title: Considerations on the quinine actinometry calibration method used in photostability testing of pharmaceuticals.
abstract: This paper addresses two critical issues concerning the guidelines adopted by the ICH on the photostability testing: the quinine actinometry method and the light/radiation exposure map distribution of the photostability chamber. Using a qualified non-commercial photostability chamber tests were performed using quinine and physical actinometry and compared the results to those which are used as the basis of the ICH guidelines. The statistical analysis on the results showed that: (i) the calibration curve of the quinine solution depends on its concentration and on its location in the chamber; (ii) the quinine actinometry method currently recommended by the ICH guidelines should not be generalized to any photostability chamber.
authors.affiliation: Núcleo de Pesquisas em Nutrição Parenteral, Centro de Ciências da Saúde, Departamento de Ciências Farmacêuticas, UFPE, Recife, Brazil. claytonazevedo@hotmail.com
authors.forename: Clayton Anderson
authors.initials: CA
authors.lastname: de Azevedo Filho
authors.forename: Daniel
authors.initials: D
authors.lastname: de Filgueiras Gomes
authors.forename: João Paulo
authors.initials: JP
authors.lastname: de Mélo Guedes
authors.forename: Rayana Muniz Falcão
authors.initials: RM
authors.lastname: Batista
authors.forename: Beate Saegesser
authors.initials: BS
authors.lastname: Santos
mesh_terms: D000962:Antimalarials / Q000737:chemistry* / Q000528:radiation effects*; D002138:Calibration; D004355:Drug Stability; D017408:Guidelines as Topic; D007700:Kinetics; D009994:Osmolar Concentration; D010782:Photolysis; D011803:Quinine / Q000737:chemistry* / Q000528:radiation effects*; D015203:Reproducibility of Results; D013053:Spectrophotometry / Q000295:instrumentation*; D013678:Technology, Pharmaceutical; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D000962:Antimalarials; D011803:Quinine