Fast rolitetracycline stability determination by spectrophotometer variable-temperature kinetic experiments.

The pseudo-first order rate constant for the hydrolysis of rolitetracycline as a function of temperature was obtained by performing variable-temperature kinetic experiments. The results are in agreement with those obtained at constant-parameter kinetics but saving experimental time and chemicals.

13C-NMR spectroscopy of three tetracycline antibiotics: minocycline hydrochloride, meclocycline, and rolitetracycline.

13C-NMR data and spectral assignments are presented for tetracycline antibiotics minocycline hydrochloride, meclocycline, and rolitetracycline.

A high pressure liquid chromatographic method for the determination of tetracyclines in blood and organs of experimental animals.

A high-pressure liquid chromatographic method has been developed for the quantitative analysis of tetracyclines from biological material. Tetracyclines can be extracted from serum or organ homogenates by means of acetonitrile containing buffer. The extract is chromatographed on a reversed-phase column and the tetracyclines are monitored spectrophotometerically at 357 nm. Tetracyclines, pyrrolidinomethyl-tetracycline, 4-epitetracycline, and doxycycline are thus separated within 8 min. The lowest concentration for the intact molecule detectable are 0.2 micrograms/ml serum or blood and 0.4 micrograms/g organ. In a comparative study the new extraction procedure and the chromatographic analysis yielded the same results as a microbiological method.

Distribution of pyrrolidinomethyl-tetracycline (rolitetracycline) and tetracycline in blood and various organs of mice measured by high pressure liquid chromatography.

By means of a newly developed high-pressure liquid chromatographic method the organ distribution of tetracycline (TC) and pyrrolidinomethyl-tetracycline (PMT) has been studied. When mice were treated with 50 mg/kg i.v. TC or PMT these antibiotics could be detected in all organs investigated (liver, kidney, heart, lung, muscle, spleen). Especially high concentrations were found in liver and kidneys, where TC and PMT could be detected up to 6 h. In animals treated with PMT part of the PMT applied decomposed slowly yielding TC, which was found together with PMT in blood and all organs.

A high performance liquid chromatographic system for the analysis of tetracycline drug standards, analogs, degradation products and other impurities.

This paper describes the high performance liquid chromatographic (HPLC) analysis of eight parent tetracycline standards: tetracycline, chlortetracycline, rolitetracycline, oxitetracycline, minocycline, doxycycline, democlocycline, methacycline; and three tetracycline epimers: epitetracycline, epianhydrotetracycline, and anhydrotetracycline. The HPLC system employs an octadecylsilane reverse phase column and an isopropanol-diethanolamine-phosphate-ammonium EDTA-water mobile phase. This system produced at least partial resolution of all eight parent compounds and many of their degradation products.

[Antibiotic concentrations of the gallbladder following cystic duct stenosis. Clinical studies and animal experiments]. / Antibioticakonzentrationen der Gallenblase nach Cysticusverschluss. Klinische und tierexperimentelle Untersuchung.

Serum and bile kinetics are measured after experimental cystic duct ligation in 24 rabbits and after acute stone obstruction in 24 clinical cases. Tissue, bile, and serum levels are compared. The results clearly demonstrate that pharmacologic data alone do not give sufficient indications for antibiotic therapy in biliary tract infection. Expected pathologic bacteria and their actual resistance are considered to be of great importance in the indication of antibiotic therapy.

The stability of N-pyrrolidinomethyltetracycline in solutions.

In aqueous solution N-pyrrolidinomethyltetracycline (PTC) undergoes decomposition into tetracycline, epitetracylcine, anhydroepitetracycline and ynhydrotetracycline. The decomposition products were identified and separated by TLC and their activity was estimated microbiologically.

Simultaneous high-speed liquid chromatographic determination of tetracycline and rolitetracycline in rolitetracycline formulations.

A rapid, precise high-speed liquid chromatographic procedure for the simultaneous determination of tetracycline and rolitetracycline in rolitetracycline formulations is described. Samples are dissolved in water, chilled to 0 degrees, and chromatographed on a pellicular cation-exchange resin, The specificity of this method represents a significant improvement over present analytical procedures, which fail to differentiate between rolitetracycline and its hydrolysis product, tetracycline, in these formulations.