Improvements Are Coming to the Inactive Ingredient Database (IID)
In a new draft guidance released by the FDA on July 11th, the promise was made for access to quantitative data on maximum daily exposure levels (MDEs) of excipients by October 1, 2020. This will go a long way to making the IID more useful to sponsors trying to use it to qualify the safety of the excipients present in their drug products. This is especially true for those sponsors using excipients at levels greater than are currently posted in the database. A major impediment to using the database to substantiate the safety of excipients in drug products has been the expression of quantitative data in terms of the amount of excipient per unit dose without corresponding information on the maximum number of unit doses that may be used per day. With the addition of a query function to obtain maximum daily exposure levels for a particular dosage form, the database will become a much more useful tool for drug development. It will be interesting to see how the FDA meets the challenge of identifying maximum daily exposure levels for topical products for which IID levels are expressed as percentage values (%w/w, %w/v, %v/v) and for which exact dosage units do not exist.
For users who are new to the IID, the guidance also provides information on the different data fields currently present in the database and some information on how data are extracted from approved drug products for inclusion in the database. The guidance also reminds sponsors that the simple appearance of a level of an excipient in the IID at a given milligram amount or percentage present in a formulation does not necessarily confirm safety for all products for which levels a=of exposure are lower. The FDA also considers whether a new product differs significantly from the one from which the maximum unit dose information appearing in the IID was taken. Differences in the patient population, route of administration, or duration of treatment between products can complicate the extrapolation of safety. One can hope that data on duration of product use (acute versus chronic), exposed patient demographic groups (adult, juvenile, male only, female only), and product risk tolerance (products intended for use by the general population versus those intended for use by those with few therapeutic options) will also someday be accessible in the IID. But in the meantime, quantitative data on maximum daily exposures will certainly be appreciated.