Advances in tracking of polysaccharides in vivo: Labeling strategies, potential factors and applications based on pharmacokinetic characteristics.

Due to their good physicochemical properties, high biocompatibility and low toxicity, polysaccharides have been widely used as biomaterials in the fields of medicine and biology. However, in vivo investigations of their pharmacokinetics are significantly restricted by the difficulty in detection of polysaccharides. To date, polysaccharide labeling has become one of the most promising approaches for tracking polysaccharides in vivo. Here, we review fluorescent and radioisotopic labeling methods for polysaccharides and their applications in tracking polysaccharides in vivo, and compare the advantages and disadvantages of different labeling methods. The potential factors affecting the pharmacokinetics of polysaccharides in vivo were summarized, including the monosaccharide composition, charge, molecular weight and dosage of polysaccharides, as well as the physiological state of the organism. This review also prospects the applications of polysaccharides in medicine based on the reported pharmacokinetic characteristics in vivo.

Safety Assessment of Monosaccharides, Disaccharides, and Related Ingredients as Used in Cosmetics.

The Cosmetic Ingredient Review Expert Panel (Panel) assessed the safety of 25 monosaccharides, disaccharides, and related ingredients and concluded these are safe in the present practices of use and concentration described in the safety assessment. Many of these ingredients are common dietary sugars, dietary sugar replacements, or very closely related analogs and salts; 7 of the ingredients are listed by the Food and Drug Administration as generally recognized as safe food substances. The most commonly reported cosmetic function is as a skin-conditioning agent; other commonly reported functions are use as a humectant or as a flavoring agent. The Panel reviewed the animal and clinical data included in this assessment, acknowledged that the oral safety of many of these ingredients has been well established, and found it appropriate to extrapolate the existing information to conclude on the safety of all the monosaccharides, disaccharides, and related ingredients.

Kinsenoside: A Promising Bioactive Compound from Anoectochilus Species.

Kinsenoside is a main active component isolated from plants of the genus Anoectochilus, and exhibits many biological activities and pharmacological effects, including hepatoprotective, anti-hyperglycemic, anti-hyperliposis, anti-inflammatory, vascular protective and anti-osteoporosis effects and so on, which is contributing to its promising potency in disease treatments. This review aims to recapitulate the pharmacological functions of kinsenoside, as well as its source, extraction, identification, quantitative analysis, pharmacokinetics, synthesis and patent information. The data reported in this work can confirm the therapeutic potential of kinsenoside and provide useful information for further new drug development.

[Nasal resorption of prim-O-glucosylcimifugin and 5-O-methylvisammioside in rats].

In this experiment, rat nasal mucosa absorption characteristics of prim-O-glucosylcimifugin and 5-O-methylvisammioside were studied to provide a basis for drug delivery of Toutongning nasal spray. The nasal mucosa absorption test in rats was conducted with in situ nasal perfusion method after pH 6 buffer solution was used to prepare high, medium and low concentrations of prim-O-glucosylcimifugin, 5-O-methylvisammioside mixed solution as liquid circulation in nasal cavity. Then the concentrations of the circulating liquid compositions to be measured were determined by HPLC, and the absorption rates of prim-O-glucosylcimifugin and 5-O-methylvisammioside under different pH conditions were also investigated. According to the results, the absorption rate constant was (0.588±0.041)×10⁻³, (0.547±0.023)×10⁻³, (0.592±0.063)×10⁻³ min⁻¹ for prim-O-glucosylcimifugin high, middle and low concentrations, and (0.438±0.041)×10⁻³, (0.407±0.023)×10⁻³, and (0.412±0.063)×10⁻³ min⁻¹ for 5-O-methylvisammioside high, middle and low concentrations. There was no significant difference among high, middle and low concentration groups, and the absorption under pH 6 was better than that under other pH conditions. Therefore, we can get the conclusion that the main active ingredient of Toutongning nasal sprays can be absorbed through the nasal mucosa, and it is feasible to make nasal spray; in addition, pH 6 of nasal spray is scientific and reasonable.

Prediction of Plasma Concentration-time Profiles of Drugs in Humans from Animals Following Oral Administration: An Allometric Approach.

