ABSTRACT
This work proposes a new method for the in vitro evaluation of the effect of UV irradiation on the production of free radicals and other reactive species during the photodecomposition of drugs. The method was based on the UV irradiation of antibiotics molecules to generate excited states that undergo to homolytic bond cleavages. These reactive species can be detected by their ability to oxidize the luminol, producing the electronically excited aminophtalate, which decays to the ground state releasing electromagnetic radiation in the visible zone of the spectrum. This method was applied to penicillin G, nafcillin, azlocillin and neomycin dissolved in water. It was found that the intensity of the luminol chemiluminescence emission (CL) was proportional to the concentration and dependent on the molecular structure of these drugs. Under the optimized conditions, it was found that penicillin and azlocillin were the most susceptible to photodegradation, while neomycin sulfate was the less affected by the UV light. It was observed that the addition to the antibiotics dissolutions of a hydro-alcoholic extract of petals of calyxes of Roselle reduced the CL intensity, indicating that the extract was able to scavenge the free radicals in the irradiated drugs. This result suggest that its addition to the antibiotics can help in the protection against the radicals formed during the exposition to solar light of patients treated with topic similar antibiotics.
Subject(s)
Anti-Bacterial Agents/radiation effects , Free Radical Scavengers/pharmacology , Free Radicals/antagonists & inhibitors , Hibiscus/chemistry , Luminescent Measurements/methods , Plant Extracts/pharmacology , Administration, Topical , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/chemistry , Azlocillin/administration & dosage , Azlocillin/chemistry , Azlocillin/radiation effects , Dermatitis, Phototoxic/etiology , Dermatitis, Phototoxic/prevention & control , Flowers/chemistry , Free Radicals/chemistry , Free Radicals/toxicity , Luminescent Agents/chemistry , Luminol/chemistry , Neomycin/administration & dosage , Neomycin/chemistry , Neomycin/radiation effects , Oxidation-Reduction , Penicillins/administration & dosage , Penicillins/chemistry , Penicillins/radiation effects , Sunlight/adverse effects , Ultraviolet Rays/adverse effectsABSTRACT
In this paper, Sn-doped TiO(2) photocatalyst was prepared and immobilized on a glass substrate using an about-to-gel SiO(2) sol as a nanoglue. The characterization of the Sn-doped TiO(2) by XRD showed that 5% Sn content is formed by anatase and rutile crystallites. Characterization of the nanoglued photocatalyst by the BET measurement, TEM, and SEM showed that the photocatalyst was a nanoporous material with a high-surface area. The Sn-doped TiO(2) was uniformly dispersed within the three-dimensional network of the silica in the form of nanoparticles. The nanoglued photocatalyst showed high photocatalytic activity during the degradation of penicillin under UV light. The effect of different Sn content on the amount of hydroxyl radical was discussed by using salicylic acid as probe molecules. The results show that an appropriate amount of Sn dopant can greatly increase the amount of hydroxyl radicals generated by TiO(2) nanoparticles, which are responsible for the obvious increase of photocatalytic activity.
