2-Nitrobenzaldehyde: a convenient UV-A and UV-B chemical actinometer for drug photostability testing

We report the development of a new 'photochemical titration' actinometric m ethod for measurement of UV-B (290-330 nm) and UV-A (320-400 nm) light dose during drug photostability testing. It is based upon photolysis of aqueous 2-nitrobenzaldehyde solution, a well-characterized reaction that has been previously demonstrated to be useful as an accurate and reliable actinometr ic method. Our new method can be performed by a chemical technician using o nly common reagents. It has been developed for use with xenon are lamp illu mination chambers which are commonly employed fur drug photostability testi ng, but can be readily modified for use with the: other illumination source s. (C) 2000 Elsevier Science B.V. All rights reserved.