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Iletin II Lente
Lente by Eli Lilly
intermediate-acting
Porcine
U40, U100 Zinc
Action in dogs:
  • onset onset <1 hour,
  • peak gentle peak 4-8h,
  • duration 12h [1]
Line: Iletin
Also known as: Pork Lente
Similar to: Caninsulin U 40, Vetsulin U 40
Lente CHO U80 Monotard Pork U 100
Betasint Porcine Lente U 40, U 80, 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
See Caninsulin/Vetsulin for current handling notes on pork lente insulin.
00002841 101

Iletin II Lente-U100 pork insulin by Lilly. This was discontinued in 2003.


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

A 100% porcine U100 insulin formerly produced by Eli Lilly, [6] discontinued in 2003 [7] and comprised of 30% semilente insulin and 70% Ultralente insulin.

Like all other Lente insulins [8][9] it was a suspension of crystalline (ultralente) and amorphous (semilente) insulins in the ratio shown above. [10]

It is identical to Monotard Pork, which Novo Nordisk also used to produce, and to Betasint Porcine Lente U100. It is also identical to Caninsulin [11][12] and Vetsulin in all respects except strength; they are U40 insulins. More equivalents are Betasint Porcine Lente in U 40 and U80 strengths and Polfa Tarchomin's Lente CHO, which is a U80 insulin.

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.[13] 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.[14]

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 [15] or any R/Neutral insulin. [16][17]

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. [18][19]

The zinc suspension of Lente-type insulin binds R/Neutral, causing the short-acting insulin to slow, losing its short-acting effect. [20][21]

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.[22]

Combining Lente Family Insulins[]

Insulin manufacturers [23] 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. [17][24][25][26]

None of the Lente family of insulins (semilente, Lente, Ultralente) can be combined with [27] 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. [28][26]

Keeping the phenol preservatives in mind, all protamine-suspended insulin mixes would be "off limits" regarding same syringe mixing with any Lente-type insulins. [26]



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.

References[]

  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. Copy of Iletin II Lente Patient Information Leaflet. Drugs.com.
  7. Iletin II Lente Discontinuation Material. US Food and Drug Administration (2003).
  8. Scientific Discussion-Monotard. EMEA.
  9. Definition of Lente Insulin. Merck Manual.
  10. 10.0 10.1 Iletin II Lente Carton. Cite error: Invalid <ref> tag; name "Carton" defined multiple times with different content
  11. Horn, B., Mitten, RW. (2000). Evaluation of an insulin zinc suspension for control of naturally occurring diabetes mellitus in dogs. Australian Veterinary Journal.
    Refers to the David B. Church Study Equating Caninsulin with Novo's old Pork Monotard
  12. Correspondence re: Horn-Mitten Study. Australian Veterinary Journal (2001).
    More Re: Caninsulin Being Equivalent to Pork Monotard
  13. Dumitriu, Severian (2001). Polymeric Biomaterials, Revised and Expanded 1104. CRC Press.
  14. Greco, Deborah (2010). Treating Diabetes Mellitus in Dogs and Cats. Western Veterinary Conference.
  15. Combining Lente-type Insulins with Phenol-Preserved Insulins. National Federation for the Blind.
  16. Lente Zinc Suspension Causes Loss Of R/Neutral Short-Acting Effect. Endotext.org.
  17. 17.0 17.1 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
  18. Lente-Type Insulins & NPH/Isophane Insulins-A Bad Combination. National Federation for the Blind.
  19. 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.
  20. Deckert, T. (1980). Intermediate-Acting Insulin Preparations: NPH (Isophane) & Lente. Diabetes Care.
    Note--in 1980, there were no r-DNA/GE/GM insulins
  21. Resource Guide. American Diabetes Association (2005).
  22. Hanas, Ragnar (1999). Insulin-Dependent Diabetes-Page 10. ChildrenWithDiabetes.
  23. Insulin Producers vs Doctors Re:Combining R/Neutral & Lente-type Insulins. Endotext.org.
  24. 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.
  25. 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.
  26. 26.0 26.1 26.2 Insulin Therapy-Mixing Precautions. RxEd.org. 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
  27. Phenol Preservatives & Lente-type Insulins--A Bad Combination. National Federation for the Blind.
  28. Lente-Type Insulins & NPH/Isophane Insulins-A Bad Combination. National Federation for the Blind.
  29. Iletin I Lente-Beef/Pork Insulin Shown at Right.

More Information[]

Related Pages
Caninsulin 10764 420 Betasint Insulinum Lente 400px Lentetap
Caninsulin
Vetsulin
Betasint Porcine Lente
Lente CHO
Monotard Pork
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