Vetsulin, PZA and the Humulin family of insulins uses insulin compounded with different substances to extend its duration. PZI has the additive protamine Zinc. Vetsulin has 30% amorphous and 70% crystalline zinc. The additives for the Humulins vary depending upon the specific type of Humulin. Humulin is Lilly's tradmark for a family of insulins made using insulin made from bacteria ( HUMAN INSULIN (rDNA ORIGIN)). Humulin R does not have an additive. Humulin N has ISOPHANE.
Vetsulin uses a porcine (pork) insulin obtained from pig pancreas. PZI can use different insulins. The newest, ProZinc uses the human INSULIN (rDNA ORIGIN) insulin. The old PZI Vet used 10% porcine and 90% bovine insulin.
Lantus is a totally synthetic insulin. This is from the insert for Lantus:
"LANTUS (insulin glargine [rDNA origin] injection) is a sterile solution of insulin glargine for use as a subcutaneous injection. Insulin glargine is a recombinant human insulin analog that is a long-acting (up to 24-hour duration of action), parenteral blood-glucose-lowering agent [See Clinical Pharmacology (12)]. LANTUS is produced by recombinant DNA technology utilizing a non-pathogenic laboratory strain of Escherichia coli (K12) as the production organism. Insulin glargine differs from human insulin in that the amino acid asparagine at position A21 is replaced by glycine and two arginines are added to the C-terminus of the B-chain. Chemically, insulin glargine is 21A-Gly-30Ba-L-Arg-30Bb-L-Arg-human insulin and has the empirical formula C267H404N72O78S6 and a molecular weight of 6063. Insulin glargine has the following structural formula:"
Levemir is another new human insulin. It has a long duration (one per day like Lantus in humans) and is synthetic. YOu can Google for more info about it.