Nouredine Sadeg

Rapid, specific and sensitive method for isoniazid determination in serum.

An original simple, specific and rapid high-performance liquid chromatographic assay for the determination of isoniazid (INH) in human serum is presented. The drug was extracted from the serum by protein precipitation with 30% (w/v) trichloroacetic acid, then the drug was reacted with the coupling reagent, trans-cinnamaldehyde, to form a derivative absorbing at 340 nm. A 20-microliters aliquot was injected into the chromatograph after neutralization with 1 M KOH solution. A liquid chromatograph equipped with a reversed-phase 30-microns C18 precolumn linked to a 4-microns C18 analytical column was used. The drug was eluted with a mixture of acetonitrile-water-triethylamine-acetic acid (400:600:2:1, v/v), pH value was 5 +/- 1. Flow-rate and wavelength were set at 1 ml/min and 340 nm, respectively. The extraction recoveries from human serum averaged 100% for INH at concentrations of 1, 2 and 4 mg/l. The coefficients of variation for three different concentrations for INH in serum in the within-day study varied between 1.2 and 3.5%, whereas those in the day-to-day study varied between 2.8 and 4.3%.

Enantioselective high-performance liquid chromatography determination of methadone enantiomers and its major metabolite in human biological fluids using a new derivatized cyclodextrin-bonded phase

The simultaneous determination of methadone (Mtd) enantiomers and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), in human urine and serum by enantioselective HPLC using a new Cyclobond 1-2000 RSP column is described. After alkaline extraction from urine or serum with estazolam as an internal standard, Mtd enantiomers and its metabolite (EDDP) are separated on the previous column with reversed-mobile phase and detected at 210 nm. Peak resolutions are about 2.0 for Mtd enantiomers. The relative standard deviations (R.S.D.) of Mtd and EDDP standards are between 0.5 and 4.5%. Most drugs of abuse are shown not to interfere with this technique. The method has been applied to study the levels of each Mtd enantiomer and of its racemic metabolite in urine and serum of patients under maintenance treatment for opiate dependence. In urine, R-(-)-Mtd levels are always higher (about 2+/-0.5-fold) than those of S-(+)-Mtd and in most cases, metabolite concentrations are greater than those of global Mtd enantiomers. However, the R-(-) enantiomer levels of residual drug in serum of some patients were lower than those of its antipode. This method is suitable for pharmacokinetic and toxicological studies of Mtd enantiomers and its major metabolite in biological fluids.

In Vitro and In Vivo Comparative Studies on Immunosuppressive Properties of Cyclosporines A, C, D and Metabolites M1, M17 and M21

Cyclosporine A (CsA) and its major metabolites: M1, M17 and M21 and two analogues: cyclosporines C (CsC) and D (CsD), were studied for their capacity to interfere with different in vitro activation pathways. Their inhibition potentials against the reaction of Graft-versus-Host (GvH) were also studied. The results showed: CsA, CsC and metabolite M17 were the most active compounds upon the inhibition of lymphocyte proliferation induced by different mitogens (ConA, PHA, PWM) and also on the proliferation of mixed lymphocyte cultures (MLC). The same results were observed concerning the direct activation by protein kinase C using a combined action of phorbol ester + calcium ionophore. In vivo using local GvH reaction, CsA and CsC proved more active than M17 in the two different combinations: H-2d --> (H-2b x H-2d)F1 and H-2k --> (H-2b x H-2k)F1 CsD and two metabolites M1 and M21 showed no or weak immunosuppressive effects. Overall, the immunosuppressive potency of six compounds could be schematized as: CsA > or = CsC > M17 > M1 > or = CsD > M21.

Case Report of Cathinone-Like Designer Drug Intoxication Psychosis and Addiction With Serum Identification

The use of designer drugs commonly marketed as “Bath Salts” or “Energy” has dramatically risen in recent years. Fatalities and cases of aggressive behavior, even cannibalism have been recently reported in the media. However, these cases have been poorly documented. In this paper, we report a case of repetitive and similar acute psychotic episodes induced by Energy 3 intake. Comparative Analyses of Energy 3 sample and patient’s serum by gas chromatography-mass spectrometry detected the presence of 2 synthetic cathinone derivatives: methylenedioxypyrovalerone and pentylone. Finally, this patient’s clinical picture is characterized by the insidious development of dependence to this product. The absence of patient’s personal addiction history, the late onset of this dependence, and its high intensity, suggest a high addiction potential of these substances.