Association between polymorphisms in genes encoding estrogen receptors (ESR1 and ESR2) and excreted bisphenol A levels after orthodontic bracket bonding: a preliminary study.

BACKGROUND: Bisphenol A (BPA) is released from orthodontic composites used for bracket bonding. Genetic variations could modify the metabolism of this chemical within the organism. Considering that free BPA binds to estrogen receptors causing harmful effects to health, the present in vivo study aimed to evaluate the association between genetic polymorphisms in genes encoding estrogen receptors (ESR1 and ESR2) and excreted BPA levels in orthodontic patients. METHODS: Quantification of BPA levels in the urine of 16 patients was performed in a gas chromatograph mass spectrometer before (T0), at 24 h (T1), and 1 week (T2) after bracket bonding. DNA was extracted from saliva, and one genetic polymorphism in ESR1 (rs2234693) and two in ESR2 (rs4986938 and rs1256049) were analyzed by real-time PCR. Increases in BPA levels in the urine at T1 and T2 were grouped according to the genotype, and mean differences were compared by unpaired T test or Mann-Whitney test according to the normality of the data. The established alpha was 5%. RESULTS: BPA levels increased significantly at T1 and T2. There were no statistically significant differences in the increases in BPA levels according to the genotype for any genetic polymorphism (P > 0.05), at neither 24 h nor 1 week after bracket bonding. CONCLUSIONS: The results suggested that there are no association between excreted BPA levels after bracket bonding and the evaluated genetic polymorphisms in ESR1 and ESR2. Further research should be performed in order to confirm these results.

Hybrid silica monolith for microextraction by packed sorbent to determine drugs from plasma samples by liquid chromatography-tandem mass spectrometry.

The present study (1) reports on the synthesis of two hybrid silica monoliths functionalized with aminopropyl or cyanopropyl groups by the sol-gel process; (2) evaluates these monoliths as selective stationary phase for microextraction by packed sorbent (MEPS) to determine drugs in plasma samples via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the multiple reactions monitoring (MRM) mode; and (3) discusses important factors related to the optimization of MEPS efficiency as well as the carryover effect. The prepared hybrid silica monoliths consisted of a uniform, porous, and continuous silica monolithic network. The structure of the aminopropyl hybrid silica monolith was more compact than the structure of the cyanopropyl hybrid silica monolith. The Fourier-transform infrared spectroscopy (FTIR) spectra of the hybrid silica monoliths displayed readily identifiable peaks, characteristic of the cyanopropyl and aminopropyl groups. Compared with the aminopropyl hybrid silica phase, the cyanopropyl hybrid silica phase exhibited higher binding capacity for most of the target drugs. The developed method afforded adequate linearity at concentrations ranging from the lower limit of quantification (0.05-1.00 ng mL(-1)) to the upper limit of quantification (40-10,500 ng mL(-1)); the coefficients of determination (r(2)) were higher than 0.9955. The precision of the method presented coefficients of variation (CV) lower than 14%; the relative standard error (RSE) of the accuracy ranged from -12% to 14%. The developed method allowed for simultaneous analysis of five antipsychotics (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine) in combination with seven antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, fluoxetine), two anticonvulsants (carbamazepine and lamotrigine), and two anxiolytics (diazepam and clonazepam) in plasma samples from schizophrenic patients, which should be valuable for therapeutic drug monitoring purposes.

Simultaneous plasma lamotrigine analysis with carbamazepine, carbamazepine 10,11 epoxide, primidone, phenytoin, phenobarbital, and PEMA by micellar electrokinetic capillary chromatography (MECC).

The determination of lamotrigine (LTG) simultaneously with carbamazepine (CBZ), carbamazepine 10,11 epoxide (CBZ-E), primidone (PRM), phenytoin (PHT), phenobarbital (PB), and 2-phenyl-2-ethyl-malonamide (PEMA) in human plasma was developed using micellar electrokinetic capillary chromatography (MECC) with a diode-array detector. The reproducibility of both separation and quantitation with MECC analysis were appropriate for the intra- and interassay coefficients. The evaluated drugs concentration intervals of LTG, 0.5-10.0 micro g/mL; CBZ, 1.0-16.0 micro g/mL; PEMA, 1.0-20.0 micro g/mL; PB, 1.0-60.0 micro g/mL; PRM, 1.0-20.0 micro g/mL; PHT, 0.7-40.0 micro g/mL; and CBZ-E, 1.0-14.0 micro g/mL were linear with correlation coefficients higher than 0.987 and coefficients of the variation of the points of the calibration curve lower than 10%. The limit of quantitation of the investigated drugs in plasma varied from 0.5 to 1.0 micro g/mL, depending upon the drug. The MECC technique was sensitive enough to work with microsamples into the subtherapeutic, therapeutic, and toxic concentrations, as well as showed to be simple and efficient when applied to monitoring therapeutic drugs in patients treated with a combination of lamotrigine and other antiepileptic drugs such as hepatic enzyme-inducing agents.

Simultaneous Determination of six Antiepileptic Drugs in Plasma Samples by High-Performance Liquid Chromatography / Simultaneous Determination of six Antiepileptic Drugs in Plasma Samples by High-Performance Liquid Chromatography

Determinação Simultânea de Seis Antiepilépticos em Amostras de Plasma por Cromatografia a Líquido de Alta Eficiência. Um método simples, rápido e sensível foi proposto para a determinação simultânea de carbamazepina, fenitoína, fenobarbital, peimidona e seus principais metabólitos em amostras plasma por cromatografia a líquido de alta eficiência. Acetonitrila foi adicionada às aoatras de plasma para precipitar as proteínas. Após a centrifugação, 100µL do sobrenadante foram transferidos para um tubo de ensaio cônico e evaporado à secura com N2. O extrato foi reconstituído com 100µL de água e 10µL foram utilizados para análises cromatográficas. A separação dos fármacos foi realizada em coluna analítica C18 (25cm x 4,6 mm D.I.x 0,5 µm partícula) com a fase móvel tampão fosfato pH 4,8 - acetonitrila - metanol (55:25:20 v/v/v). A detecção foi realizada com detector ultravioleta a 210nm