Cellular toxicity of isoniazid together with rifampicin and the metabolites of isoniazid on QSG-7701 hepatocytes

OBJECTIVE@#To investigate the cellular toxicity of isoniazid together with rifampicin and the metabolites of isoniazid on cultured QSG-7701 cells lines.@*METHODS@#Isoniazid, rifampicin, mixture of rifampicin and isoniazid, acetylhydrazine, hydrazine were added in cultural media of QSG-7701 cells and cultured for 48 hours. The survival rate of cells was determined by MTT method. The cultural media and cells were collected and the activity of lactate dehydrogenase was detected by chromatometry.@*RESULTS@#Compared with control group, the survival rate decreased significantly and the lactate dehydrogenase released from cell increased significantly in cells treated with isoniazid, rifampicin, acetylhydrazine, hydrazine. Hydrazine, the metabolite of isoniazid produced significant damage on hepatocytes in low concentration.@*CONCLUSIONS@#Rifampicin together with rifampicin and metabolites of isoniazid produce cellular toxic effects and hydrazine may be the most toxiferous metabolite.

Determination of unconjugated neurosteroids in rat brain regions by liquid chromatography-negative atmospheric pressure ionization mass spectrometry / 药学学报

<p><b>AIM</b>To simultaneously determine three unconjugated neurosteroids, dehydroepiandrosterone (DHEA) , pregnenolone (PREG), allopregnenolone (AP), from several brain regions of the rat.</p><p><b>METHODS</b>Neurosteroids were isolated separately in a two steps procedure by using ethyl acetate-n-hexane (90:10) as the first step to extract the unconjugated steroids, then the steroid fractions were further purified by SPE. All steroids were derivatized with 2-nitro-4-trifluoromethylphenylhydrazine (2-NFPH) and analyzed by HPLC-MS ( APCI) using selected-ion monitoring. Methyltestosterone was chosen as the internal standard. Results The linear calibration curve of DHEA was obtained in the concentration range of 0.030-2.00 microg x L(-1). The linear calibration curves of PREG and AP were obtained in the concentration range of 0.025-2.00 microg x L(-1). The concentrations of DHEA, PREG and AP in male rat brain regions were (0.70 +/- 0.23), (4.8 +/- 1.9), (1.1 +/- 0.6) ng x g(-1) for frontal cortex, (0.57 +/- 0.28), (6 +/- 3), (0.5 +/- 0.3) ng x g(-1) for hippocampus, (1.5 +/- 1.0), (9 +/- 5), (1.4 +/- 0.9) ng x g(-1) for amygdale, (0.52 +/- 0.14), (7.7 +/- 2.8), (0.5 +/- 0.6) ng x g(-1) for striatum, (2.9 +/- 1.6), (18 +/- 9), (1.6 +/- 1.3) ng x g(-1) for nucleus accumbens, (4.0 +/- 2.0), (27 +/- 12), (0.8 +/- 0.5) ng x g(-1) for pituitary gland, (1.7 +/- 1.2), ( 16 +/- 10), and (0. 8 +/- 0.7) ng x g(-1) for hypothalamus, respectively.</p><p><b>CONCLUSION</b>Good linearity and accuracy were observed for each steroid. The procedure was suitable for measuring concentrations of the unconjugated steroids in rat brain simultaneously.</p>

Effects of morphine dependence on the levels of neurosteroids in rat brain / 药学学报

<p><b>AIM</b>To establish the rat model of morphine-induced conditioned place preference (CPP) and to investigate the effects of morphine psychical dependence on the levels of neurosteroids in rat brain.</p><p><b>METHODS</b>Rats were ip administered morphine 5 mg x kg(-1) for 10 days to induce CPP in morphine group. The concentrations of dehydroepiandrosterone (DHEA), pregnenolone (PREG), allopregnanolone (AP), dehydroepiandrosterone sulfate (DS) and pregnenolone sulfate (PS) in nucleus accumbens (Nac), hypothalamus (Ht), amygdale (A) and plasma of rats were determined with liquid chromatography-negative atmospheric pressure ionization mass spectrometry (LC-MS).</p><p><b>RESULTS</b>Trained with morphine for 10 days resulted in the acquisition of CPP in morphine group with the time that the rats spent in drug-pairing room was longer than that of control group. Compared with control group, morphine treatment could significantly decrease the contents of DHEA in Nac and plasma, decrease that of PREG in Ht.</p><p><b>CONCLUSION</b>Morphine could induce the CPP in rats and affected the contents of some neurosteroids in rat brain, which suggests that endogenous neurosteroids might he related to the development of morphine dependence.</p>

