ABSTRACT
INTRODUCTION Many drugs in various dosage forms, particularly in solutions, have been reported to undergo photodecomposition under the influence of various radiation sources. In the past, the investigation of photostability of drugs was more or less ignored since more attention was paid to the effects of temperature, humidity, and oxygen on drug stability. The number of therapeutically active drugs reported to be photolabile has increased considerably over the last three decades. They include antibiotics, antibacterials, analgesics, antidepressants, antihypertensive agents, antihistamines, steroids, nonsteroidal anti-inflammatory agents, vitamins, and antineoplastic agents. Nontherapeutic agents, e.g., excipi ents, impurities, and dyes used to color various pharmaceutical preparations are also known to undergo photodecomposition.
