Detection and determination of active metabolites of 1-(2-o-chlorobenzoyl-4-chlorophenyl)-5-glycyl-aminomethyl-3-dimethylcarbamoyl-1H-1,2,4-triazole hydrochloride dihydrate, (450191-S), in rat tissues, using a radioreceptor assay for benzodiazepines

A radioreceptor assay for chlorpromazine in serum, which is based on binding to dopamine receptors, is described. This method has been postulated to measure all active metabolites as well as the parent drug. We have compared this method with an HPLC method for chlorpromazine. Dopamine-blocking activity, measured in serum samples from schizophrenic patients receiving chlorpromazine, was 1·85–9·1 times higher than serum chlorpromazine level measured by HPLC. The correlation between the two methods was 0·75. Dopamine-blocking activity was related more closely to dose of drug and to serum prolactin level than was serum chlorpromazine level measured by HPLC.

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Simplified and Rapid Determination of Primaquine and 5,6-Orthoquinone Primaquine by UHPLC-MS/MS: Its Application to a Pharmacokinetic Study

Molecules ◽

10.3390/molecules26144357 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4357

Author(s):

Waritda Pookmanee ◽

Siriwan Thongthip ◽

Jeeranut Tankanitlert ◽

Mathirut Mungthin ◽

Chonlaphat Sukasem ◽

...

Keyword(s):

Pharmacokinetic Study ◽

High Performance ◽

Rapid Determination ◽

Active Metabolites ◽

Chromatography Tandem Mass Spectrometry ◽

Accuracy And Precision ◽

The Matrix ◽

Liquid Chromatography Tandem Mass ◽

Isocratic Mode

The method for the determination of primaquine (PQ) and 5,6-orthoquinone primaquine (5,6-PQ), the representative marker for PQ active metabolites, via CYP2D6 in human plasma and urine has been validated. All samples were extracted using acetonitrile for protein precipitation and analyzed using the ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) system. Chromatography separation was carried out using a Hypersil GOLDTM aQ C18 column (100 × 2.1 mm, particle size 1.9 μm) with a C18 guard column (4 × 3 mm) flowed with an isocratic mode of methanol, water, and acetonitrile in an optimal ratio at 0.4 mL/min. The retention times of 5,6-PQ and PQ in plasma and urine were 0.8 and 1.6 min, respectively. The method was validated according to the guideline. The linearity of the analytes was in the range of 25–1500 ng/mL. The matrix effect of PQ and 5,6-PQ ranged from 100% to 116% and from 87% to 104% for plasma, and from 87% to 89% and from 86% to 87% for urine, respectively. The recovery of PQ and 5,6-PQ ranged from 78% to 95% and form 80% to 98% for plasma, and from 102% to from 112% to 97% to 109% for urine, respectively. The accuracy and precision of PQ and 5,6-PQ in plasma and urine were within the acceptance criteria. The samples should be kept in the freezer (−80 °C) and analyzed within 7 days due to the metabolite stability. This validated UHPLC-MS/MS method was beneficial for a pharmacokinetic study in subjects receiving PQ.

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Enzymological determination of free carnitine concentrations in rat tissues

The Journal of Lipid Research ◽

10.1016/s0022-2275(20)40236-6 ◽

1964 ◽

Vol 5 (2) ◽

pp. 184-187

Author(s):

Norman R. Marquis ◽

Irving B. Fritz

Keyword(s):

Free Carnitine ◽

Rat Tissues

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Toxicity of Glycols and Allyl Alcohol Evaluated by Means of Co-cultures of Microcarrier-attached Rat Hepatocytes and BALB/C 3T3 Mouse Fibroblasts

Alternatives to Laboratory Animals ◽

10.1177/026119299202000216 ◽

1992 ◽

Vol 20 (2) ◽

pp. 266-270

Author(s):

Jens-Uwe Voss ◽

Hasso Seibert

Keyword(s):

Lactate Dehydrogenase ◽

Ethylene Glycol ◽

Allyl Alcohol ◽

Rat Hepatocytes ◽

3T3 Cells ◽

Active Metabolites ◽

Mediated Effects ◽

Cells Cultured

The toxicity of allyl alcohol and several glycols (ethylene glycol, 1,2-propanediol, 1,3-propanediol, methoxyethanol, and the glycol ether dioxane) was studied in cultures of 3T3 cells and in co-cultures of 3T3 cells with microcarrier-attached hepatocytes. Metabolism-mediated effects on the cytotoxicity to 3T3 cells were recorded by differences in the growth of the cultures exposed in the presence or absence of hepatocytes. Hepatocyte viability was determined by depletion of intracellular lactate dehydrogenase and effects on the biotransformation ability of hepatocytes were assessed by determination of O-deethylation of 7-ethoxycoumarin (EOD activity). Allyl alcohol was the only substance more toxic to the hepatocytes than to 3T3 cells cultured in the absence of hepatocytes. Toxicity to 3T3 cells of allyl alcohol, ethylene glycol, and 1,3-propanediol, but not of 1,2-propanediol, methoxyethanol and dioxane, was markedly enhanced when the cells were co-cultured with hepatocytes. The results indicate that the toxicity of allyl alcohol, ethylene glycol, and 1,3-propanediol, to 3T3 cells depends on the formation of active metabolites. For ethylene glycol and 1,3-propanediol, growth of 3T3 cells in co-cultures was reduced at concentrations without effects on hepatocyte viability. Co-culture of 3T3 cells with microcarrier-attached rat hepatocytes represents a suitable approach for the in vitro evaluation of metabolism-mediated cytotoxicity.

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