BACKGROUND: Allometric scaling is regularly used for the prediction of human pharmacokinetic (PK) parameters from animal PK studies. The predicted human PK parameters can also be used for the prediction of plasma concentration-time profiles in humans. OBJECTIVES: The main objective of this work is to predict human concentration-time profiles of drugs (one-compartment model) following oral administration using animal oral pharmacokinetic parameters. METHODS: Six drugs from the literature were chosen that were described by one-compartment model in both humans and animals following oral administration. Pharmacokinetic parameters such as oral clearance, oral volume of distribution of the central compartment, time to reach maximum plasma concentration, absorption rate constant, and half-life in humans were predicted from animals using allometric scaling. These predicted human pharmacokinetic parameters were then used to predict human plasma concentrations-time profiles of drugs. RESULTS: The results of this study indicate that the proposed method can be used to predict human plasma concentrations- time profiles of drugs with reasonable accuracy (≤50% prediction error). CONCLUSIONS: Given the complexity in the pharmacokinetics of oral drugs there remains some uncertainty in this entire exercise. One can minimize the prediction error by experience in allometric scaling, scientific judgment, and unconventional or innovative thinking.

Synthesis and preclinical characterization of 1-(6'-deoxy-6'-[18F]fluoro-ß-d-allofuranosyl)-2-nitroimidazole (ß-6'-[18F]FAZAL) as a positron emission tomography radiotracer to assess tumor hypoxia.

Positron emission tomography (PET) using fluorine-18 (18F)-labeled 2-nitroimidazole radiotracers has proven useful for assessment of tumor oxygenation. However, the passive diffusion-driven cellular uptake of currently available radiotracers results in slow kinetics and low tumor-to-background ratios. With the aim to develop a compound that is actively transported into cells, 1-(6'-deoxy-6'-[18F]fluoro-ß-d-allofuranosyl)-2-nitroimidazole (ß-[18F]1), a putative nucleoside transporter substrate, was synthetized by nucleophilic [18F]fluoride substitution of an acetyl protected labeling precursor with a tosylate leaving group (ß-6) in a final radiochemical yield of 12±8% (n=10, based on [18F]fluoride starting activity) in a total synthesis time of 60min with a specific activity at end of synthesis of 218±58GBq/µmol (n=10). Both radiolabeling precursor ß-6 and unlabeled reference compound ß-1 were prepared in multistep syntheses starting from 1,2:5,6-di-O-isopropylidene-α-d-allofuranose. In vitro experiments demonstrated an interaction of ß-1 with SLC29A1 and SLC28A1/2/3 nucleoside transporter as well as hypoxia specific retention of ß-[18F]1 in tumor cell lines. In biodistribution studies in healthy mice ß-[18F]1 showed homogenous tissue distribution and excellent metabolic stability, which was unaffected by tissue oxygenation. PET studies in tumor bearing mice showed tumor-to-muscle ratios of 2.13±0.22 (n=4) at 2h after administration of ß-[18F]1. In ex vivo autoradiography experiments ß-[18F]1 distribution closely matched staining with the hypoxia marker pimonidazole. In conclusion, ß-[18F]1 shows potential as PET hypoxia radiotracer which merits further investigation.

Toxicological characterisation of a thio-arsenosugar-glycerol in human cells.

Arsenosugars are water-soluble arsenic species predominant in marine algae and other seafood including mussels and oysters. They typically occur at levels ranging from 2 to 50mg arsenic/kg dry weight. Most of the arsenosugars contain arsenic as a dimethylarsinoyl group (Me2As(O)-), commonly referred to as the oxo forms, but thio analogues have also been identified in marine organisms and as metabolic products of oxo-arsenosugars. So far, no data regarding toxicity and toxicokinetics of thio-arsenosugars are available. This in vitro-based study indicates that thio-dimethylarsenosugar-glycerol exerts neither pronounced cytotoxicity nor genotoxicity even though this arsenical was bioavailable to human hepatic (HepG2) and urothelial (UROtsa) cells. Experiments with the Caco-2 intestinal barrier model mimicking human absorption indicate for the thio-arsenosugar-glycerol higher intestinal bioavailability as compared to the oxo-arsenosugars. Nevertheless, absorption estimates were much lower in comparison to other arsenicals including arsenite and arsenic-containing hydrocarbons. Arsenic speciation in cell lysates revealed that HepG2 cells are able to metabolise the thio-arsenosugar-glycerol to some extent to dimethylarsinic acid (DMA). These first in vitro data cannot fully exclude risks to human health related to the presence of thio-arsenosugars in food.

