All insulins have and need preservatives so that the insulin--whether in vials, pens, or cartridges--has some "shelf life" after the container is opened/started. Preservatives keep bacteria from growing in the containers of insulin once they've had their first use[1].
Though most of the food we eat has some kind or preservatives in it to keep it fresher longer, no one expects that a loaf of bread, will keep indefinitely in the refrigerator without becoming moldy.
The same is true for insulin; it also has preservatives in it to allow us to keep it for a given time period[2]. Just as the bread's preservatives won't keep the bread fresh forever, neither will the insulin's preservatives. This is one of the reasons manufacturers provide information regarding how long opened insulins should be kept.
Use of the wrong preservative with the various types of insulin can make it totally worthless; this is why when using manufactured diluents, care must be taken to match the proper diluent with the insulin[3].
Meta-cresol preservative[]
Meta-cresol Preservative | |
---|---|
Generic Names: |
|
Brand Names: |
Humulin R, Humulin S |
Brand Names: |
Hypurin Bovine Neutral Insuvet Neutral, Iletin I R, |
Brand Names: |
Hypurin Porcine Neutral Hypurin Pork Regular Iletin II R, Pork Actrapid |
Generic Names: |
|
Brand Names: |
Apidra,Humalog Novolog, NovoRapid |
Brand Names: |
Lantus |
Meta-cresol and phenol preservatives: non-mixed[]
Meta-cresol & Phenol Preservatives: Non-mixed | |
---|---|
Generic Names: |
|
Brand Names: |
Humulin I, Humulin N |
Brand Names: |
Hypurin Bovine Isophane Iletin I NPH |
Brand Names: |
Hypurin Porcine Isophane Hypurin Pork NPH Iletin II NPH, Pork Insulatard |
Generic Names: |
Detemir |
Brand Names: |
Levemir |
Meta-cresol and phenol preservatives: mixed[]
Meta-cresol & Phenol Preservatives: Mixed | |
---|---|
All intermediate-acting: | |
Generic Names: |
Biphasic[6] |
Brand Names: |
Actraphane 20/80, Actraphane 30/70 |
Brand Names: |
|
Brand Names: |
Humalog 75/25, Humalog Mix 25 |
NPH/isophane,Levemir, all NPH/isophane Mixed Insulins--regardless of origin--have both m-cresol and phenol as preservatives.
Phenol preservative[]
Phenol Preservative | |
---|---|
All slow-acting: | |
Generic Names: |
|
Brand Names: |
|
Brand Names: |
BCP PZI Hypurin Bovine Protamine Zinc Hypurin Vet Protamine Zinc Insuvet Protamine Zinc |
PZIs contain only phenol as a preservative.
Methylparaben preservative[]
Methylparaben Preservative | |
---|---|
Generic Names: |
|
Brand Names: |
|
Generic Names: |
|
Brand Names: |
Humulin L, Novolin L Monotard |
Brand Names: |
Insuvet Lente Hypurin Bovine Lente Iletin I Lente |
Brand Names: |
Caninsulin, Vetsulin Iletin II Lente Monotard Pork |
Generic Names: |
ultralente Insulin Zinc Suspension (crystalline)[10] |
Brand Names: |
Humulin U, Humulin Zn Novolin U, Ultratard |
Lente, semilente and ultralente use methylparaben as a preservative. Another name for it is methyl hydroxybenzoate[11].