  35. Insuvet Dosage and Administration. NOAH Compendium-UK.
  36. Insuvet-Contraindications/Warnings. NOAH Compendium-UK.
  37. Insuvet Pharmaceutical Information. NOAH Compendium-UK.
  38. Phenol Preservatives & Lente-type Insulins--A Bad Combination. National Federation for the Blind.
  39. Lente-Type Insulins & NPH/Isophane Insulins-A Bad Combination. National Federation for the Blind.
  40. 40.0 40.1 40.2 Insulin Therapy-Mixing Precautions. Cite error: Invalid <ref> tag; name "Rx" defined multiple times with different content
  41. Insulin Producers vs Doctors Re:Combining R/Neutral & Lente-type Insulins.
  42. 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.
  43. 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.
  44. Iletin I Lente-Beef/Pork Insulin Shown at Right.
  45. Carton Image-Iletin II Lente.

More information[]

Related pages
Lilly human insulins1992charts
Cp wockhardt bovine insulins
Iletin Lente
Hypurin Bovine Lente
Betasint Bovine Lente