Health risk assessment of a paraben excipient in a pharmaceutical product


An international pharmaceutical company.


A regulatory agency required our client to qualify the use of a paraben compound as an excipient in a drug used as a chronic treatment for seizures in epilepsy patients.

Project Goals

Bibra was asked to give an independent opinion on whether ingestion of the excipient at the intended concentration could pose significant health risks to patients. The patient population, on this occasion, included paediatric patients and also individuals with varying degrees of hepatic/renal impairment (e.g. on dialysis).


Bibra utilised the in-house TRACE database to identify critical reviews/Expert Opinions on the toxicology of the excipient and these were used as the basis of the assessment. Supplementary searches were conducted to ensure that no critical, more recent data was overlooked. A detailed analysis of the endocrine disrupting effects of the excipient was undertaken. For the risk assessment, bibra divided the patient population into multiple sub-groups for separate analysis since there was concern regarding the ability of certain of these (e.g. infants and individuals with liver disease) to metabolise the paraben in question.

Project Outcome

From the available data bibra was able to identify the critical studies and derive tolerable levels for the various patient sub-populations. It was concluded that, at the intended exposures, the excipient is unlikely to pose a significant health risk to such groups. However, there remains some degree of uncertainty regarding certain patient populations, notably infants (immature metabolic capacity) and those with varying degrees of renal/hepatic impairment (e.g. liver disease and those on dialysis).

Project Leader

Daniel Threlfall
Richard Young
Pete Watts



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