Impurity in duloxetine capsules (D-0514-2026) — found above the limit at the twelve and eighteen month stability intervals

1Not visible at the time of release

What stands out here is when the impurity was found: at the twelve and eighteen month long-term stability intervals, a year to a year and a half after manufacture. Testing at release had shown nothing.

1. 1ManufactureTesting at release meets the standard
2. 2DistributionThe product reaches the market and is used
3. 3At twelve monthsA stability test identifies the impurity
4. 4At eighteen monthsIt is identified again, above the recommended limit

Medicines change over time after manufacture, which is why retained samples are examined at set intervals in long-term stability testing. That testing exists to support an expiry date, but it also functions as the mechanism that finds problems emerging only with time.

2Nitrosamine impurities

Nitrosamine impurities are known to be capable of forming from combinations of substances and conditions in an active ingredient or excipients, and have arisen across several medicines. The agency publishes recommended intake limits by substance, and a figure of 0.83 ppm is cited here.

3The scale of the quantity

Above three hundred thousand packs is large among the records this site holds. For medicines taken chronically, one lot reaches many patients over a long period, which is why the scope of a recall grows.

4Why Class I is rare among drugs

Across the records this site holds as of 2026-09-04, drugs run 14 Class I to 274 Class II, a smaller share of Class I than food or devices. Impurity questions like this one are assessed less as immediate serious harm than as an increase in risk from long-term intake. Since classification turns on the harm judged likely to follow, that mode of assessment shows up in the distribution.