Isophane Insulin Suspension
» Isophane Insulin Suspension is a sterile suspension of zinc-insulin crystals and Protamine Sulfate in buffered Water for Injection, combined in a manner such that the solid phase of the suspension consists of crystals composed of insulin, protamine, and zinc. The Protamine Sulfate is prepared from the sperm or from the mature testes of fish belonging to the genus Oncorhynchus Suckley, or Salmo Linné (Fam. Salmonidae). Its potency, based on the sum of its insulin and desamido insulin components, is not less than 95.0 percent and not more than 105.0 percent of the potency stated on the label, expressed in USP Insulin Units per mL.
Packaging and storage Preserve in the unopened multiple-dose container provided by the manufacturer. Do not repackage. Store in a refrigerator, protect from sunlight, and avoid freezing.
Labeling Label it to indicate the one or more animal species to which it is related, as porcine, as bovine, or as a mixture of porcine and bovine. Where it is purified, label it as such. The Suspension container label states that the Suspension is to be shaken carefully before use. The label states the potency in USP Insulin Units per mL. Label it to state that it is to be stored in a refrigerator and that freezing is to be avoided.
USP Reference standards 11
USP Endotoxin RS
Identification It meets the requirements of the Identification test under Insulin Injection.
Bacterial endotoxins 85 It contains not more than 80 USP Endotoxin Units per 100 USP Insulin Units.
Sterility 71 It meets the requirements when tested as directed for Membrane Filtration under Test for Sterility of the Product to be Examined, the Suspension being filtered immediately after it has been reduced to a clear solution by the addition of a freshly prepared 1 in 100 solution of ascorbic acid in Fluid A.
pH 791: between 7.0 and 7.8, determined potentiometrically.
Zinc content 591: between 10 and 40 µg for each 100 USP Insulin Units.
Insulin in the supernatant
Test solution Centrifuge 10 mL of the Suspension at 1500 × g for 10 minutes. Use the supernatant.
Procedure Determine the insulin content of the Test solution by a suitable method: the insulin concentration is not more than 1.0 USP Insulin Unit per mL.
Limit of high molecular weight proteins Proceed as directed in the test for Limit of high molecular weight proteins under Insulin Injection: not more than 3.0% is found.
Assay Proceed as directed in the Assay under Insulin Injection.
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 3511Pharmacopeial Forum: Volume No. 36(6) Page 1538