Modification on the O-glucoside of Sergliflozin-A: A new strategy for SGLT2 inhibitor design.

Poor pharmacokinetic stability is one of the issues of O-glucoside SGLT2 inhibitors in clinical trials, hence C-glucoside inhibitors have been developed and extensively applied. Herein, we provided an alternative approach to improve the pharmacokinetic stability of such inhibitors. Nine derivatives of Sergliflozin-A with modifications on the O-glucoside fragment were prepared, among which the 4-O-methyl derivative exhibited similar pharmacodynamics potency in excreted glucose urine test. Most attractively, significantly increased pharmacokinetic stability was observed for 4-O-methyl derivative of O-glucosides. This work proved that modification on the O-glucoside fragment could be a promising approach to the future SGLT2 inhibitor design.

Development of a hydrophilic interaction liquid chromatography-tandem mass spectrometric method for the determination of kinsenoside, an antihyperlipidemic candidate, in rat plasma and its application to pharmacokinetic studies.

Kinsenoside is a major bioactive constituent isolated from Anoectochilus formosanus and is investigated as an antihyperlipidemic candidate. In this study, a rapid, sensitive, and reliable bioanalytical method was developed for the determination of kinsenoside in rat plasma using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). The plasma sample was pretreated with 1% acetic acid, followed by protein precipitation with acetonitrile:methanol (70:30). Chromatographic separation was performed on a HILIC silica column (2.1mm×100mm, 3µm). The mobile phases consisted of 0.1% acetic acid in distilled water (solvent A) and 0.1% acetic acid in acetonitrile (solvent B). A gradient program was used at a flow rate of 0.2mL/min. For mass spectrometric detection, the multiple reaction monitoring mode was used; the MRM transitions were m/z 265.2→m/z 102.9 for kinsenoside and m/z 163.3→m/z 132.1 for the internal standard (IS) nicotine in the positive ionization mode. A calibration curve was constructed in the range of 2-500ng/mL. The intra- and interday precision and accuracy were within 5%. The HILIC-MS/MS method was specific, accurate, and reproducible and was successfully applied in a pharmacokinetic study of kinsenoside in rats.

Development and validation of a UFLC-MS/MS method for the determination of anhydrosafflor yellow B in rat plasma and its application to pharmacokinetic study.

A sensitive ultrafast liquid chromatography coupled with triple quadrupole mass spectrometric (UFLC-MS/MS) method for the quantification of anhydrosafflor yellow B (AHSYB), a major active water-soluble pigment from Carthamus tinctorius, in rat plasma has been developed and validated. Sample preparation was achieved by protein precipitation of plasma with four volumes of methanol. Rutin was used as the internal standard (IS). The analytes were separated using a C18 column with an 8min gradient elution, followed by mass spectrometric detection using negative electrospray ionization (ESI(-)) in multiple reaction monitoring (MRM) mode. The method was linear in the concentration range of 25-10,000ng/mL for AHSYB. Intra-day and inter-day precision variation was less than 6.5%. The relative error of accuracy was within ±9.4%. The mean recovery of AHSYB was higher than 70.9%. The established method was successfully applied to the pharmacokinetic study after intravenous (2.5mg/kg) and oral (30mg/kg) dosing of AHSYB in normal rats. And the pharmacokinetic properties of AHSYB in rats with acute blood stasis and the differences between normal and acute blood stasis syndrome rats were also investigated. The results showed that the compound was poorly absorbed (∼0.3%) and the AUC0-t, AUC0-∞ and F were all significantly lower (P<0.05) in acute blood stasis syndrome rats, suggesting that disease condition may alter the body metabolism by enhancing metabolite enzyme activity.

Urinary excretion of polyols and sugars in children with chronic kidney disease.

