Comparison of Temperature Rise Interpretations Between European and United States Pharmacopeias' Pyrogen Tests

Jürg Tschumi

This article has a correction. Please see:

Erratum - September 01, 2003

Abstract

The European Pharmacopeia (EP) and the United States Pharmacopeia (USP) pyrogen test for parenterals involve the measurement of the temperature rise in rabbits following the intravenous injection of the test solution. Between the two methods, the conditions for the result “pyrogen free” or “pyrogen”, as well as the number of rabbits tested, differ substantially. Therefore, both methods were compared with respect to the differences in temperature rise interpretations with special attention to the selectivity of the tests.

To exclusively study the temperature rise interpretations, the temperature measurements were simulated with models.

With an increasing mean temperature rise, an intermediate range exists where the probability of “pyrogen free” and of “pyrogen” cannot be ignored. A single pyrogen test still gives an unambiguous result, but in this range, the probability is rather high that additional tests will not reproduce the same result. This range is approximately 0.3°C wide for the USP test and 0.2°C wide for the EP test.
Simulating the temperature rise with a normally distributed model, the intermediate range is narrower for the interpretation according to the EP than the USP. For a USP test, the probability of the test result “pyrogen free” decreases as lower mean temperature rises. However, the two methods are similar in the high probability range for the presence of pyrogens. At the edge of the intermediate range, a slight mean temperature rise of 0.05°C significantly changes the probability of a pyrogen result.
Within a rather wide mean temperature rise range (approximately 0.15°C wide), a product will reliably fulfil the EP requirements but not the USP requirements.

These main statements are rather robust and do not depend significantly on the model used. Different temperature rise distributions only result in negligible variations in the interpretation of the tests. Information more detailed than mean temperature rise and standard deviation of the temperature rises is not absolutely necessary.

For product quality, it is much more useful to review and interpret all individual temperature rises measured than to interpret the results of the pyrogen test only.

casting solution difference

Footnotes

PDA members receive access to all articles published in the current year and previous volume year. Institutional subscribers received access to all content. Log in below to receive access to this article if you are either of these.

If you are neither or you are a PDA member trying to access an article outside of your membership license, then you must purchase access to this article (below). If you do not have a username or password for JPST, you will be required to create an account prior to purchasing.

Full issue PDFs are for PDA members only.

Note to pda.org users

The PDA and PDA bookstore websites (www.pda.org and www.pda.org/bookstore) are separate websites from the PDA JPST website. When you first join PDA, your initial UserID and Password are sent to HighWirePress to create your PDA JPST account. Subsequent UserrID and Password changes required at the PDA websites will not pass on to PDA JPST and vice versa. If you forget your PDA JPST UserID and/or Password, you can request help to retrieve UserID and reset Password below.