[Structures of leucogen and its related substances in solution state].

AIM: To study the four diastereomers of leucogen and structure of the related substances. METHODS: LC-DAD, LC-MS/MS and LC- 1H NMR were used. LC was carried out with a Phenomnex Luna C18 (250 mm x 4.60 mm ID, 5 microm) column and a mobile phase of water-acetonitrile-glacial acetic acid (58:42: 0.3). RESULTS: The structures of leucogen and its related substances were identified. Leucogen and the related substances were found to have four diastereomers in solution state separately. The stability and transformation of the four diastereomers were analyzed and 3R4S5R was found to be more stable than the others according to quantum calculations. CONCLUSION: Leucogen have four diastereomers in solution state and it can transform from one diastereomer to the others, and the 3R4S5R is more stable than the others.

[Excretion of (-)-clausenamide in rats].

AIM: To study the excretion of (-)-clausenamide in rats. METHODS: The urine, feces and bile were collected at predetermined time points after (-)-clausenamide was orally administrated to 6 rats (30 mg x kg(-1)). The concentrations of (-)-clausenamide and its metabolite 6-OH-(-)-clausnamide were determined by HPLC-MS/MS method using glipzide as the internal reference, and the accumulative excretion amount of (-)-clausenamide and 6-OH-(-)-clausenamide was calculated in the urine, feces and bile, separately. RESULTS: (-)-Clausenamide was recovered mostly (44%) from feces in 112 hours, 7.1% was found from urine in 120 hours and 0.013% was detected from bile in 24 hours. The accumulative excretions of 6-OH-(-)-clausenamide were 0.92% , 0.46% and 0.0003% of the administered dose from feces, urine and bile, respectively. CONCLUSION: The major amount of (-)-clausenamide was recovered from feces after (-)-clausenamide was orally administrated to rats (30 mg kg(-1)).

Determination of trace trichlorfon by high performance liquid chromatography with UV detection based on its catalytic effect on sodium perborate oxidizing benzidine.

Trichlorfon has the capacity to catalyze the oxidation of benzidine (4,4'-diamino-biphenyl) to 4-amino-4'-nitro biphenyl in the presence of sodium perborate. The product of the catalyzed reaction was validated by LC-MS method. Reversed-phase high performance liquid chromatography with 365 nm UV detection was used for separation and quantification of 4-amino-4'-nitro biphenyl. It can be proven there is a linear relationship between the peak areas of 4-amino-4'-nitro biphenyl and trichlorfon in the concentration range of 0.02-0.5 mg L(-1) (r=0.9988). Limit of detection was 2.0 microg L(-1). A method for the indirect determination of trichlorfon using HPLC was developed based on catalytic effect of trichlorfon. Method validation was performed on samples spiked at three levels (0.5, 1.0, 1.5 mg kg(-1)), the recoveries ranged from 67.5 to 82.1%, with relative standard deviations between 4.5 and 7.3%. 0.01 mol L(-1) sodium dodecyl sulphate (SDS) solution was used to extract trichlorfon from samples and solid-phase extraction was used to isolate and concentrate trichlorfon in SDS solution. The recoveries of trichlorfon obtained with percolating the extraction through a SPE system were essentially in agreement with those obtained by liquid-liquid extraction. This new isolation technique decreases the use of toxic solvents and satisfies the requirements of Green Analytical Chemistry.