BACKGROUND: The urinary concentrations of monosaccharides and polyols are used for diagnosing inborn errors of metabolism and renal tubular disorders. Reference values are age-related and depend on the method of detection. However, the influence of the renal function is often still neglected. In this study we examined the urinary excretion of monosaccharides and polyols in children with various degrees of chronic kidney disease (CKD), but with no known metabolic or renal tubular disorders. CASE DIAGNOSIS/TREATMENT: In 25 patients with CKD stage 1-5, urinary concentrations of 18 monosaccharides and polyols were measured by gas chromatography-mass spectrometry (GC-MS) in random urinary samples and were compared with age-related reference values. Serum creatinine was measured at the time of the urine sample, and the height-independent estimated glomerular filtration rate (eGFR-Pottel) was calculated. Urinary excretions of monosaccharides and polyols were above the reference values in 8-88% of all patients. A significant difference between CKD stage 1-2 compared with CKD stage 3-5 was found for allose, arabitol and sorbitol (p < 0.05) and for arabinose, fucose, myoinositol, ribitol, xylitol, and xylose (p < 0.01). CONCLUSIONS: We show that the excretion of polyols and sugars depends on eGFR, which warrants a cautious interpretation of the results in patients with CKD.

Pharmacokinetic Interaction of astragaloside IV with atractylenolide I and prim-O-glucosylcimifugin in male Sprague Dawley rats.

Astragaloside IV, atractylenolide I, and prim-O-glucosylcimifugin are main medicinal components of the traditional Chinese medicine prescription Yu-ping-feng which is composed of three herbs: Astragalus membranaceus, Atractylodes macrocephala, and Saposhnikovia divaricata. This study is aimed to assess the influence of atractylenolide I and prim-O-glucosylcimifugin on the pharmacokinetic profile of astragaloside IV so as to investigate the pharmacokinetic mechanisms of the Yu-ping-feng prescription. Fifteen Sprague Dawley rats were randomized to three groups; astragaloside IV, astragaloside IV plus atractylenolide I, and a combination of astragaloside IV, atractylenolide I, and prim-O-glucosylcimifugin were respectively administered to rats of these three groups via intragastric gavage. Serum samples were collected at different times after drug administration, and serum concentrations of astragaloside IV and atractylenolide I were simultaneously detected using HPLC-electrospray ionization-MS. Compared with administration of astragaloside IV alone, concentrations of astragaloside IV in the serum were significantly increased when it was given in combination with atractylenolide I or atractylenolide I+prim-O-glucosylcimifugin, with higher values for Cmax (p = 0.019 and p = 0.033 compared with astragaloside IV + atractylenolide I and astragaloside IV + atractylenolide I + prim-O-glucosylcimifugin groups, respectively) and AUC (p = 0.0052 and p = 0.0047 compared with astragaloside IV + atractylenolide I and astragaloside IV + atractylenolide I + prim-O-glucosylcimifugin groups, respectively). Improvement in mean oral Cmax and mean systemic serum exposure because of the pharmacokinetic interaction between astragaloside IV and atractylenolide I might explain the rationale for the use of multiple herbs in Yu-ping-feng and of combinations of A.membranaceus and A. macrocephala.

[Studies on effects of calycosin-7-O-ß-D-glucoside on prim-O-glucosylcimifugin and cimifugin in vivo pharmacokinetics].

Study on the effects of Astragali Radix main active flavone calycosin-7-O-ß-D-glucoside on Saposhnikoviae Radix main active ingredients prim-O-glucosylcimifugin and cimifugin, a UPLC-MS/MS method for simultaneous determination of prim-O-glucosylcimifugin and cimifugin in rat plasma was established, and the comparative pharmacokinetics of prim-O-glucosylcimifugin and cimifugin after oral administration of prim-O-glucosylcimifugin and calycosin-7-O-ß-D-glucoside-prim-O-glucosylcimifugin to rats were carried out, which might be conductive in exploring the rationality of Astragali Radix - Saposhnikoviae Radix herb couple. Twelve male SD rats were divided into two groups. Prim-O-glucosylcimifugin and cimifugin in rat plasma of different time points after oral administration of prim-O-glucosylcimifugin and calycosin-7-O-ß-D-glucoside - prim-O-glucosylcimifugin to rats were determinated. And the main pharmacokinetic parameters were investigated using DAS 3. 2. 4. The established method was rapid, accurate and sensitive for simultaneous determination of prim-O-glucosylcimifugin and cimifugin in rat plasma. The analysis was performed on a Waters Acquity BEH C18 column (2.1 mm x 100 mm, 1.7 µm) with the mixture of acetonitrile and 0.1% formic acid/water as mobile phase, and the gradient elution at a flow rate of 0.3 mL x min(-1). The analytes were detected by tandem mass spectrometry with the electrospray ionization (ESI) source and in the multiple reaction monitoring (MRM) mode. Compared with prim-O-glucosylcimifugin group, the AUC(0-t)., and AUC(0-∞) of p-O-glucosylcimifugin as well as the C(max) of cimifugin significantly increased (P < 0.05) in calycosin-7-O-ß-D-glucoside-prim-O-glucosylcimifugin group. Calycosin-7-O-ß-D-glucoside could enhance the absorption of prim-O-glucosylcimifugin and cimifugin and improve the bioavailability, explaining preliminarily the rationality of Astragali Radix-Saposhnikoviae Radix herb couple.

