Drop-to-drop solvent microextraction coupled with gas chromatography/mass spectrometry for rapid determination of trimeprazine in urine and blood of rats: application to pharmacokinetic studies.

A simple and rapid method based on drop-to-drop solvent microextraction (DDSME) coupled with gas chromatography/mass spectrometry (GC/MS) has been successfully applied for the pharmacokinetic studies of trimeprazine in 8 microL of urine and blood samples of rats. Several factors that influenced the extraction efficiency of DDSME, such as selection of organic solvent, extraction time, exposure volume of organic phase, addition of salt and pH, were optimized. Linearity was obtained over the concentration ranges of 0.2-10, 0.25-7.0 and 0.5-6.0 microg/mL with correlation coefficients of 0.998, 0.996 and 0.993 in deionized water, urine and blood samples of rats, respectively. The limits of detection (LODs) of trimeprazine were 0.05, 0.06 and 0.1 microg/mL in deionized water, urine and blood samples. The concentrations of trimeprazine obtained in urine and blood samples of rats were 0.21-1.25 and 2.72-0.22 microg/mL, respectively, after a single intravenous administration of this drug. The enrichment factors and LOD values obtained by DDSME coupled to GC/MS were compared with those of hollow fiber liquid-phase microextraction (HF-LPME) combined with GC/MS. We believe that this novel approach can be very useful in clinical application since only one microdrop of biological samples was required to perform the pharmacokinetic studies from rats, so the sample pretreatments for animal experiments can be very easy too.

Reversal of an antihistamine-induced coma with flumazenil.

Flumazenil is a competitive antagonist with specific action at the central benzodiazepine receptor. It is used when benzodiazepine intoxication is suspected. Its use has also been reported in cannabis intoxication, chloral hydrate overdose, hepatic encephalopathy, and alcohol intoxication. We report the case of a 7-month-old male infant with a depressed level of consciousness after intentional intoxication of antihistamines, whose mental status fully recovered after administration of flumazenil. To our knowledge, this is the first case in children where flumazenil has been reported to reverse antihistamine-induced coma.

Sensitive determination of phenothiazines in body fluids by gas chromatography with surface ionization detection.

Fourteen phenothiazine derivatives were tested for their detection by gas chromatography (GC) with surface ionization detection (SID). The sensitivity of GC-SID was highest with trimeprazine and levomepromazine, which contain aliphatic tertiary amino side chains, and lowest with thiethylperazine and thioproperazine, which contain sulphur residues. Chlorpromazine, trimeprazine and promazine showed excellent linearity between the SID response and the drug amount in the range 0.25-3.0 pmol on-column. Their detection limits were as low as ca. 5-10 pg (15-30 fmol) on-column (250-500 pg per ml of body fluid). A detailed procedure for isolation of phenothiazines from human whole blood and urine using Sep-Pak C18 cartridges, before the GC with SID, is also presented. The recoveries of the drugs (100 pmol), which were added to 1 ml of whole blood or urine, were more than 79%. The baselines remained steady as the column temperature was increased.

Identification of new urinary metabolites of trimeprazine in rats by gas chromatography-mass spectrometry.

The metabolites of trimeprazine were identified in urine of rats by gas chromatography-mass spectrometry. After the oral administration of trimeprazine, the urinary metabolites were extracted with diethyl ether before or after hydrolysis with beta-glucuronidase. The identified metabolites were N-demethyltrimeprazine,3-hydroxytrimeprazine,N-demethyl-3-++ +hydroxytrimeprazine and trimeprazine sulphoxide.

[Biotransformation of alimemazine]. / Biotransformation von Alimemazin.

After application of alimemazine (1) 14 phenothiazine derivatives were detected in the rat urine. The structure of 9 metabolites was elucidated (TLC detection, UV, MS), which are hydroxy, N-dealkyl, S-oxide, and sulfone derivatives of 1. The hydroxy compounds, which are the main metabolites (greater than 50%), are partly conjugated. 5-10% of sulfones were observed. Some of the metabolites were detected in the feces, too. The relationship of the excretion products in urine and feces is 75:25%.