Stereoselectivity in biliary excretion of trans tramadol and trans O-demethyltramadol in rats / 药学学报

<p><b>AIM</b>To investigate the stereoselectivity in biliary excretion of trans tramadol (trans T) and trans O-demethyltramadol (M1) in rats.</p><p><b>METHODS</b>After a single intravenous dose of trans T hydrochloride (10 mg.kg-1) or M1 (2.5 mg.kg-1) to rats, the bile was collected for 30 min, then, blood was obtained from the heart. The enantiomers of trans T, M1 and M1 conjugated with glucuronic acid (M1c) in the bile and plasma were analyzed by high performance capillary electrophoresis (HPCE).</p><p><b>RESULTS</b>After the rats were given trans T, the bile concentrations of (+)-trans T were higher than those of (-)-trans T, and the (+)/(-)-trans T ratios were lower compared with those in the plasma. After the rats were given M1, the bile concentrations of (+)-M1 were higher than those of (-)-M1, and the bile concentrations of (+)-M1c were lower than those of (-)-M1c. The glucuronidation rate of (+)-M1 was lower than that of (-)-M1 in the bile.</p><p><b>CONCLUSION</b>The biliary excretion of trans T and M1 was stereoselective, (+)-trans T and (-)-M1 being preferentially excreted.</p>

Stereoselectivity in O-demethylation of trans tramadol in rat liver microsomes in vitro / 药学学报

<p><b>AIM</b>To study the stereoselectivity in O-demethylation of trans tramadol.</p><p><b>METHODS</b>With or without quinine and quinidine as inhibitors, rat liver microsomes were incubated in vitro with the enantiomers or the racemate of trans tramadol. The concentrations of the enantiomers of trans tramadol and O-demethyltramadol in the incubates were determined by high performance capillary electrophoresis. The O-demethylation processes were assayed by using the enzyme kinetic analysis method.</p><p><b>RESULTS</b>After incubation, the concentrations of (-)-O-demethyltramadol were higher than those of (+)-enantiomer in all rat liver microsomal incubates. Enzyme kinetic analysis showed that the Km of the formation of the enantiomers of O-demethyltramadol were similar; The Vmax and Clint of the formation of (-)-O-demethyltramadol were significantly higher than those of the formation of (+)-enantiomer. When the racemate of trans tramadol was used as the substrate, there was interaction between the two enantiomers. The Km of the formation of the enantiomers of O-demethyltramadol increased, the Vmax of the formation of (+)-O-demethyltramadol decreased, the Vmax of the formation of (-)-O-demethyltramadol increased slightly. The O-demethylation of the enantiomers of trans tramadol was shown to be inhibited competitively by quinine and quinidine. The Ki of quinine and quinidine were 1.6 and 10.8 mumol.L-1 to the formation of (-)-O-demethyltramadol, 0.8 and 3.4 mumol.L-1 to the formation of (+)-O-demethyltramadol, respectively. Furthermore, quinine and quinidine were found to have stereoselective inhibition on the formation of O-demethyltramadol, both mainly inhibited the formation of (+)-O-demethyltramadol.</p><p><b>CONCLUSION</b>The O-demethylation of trans tramadol was found to be stereoselective in rat liver microsomes in vitro, preferentially metabolized (-)-enantiomer. The stereoselectivity could be influenced by the interaction between the two enantiomers and the enzyme selective inhibitors.</p>

Mornitoring of the enantiomers of (?) -trans tramadol andits active metabolite in the serum of postoperative patients afterdifferent intravenous doses of (?)-trans tramadol hydrochloride injection / 中国临床药理学与治疗学

Aim To investigate the relationship between the clinical actions and the serum concentrations of the enantiomers of (?)-trans tramadol and its active metabolite. Methods 20 postoperative patients were divided into two groups and given multiple intravenous doses of (?)-trans tramadol hydrochloride injection, 400 mg?d-1 (group A) or 300 mg?d-1 (group B). The blood samples were taken at 38 h after the initial dose. The concentrations of the enantiomers of (?)-trans tramadol and its active metabolite, (?)-trans O-demethyltramadal were determined with high performance capillary electrophoresis(HPCE). Results The concentrations of the enantiomers of (?)-trans tramadol, the frequency and serious level of adverse reactions were higher in group A than in group B. The concentrations of the enantiomers of (?)-trans O-demethyltramadal, the analgesic effect were similar between group A and group B. Conclusion There is much closer relation between the analgesic effect and the concentration of (+)-O-demethyltramadal. The frequency and serious level of adverse reactions may be attributed to the higher concentrations of the enantiomers of (?)-trans tramadol, which are caused by the saturated metabolism.