Synthesis, enzyme kinetics and computational evaluation of N-(ß-D-glucopyranosyl) oxadiazolecarboxamides as glycogen phosphorylase inhibitors.

All possible isomers of N-ß-D-glucopyranosyl aryl-substituted oxadiazolecarboxamides were synthesised. O-Peracetylated N-cyanocarbonyl-ß-D-glucopyranosylamine was transformed into the corresponding N-glucosyl tetrazole-5-carboxamide, which upon acylation gave N-glucosyl 5-aryl-1,3,4-oxadiazole-2-carboxamides. The nitrile group of the N-cyanocarbonyl derivative was converted to amidoxime which was ring closed by acylation to N-glucosyl 5-aryl-1,2,4-oxadiazole-3-carboxamides. A one-pot reaction of protected ß-D-glucopyranosylamine with oxalyl chloride and then with arenecarboxamidoximes furnished N-glucosyl 3-aryl-1,2,4-oxadiazole-5-carboxamides. Removal of the O-acetyl protecting groups by the Zemplén method produced test compounds which were evaluated as inhibitors of glycogen phosphorylase. Best inhibitors of these series were N-(ß-D-glucopyranosyl) 5-(naphth-1-yl)-1,2,4-oxadiazol-3-carboxamide (Ki = 30 µM), N-(ß-D-glucopyranosyl) 5-(naphth-2-yl)-1,3,4-oxadiazol-2-carboxamide (Ki =33 µM), and N-(ß-D-glucopyranosyl) 3-phenyl-1,2,4-oxadiazol-5-carboxamide (Ki = 104 µM). ADMET property predictions revealed these compounds to have promising oral drug-like properties without any toxicity.

C-Glucosides with heteroaryl thiophene as novel sodium-dependent glucose cotransporter 2 inhibitors.

Canagliflozin (1), a novel inhibitor for sodium-dependent glucose cotransporter 2 (SGLT2), has been developed for the treatment of type 2 diabetes. To investigate the effect of replacement of the phenyl ring in 1 with heteroaromatics, C-glucosides 2 were designed, synthesized, and evaluated for their inhibitory activities against SGLT2. Of these, 3-pyridyl, 2-pyrimidyl or 5-membered heteroaryl substituted derivatives showed highly potent inhibitory activity against SGLT2, while 5-pyrimidyl substitution was associated with slightly reduced activity. In particular, 2g (TA-3404) had remarkable anti-hyperglycemic effects in high-fat diet fed KK (HF-KK) mice.

In vitro intestinal bioavailability of arsenosugar metabolites and presystemic metabolism of thio-dimethylarsinic acid in Caco-2 cells.

Whereas inorganic arsenic is classified as a human carcinogen, risks to human health related to the presence of arsenosugars in marine food are still unclear. Since studies indicate that human inorganic arsenic metabolites contribute to inorganic arsenic induced carcinogenicity, a risk assessment for arsenosugars should also include a toxicological characterization of their respective metabolites. Here we assessed intestinal bioavailability of the human arsenosugar metabolites oxo-DMAA(V), thio-DMAA(V), oxo-DMAE(V), thio-DMAE(V) and thio-DMA(V) in relation to arsenite in the Caco-2 intestinal barrier model. Whereas arsenite and thio-DMA(V) caused barrier disruption at concentrations ≥10 µM, all other metabolites did not cause a barrier leakage, even when applied at 50 times higher concentrations than arsenite and thio-DMA(V). The transfer studies point to a strong intestinal bioavailability of thio-DMA(V) and thio-DMAE(V), whereas oxo-DMAA(V), thio-DMAA(V) and oxo-DMAE(V) passed the in vitro intestinal barrier only to a very small extent. Detailed influx and efflux studies indicate that arsenite and thio-DMA(V) cross the intestinal barrier most likely by passive diffusion (paracellular) and facilitated (transcellular) transport. LC-ICP-QMS based arsenic speciation studies during the transfer experiments demonstrate transfer of thio-DMA(V) itself across the intestinal barrier and suggest metabolism of thio-DMA(V) using the in vitro intestinal barrier model to its oxygen-analogue DMA(V). In the case of arsenite no metabolism was observed. In summary the two arsenosugar metabolites thio-DMA(V) and thio-DMAE(V) showed intestinal bioavailability similar to that of arsenite, and about 10-fold higher than that reported for arsenosugars (Leffers et al., Mol. Nutr. Food Res., 2013, DOI: 10.1002/mnfr.201200821) in the same in vitro model. Thus, a presystemic metabolism of arsenosugars might strongly impact arsenic intestinal bioavailability after arsenosugar intake and should therefore be considered when assessing the risks to human health related to the consumption of arsenosugar-containing food.

