The Effects of pH and PEG 400–Water Cosolvents on Oxytetracycline–Magnesium Complex Formation and Stability

Tongaree, Sauwaluxana; Goldberg, Alan M.; Flanagan, Douglas R.; Poust, Rolland I.

doi:10.1081/pdt-100100534

Cited by 10 publications

(4 citation statements)

References 25 publications

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“…Data on mineral surface‐catalyzed reactions of OTC were not available. Because TC is stabilized by Cu 2+ [28] and either Mg 2+ or polyethylene glycol‐400 (molecular mass, ˜16,000) [30], we assumed that sorption to particles or DOM stabilizes OTC and, thus, permitted transformation only for the truly dissolved fraction in both the water column and the benthic layer. Because of the lack of reliable rate constants for OTC biotransformation, this process was ignored in model simulations.…”

Section: Methodsmentioning

confidence: 99%

Fate of oxytetracycline in streams receiving aquaculture discharges: Model simulations

Rose

Pedersen

2005

Enviro Toxic and Chemistry

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The potential aquatic fate of oxytetracycline (OTC) in streams receiving discharge from fish hatcheries was examined using the Water-Quality Analysis Simulation Program (WASP, Ver 6.1) model. The modeled 4.4-km stream network included a settling pond, a receiving segment, and two downstream segments. Attainment of quasi-steady state concentrations (concentration variation, <7.5 mg kg(-1)) in the sediment layers of the receiving segment and first downstream segment required several years. Median water-column concentrations (truly dissolved and colloid- and particle-associated) were 0, 0.57, 0.80, and 0.83 ng L(-1) in the settling pond, receiving segment, first downstream segment, and second downstream segment. Truly dissolved fractions in the water column during dosing were 16% in the settling pond, 64% in the receiving segment, and approximately 78% in the river segments. Concentrations declined 20- to 400-fold, depending on the segment considered, within 1 d of dosing. Truly dissolved fractions in the water column after cessation of dosing were 96% in the settling pond and approximately 78% in the river segments. Expected sediment-bound concentrations were approximately 4 mg kg(-1) in the receiving segment during dosing, with a median annual concentration of approximately 1.5 mg kg(-1) . Expected concentrations in downstream sediments were 0.2 mg kg(-1) or less. Sensitivity analyses indicated the most important factors influencing fate under the hydrodynamic conditions simulated were settling-pond biosolids load, biosolids settling velocity, OTC depuration kinetics from biosolids, and OTC river particle-water distribution coefficient(s).

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Section: Methodsmentioning

confidence: 99%

Fate of oxytetracycline in streams receiving aquaculture discharges: Model simulations

Rose

Pedersen

2005

Enviro Toxic and Chemistry

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“…Tongaree et al mentioned that the degradation of TCs is complex and the pharmaceuticals are subject to decomposition in both acidic and alkaline media. [22] After the degradation or change in the structure of the pharmaceuticals, they could not be detected by LC/MS/MS. Therefore, the percent loss of pharmaceuticals was found to increase with the increase in the storage time (see Figure 3).…”

Section: Effect Of Storage Time On Amounts Of Pharmaceuticalsmentioning

confidence: 99%

Phosphorus recovery: minimization of amount of pharmaceuticals and improvement of purity in struvite recovered from hydrolysed urine

Kemacheevakul

Chuangchote

Otani

et al. 2014

Environmental Technology

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Struvite (MgNH₄PO₄·6H₂O) is normally used as a fertilizer in agriculture, where struvite crystallization from hydrolysed human urine is a simple and reliable method for phosphorus (P) recovery. Human urine, however, contains high amount of pharmaceuticals, which may cause health risk for applications. This research investigates the possibility of decreasing the amount of pharmaceuticals (tetracycline, demeclocycline and oxytetracycline) in struvite crystals recovered from synthetic and human urines by focusing on storage time, and of increasing the quality of struvite production. Urines were stored for different times up to 15 days prior to recovery of phosphorus by two steps, spontaneous precipitation and struvite crystallization. The morphology of spontaneous precipitates and struvite crystals was observed. Spontaneous precipitation removed around 17-24% of phosphate from synthetic and human urines, while pharmaceuticals were removed with a quite high amount at a short storage time (5 days) and this amount decreased with increasing the storage time (10 and 15 days). Urines with>70% remaining phosphates were re-used for struvite crystallization by adding extra magnesium. It was found that maximum P-recovery efficiency could be achieved from struvite crystallization at 5-day storage time, 70% and 68% of remaining P in the separated supernatant from synthetic and human urines, respectively, whereas less than 1% pharmaceuticals remained in the struvite crystals from both samples. This indicates that the procedure in this work is a good method for phosphorus recovery, in which high struvite purity (>99%) is obtained with low amount of pharmaceuticals.

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“…The administration of TC in many dosage forms is also limited by the poor aqueous solubility and by the acidic nature of their hydrochloride salt solutions. In addition, the color of their solutions often changes from yellow to brown over storage (Tongaree et al, 2000). Such a color change is attributed to the formation of degradation products.…”

Section: Introductionmentioning

confidence: 96%

Degradation patterns of tetracycline antibiotics in reverse micelles and water

Sah

2006

Biomed. Chromatogr.

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The objective of this study was to determine the chemical stability of tetracycline and oxytetracycline hydro-chlorides in reverse micelles. Their reverse micellar solutions were prepared using cetyltrimethylammonium bromide, water and ethyl formate. The aqueous solutions of the tetracycline antibiotics were also prepared for comparison. The reverse micellar and aqueous solutions were stored at 37 degrees C. Samples were analyzed by high performance liquid chromatography. When evaluation was performed on an aqueous tetracycline HCl solution, its half-life was estimated to be 329 h. Its chemical stability was not improved after being dissolved in the reverse micelles, and a similar half-life of 330 h was observed. However, there were noticeable differences between the two systems in terms of degradation kinetics and degradation byproducts. On the other hand, oxytetracycline HCl was unstable in water so that its half-life was only 34 h. Very interestingly, pronounced improvement in stability was attained with the reverse micellar system: upon dissolving in the reverse micelles, its half-life was increased to 2402 h. There were also marked differences in degradation patterns and mechanisms of oxytetracycline HCl in water and the reverse micelles. Our study indicates that the reverse micellar system has potential applications in solubilizing and stabilizing oxytetracycline HCl, thereby contributing to the development of its dosage forms.

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The Effects of pH and PEG 400–Water Cosolvents on Oxytetracycline–Magnesium Complex Formation and Stability

Cited by 10 publications

References 25 publications

Fate of oxytetracycline in streams receiving aquaculture discharges: Model simulations

Fate of oxytetracycline in streams receiving aquaculture discharges: Model simulations

Phosphorus recovery: minimization of amount of pharmaceuticals and improvement of purity in struvite recovered from hydrolysed urine

Degradation patterns of tetracycline antibiotics in reverse micelles and water

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