Real-time 2D separation by LC × differential ion mobility hyphenated to mass spectrometry.

The liquid chromatography-mass spectrometry (LC-MS) analysis of complex samples such as biological fluid extracts is widespread when searching for new biomarkers as in metabolomics. The success of this hyphenation resides in the orthogonality of both separation techniques. However, there are frequent cases where compounds are co-eluting and the resolving power of mass spectrometry (MS) is not sufficient (e.g., isobaric compounds and interfering isotopic clusters). Different strategies are discussed to solve these cases and a mixture of eight compounds (i.e., bromazepam, chlorprothixene, clonapzepam, fendiline, flusilazol, oxfendazole, oxycodone, and pamaquine) with identical nominal mass (i.e., m/z 316) is taken to illustrate them. Among the different approaches, high-resolution mass spectrometry or liquid chromatography (i.e., UHPLC) can easily separate these compounds. Another technique, mostly used with low resolving power MS analyzers, is differential ion mobility spectrometry (DMS), where analytes are gas-phase separated according to their size-to-charge ratio. Detailed investigations of the addition of different polar modifiers (i.e., methanol, ethanol, and isopropanol) into the transport gas (nitrogen) to enhance the peak capacity of the technique were carried out. Finally, a complex urine sample fortified with 36 compounds of various chemical properties was analyzed by real-time 2D separation LC×DMS-MS(/MS). The addition of this orthogonal gas-phase separation technique in the LC-MS(/MS) hyphenation greatly improved data quality by resolving composite MS/MS spectra, which is mandatory in metabolomics when performing database generation and search.

Metabolism and urinary excretion of a new quinoline anticancer drug, TAS-103, in humans.

1. TAS-103, a novel condensed quinoline derivative, has been developed as an anticancer drug targeting topoisomerases I and II. 2. The purpose of the present study was to characterize the metabolism and urinary excretion of TAS-103 after the intravenous infusion of a single dose to patients in Phase I clinical trials. 3. Five metabolites were detected using high-performance liquid chromatography (HPLC) photodiode array and a precursor scan by liquid chromatography mass spectrometry mass spectrometry (LC/MS/MS). 4. Structures of the five metabolites were determined using the results of enzymatic hydrolysis and the analysis of production mass spectra obtained by LC/MS/MS, and by comparing HPLC retention times and UV, mass and production mass spectra of authentic standards. 5. The metabolites were identified as demethyl-TAS-103 glucuronide (DM-TAS-103-G), TAS-103 glucuronide (TAS-103-G), TAS-103 glucuronide N-oxide (NO-TAS-103-G), demethyl-TAS-103 (DM-TAS-103) and TAS-103 N-oxide (NO-TAS-103). 6. The mean total amount of TAS-103 and TAS-103-G in urine was only 6.03% of the dose, suggesting that urine is not the main elimination route. TAS-103 was extensively metabolized, and a small percentage of the parent drug (0.41%) was found in urine.

The epidemiology of malaria in a population surrounding Madang, Papua New Guinea.

Malaria is prevalent throughout coastal and lowland Papua New Guinea. Recent changes, including a shift from predominance of Plasmodium vivax to Plasmodium falciparum, appearance of chloroquine-resistant P. falciparum and decreased effectiveness of vector control programs have been observed. Epidemiological features of malaria were studied through four six-month surveys of a population of 16,500 in Madang Province from 1981-1983. Baseline data on parasitology, splenic enlargement, serology, hemoglobin levels, prevalence of 4-aminoquinolines, utilization of mosquito nets and incidence of fever were collected for use in future evaluation of malaria control measures including possible field trials of an antimalarial vaccine. Prevalence of parasitemia (all species, all ages) varied from 35.0% to 42.7% over the four surveys each of which covered a random sample of 25% of the population. The ratio of parasite species was: P. falciparum 70:P. vivax 25:P. malariae 5 in the dry seasons, shifting slightly in favor of P. falciparum during the wet seasons. Intense year-round transmission was indicated by decreasing parasite prevalence and splenic enlargement with age, low density asymptomatic parasitemias and high prevalence of antimalarial antibodies (i.e., greater than 80% of the population over five years of age was ELISA-positive). Levels of endemicity varied geographically, presence of 4-aminoquinolines in urine samples was relatively common (12.7% positive) and chloroquine resistance was widespread (81.6% in vitro, 46.6% in vivo).

Determination of antrafenine and its main acid metabolite, 2-{[7-(trifluoromethyl)-4-quinolinyl]amino}-benzoic acid, in biological fluids using high-performance liquid chromatography with large volume automatic injection and gas-liquid chromatography with derivative formation.

Specific and sensitive analytical methods have been developed for the measurement of antrafenine and its main acid metabolite, 2-([17-(trifluoromethyl)-4-quinolinyl] amino) benzoic acid (FQB), at therapeutic concentrations in plasma and urine. Following the addition of internal standards (the methyl ester of FQB and 2-([8-(trifluoromethyl)-4-quinolinyl] amino) benzoic acid) the parent drug and the metabolite were extracted from biological material with diethyl ether at a weakly acid pH. Drug extracts were evaporated to dryness prior to chromatographic analysis. Antrafenine was measured by high-performance liquid chromatography using a Spherisorb 5-micrometer ODS column with acetonitrile-0.1 M sodium acetate as the mobile phase. Samples were injected automatically using a 500-microliter injection loop. The detector wavelength was 353 nm corresponding to the maximum UV absorption of both drug and internal standard. The coefficient of variation (C.V.) for the determination of antrafenine concentrations between 5 and 250 ng/ml ranged between 24 and 3%, respectively. The acid metabolite of antrafenine was measured by gas-liquid chromatography with electron-capture detection using a 1 m column packed with 3% OV-225 on Gas-Chrom Q (100-120 mesh) at 240 degrees C and on-column methylation with trimethylphenyl ammonium hydroxide. The C. V. of the method for the analysis of metabolite concentrations between 10 and 500 ng/ml ranged between 3 and 9%, respectively.

Amodiaquine resistant falciparum malaria in Thailand.

Amodiaquine cured 38% (13/34) of patients with falciparum malaria in Southeast Thailand. Chloroquine cured 0% (0/13). The cure rates with amodiaquine were the same whether a 1.5 g or 2.0 g course was used. Most patients were resistant to amodiaquine at the RI level and to chloroquine at the RII level. In hospital, amodiaquine cleared parasitemia more frequently than did chloroquine. With the 2.0 g course of amodiaquine, the parasite clearance time was 77 hours; the fever clearance time of 36 hours was low and suggests that amodiaquine does not cause a drug fever. Because of resistance, chloroquine should not be used for falciparum malaria in Thailand. Routine use of amodiaquine is not indicated because more effective drugs are available.