Photodecomposition of drugs.

摘要: Publisher Summary This chapter discusses those drugs where one or more photoderivatives have been positively identified and photosensitizers which, although unchanged themselves, photocatalyse the degradations of biomolecules. Precautions against photodegradation in storage are easily taken, but light-induced changes after patient has taken medicine may lead to serious side-effects––typically erythema, oedema, vesicle formation exaggerated sunburn. Sunlight penetrates skin a depth sufficient reach blood circulating surface capillaries. Two types photosensitivity as result foreign chemicals stream described––namely, phototoxicity photoallergy. In phototoxicity, excited state drug molecule can induce cellular damage at least three ways: by inducing radical an endogenous molecule, converting oxygen from its ground (triplet) highly toxic singlet state, electron transfer, it generate very reactive superoxide radical. Phototoxicity occurs only areas exposed light is characterized relief symptoms when withdrawn. It be effective with dose combination exposure sun (or ultraviolet lamp). With high enough dose, phototoxic response elicited all individuals. Examples that chloroquine, frusemide, nalidixic acid, naproxen. Superoxide generators chlorpromazine, mercaptopurine, some tetracyclines, psoralens.