In vitro toxicological characterization of two arsenosugars and their metabolites.

SCOPE: In their recently published Scientific Opinion on Arsenic in Food, the European Food Safety Authority concluded that a risk assessment for arsenosugars is currently not possible, largely because of the lack of relevant toxicological data. To address this issue, we carried out a toxicological in vitro characterization of two arsenosugars and six arsenosugar metabolites. METHODS AND RESULTS: The highly pure synthesized arsenosugars, DMA(V) -sugar-glycerol and DMA(V) -sugar-sulfate, investigated in this study, as well as four metabolites, oxo-dimethylarsenoacetic acid (oxo-DMAA(V) ), oxo-dimethylarsenoethanol (oxo-DMAE(V) ), thio-DMAA(V) and thio-DMAE(V) , exerted neither cytotoxicity nor genotoxicity up to 500 µM exposure in cultured human bladder cells. However, two arsenosugar metabolites, namely dimethyl-arsinic acid (DMA(V) ) and thio-dimethylarsinic acid (thio-DMA(V) ), were toxic to the cells; thio-DMA(V) was even slightly more cytotoxic than arsenite. Additionally, intestinal bioavailability of the arsenosugars was assessed applying the Caco-2 intestinal barrier model. The observed low, but significant transfer rates of the arsenosugars across the barrier model provide further evidence that arsenosugars are intestinally bioavailable. CONCLUSION: In a cellular system that metabolizes arsenosugars, cellular toxicity likely arises. Thus, in strong contrast to arsenobetaine, arsenosugars cannot be categorized as nontoxic for humans and a risk to human health cannot be excluded.

Novel multi-sugar assay for site-specific gastrointestinal permeability analysis: a randomized controlled crossover trial.

BACKGROUND & AIMS: Increased gastrointestinal (GI) permeability is an important hallmark of many conditions, potentially leading to antigen exposure and sepsis. Current permeability tests are hampered by analytical limitations. This study aims to compare the accuracy of our multi-sugar (MS) and the classical dual sugar (DS) test for detection of increased GI permeability. METHODS: Ten volunteers received permeability analysis using MS (1 g sucrose, lactulose, sucralose, erythritol, 0.5 g rhamnose in water) or DS (5 g lactulose, 0.5 g rhamnose), after indomethacin or placebo. Blood and urine were analyzed by isocratic LC-MS. RESULTS: MS testing revealed significantly elevated urinary lactulose/rhamnose (L/R) ratios after indomethacin, due to enhanced lactulose excretion (P < .01) and unaltered rhamnose excretion. The DS test showed increased L/R ratios, due to increased lactulose excretion and decreased rhamnose excretion (both P < .05). After indomethacin, plasma L/R increased in both assays (P < .05 and P < .01). Urinary and plasma L/R ratios correlated significantly. Indomethacin increased sucrose excretion and 0-1 h sucrose/rhamnose. Colon permeability was unchanged. CONCLUSIONS: Sensitive permeability analysis is feasible in plasma and urine using MS or DS test. In contrast to the DS test, monosaccharide excretion is not decreased by the MS test. In short, the MS test provides accurate, site-specific information on gastroduodenal, small, and large intestinal permeability. Registered at US National Library of Medicine (http://www.clinicaltrials.gov, NCT00943345).

Metabolite discovery of helicidum in rat urine with XCMS based on the data of ultra performance liquid chromatography coupled to time-of-flight mass spectrometry.

