Photostability studies

J. C. White and L. Stryer, Photostability studies of phycobiliprotein fluorescent labels, Anal. Biochem. 161, 442 152 (1987). 

The understanding of some photodegradation pathways appears to be still in its infancy. Photostability studies on a new ester of methylprednisolone... 

Drew, H. D., Brower, J. F., Juhl, W. E., and Thornton, L. K. (1998), Quinine photochemistry A proposed chemical actinometer system to monitor UV exposure in photostability studies of pharmaceutical drug substances and drug products, Pharmacopeial Forum, 24(3), 6334. 

Drew HD. Photostability of drug substances and drug products a validated reference method for implementing the ICH photostability study guidelines. In Albini A, Fasani E. Drugs Photochemistry and Photostability. Cambridge The Royal Society of Chemistry, 1998 227-242. 

He is the author of this volume s Chapter 9 on the "Photostability Testing Sample Presentation." As well as two others in other texts addressing "Sample Presentation for Photostability Studies Problems and Solutions" (274) and "Photostability Testing the Questions Most Frequently Asked" (275). 

Reisch J, Zappel J, Raghu A, Rao R. Photostability studies of ouabain, (-acetyldigoxin and digoxin in the solid state. Pharm Acta Helv 1994 69 47-50. 

Sequeira F, Vozone C. Photostability studies of drug substances and products. Pharm Tech 2000 30-35. 

Piechocki J, Wolters R. Photon sources in photostability studies Part I. Joint Meeting of FDA/Pharmaceutical Manufacturers Association (PMA) in Rockville, MD, December 14,1993. 

Piechocki J. Pharmaceuticals—design photostability studies within FDA and ICH guidelines. Center for Business Intelligences. 2nd Annual Regulatory Compliance and... 

Baertschi SW. Designing and implementing photostability studies in alignment with ICH guidelines. Bamett-Parexels Conference on Stability Testing, Washington, D.C., September 14,1998. 

Baertschi SW. Current trends in photostability. Practical considerations in designing and implementing photostability studies. Stability of Pharmaceuticals Current Issues, Practices, and Technologies, University of Wisconsin-Madison Seminar Series, Costa Mesa, CA, November 13-14, 2000. 

Baertschi SW, Thatcher SR. Sample presentation for photostability studies problems and solutions. In Piechocki J, Thoma K, eds. Pharmaceutical Photostability and Stabilization Technology New York. 

In some cases, a drug product can even be exposed to direct sunlight. Clearly, it is difficult to predict the amount of UV and VIS irradiation to which the product is exposed during the shelf life. The spectral power distribution and the overall illuminance used in a photostability study should therefore provide a "worst-case" exposure. 

Of all of the topics in the International Conference on Harmonisation (ICH) QIB document, none is more important than that related to the source. The source is the active agent in photostability studies. Without control of the source, results are questionable. 

In the International Conference on Harmonization (ICH) QIB document (1) little attention is paid to the problem of the different glasses used for photostability studies or the differences in their physical shapes. In Option 1 the use of an "appropriate filter" to remove "significant radiation below 320 nm" is specified. No details are given as to the characteristics of said filter, nor concern that to use such a filter would mean that the specifications for the standard could not be met. 

Figure 15 (A) Spectral transmission curves showing effect of glass type and thickness. (B) Transmittance curves of ampoules (61) and vials (62) used in original and subsequent Japanese photostability studies. (61) 20mL colorless ampoules (JIS R3512, No. 5), (62) 15mL colorless vials (N-16, Mamemu, Osaka). Source From Ref. 5.

Sample Presentation for Photostability Studies Problems and Solutions... 

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