Preservatives

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] If bacteria begins growing in a vial, it can degrade the insulin, thus making it ineffective. ^[2]^[3]

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. ^[4] 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. ^[5]

Meta-cresol preservative[]

Meta-cresol Preservative
Generic Names: Non-analog-Rapid-acting:	R/neutral ^[6]
Brand Names: Non-analog Human	Humulin R, Humulin S Actrapid, Novolin R ReliOn/Novolin R Insuman Rapid, Winthrop Rapid, Huminsulin Normal
Brand Names: Non-analog Bovine	Hypurin Bovine Neutral, Iletin R, Insuvet Neutral
Brand Names: Non-analog Porcine	Hypurin Porcine Neutral, Iletin II R Hypurin Pork Regular, Pork Actrapid
Brand Names: Non-analog Bovine/Porcine	Iletin I R
Generic Names: Analog	Aspart, Glargine Glulisine, Lispro
Brand Names: Analog-Rapid-acting:	Apidra,Humalog Novolog, NovoRapid
Brand Names: Analog-Slow-acting:	Lantus

Meta-cresol and phenol preservatives: non-mixed[]

Meta-cresol & Phenol Preservatives: Non-mixed
Generic Names: Non-analog-Intermediate-acting:	NPH/isophane ^[7]
Brand Names: Non-analog Human	Humulin I, Humulin N Insulatard, Novolin N Protaphane, Insuman Basal ReliOn/Novolin NPH Winthrop Basal, Huminsulin Basal, Humulina NPH, Humuline NPH, Umuline NPH, Insuhuman Basal
Brand Names: Non-analog Bovine	Hypurin Bovine Isophane, Iletin NPH
Brand Names: Non-analog Porcine	Hypurin Porcine Isophane, Iletin II NPH Hypurin Pork NPH, Pork Insulatard
Brand Names: Non-analog Bovine/Porcine	Iletin I NPH
Generic Names: Analog-Slow-acting:	Detemir
Brand Names: Analog-Slow-acting:	Levemir

Meta-cresol and phenol preservatives: mixed[]

Meta-cresol & Phenol Preservatives: Mixed
All intermediate-acting:
Generic Names:	Biphasic ^[8]
Brand Names: Non-analog Human	Actraphane 20/80, Actraphane 30/70 Actraphane 50/50, Humulin M2 Humulin M3, Humulin M5, Humulin 10/90, Humulin 20/80,Humulin 40/60, Humulin 70/30,Humulin 50/50, Insuman Comb 15, Insuman Comb 25, Insuman Comb 50, Mixtard 10, Mixtard 20, Mixtard 30, Mixtard 40 Mixtard 50, Novolin 70/30 ReliOn/Novolin 70/30, Penmix 10 Penmix 20, Penmix 30,Penmix 40, Penmix 50 Winthrop Comb 15, Winthrop Comb 25, Winthrop Comb 30, Winthrop Comb 50, Huminsulin Profil I, Huminsulin Profil II, Huminsulin Profil III, Huminsulin Profil IV, Humulina 10/90, Humulina 20/80, Humulina 30/70, Humulina 40/60, Humulina 50/50, Humuline 10/90, Humuline 20/80, Humuline 30/70, Humuline 40/60, Humuline 50/50, Umuline Profil 30, Umuline Profil 20, Isuhuman Comb 25, Insuhuman Comb 15, Insuhuman Comb 25, Insuhuman Comb 50 Humulin M, Humulin M1, Humulin M4, Novolin 30R
Brand Names: Non-analog Porcine	Hypurin Porcine 30/70 Mix, Pork Mixtard 30
Brand Names: Analog	Humalog 75/25, Humalog Mix 25 Humalog Mix 50, Humalog 50/50 NovoMix 30, Novolog Mix

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: Non-analog	PZI Protamine Zinc Insulin ^[9]
Brand Names: Non-analog Bovine/Porcine	PZI Vet
Brand Names: Non-analog Bovine	BCP PZI, Hypurin Bovine Protamine Zinc Hypurin Vet Protamine Zinc Insuvet Protamine Zinc
Brand Names: Non-analog R-DNA	ProZinc

PZIs contain only phenol as a preservative.

Methylparaben preservative[]

Methylparaben Preservative
Generic Names: Non-analog-Fast-acting:	semilente Insulin Zinc Suspension (amorphous) ^[10]
Brand Names: Non-analog Porcine	Novo Semilente MC
Brand Names: Non-analog Bovine/Porcine	Iletin I Semilente
Generic Names: Non-analog Intermediate-acting:	Lente Insulin Zinc Suspension ^[11]
Brand Names: Non-analog Human	Humulin L, Novolin L, Monotard, Humulina L, Humuline Long, Umuline Zinc Compose
Brand Names: Non-analog Bovine	Insuvet Lente, Iletin Lente Hypurin Bovine Lente
Brand Names: Non-analog Porcine	Caninsulin, Vetsulin Iletin II Lente, Monotard Pork
Brand Names: Non-analog Bovine/Porcine	Iletin I Lente
Generic Names: Non-analog Slow-acting:	ultralente Insulin Zinc Suspension (crystalline) ^[12]
Brand Names: Non-analog Human	Humulin U, Humulin Zn Novolin U, Ultratard,Umuline Zinc Humulina Ultralenta, Humuline Ultralong
Brand Names: Non-analog Bovine/Porcine	Iletin I Ultralente

Lente, semilente and ultralente use methylparaben as a preservative. Another name for it is methyl hydroxybenzoate. ^[13]

References[]

↑ Diabetes Forecast-page 5. American Diabetes Association (2006).
↑ Cook, Audrey (1 April 2010). Identifying the reasons behind difficult-to-control diabetes in dogs. DVM 360.
↑ Insulins-How To Store Insulin. DiabetesNet.
↑ Resource Guide. American Diabetes Association (2005).
↑ Lilly Discontinues Diluent for all Lente & Ultralente Insulins. Diabetes In Control.
↑ Insulin. InChem.
↑ Insulin. InChem.
↑ Insulin. InChem.
↑ Insulin. InChem.
↑ Insulin. InChem.
↑ Insulin. InChem.
↑ Insulin. InChem.
↑ Insulin. InChem.

[1] Diabetes Forecast-page 5. American Diabetes Association (2006).

[2] Cook, Audrey (1 April 2010). Identifying the reasons behind difficult-to-control diabetes in dogs. DVM 360.

[3] Insulins-How To Store Insulin. DiabetesNet.

[4] Resource Guide. American Diabetes Association (2005).

[5] Lilly Discontinues Diluent for all Lente & Ultralente Insulins. Diabetes In Control.

[6] Insulin. InChem.

[7] Insulin. InChem.

[8] Insulin. InChem.

[9] Insulin. InChem.

[10] Insulin. InChem.

[11] Insulin. InChem.

[12] Insulin. InChem.

[13] Insulin. InChem.

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