Metabolic markers of the synthetic cannabinoid 5F-EMB-PICA in zebrafishEI北大核心CSCD

利用斑马鱼实验模型,借助液相色谱组合型四极杆Orbitrap质谱联用技术对N-(1-乙氧基羰基-2-甲基丙基)-1-(5-氟戊基)吲哚-3-甲酰胺(5F-EMB-PICA)的体内代谢产物进行分析,筛选潜在代谢标志物。结果表明,在斑马鱼实验模型中5F-EMB-PICA经过代谢共产生13种Ⅰ相代谢产物和6种Ⅱ相代谢产物。Ⅰ相代谢的途径包括酰胺水解、氟戊烷基侧链氧化脱氟、N-脱烷基化、羟基化和酯水解等。Ⅱ相代谢的途径主要为葡萄糖醛酸化。其中酯水解代谢产物(M5.1)响应强度最高,推荐作为5F-EMB-PICA的潜在代谢标志物。为建立生物样品中5F-EMB-PICA的标准检验方法提供相关代谢研究数据,为相关案件的检验鉴定提供技术支持。     

Metabolism of α-ketol derivative of linolenic acid (KODA), a flowering-related compound, in Pharbitis nil

α-Ketol of octadecadienoic acid (KODA, 1) has been suggested to play a role in the photoperiod-regulated flowering in Pharbitis nil. The level of 1 in cotyledons is temporarily controlled during short-day conditions. The biosynthesis of 1 is well studied in plants; however, its in vivo conversion is less understood. We have investigated this issue by studying the metabolism of exogenously-applied [U-¹³C]-1, [1-¹⁴C]-1, and non-labeled 1 in P. nil seedlings by the spectroscopic methods and identified six major metabolites (4-9). We have also found that the enantiomers of 1 are differentially metabolized in P. nil seedlings.     

Capillary electrophoretic method for nucleotide analysis in cells: application on inherited metabolic disorders

Purine and pyrimidine nucleotides influence many metabolic pathways and their analogs have been widely used in medicine. A capillary electrophoretic method was developed for measuring intracellular nucleotides. The final BGE consisted of 40 mM citric acid with addition of 0.8 mM CTAB titrated by gamma-aminobutyric acid to pH 4.4. The electrophoretic separations were carried out in an uncoated silica capillary (id/od - 75/375 microm; effective/total length - 90/97 cm). The method allows a complete separation of 21 nucleotides and deoxynucleotides within 15 min with separation efficiencies up to 400,000 theoretical plates per meter. Due to the use of an acidic separation medium, the method offers a high selectivity toward the studied analytes versus possible interferences from matrices. Sample preparation was optimized in order to shorten work-time and prevent analyte degradation. The method was applied for analyzing nucleotides in human erythrocytes and Chinese hamster ovary cells. Diagnostic potential for inherited metabolic disorders of nucleotide metabolism is presented.     

Metabolic studies of mesterolone in horses

Mesterolone (1α-methyl-5α-androstan-17β-ol-3-one) is a synthetic anabolic androgenic steroid (AAS) with reported abuses in human sports. As for other AAS, mesterolone is also a potential doping agent in equine sports. Metabolic studies on mesterolone have been reported for humans, whereas little is known about its metabolic fate in horses. This paper describes the studies of both the in vitro and in vivo metabolism of mesterolone in racehorses with an objective to identify the most appropriate target metabolites for detecting mesterolone administration.In vitro biotransformation studies of mesterolone were performed by incubating the steroid with horse liver microsomes. Metabolites in the incubation mixture were isolated by liquid-liquid extraction and analysed by gas chromatography-mass spectrometry (GC-MS) after acylation or silylation. Five metabolites (M1-M5) were detected. They were 1α-methyl-5α-androstan-3α-ol-17-one (M1), 1α-methyl-5α-androstan-3β-ol-17-one (M2), 1α-methyl-5α-androstane-3α,17β-diol (M3), 1α-methyl-5α-androstane-3β,17β-diol (M4), and 1α-methyl-5α-androstane-3,17-dione (M5). Of these in vitro metabolites, M1, M3, M4 and M5 were confirmed using authentic reference standards. M2 was tentatively identified by mass spectral comparison to M1.For the in vivo metabolic studies, Proviron^® (20 tablets × 25 mg of mesterolone) was administered orally to two thoroughbred geldings. Pre- and post-administration urine samples were collected for analysis. Free and conjugated metabolites were isolated using solid-phase extraction and analysed by GC-MS as described for the in vitro studies. The results revealed that mesterolone was extensively metabolised and the parent drug was not detected in urine. Three metabolites detected in the in vitro studies, namely M1, M2 and M4, were also detected in post-administration urine samples. In addition, two stereoisomers each of 1α-methyl-5α-androstane-3,17α-diol (M6 and M7) and 1α-methyl-5α-androstane-3,16-diol-17-one (M8 and M9), and an 18-hydroxylated metabolite 1α-methyl-5α-androstane-3,18-diol-17-one (M10) were also detected. The metabolic pathway for mesterolone is postulated. These studies have shown that metabolites M8, M9 and M10 could be used as potential screening targets for controlling the misuse of mesterolone in horses.     

