Spectrofluorimetric determination of 2-aminopyridine as a potential impurity in piroxicam and tenoxicam within the pharmacopoeial limit.

The British Pharmacopoeia defines 2-aminopyridine (2-AP) as a potential impurity in piroxicam (PX) and tenoxicam (TX). Selective spectrofluorimetric determination of 2-AP in PX and TX, within or near the pharmacopoeial level, 0.2%, was developed, based on the measurement of the native fluorescence either in aqueous 0.1N sulfuric acid or in dioxane. Accordingly, this approach was followed for confirming purity of PX and TX in bulk and pharmaceutical preparations. The study was also extended to include simultaneous determinations of PX/2-AP and TX/2-AP systems based on selective fluorescence measurements in the cited solvents.