Potent Compound Corner

What is an OEB 5 compound?

OEB 5 compounds are active pharmaceutical ingredients that have been assigned to an occupational exposure band (OEB) rating of 5, or the most severe rating in a 5-band occupational exposure banding system. A rating of OEB 5 represents those APIs that may have any of the following properties:

  • Are highly potent (therapeutic doses less than 0.5 mg/day); or
  • Have significant adverse effects at low doses (life-threatening, irreversible, or severe sensitizers); or
  • May be genotoxic, carcinogenic, or have reproductive effects at relevant doses.

Depending on the company’s specific banding system, OEB 5 compounds typically would have numerical occupational exposure limits (OEL) less than 1 μg/m3 or an ADE or permitted daily exposure (PDE) of less than 5 ug/day. This information will be listed on the PDE report for the specific active pharmaceutical ingredient.

The determination of whether a compound should be assigned a rating of OEB 5 or not should be performed by an expert occupational toxicologist. In order to make this determination, the expert toxicologist must review all the relevant pre-clinical and clinical information.

It is important to note, that often compounds are assigned to an occupational exposure band before there is enough data to formally develop a numerical occupational exposure limit (OEL). Once there is more human clinical data, the assignment to a specific OEB should be revisited and a numerical OEL should be developed. It is also important to mention that all OEB 5 compounds should have a thoroughly documentation OEL and ADE/PDE.

Examples of OEB 5 compounds include bimatoprost, doxorubicin, gemcitabine, vincristine, and many others. It is also important to note that compounds other than oncology products can be OEB 5 compounds. For example, Vitamin D3 (also known as cholecalciferol) is an OEB 5 compound.

You can determine if your compound has been assigned an OEB 5 by visiting our OEL Fastrac catalog and purchasing the appropriate OEL Fastrac monograph. If you have a novel, new chemical entity, or proprietary compound, the toxicology experts at Affygility Solutions can also assist you in assigning an OEB to your compound.

Controlling Exposures to OEB 5 Compounds

Controlling occupational exposure to OEB 5 compounds is difficult. It will require the highest level of containment (such as isolators) that involves no open handling, closed transfers through validated systems (such as high-containment values), and the most skilled operators. To ensure that the correct systems are in place, prior to handling OEB 5 compounds, containment validation by industrial hygiene experts in the pharmaceutical industry should be performed. The experts at Affygility Solutions can assist you in determining if your facility is “OEB 5 ready” by performing a potent compound safety gap assessment. We have performed these assessment throughout North America, Europe, the Middle East, and Asia.


Not protecting your employees from occupational exposure to OEB 5 compounds is risky and is not socially responsible. In addition, if improperly contained or handled, the risk of cross-contamination is high and can result in regulatory warning letters or product recalls.

As always, if you have any questions regarding potent compound safety or occupational toxicology, please contact us at Affygility Solutions.

Published July 4, 2018 / Updated June 21, 2021

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