Modeling chemical reactions for drug design

Chemical reactions are involved at many stages of the drug design process. This starts with the analysis of biochemical pathways that are controlled by enzymes that might be downregulated in certain diseases. In the lead discovery and lead optimization process compounds have to be synthesized in order to test them for their biological activity. And finally, the metabolism of a drug has to be established. A better understanding of chemical reactions could strongly help in making the drug design process more efficient. We have developed methods for quantifying the concepts an organic chemist is using in rationalizing reaction mechanisms. These methods allow a comprehensive modeling of chemical reactivity and thus are applicable to a wide variety of chemical reactions, from gas phase reactions to biochemical pathways. They are empirical in nature and therefore allow the rapid processing of large sets of structures and reactions. We will show here how methods have been developed for the prediction of acidity values and of the regioselectivity in organic reactions, for designing the synthesis of organic molecules and of combinatorial libraries, and for furthering our understanding of enzyme-catalyzed reactions and of the metabolism of drugs.     

Biodegradable Polymeric Materials—Not the Origin but the Chemical Structure Determines Biodegradability

It is completely plausible that unmodified materials of natural origin, such as the native macromolecules cellulose or starch, are biodegradable. If these materials are modified then degradation may, depending on the degree of modification, be more difficult or even impossible. In the same manner synthesized macromolecules, whether from renewable or petrochemical sources, could be inert or completey biodegradable, depending on their chemical structure.     

Development and validation of an HPLC method to determine metabolites of 5‐hydroxymethylfurfural (5‐HMF)

The food component 5‐hydroxymethylfurfural is supposed to have antioxidative properties and is therefore used as an acting agent in a novel anticancer infusion solution, named Karal®, and an oral supplementation. Previous studies showed that after oral and intravenous application, the substance is completely decomposed to its metabolites: 5‐hydroxymethylfuroic acid, 2,5‐furandicarboxylic acid, and N‐(hydroxymethyl)furoyl glycine. The formation of a fourth metabolite, namely 5‐sulphoxymethylfurfural, is still not clarified according to literature. Due to commercial unavailability, synthesis of 5‐sulphoxymethylfurfural was conducted and a synthesis procedure for N‐(hydroxymethyl)furoyl glycine had to be developed. Identification of the synthesised compounds was proven by LC‐MS and NMR. An appropriate HPLC method was established to obtain good separation of the four possible metabolic substances and 5‐hydroxymethylfurfural within 12 min via a HILIC column (150 × 4.6 mm, 5 μm) using a gradient grade system switching from mobile phase A (ACN/ammonium formate 100 mM, pH 2.35, 95:5, v/v) to mobile phase B (ACN/ammonium formate 100 mM, pH 2.35, 85:15, v/v). The procedure was afterward validated following ICH guidelines in terms of selectivity, linearity, precision, LOD, and LOQ.     

高效液相色谱-质谱法分析啶菌噁唑在番茄灰霉病菌中的代谢行为

采用高效液相色谱-质谱法(HPLC-MS)分析了杀菌剂啶菌唑在番茄灰霉病菌液体摇培体系中的代谢动态.啶菌唑液相色谱定量检测法的线性回归方程为y＝54.5x+11.2(r＝0.9997),在2.07～72.34 mg/L范围内,方法回收率和精密度符合农药痕量分析要求.代谢影响因子研究结果显示,培养24 h孢子初萌发阶段的...     

Rapid and sensitive drug metabolism studies by SU-8 microchip capillary electrophoresis-electrospray ionization mass spectrometry

Monolithically integrated, polymer (SU-8) microchips comprising an electrophoretic separation unit, a sheath flow interface, and an electrospray ionization (ESI) emitter were developed to improve the speed and throughput of metabolism research. Validation of the microchip method was performed using bufuralol 1-hydroxylation via CYP450 enzymes as the model reaction. The metabolite, 1-hydroxybufuralol, was easily separated from the substrate (R(s)=0.5) with very good detection sensitivity (LOD=9.3nM), linearity (range: 50-500nM, r(2)=0.9997), and repeatability (RSD(Area)=10.3%, RSD(Migrationtime)=2.5% at 80nM concentration without internal standard). The kinetic parameters of bufuralol 1-hydroxylation determined by the microchip capillary electrophoresis (CE)-ESI/mass spectrometry (MS) method, were comparable to the values presented in literature as well as to the values determined by in-house liquid chromatography (LC)-UV. In addition to enzyme kinetics, metabolic profiling was demonstrated using authentic urine samples from healthy volunteers after intake of either tramadol or paracetamol. As a result, six metabolites of tramadol and four metabolites of paracetamol, including both phase I oxidation products and phase II conjugation products, were detected and separated from each other within 30-35s. Before analysis, the urine samples were pre-treated with on-chip, on-line liquid-phase microextraction (LPME) and the results were compared to those obtained from urine samples pre-treated with conventional C18 solid-phase extraction (SPE, off-chip cartridges). On the basis of our results, the SU-8 CE-ESI/MS microchips incorporating on-chip sample pre-treatment, injection, separation, and ESI/MS detection were proven as efficient and versatile tools for drug metabolism research.