Content continues after advertisement

Compounded Versus Commercial PZI

Clinician's Brief (Capsule)

Sign in to Print/View PDF

Protamine zinc insulin (PZI), a long-acting insulin preparation in which protamine and zinc are complexed with insulin to delay absorption, has good glycemic control in 85% to 90% of diabetic cats. Proper release of PZI depends on consistent formulation of its 3 critical components: protamine, zinc, and insulin. Originally, PZI was of bovine and porcine origin, but an FDA-approved human recombinant PZI product now available reportedly has comparable efficacy. Alternative PZI products are available through veterinary compounding pharmacies.

This study compared the characteristics of a commercially manufactured PZI product with those of PZI products from 12 compounding pharmacies. A total of 112 vials (16 commercial samples, 8 samples from each compounding pharmacy) were purchased over 8 months. Products were analyzed for endotoxin concentration, crystal size, insulin concentration in the supernatant, pH, total insulin and zinc concentrations, and species of insulin origin. The 16 commercially manufactured samples met US Pharmacopeia (USP) specifications. Of the compounded products, only 1 of the 96 vials tested met USP specifications; furthermore, 54% did not meet specifications for zinc concentration and 38% had total insulin concentrations <90% of the labeled concentration.

Commentary
PZI and glargine insulin are currently the most frequently recommended insulin products for treatment of diabetic cats. This study arms veterinarians with evidence against the use of compounded PZI. The less costly option may be attractive to clients, but the variation in insulin concentrations, even among vials from the same source, can lead to unregulated diabetes and/or hypoglycemia. The extra cost associated with identifying why a cat is no longer regulated can outweigh the initial savings of using compounded PZI. Although the commercial PZI product evaluated in this study is no longer manufactured, another FDA-approved product manufactured with the same current good manufacturing practices and quality-control standards is available.—Patty Lathan, VMD, DACVIM
 


Source
Characteristics of commercially manufactured and compounded protamine zinc insulin. Scott-Moncrieff JCR, Moore GE, Coe J, et al. JAVMA 240:600-605, 2012.

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Clinician's Brief may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.

Podcasts

Clinician's Brief:
The Podcast
Listen as host Alyssa Watson, DVM, talks with the authors of your favorite Clinician’s Brief articles. Dig deeper and explore the conversations behind the content here.
Clinician's Brief provides relevant diagnostic and treatment information for small animal practitioners. It has been ranked the #1 most essential publication by small animal veterinarians for 9 years.*

*2007-2017 PERQ and Essential Media Studies

© 2023 Educational Concepts, L.L.C. dba Brief Media ™ All Rights Reserved. Terms & Conditions | DMCA Copyright | Privacy Policy | Acceptable Use Policy