Paper Chromatographic Determination of Oxytetracycline

Sina, Aly; Youssef, Muhammad; Kassem, Ahlam Azzam; Attia, I.A.

doi:10.1002/jps.2600601024

Cited by 17 publications

(8 citation statements)

References 8 publications

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“…The definite decomposition mechanisms of OTC have not yet to be elucidated, but several compounds are known to be generated: 4-epi-derivatives; anhydro-derivatives; and apooxytetracyclines (apo-OTC). [10][11][12] Epimerisation at C-4 yields 4-epi-tetracyclines. This rearrangement is slow in the case of OTC due to the stereochemical effect of the hydroxy group of C-5.…”

Section: Depolymerization Of Other Polysaccharidesmentioning

confidence: 99%

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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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Section: Depolymerization Of Other Polysaccharidesmentioning

confidence: 99%

“…Separation, identification and measurement of OTC and some decomposition products have been described, 11,12) but simple, reliable methods have not yet to be established. Furthermore, reference substances for decomposition products are not readily available.…”

Section: Depolymerization Of Other Polysaccharidesmentioning

confidence: 99%

Hyaluronate Depolymerization Following Thermal Decomposition of Oxytetracycline.

Miyazaki¹,

Yomota²,

Okada³

2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…A crystal growth study of chloramphenicol and prednisolone in injection suspensions led to the definition and the development of a reproducible method to control particle size and included number of particles to be counted, sample preparation, and method of dilution (87). The effects of pH, buffer components, magnesium and calcium salts, ethylenediaminetetraacetic acid, and a number of antioxidants on the stability of oxytetracycline solutions were studied (88). Formulas containing magnesium chloride, phydroxybenzoic acid, dimethylformamide, propylene glycol, and sodium sulfite at pH 7.5 were the most stable.…”

Section: General Pharmacymentioning

confidence: 99%

“…Stability kinetic studies of oxytetracycline hydrochloride in solutions were performed (168). The effect of different pH's and buffers on the solubility and stability was determined.…”

Section: General Pharmacymentioning

confidence: 99%

“…Two stable injection formulations were presented. Another study found that the addition of glycerin, propylene glycol, polyethylene glycol 400, dimethyl sulfoxide, and water was detrimental to oxytetracycline in ointments (169). Rolitetracycline was found to hydrolyze rapidly in dilute aqueous solution (170), and the base was less stable than the nitrate salt.…”

Section: General Pharmacymentioning

confidence: 99%

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Pharmaceutical Sciences—1974: Literature Review of Pharmaceutics

Haleblian¹,

Goodhart²

1975

Journal of Pharmaceutical Sciences

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Thermodynamics and Kinetics of the Hydride‐Transfer Cycles for 1‐Aryl‐1,4‐dihydronicotinamide and Its 1,2‐Dihydroisomer

Zhu

Cao

Liu

et al. 2003

Chemistry A European J

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Five 1-(p-substituted phenyl)-1,4-dihydronicotinamides (GPNAH-1,4-H(2)) and five 1-(p-substituted phenyl)-1,2-dihydronicotinamides (GPNAH-1,2-H(2)) were synthesized, which were used to mimic NAD(P)H coenzyme and its 1,2-dihydroisomer reductions, respectively. When the 1,4-dihydropyridine (GPNAH-1,4-H(2)) and the 1,2-dihydroisomer (GPNAH-1,2-H(2)) were treated with p-trifluoromethylbenzylidenemalononitrile (S) as a hydride acceptor, both reactions gave the same products: pyridinium derivative (GPNA(+)) and carbanion SH(-) by a hydride one-step transfer. Thermodynamic analysis on the two reactions shows that the hydride transfer from the 1,2-dihydropyridine is much more favorable than the hydride transfer from the corresponding 1,4-dihydroisomer, but the kinetic examination displays that the former reaction is remarkably slower than the latter reaction, which is mainly due to much more negative activation entropy for the former reaction. When the formed pyridinium derivative (GPNA(+)) was treated with SH(-), the major reduced product was the corresponding 1,4-dihydropyridine along with a trace of the 1,2-dihydroisomer. Thermodynamic and kinetic analyses on the hydride transfer from SH(-) to GPNA(+) all suggest that the 4-position on the pyridinium ring in GPNA(+) is much easier to accept the hydride than the 2-position, which indicates that when the 1,4-dihydropyridine is used the hydride donor to react with S, the formed pyridinium derivative GPNA(+) may return to the 1,4-dihydropyridine by a hydride transfer cycle; but when the 1,2-dihydropyridine is used as the hydride donor, the formed pyridinium derivative can not return to the 1,2-dihydropyridine by the hydride reverse transfer from SH(-) to GPNA(+). These results clearly show that the hydride-transfer cycle is favorable for the 1,4-dihydronicotinamides, but unfavorable for the corresponding 1,2-dihydroisomers.

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Paper Chromatographic Determination of Oxytetracycline

Cited by 17 publications

References 8 publications

Hyaluronate Depolymerization Following Thermal Decomposition of Oxytetracycline.

Hyaluronate Depolymerization Following Thermal Decomposition of Oxytetracycline.

Pharmaceutical Sciences—1974: Literature Review of Pharmaceutics

Thermodynamics and Kinetics of the Hydride‐Transfer Cycles for 1‐Aryl‐1,4‐dihydronicotinamide and Its 1,2‐Dihydroisomer

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