Journal of Chromatography B (v.767, #1)

News Section (N1-N3).

Liquid chromatography–tandem mass spectrometric assays were developed for the sensitive, rapid and high throughput bioanalyses of thalidomide in human plasma and semen. The matrices were first stabilized with 0.025 M Sorensen’s citrate buffer at pH 1.5 to prevent spontaneous hydrolysis. Buffered thalidomide was stable when stored at room temperature for 24 h and for up to three freeze–thaw cycles. Samples were extracted using SPE cartridges. Extracts were then injected into the LC–MS–MS equipped with a reversed-phase column and an APCI interface in the negative ion mode. Calibration curves for both matrices were linear with r>0.99 from 2 to 250 ng/ml and ng/g. Inter-assay precision (RSD) of plasma and semen calibration standards were 2.6–11.6 and 1.9–12.4%, respectively. Recoveries from plasma and semen were greater than 69 and 78%, respectively. Batch sizes of 100 samples per matrix were analyzed with a total run time of 5 h. The methods successfully determined concentrations of thalidomide from a clinical study to levels as low as 7 ng/ml plasma and 8 ng/g semen, respectively.
Keywords: Thalidomide;

A rapid and simple method was developed for the simultaneous separation and quantification of cloricromene, a coumarine derivative, and its active metabolite, cloricromene acid, in rabbit aqueous humor. The analyses were performed by high-performance liquid chromatography using a C18 reversed-phase column (Hypersil ODS) with UV detection at 318 nm. The mobile phase consisted of acetonitrile–water containing 1% triethylamine pH 3.5, adjusted with orthophosphoric acid. An acetonitrile gradient was necessary to achieve good separation within 13 min. Timolol was found to be a suitable internal standard. The retention times ranged from 5.72 to 11.25 min. A simple pre-treatment with acetonitrile containing 0.6% HClO4 was used to deproteinize aqueous humor samples. The limit of quantitation ranged between 10 and 20 ng/ml. The recovery was >90%. The relationship between peak areas and concentration was linear over the range between 0.01 and 3.8 μg/ml, with r 2>0.99. The assay provided good reproducibility and accuracy for both analytes and proved to be suitable for pharmacokinetic studies of cloricromene.
Keywords: Cloricromene;