The identification and stereochemical study of tetracycline antibiotics by 1H nuclear magnetic resonance spectroscopy

Casy, A. F.; Yasin, Ahmed

doi:10.1016/0731-7085(83)80040-5

Cited by 19 publications

(8 citation statements)

References 16 publications

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“…5a); the detail in the stack of the aromatic regions (Fig. 5b) is superimposable showing signals at δ 6.95 (d, J = 8 Hz), 7.18 (d, J = 8 Hz) and 7.54 (t, J = 8 Hz) ppm for H-9, H-7, and H-8respectively, entirely consistent with both an authentic sample and the literature data[34].…”

supporting

confidence: 84%

“…It is well known that light, temperature, moisture, and duration of storage influence the stability of Tet leading to a decrease in its microbiological activity and an increase in its toxicity [33,34] 3 and 4), the chemical integrity of loaded Tet HCl was maintained after the electrospinning process as all the signals of Tet HCl and the polymers could be observed, comparable with the literature data [34]. Such a spectroscopic measure of chemical stability after electrospinning has been reported in the analysis of nanofibres containing the antibiotic cefoxitin sodium (Mefoxin) [36], a range of NSAIDs [37], and even the protein bovine serum albumin (BSA) [38].…”

Section: Chemical Stability Of Tet Hclmentioning

confidence: 99%

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Electrospun matrices for localised controlled drug delivery: release of tetracycline hydrochloride from layers of polycaprolactone and poly(ethylene-co-vinyl acetate)

Alhusein

Blagbrough

Bank

2012

Drug Deliv. and Transl. Res.

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We report the controlled release of tetracycline (Tet) HCl from a three-layered electrospun matrix for the first time. Five formulations of electrospun poly-ε-caprolactone (PCL) and poly(ethylene-co-vinyl acetate) (PEVA) have been designed, prepared as micro/nanofibre layers, and assayed for the controlled release of the clinically useful antibiotic Tet HCl with potential applications in wound healing and especially in complicated skin and skin-structure infections. Tet HCl was also chosen as a model drug possessing a good ultraviolet (UV) chromophore and capable of fluorescence together with limited stability. Tet HCl was successfully incorporated (essentially quantitatively at 3 %, w/w) and provided controlled release from multilayered electrospun matrices. The Tet HCl release test was carried out by a total immersion method on 2 × 2 cm(2) electrospun fibrous mats in Tris or phosphate-buffered saline heated to 37 °C. The formulation PCL/PEVA/PCL with Tet HCl in each layer gave a large initial (burst) release followed by a sustained release. Adding a third layer to the two-layered formulations led to release being sustained from 6 days to more than 15 days. There was no detectable loss of Tet chemical stability (as shown by UV and NMR) or bioactivity (as shown by a modified Kirby-Bauer disc assay). Using Tet HCl-sensitive bacteria, Staphylococcus aureus (ATCC 25923), the Tet HCl-loaded three-layered matrix formulations were still showing significantly higher antibacterial effects on days 4 and 5 than commercially available Antimicrobial Susceptibility Test Discs of Tet HCl. Electrospinning provides good encapsulation efficiency of Tet HCl within PCL/PEVA/PCL polymers in micro/nanofibre layers which display sustained antibiotic release.

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supporting

confidence: 84%

Section: Chemical Stability Of Tet Hclmentioning

confidence: 99%

Electrospun matrices for localised controlled drug delivery: release of tetracycline hydrochloride from layers of polycaprolactone and poly(ethylene-co-vinyl acetate)

Alhusein

Blagbrough

Bank

2012

Drug Deliv. and Transl. Res.

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“…[17][18][19][20][21][22][23] Two regions in Dox 1 H NMR spectrum are of special interest for the attribution of metal coordination sites: the D ring aromatics and the dimethylamino, C4, C4a, and C6 protons on ring A. These protons are not labile and their chemical shift, which is very sensitive to metal coordination, can be distinguished if the coordination occurs through O10 and O12 sites or through A ring sites.…”

Section: Resultsmentioning

confidence: 99%

Three new complexes of platinum(II) with doxycycline, oxytetracycline and chlortetracycline and their antimicrobial activity

Guerra

Silva

Azevedo

et al. 2006

J. Braz. Chem. Soc.

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Este artigo descreve a síntese e a caracterização de três novos complexos de platina(II) com a oxitetraciclina, doxiciclina e clortetraciclina por análise elementar, espectroscopias IV e RMN de II ions as a function of the pH were studied by 1 H NMR. All the investigated tetracyclines form 1:1 complexes with Pt II via the oxygen of the hydroxyl group and oxygen of the amide group at ring A. The minimal inhibitory concentrations (MIC) of the ligands and those of their Pt II compounds were determined in two sensitive strains (E. coli HB 101 and E. coli ATCC 25922) and in a resistant one (E. coli HB101/ pBR322). Platinum complex of doxycycline is twice as potent as the free antibiotic in the resistant strain. Octanol/water partition coefficients of the complexes were determined. Increasing lipophilicity enhances antimicrobial activity in the resistant strain.

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“…This could have implied that the amide group did not participate in the salt formation reactions. For the C 10 -C 12 ketophenolic hydroxyl groups, the C 10 -and C 12 -hydroxyl protons were intramolecularly hydrogen-bonded to the nearby carbonyl oxygen at C 11 and C 1 , respectively (26 The UV spectra show that the three salts had the same peaks (λ max ) and troughs (λ min ) (Table I and Fig. S2).…”

Section: Identification Of the Interaction Between Ctc And Acidsmentioning

confidence: 95%

“…The 1 H NMR spectra of the different CTC salts displayed intense resonances near 2.9 ppm attributable to the common C 4 -dimethylamino group (26). The N-protonation led to a pronounced downfield shift of N-methyl resonances from 2.6 to 2.9 ppm in CTC.…”

Section: Identification Of the Interaction Between Ctc And Acidsmentioning

confidence: 98%

Synthesis and evaluation of bisulfate/mesylate-conjugated chlortetracycline with high solubility and bioavailability

et al. 2020

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The aim of this work is to improve the solubility and bioavailability of chlortetracycline and the function of the immune response. Chlortetracycline bisulfate and chlortetracycline mesylate were successfully synthesized and characterized with several techniques, including spectroscopy, chromatography and mass spectrometry, which demonstrated that the C4-dimethylamino group of chlortetracycline can accept a proton from sulfuric acid and methanesulfonic acid to form the corresponding salts. In addition, chlortetracycline bisulfate and chlortetracycline mesylate were more soluble in water than chlortetracycline hydrochloride, but the antibacterial activity was not enhanced. The influences of chlortetracycline hydrochloride, chlortetracycline bisulfate and chlortetracycline mesylate on chlortetracycline and immunoglobulin concentrations in mouse serum were also investigated. These results suggested that the chlortetracycline bisulfate and chlortetracycline mesylate have good bioavailability and strong immune response and have potential applications in animal breeding and formulation technologies.

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The identification and stereochemical study of tetracycline antibiotics by 1H nuclear magnetic resonance spectroscopy

Cited by 19 publications

References 16 publications

Electrospun matrices for localised controlled drug delivery: release of tetracycline hydrochloride from layers of polycaprolactone and poly(ethylene-co-vinyl acetate)

Electrospun matrices for localised controlled drug delivery: release of tetracycline hydrochloride from layers of polycaprolactone and poly(ethylene-co-vinyl acetate)

Three new complexes of platinum(II) with doxycycline, oxytetracycline and chlortetracycline and their antimicrobial activity

Synthesis and evaluation of bisulfate/mesylate-conjugated chlortetracycline with high solubility and bioavailability

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