ABSTRACT
The rst law of photochemistry states that only light which is absorbed by a system can bring about a photochemical change, and the second (Stark-Einstein’s law of photochemistry) states that for each photon of light absorbed by a chemical system, only one molecule is activated for a photochemical reaction. Molecules possessing suitable chromophores (moieties capable of absorbing ultraviolet [UV] or visible light in the range of 290-700 nm such as those with the extended conjugation of double bonds or aromatic rings) may be activated photochemically by UV or visible radiation. Consequently, these photoactivated molecules may alter biological systems and if the exposure is sufcient, may elicit harmful effects, including phototoxicity (e.g., erythema/edema, pigmentary alterations, and visual impairment/
14.1 Introduction ................................................................................................ 233 14.2 Betahistine .................................................................................................234 14.3 Betamethasone ........................................................................................... 235 14.4 Carbamazepine .......................................................................................... 236 14.5 Fexofenadine .............................................................................................. 238 14.6 Fluoroquinolones ....................................................................................... 239
14.6.1 Dioxacin .......................................................................................240 14.6.2 Moxioxacin................................................................................... 241 14.6.3 Sparoxacin .................................................................................... 243
14.7 Fluoxetine...................................................................................................245 14.8 Glycyrrhetic Acid ....................................................................................... 247 14.9 Itraconazole ................................................................................................248 14.10 Propafenone Hydrochloride .......................................................................249 14.11 Tianeptine .................................................................................................. 251 Acknowledgments .................................................................................................. 252 References .............................................................................................................. 252
ocular damage), photoallergy, or photocarcinogenicity. Especially, there are specic chemical classes of pharmaceuticals, such as the uoroquinolone antibiotics, which have been associated with a manifestation/exacerbation of these effects [1]. The photostability of active pharmaceutical ingredients (APIs) and drug products (DPs) may impact the potency, shelf life, handling, and packaging of the product. A photounstable API may be problematic to isolate or to formulate, complex to pack for shipping, or difcult to dose (e.g., infusion), and it is an indicator for photosafety concerns that may require further investigation [2]. Therefore, stability testing of the drug substances and the nal preparation is important and recommended by International Conference on Harmonization (ICH) guidelines [3].
