Excipients are inactive drug substances used in the manufacture of the pharmaceutical product to stabilise or enhance the active ingredients, amongst other uses.
The study found that, for a large proportion of medicines, more than half of the formulation is made up of excipients, and this can rise to around 99% in selected examples.
As a result, researchers from Massachusetts Institute for Technology (MIT) and Brigham and Women’s Hospital wanted to assess how benign the excipients were and whether there was a risk of an allergic reaction to the inactive ingredients used.
The researchers identified a number of excipients commonly used pose a risk, though only for certain patients. Common inactive ingredients include lactose, fructose, starch, dyes, and peanut oil – although when the latter is used, the medicine must carry a warning label.
“For most patients, it doesn’t matter if there’s a little bit of lactose, a little bit of fructose, or some starch in there. However, there is a subpopulation of patients, currently of unknown size, that will be extremely sensitive to those and develop symptoms triggered by the inactive ingredients,” said Daniel Reker, a postdoc researcher at MIT’s Koch Institute for Integrative Cancer Research and one of the lead authors of the study.
In particular, researchers highlighted that patients over the age of 65 could be at an increased risk due to the number of tablets they are often taking – upping the intake of excipients that could cause an allergic reaction.
Giovanni Traverso, an assistant professor in MIT’s Department of Mechanical Engineering and senior author of the study, suggested that there is currently a lack of information regarding excipients and their potential impact on patients’ health.
Minimising the risk
Researchers involved suggested that listing the quantities of inactive ingredients in medication may be a method of countering the issue, as well as clearly labelling the ingredients that could cause an allergic reaction.
In addition, the researchers called for manufacturers to provide more information on inactive ingredients in formulations and to develop alternative formulations suitable for patients with allergies.
The same researchers are now involved in a follow-up study to determine how common allergic reactions are to excipients and are pursuing clinical trials to determine what symptoms present in patients who may be intolerant to specific inactive ingredients.
Traverso concluded, “I think there’s a tremendous under-appreciation of the potential impact that inactive ingredients may have.”