Monograph: |
Biphasic Isophane Insulin
In order to prolong the duration of action of insulin,
preparations may be formulated as suspensions in 2
general ways. The first involves complexing insulin
with a protein from which it is slowly released; ex-
amples are protamine zinc insulin, which contains
an excess of protamine, and isophane insulin
contains equimolecular amounts of insulin
and protamine. The second method of prolonging
the action of insulin is to modify the particle size and
the various insulin zinc suspensions are in this cat-
egory.
Biphasic insulins are mixtures providing for both
immediate and prolonged action.
It is the buffered suspension of porcine insulin or human insulin complexed with
protamine sulphate or other suitable protamine, in a solution of porcine insulin or
human insulin respectively. It contains the equivalent of 300-600 mcg of protamine
sulphate per 100 units of insulin in the complex.
Its action starts within 2 hrs, peak effect lasts for about 4-12 hrs and lasts for
up to 24 hrs.
|