Karen Zink McCullough

A Summary of USP’s Workshop on “The Future of Endotoxins and Pyrogen Testing: Reference Standards and Procedures”
Wednesday, October 30, 2019
All parenteral articles and medical devices that contact body tissue or fluids have to be sterile and pyrogen free. A standard method that utilizes increase in body temperature of rabbits to detect acceptable level of ... read more
“Fit For Purpose” Endotoxin Analytes
Wednesday, October 23, 2019
One of the essential but as yet unresolved questions arising from USP’s June 2019 “Workshop on the Future of Endotoxins and Pyrogen Testing: Reference Standards and Procedures” is the issue of an appropriate “fit for purpose”... read more
Calculating Endotoxin Limits for Drug Products
Wednesday, September 26, 2018
Analysts working on Bacterial Endotoxins Test (BET) method development are often presented with new compounds or new products, and are asked to calculate an endotoxin limit, develop a test method for the new material and ... read more
USP <1228.x>; An Evolving Series of Informational Chapters on Depyrogenation
Friday, February 16, 2018
The first mention of depyrogenation in the United States Pharmacopeia can be traced back to an informational chapter that appeared in the Fifth Supplement to USP 20-NF 15 entitled, “Sterilization and Sterility Assurance of ... read more
Why Not?
Thursday, March 16, 2017
As scientists, we recognize that ours is not a static discipline. We are trained to reflect on the scientific literature so that we can codify accumulated knowledge, test new hypotheses and move forward. We are innovators. In... read more
Current USP Perspectives on Low Endotoxin Recovery (LER)
Friday, July 29, 2016
The topic of LER, or “Low Endotoxin Recovery” has dominated endotoxin discussions since 2013. What is LER? The term was coined to describe an LAL assay interference (inhibition) that was observed in an undiluted monoclonal... read more
LER Frequently Asked Questions
Tuesday, August 25, 2015
Since the initial reports of Low Endotoxin Recovery (LER) in 2013 drug manufacturers and regulators have voiced concern that there may be conditions under which the Bacterial Endotoxins Test (BET) could under-report endotoxin... read more
Are You Smarter than a Fifth Grader? (Bacterial Endotoxins Version)
Thursday, August 28, 2014
Various Bacterial Endotoxin Test (BET) assays, starting with the gel clot test and working through endpoint and kinetic assays, have been used in our industry for almost 40 years, and have performed remarkably well as tools... read more
The Bacterial Endotoxins Test – Back to the Future
Friday, October 25, 2013
The fifteenth anniversary of American Pharmaceutical Review prompted my reflection on the 40+ years of evolution of the Limulus Amebocyte Lysate (LAL) test in our industry. This article will reflect on where the Bacterial ... read more