U.S. PHARMACOPEIA

Search USP29  
Insulin Zinc Suspension

Insulin zinc.
Insulin zinc [8049-62-5].
» Insulin Zinc Suspension is a sterile suspension of Insulin in buffered Water for Injection, modified by the addition of a suitable zinc salt in a manner such that the solid phase of the suspension consists of a mixture of crystalline and amorphous insulin in a ratio of approximately 7 parts of crystals to 3 parts of amorphous material. 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.
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.
pH 791: between 7.0 and 7.8, determined potentiometrically.
Zinc content 591: between 0.12 mg and 0.25 mg for each 100 USP Insulin Units.
Zinc in the supernatant— Centrifuge a portion of Suspension sufficient for the test, and determine the zinc content of the clear supernatant as directed under Zinc Determination 591: the zinc concentration, in mg per mL, is between 20% and 65% of the zinc concentration of the Suspension.
Insulin not extracted by buffered acetone solution— Centrifuge an amount of Suspension representing 1000 USP Insulin Units, and discard the supernatant. Suspend the residue in 8.4 mL of water, quickly add 16.6 mL of buffered acetone TS, shake or stir vigorously, and centrifuge within 3 minutes after the addition of the buffered acetone TS. Discard the supernatant, repeat the treatment with water and buffered acetone TS, centrifuge, and discard the supernatant. Dissolve the crystalline residue in 5 mL of dilute hydrochloric acid (1 in 100), transfer to a 25-mL flask, and dilute with water to volume. The insulin concentration, determined by an appropriate method, is between 63% and 77% of the insulin content of an equal amount of the Suspension.
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 1.5% is found.
Other requirements— It meets the requirements in the tests for Sterility and Insulin in the supernatant under Isophane Insulin Suspension.
Assay— Proceed as directed in the Assay under Insulin Injection.
Auxiliary Information— Staff Liaison : Larry N. Callahan, Ph.D., Scientist
Expert Committee : (BBPP05) Biologics and Biotechnology - Proteins and Polysaccharides
USP29–NF24 Page 1139
Pharmacopeial Forum : Volume No. 27(2) Page 2169
Phone Number : 1-301-816-8385