Bacteria

M. abscessus subspecies

Preparation method

The solubility of this compound in DMSO is > 42.4 mg/mL. General tips for obtaining a higher concentration: Please warm the tube at 37 ℃ for 10 minutes and/or shake it in the ultrasonic bath for a while. Stock solution can be stored below - 20 ℃ for several months.

Reacting condition

0.1 or 0.5 μM (MIC90s)

Applications

Pretreating M. abscessus subspecies abscessus and bolletii with 0.5 μM Rifabutin, as well as M. abscessus subspecies massiliense with 0.1 μM Rifabutin did not affect the MIC90s, which implied that M. abscessus did not have inducible Rifabutin resistance mechanisms. In addition, at the doses which are 2-fold of the MIC90s, Rifabutin showed similar or higher bactericidal activities than Clarithromycin.

Animal models

Mice inoculated with tachyzoites or cysts of Toxoplasma gondii

Dosage form

50, 100, 200, 300 or 400 mg/kg; p.o.; q.d., for 10 days

Applications

In mice inoculated with tachyzoites or cysts of Toxoplasma gondii, 300 mg/kg and 400 mg/kg Rifabutin protected all infected mice against death. At the doses of 100 mg/kg and 200 mg/kg, Rifabutin protected 80% and 10 ~ 40% of the infected mice against death, respectively. However, at the dose of 50 mg/kg, Rifabutin only induced a delay in time to death.

Other notes

Please test the solubility of all compounds indoor, and the actual solubility may slightly differ with the theoretical value. This is caused by an experimental system error and it is normal.

Rifabutin is a naphthalenic ansamycin that derives from rifamycin S and has the activity to against mycobacteria infection with MICs ranged from 0.125 to 0.25 µg/ml [1].
TB (tuberculosis) is a chronic infectious disease caused by Mycobacterium tuberculosis infection. TB can invade to human organs whole body, but mainly affects the lung which is called pulmonary tuberculosis. About 2 billion people has been infected with TB all around the word and the emergence of new infected TB patients is about 8-10 million every year. Rifabutin is an anti-TB medicine used to treat TB infected patients with fewer side effects [1].
Rifabutin is a potent antimycobacterial medicine and has lower toxic than rifampicin. When tested with the mimic human-bacterial plasma membranes, Rifabutin showed high affinity for the bacterial membrane mediated by electrostatic interactions with the phospholipid head groups [2]. In patients with organ transplant, Rifabutin was an excellent medicine to reduce the incidence of TB (tuberculosis) infection [3]. When tested 34 isolates of clinical drug resistant M.tuberculosis with Rifabutin, they showed sensitive to Rifabutin compared with rifampicin treatment [1].
In mice model with TB infected, intravenous administration of Rifabutin reduced bacterial loads in spleen, liver and lung [4].
References:
[1].    Pham, D.D., E. Fattal, and N. Tsapis, Pulmonary drug delivery systems for tuberculosis treatment. Int J Pharm, 2014. 478(2): p. 517-529.
[2].    Pinheiro, M., et al., Differential interactions of rifabutin with human and bacterial membranes: implication for its therapeutic and toxic effects. J Med Chem, 2013. 56(2): p. 417-26.
[3].    Tabarsi, P., et al., Mycobacterial infection and the impact of rifabutin treatment in organ transplant recipients: A single-center study. Saudi J Kidney Dis Transpl, 2015. 26(1): p. 6-11.
[4].    Gaspar, M.M., et al., Rifabutin encapsulated in liposomes exhibits increased therapeutic activity in a model of disseminated tuberculosis. Int J Antimicrob Agents, 2008. 31(1): p. 37-45.