rifampin and dehydrorifampicin

Rifampicin is an antibiotic used as a first line treatment for tuberculosis, as well as in the treatment of other infectious diseases. Drug quality is essential for drug efficacy. Determining the stability and activity of Rifampicin Quinone in solution is important in its role as a standard against which to determine Rifampicin quality and in its effect on treatment and AMR development. Poor quality medicines, such as antimicrobials not only increase mortality and morbidity, but can also contribute to the development of antimicrobial resistance (AMR). One common marker of poor quality in Rifampicin samples is the presence of the degradation product Rifampicin Quinone. In this study we have found that Rifampicin Quinone in solution undergoes a chemical conversion to Rifampicin that is temperature dependent. This conversion occurs in physiologically relevant temperatures (30-50 °C) and time scales (24-120 h) and was verified using HPLC and LC-MS methods. Additionally, the conversion of Rifampicin Quinone to Rifampicin results in an increase in antimicrobial activity. We believe that ours is the first study reporting the instability of Rifampicin Quinone, and this instability in solution at these temperatures and time scales raises concerns for its use as a standard in quality testing using liquid chromatography methods and in studies of the effect of Rifampicin Quinone on AMR. Due to the use of Rifampicin Quinone as a standard in determining Rifampicin quality, the instability of Rifampicin Quinone also poses public health concerns, as the incorrect determination of medicine quality risks patient health and may promote the development of AMR.

Topics: Anti-Bacterial Agents; Humans; Rifampin; Temperature; Tuberculosis

Topics: alpha-Synuclein; Cytokines; Humans; Inflammation Mediators; Microglia; Models, Biological; Molecular Structure; Neurodegenerative Diseases; Neurons; Phosphatidylinositol 3-Kinases; Receptors, Purinergic P2X7; Rifampin; Signal Transduction; Toll-Like Receptor 2

Topics: Animals; Calibration; Chromatography, Liquid; Cytochrome P-450 Enzyme System; Hep G2 Cells; Humans; Limit of Detection; Male; Mass Spectrometry; NAD(P)H Dehydrogenase (Quinone); Oxidation-Reduction; Quality Control; Quinones; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reproducibility of Results; Rifampin; Time Factors

A novel simple, fast and efficient supercritical fluid chromatography (SFC) method was developed and compared with RPLC method for the separation and determination of impurities in rifampicin. The separation was performed using a packed diol column and a mobile phase B (modifier) consisting of methanol with 0.1% ammonium formate (w/v) and 2% water (v/v). Overall satisfactory resolutions and peak shapes for rifampicin quinone (RQ), rifampicin (RF), rifamycin SV (RSV), rifampicin N-oxide (RNO) and 3-formylrifamycinSV (3-FR) were obtained by optimization of the chromatography system. With gradient elution of mobile phase, all of the impurities and the active were separated within 4 min. Taking full advantage of features of SFC (such as particular selectivity, non-sloping baseline in gradient elution, and without injection solvent effects), the method was successfully used for determination of impurities in rifampicin, with more impurity peaks detected, better resolution achieved and much less analysis time needed compared with conventional reversed-phase liquid chromatography (RPLC) methods.

Topics: Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Chromatography, Supercritical Fluid; Drug Contamination; Reproducibility of Results; Rifampin; Rifamycins; Solvents; Temperature

A qualitative analysis method to identify related substances of rifampicin by correlation of spectra in chromatography was established. Standard chromatographic and spectral data obtained by high-performance liquid chromatography with diode array detection (HPLC-DAD) were developed and used in identification of peaks in samples by calculating correlation coefficients (R). The comparison of spectra was expanded to three-dimensional space. Peaks in chromatography can be identified accurately and rapidly through chromatographic system change. The identification results were validated by LC-MS. The threshold of R was set to 0.99 in order to discriminate the impurities and the minimal amount for identification was 30 ng. Taking full advantage of chromatographic separate efficiency and spectral exclusiveness, the method is accurate and reproducible as a new and effective way to identify multi-components in drugs.

Topics: Chromatography, High Pressure Liquid; Hydrogen-Ion Concentration; Mass Spectrometry; Rifampin

Rifampicin as a potential immunosuppressive agent was tested in the rat. A freshly made-up solution of this labile antibiotic in a daily dosage of 20 mg/kg iv did not affect mean graft survival time in a heterotopic heart transplant model. However, when stored solutions of rifampicin were used mean graft survival time was significantly prolonged (from 8.2 +/- 0.4 days with the controls to 18.1 +/- 1.2 days). A similar prolongation was observed when rifampicin quinone, the major rifampicin oxidation product, was administered. We conclude that the immunosuppressive effect ascribed to rifampicin is in fact due to its oxidation product, rifampicin quinone.

Topics: Animals; Drug Stability; Female; Graft Survival; Heart Transplantation; Humans; Immunosuppressive Agents; Male; Oxidation-Reduction; Rats; Rats, Inbred BN; Rifampin

Topics: Animals; Cells, Cultured; Chick Embryo; Interferon Inducers; Interferons; L Cells; Rifampin; Time Factors