Oxidation Photosensitized by Tetracyclines

Wiebe, Joy Anne; Moore, Douglas E.

doi:10.1002/jps.2600660213

Cited by 49 publications

(20 citation statements)

References 20 publications

(2 reference statements)

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“…Absorption slowly decreases with irradiation time. The fall in the absorbance at 355 nm is accompanied by a very weak absorption in the visible region that can be attributed to the formation of 4a,12a-anhydro-4-oxo-4-dedimethylaminotetracycline [10,11]: Tetracycline photodecomposes easily and is converted to many decomposition compounds [11][12][13][14][15][16][17][18]. Side-chain degradations by deamination, desulfuration and dealkylation are typical of many photolytic processes [19][20][21][22].…”

Section: Mechanistic Aspectsmentioning

confidence: 99%

Removal of drugs in aqueous systems by photoassisted degradation

et al. 2005

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Aqueous solutions of tetracycline, lincomycin and ranitidine were irradiated with UV light in homogeneous and heterogeneous systems. Two commercial polycrystalline TiO 2 powders (Degussa P25 and Merck) were used as photocatalysts. After 5 h, an appreciable photolytic degradation of tetracycline and ranitidine was observed while the degradation of lincomycin was noticeably lower. As far as the mineralization is concerned, a small decrease of the TOC values was measured in the case of tetracycline whereas negligible variations were found for lincomycin or ranitidine. The presence of the photocatalysts greatly enhanced the degradation rates of the drugs with respect to those observed during the homogeneous experiments. The Langmuir-Hinshelwood kinetic model adequately describes the experimental results and both the pseudo-first order kinetic constants of the reactions and the adsorption constants were calculated. Merck TiO 2 was more active than P25 Degussa for the photodegradation of tetracycline and ranitidine, whereas both photocatalysts showed similar performances for lincomycin. In the presence of TiO 2 Degussa P25, tetracycline was almost completely mineralized, but the reduction of the initial TOC was ca. 60% in the case of lincomycin and ranitidine. A less significant mineralization was observed by using Merck TiO 2 .

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Section: Mechanistic Aspectsmentioning

confidence: 99%

Removal of drugs in aqueous systems by photoassisted degradation

et al. 2005

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“…Phototoxic response to systemically or topically administered drugs requires exposure to the appropriate wavelength of light, especially UVA (320Y400 nm) and UVB (290Y320 nm) radiation, and the presence of drug in the skin. Several classes of drugs exhibit this type of side effect, including antibacterials (2,3), thiazide diuretics (4), nonsteroidal antiinflammatory drugs (NSAIDs) (5), quinolones (6), and tricyclic antidepressants (7,8). Recently, the level of interest has markedly increased because of the awareness among the scientific community of the increase in the UV portion of the solar spectrum reaching the earth.…”

Section: Introductionmentioning

confidence: 99%

Analytical Studies on the Prediction of Photosensitive/Phototoxic Potential of Pharmaceutical Substances

2006

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Results indicated that known photosensitive/phototoxic compounds tested have the ability to generate ROS under light exposure, and this photochemical reaction could be associated with their photoinstability and/or phototoxic responses. Based on these findings, determination of ROS, generated from photoirradiated compounds, may be an effective predictive model in recognizing their photosensitive/phototoxic potential.

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“…Tetracyclines are known as photosensitizers. 8,9) From recent clinical reports, doxycycline appears to be the most phototoxic. However, with 365 nm irradiation, 1 mM doxycycline did not exert a major influence on the HA molecular weight.…”

Section: Resultsmentioning

confidence: 99%

“…8,9) In this paper, the depolymerization of HA by tetracyclines, expressly oxytetracycline (OTC), was investigated. From depolymerization profiles under various conditions, the probable causative derivative was identified.…”

mentioning

confidence: 99%

Hyaluronate Depolymerization Following Thermal Decomposition of Oxytetracycline.

Miyazaki¹,

Yomota²,

Okada³

2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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Hyaluronate (HA) is a glycosaminoglycan ubiquitously distributed in organisms. It has a linear structure without side chains, and a molecular weight of 10 4 to 10 7 . The huge molecular mass characterizes the physiologic and physicochemical properties of HA. High-molecular-weight HA forms entangled networks, having unique viscoelasticity and waterholding ability.1) The characteristics are molecular-weightsensitive, and yet, high molecular weight HA is easily depolymerized by various physical and chemical factors. There are many reports about HA depolymerization by photo, 2,3) thermal, 2,4) mechanical 2,5) and chemical actions. 6,7) Previously, we described HA depolymerization by phenothiazines and sulfacetamide with UV irradiation. 7) These drugs are known to cause dermatological or ophthalmic phototoxicity in patients receiving them in the long term. We have revealed the hydroxyl radicals and hydrated electrons generated during photodegradation of the drugs to be the active chemicals for HA depolymerization.Tetracyclines have also been reported to exhibit phototoxic and photoallergic reactions, with certain radicals proposed to account for in vivo and in vitro toxicity. 8,9) In this paper, the depolymerization of HA by tetracyclines, expressly oxytetracycline (OTC), was investigated. From depolymerization profiles under various conditions, the probable causative derivative was identified. ExperimentalMaterials Two sodium HA samples were used: one was extracted from culture medium of Streptococcus equi, with a weight average molecular weight (M w ) of 2.6ϫ10 6 , and the other was isolated from rooster comb, with a M w of 1.1ϫ106 . Sodium alginate of medium viscosity from kelp was a commercial product of Sigma Chemical Co. Tetracycline hydrochlorides were purchased from Sigma Chemical Co. or Wako Chemical Co. They were used without further purification. Their chemical structures are listed in Table 1. Other reagents were of analytical grade. All the water used was distilled once and then Millipore filtered.Sample Preparation Polymer solutions were mixed with tetracycline solutions to make at final concentrations of 0.1% in 0.2 M NaCl. They were incubated in test tubes in a thermostated water bath. At the desired time, a portion was removed, appropriately diluted and after drugs were eliminated by solid-phase extraction on Sep-Pak C 18 cartridges, the molecular weight was measured. For studies under anaerobic conditions, glass ampules were used in place of test tubes. Solutions in ampules were de-aerated by 10-min nitrogen bubbling, immediately before the necks of the ampules were sealed with a burner. For UV irradiation, lamps (100 V, 5 W) with 254 nm or 365 nm for TLC spot detection were employed. The distance of the vessels from the light source was set at 5 cm. In the experiments with 254 nm irradiation, the vessels were squared quartz cells.Molecular Weight Measurement M w of HA was measured using a size exclusion chromatography (SEC) equipped with a low angle laser light scattering (LALLS). SEC-LALLS (Tosoh ...

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Oxidation Photosensitized by Tetracyclines

Cited by 49 publications

References 20 publications

Removal of drugs in aqueous systems by photoassisted degradation

Removal of drugs in aqueous systems by photoassisted degradation

Analytical Studies on the Prediction of Photosensitive/Phototoxic Potential of Pharmaceutical Substances

Hyaluronate Depolymerization Following Thermal Decomposition of Oxytetracycline.

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