The present study demonstrates the use of XCMS (various forms (X) of chromatography coupled to mass spectrometry), an open-source software tool primarily used in bioinformatics, on the data of ultra-performance liquid chromatography connected online with a mass spectrometer (UPLC/MS) for the discovery of the metabolites of helicidum in urine after oral single dosage to rats. Helicidum (formaldehydephenyl-O-ß-D-pyranosyl alloside) is the major active component of the fruits of Helicid hilagirica Beed. In China, it is often used in the clinic to treat neurasthenic syndromes, vascular headache, and trigeminal neuralgia with high efficacy and low side effect and toxicity. The urine samples of five rats were collected during 0-4, 4-8, 8-12, 12-16, 16-20, 20-24, 24-32, 32-40, and 40-48 h, respectively, after oral administration of helicidum at a dosage of 25.0 mg/kg. A UPLC coupled to time-of-flight MS (UPLC/TOF MS) was used to analyze the samples. Concerning XCMS, the ".raw" format files were preliminarily converted to the open mzXML format using massWolf-4.3.1 (http://sourceforge.net/projects/sashimi/files/massWolf%20(MassLynx%20converter)/). For converting lots of files a time, we wrote a tool rawTomzXML which also uses massWolf-4.3.1. The data were processed using XCMS version l.26.0 (http://www.bioconductor.org/packages/2.8/bioc/html/xcms.html) running under R version 2.13 (http://http://www.r-project.org/) which provided the running platform for XCMS. The "centWave" method from XCMS was used for chromatographic peak detection. Based on the m/z data of the metabolites obtained by XCMS, MS was used to identify the molecular formula. Nine metabolites were finally found and identified. For six of them, the bio-transformation mechanisms of the parent compound was elucidated: glucuronide conjugation (C(19)H(24)O(14)), reduction (C(13)H(18)O(7)), oxidation (C(13)H(16)O(8)), methylation (C(14)H(18)O(7)), and the mixed transformation of reduction, methylation, and acetylation (C(16)H(22)O(8)). For the other three metabolites, C(11)H(19)N(3)O(9), C(11)H(21)N(3)O(9), and C(14)H(15)NO(7), the bio-transformation mechanisms remain unknown and need further investigation. Calculated as mass of helicidum, the cumulative urine excretion rate of the metabolites was 8.39%. The amount of oxidized helicidum was more than 50% among the metabolites while the parent compound helicidum was 13.28% and the reduced helicidum 11.72%, indicating that oxidation was the major bio-transformation that occurred in vivo.

[18F]fluoro-deoxy-glucose folate: a novel PET radiotracer with improved in vivo properties for folate receptor targeting.

The folate receptor (FR) is upregulated in various cancer types (FR-α isoform) and in activated macrophages (FR-ß isoform) which are involved in inflammatory and autoimmune diseases, but its expression in healthy tissues and organs is highly restricted to only a few sites (e.g kidneys). Therefore, the FR is a promising target for imaging and therapy of cancer and inflammation using folate-based radiopharmaceuticals. Herein, we report the synthesis and evaluation of a novel folic acid conjugate with improved properties suitable for positron emission tomography (PET). [(18)F]-fluoro-deoxy-glucose folate ([(18)F]3) was synthesized based on the click chemistry approach using 2-deoxy-2-[(18)F]fluoroglucopyranosyl azide and a folate alkyne derivative. The novel radiotracer [(18)F]3 was produced in good radiochemical yields (25% d.c.) and high specific radioactivity (90 GBq/µmol). Compared to previously published (18)F-folic acid derivatives, an increase in hydrophilicity was achieved by using a glucose entity as a prosthetic group. Biodistribution and PET imaging studies in KB tumor-bearing mice showed a high and specific uptake of the radiotracer in FR-positive tumors (10.03 ± 1.12%ID/g, 60 min p.i.) and kidneys (42.94 ± 2.04%ID/g, 60 min p.i.). FR-unspecific accumulation of radioactivity was only found in the liver (9.49 ± 1.13%ID/g, 60 min p.i.) and gallbladder (17.59 ± 7.22%ID/g, 60 min p.i.). No radiometabolites were detected in blood, urine, and liver tissue up to 30 min after injection of [(18)F]3. [(18)F]-fluoro-deoxy-glucose-folate ([(18)F]3) is thus a promising PET radioligand for imaging FR-positive tumors.