., Lay, J. O., Luo, W., McKim, K., Gehring, T. and Lochmann, R. (2000): Liquid chromatographic analysis of incurred amoxicillin residues in catfish muscle following oral administration of the drug. J. Agric. Food Chem.
., Concannon, J., Lovitt, H., Ramage, M., Tai, L. H. and McDonald, C. (1986): Stability of aqueous solutions of amoxicillin sodium in the frozen and liquid states. Am. J. Hosp. Pharm.
Authors:Ch. B. V. N. Raju, H. K. Sharma, Ch. S. Rao and G. N. Rao
Linear gradient HPLC on a C8 column has been used for separation of individual related substances of amoxicillin listed in the European Pharmacopoeia and a newly identified degradation impurity. The USP plate count for the amoxicillin peak was more than 3000 and USP tailing for the same peak was less than 2.0. Forced degradation studies were conducted on amoxicillin drug substance using ICH stress study guidelines to demonstrate the specificity and stability-indicating nature of the method. A new impurity observed after thermal and alkaline degradation was identified as N-pivaloylamoxicillin. The LOD and LOQ for individual related substances were below 0.045 and 0.086% (w/w), respectively. The method was fully validated in accordance with ICH analytical method validation guidelines. The results of the study prove the method is specific, precise, linear, robust, and can be used for evaluation of the stability of amoxicillin drug substance.
Authors:V. Ghoulipour, M. Shokri and S. Waqif-Husain
A simple and fast high-performance thin-layer chromatographic method has been developed for the simultaneous determination of ampicillin and amoxicillin. Titanium(IV) silicate (a synthetic inorganic ion-exchanger)-coated thin-layer chromatography (TLC) plates were used to separate them, employing a mixture of K2HPO4 (0.1 M) + KH2PO4 (0.1 M), 1:1 (υ/υ), as mobile phase. The development time was 18 min. The plates were sprayed with fresh 1% solution of ninhydrin in ethanol. The developed method enables highly contrasted chromatograms with red purple spots in white background. Densitometric measurements were made at wavelength 546 nm using Camag TLC Scanner-3. The ampicillin and amoxicillin recovery of the total procedure were equal to 99.99 and 100.43, respectively. The procedure is quantitatively characterized. Linearities were r2 > 0.9958 and 0.9954 for ampicillin and amoxicillin, respectively, and the relative standard deviations were <0.89 and 0.61, respectively. The limits of detection were 2.9 and 1.5 ng per spot and the limits of quantification were 14.5 and 7.5 ng per spot, respectively. The method is rapid, selective, precise, and accurate and thus can be used for the routine analysis of pharmaceutical preparations in quality control laboratories of the pharmaceutical industry. The method is successfully applied for the determination of ampicillin and amoxicillin in human blood plasma and urine.
Authors:D. Krasucka, C. Kowalski, M. Osypiuk and G. Opielak
A high-performance liquid chromatographic (HPLC) method with fluorescence detection after precolumn formaldehyde derivation was developed to detect concentrations of amoxicillin (AMX) in poultry plasma. Proteins in plasma samples spiked with AMX were precipitated with a phosphate buffer and trichloroacetic acid. After precolumn treatment of the extraction product of AMX with formaldehyde under acidic and heating conditions, HPLC analysis with fluorescence (FL) detection at an excitation wavelength of 355 nm and an emission wavelength of 450 nm was performed. A mobile phase comprising acetonitrile and a buffer solution (0.05 M KH2PO4 pH = 5.6), which yielded AMX retention time 8.58 min, was suitable for detection of AMX. The calculated standard curve of the reaction product was linear, and the correlation coefficient was greater than 0.999. The limit of detection and quantification, the accuracy, and the precision were evaluated. Recoveries of spiked amoxicillin were >92%, with a coefficient of variation in the range of 0.35–0.89%. This method has been successfully applied to a pharmacokinetic study after oral administration of amoxicillin to poultry.
Authors:H. Aki, Y. Nakashima, Y. Kawasaki and T. Niiya
action of amoxicillin (AMPC) and the inclusion complexes of AMPC with α-, β-
and γ-cyclodextrins (α-CD, β-CD and γ-CD, respectively)
to Escherichia coli B (E.
coli) was evaluated by isothermal titration microcalorimetry and
by petri-dish bioassay method. The effects of the compounds on produced heat
during the exponential phase of the E. coli
growing were measured and the growing rate constants of the cells was calculated
from the power-time (p-t) curve before
and after the treatment with AMPC. Results from the both methods showed that
the antibacterial activity became stronger in the following order: AMPC-βCD
> AMPC-γCD ≈ AMPC-αCD > AMPC only.
Authors:Isabel Stephany-Brassesco, Stefan Bereswill, Markus M. Heimesaat and Matthias F. Melzig
) that are cross-linked by peptide chains. Antibiotics with a β-lactam ring, such as amoxicillin, affect the DD-transpeptidase, also termed penicillin binding protein (PBP), subsequently inhibiting the formation of the cross links and therefore of new
, antibiotics such as rifampicin and ciprofloxacin are used; antibiotics widely used for threatening different infection forms are ampicillin, amoxicillin, cefotaxime, and tetracycline.
Materials and Methods
Altogether, 74 N