APR March 2021 - 59

spectrophotometer. For samples with tighter specifications, raising the
onset OD may allow for accurate measurements even in the presence
of some optical interference.
This method is likely to be most successful with nonpolar organic
molecules of relatively low molecular weight and uniform composition.
Product II, in which the active ingredient was suspended in a complex
and viscous proprietary solvent, proved to be highly inhibitory for the
kinetic assay, with an LVD of 1:4000. By comparison, a 1:100 dilution
of this product in a 1% solution of polysorbate 80 yielded a uniform,
opaque suspension that did not interfere with the gel-clot test. In this
case, the older technique of mechanical homogenization yielded an
assay with a lower limit of detection than the kinetic technique (1.5
EU/mL versus 4 EU/mL). For the other four products, however, the
DMSO dispersion approach resulted in a satisfactory method with
greater sensitivity than could be achieved using the gel-clot test.

References
1.

USP <85> Bacterial Endotoxins Test. In: United States Pharmacopeia and National
Formulary, USP43-NF38 through Supplement 2. Rockville, MD: United States
Pharmacopeial Convention; 2019:6434.

Chen D. A New Method for the Analysis of Bacterial Endotoxins in Ultrapure Paraffin Oil. J of
Analytical Methods in Chemistry. 2014; Article ID 575246, 4 pages.

MICROBIOLOGY

Author Biographies
Jonathon Salsbury, MS, is an associate director for the
PPD® Laboratories GMP lab in Middleton, Wisconsin,
responsible for oversight of the physical chemistry and
microbiology testing. He has been in the pharmaceutical
and contract research organization industry for nearly 20 years and has
worked globally with clients in support of pharma, as well as small and
large biotech. In this role, he is focused on analytical testing programs
featuring traditional small and large molecules, gene and cell therapies,
inhaled products, and stents in addition to other therapies.
Christopher Lester is a senior scientist specializing in
bacterial endotoxins testing within microbiology testing
services at the PPD® Laboratories GMP lab in Middleton,
Wisconsin. Chris and his team perform bacterial endotoxins
testing, which includes method development, verification and stability
testing for a wide variety of drug formulations. Chris has been performing
GxP testing in the contract research industry since 2014.
Timothy Ramsey is the lab manager of microbiology testing
services at the PPD® Laboratories GMP lab in Middleton,
Wisconsin. Tim has more than 20 years of experience in
managing microbiology operations in contract laboratory
and pharmaceutical manufacturing environments.

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APR March 2021

Table of Contents for the Digital Edition of APR March 2021

Editor's Message
Editorial Advisory Board
CN Perspectives
Social Media Connections
Manufacturing
Microbiology
Equipmet Focus
Microbiology
Vendor Viewpoint
QC Corner with Millipore Sigma
Manufacturing
Biopharmaceutical Development
Biopharmaceutical Development
Manufacturing
Microbiology
Manufacturing
Separation and Purification
P.I.N. Points
Advertiser's Index
APR March 2021 - Cover1
APR March 2021 - Cover2
APR March 2021 - 1
APR March 2021 - 2
APR March 2021 - 3
APR March 2021 - 4
APR March 2021 - 5
APR March 2021 - Editor's Message
APR March 2021 - 7
APR March 2021 - Editorial Advisory Board
APR March 2021 - 9
APR March 2021 - CN Perspectives
APR March 2021 - Social Media Connections
APR March 2021 - Manufacturing
APR March 2021 - 13
APR March 2021 - 14
APR March 2021 - 15
APR March 2021 - 16
APR March 2021 - 17
APR March 2021 - 18
APR March 2021 - 19
APR March 2021 - Microbiology
APR March 2021 - 21
APR March 2021 - 22
APR March 2021 - 23
APR March 2021 - 24
APR March 2021 - Equipmet Focus
APR March 2021 - Microbiology
APR March 2021 - 27
APR March 2021 - 28
APR March 2021 - 29
APR March 2021 - 30
APR March 2021 - 31
APR March 2021 - 32
APR March 2021 - Vendor Viewpoint
APR March 2021 - 34
APR March 2021 - 35
APR March 2021 - QC Corner with Millipore Sigma
APR March 2021 - 37
APR March 2021 - Manufacturing
APR March 2021 - 39
APR March 2021 - 40
APR March 2021 - 41
APR March 2021 - Biopharmaceutical Development
APR March 2021 - 43
APR March 2021 - 44
APR March 2021 - Biopharmaceutical Development
APR March 2021 - 46
APR March 2021 - 47
APR March 2021 - Manufacturing
APR March 2021 - 49
APR March 2021 - 50
APR March 2021 - 51
APR March 2021 - 52
APR March 2021 - 53
APR March 2021 - 54
APR March 2021 - 55
APR March 2021 - Microbiology
APR March 2021 - 57
APR March 2021 - 58
APR March 2021 - 59
APR March 2021 - Manufacturing
APR March 2021 - 61
APR March 2021 - 62
APR March 2021 - 63
APR March 2021 - 64
APR March 2021 - Separation and Purification
APR March 2021 - 66
APR March 2021 - 67
APR March 2021 - 68
APR March 2021 - 69
APR March 2021 - P.I.N. Points
APR March 2021 - 71
APR March 2021 - Advertiser's Index
APR March 2021 - Cover3
APR March 2021 - Cover4
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