Photochemical Reaction of Nalidixic Acid in Methanol
The photochemical reactions of methanolic nalidixic acid (NAL) solution in the absence and in the presence of air have been investigated using 300 nm UV light. From the reactions, 1-ethyl-7-methyl-4-oxo-4-hydro-1,8naphthyridine (EMDN), formic acid, and formaldehyde are produced. In the presence of air, hydrogen peroxide is also detected along with the products listed above. The presence of oxygen during the irradiation of methanolic NAL solution effects on the product yield. The initial quantum yields of the products and of the NAL decomposition are determined. Possible reaction pathways for the photochemical reaction are suggested on the basis of the products analysis.
TYPE I and TYPE II PHOTOSENSITIZATION BY THE ANTIBACTERIAL DRUG NALIDIXIC ACID. A LASER FLASH PHOTOLYSIS STUDY *
The 355 nm laser flash photolysis of nalidixic acid at pH 9.2 leads to the formation of the nalidixate anion triplet state (absorption Λmax= 620 nm; 5700 ≤εT≤ 9000 M−1cm−1; 0.6 ≤φT≤ 1). The first order triplet state decay (kT= 7.7 times 10−3s−1) is accompanied by a diffusion controlled triplet‐triplet annihilation. Oxygen efficiently quenches the triplet state (k = 3.2 times 109M−1s−1). The nalidixate radical dianion (absorption Λmilx= 650 nm; ε= 3000 M−1cm−1) is produced by the diffusion controlled reductive quenching of the triplet state by tryptophan and tyrosine. The superoxide anion (O−2) is produced by diffusion controlled reaction of the radical dianion with oxygen. The O−2 is characterized by its reactions with ferricytochrome c and superoxide dismutase. The physiological form of nalidixic acid is thus a good Type I and Type II photosensitizer.
AN ULTRAVIOLET RADIATION DOSIMETER BASED ON THE PHOTOSENSITISING DRUG, NALIDIXIC ACID
Abstract— The optical properties of a polymer film which incorporates the photosensitising drug, nalidixic acid, as the chromophore are described. The film is shown to be suitable as a UV dosimeter in the wavelength range 280–350 nm. It is suggested that the film could be used as a biological monitor in subjects photosensitised with 8‐methoxypsoralen. as in the photochemotherapy of psoriasis.