Modelling the enantioresolution capability of cellulose tris(3,5-dichlorophenylcarbamate) stationary phase in reversed phase conditions for neutral and basic chiral compounds

[EN] To the best of our knowledge, the prediction of the enantioresolution ability of polysaccharides-based stationary phases in liquid chromatography for structurally unrelated compounds has not been previously reported. In this study, structural information of neutral and basic compounds is used to model their enantioresolution levels obtained from an immobilised cellulose tris(3,5-dichlorophenylcarbamate) stationary phase in reversed phase conditions. Thirty-four structurally unrelated chiral drugs and pesticides, from seven families, are studied. Categorical enantioresolution levels (RsC, 0 = no baseline enantioresolution and 1 = baseline enantioresolution) are established from the experimental enantioresolution values obtained at a fixed experimental conditions. From 58 initial structural variables, three topological parameters (two of them connected to the chiral carbon), and six molecular descriptors (one of them also related with the chiral carbon), are selected after a discriminant partial least squares refinement process. The molar total charge of the molecule at the working pH is the most important variable. The relationships between RsC and the most important structural variables and the drug/pesticide family are evaluated. An explicit model is proposed to anticipate the RsC levels, which provides 100% of correct anticipations. A criterion is introduced to alert about the compounds that should not be anticipated.The authors acknowledge the Spanish Ministerio de Economia y Competitividad (MINECO) and the European Regional Development Fund (ERDF) for the financial support (Project CTQ2015-70904-R, MINECO/FEDER, UE).Martin-Biosca, Y.; Escuder-Gilabert, L.; Medina-Hernandez, MJ.; Sagrado Vives, S. (2018). Modelling the enantioresolution capability of cellulose tris(3,5-dichlorophenylcarbamate) stationary phase in reversed phase conditions for neutral and basic chiral compounds. Journal of Chromatography A. 1567:111-118. https://doi.org/10.1016/j.chroma.2018.06.061S111118156

Brenneria quercina and Serratia spp. isolated from Spanish oak trees: molecular characterization and PCR development

Brenneria quercina has been reported as one of the causal agents of oak decline in Spain. To investigate the bacterial variability of this pathogen from different Spanish oak forests, a collection of 38 bacterial isolates from seven geographic locations and from different oak species was analysed by sequencing 16S rDNA and rep-PCR fingerprinting. All Spanish isolates of B. quercina were grouped by rep-PCR into a homogenous cluster that differed significantly from B. quercina reference strains from California. 16S rDNA analysis revealed that 34 out of 38 isolates were Brenneria . However, four isolates belonged to the genus Serratia , suggesting that this bacterium could cause cankers in oak trees. The information obtained by rep-PCR fingerprint analysis was used to develop PCR primers for the sensitive and specific detection of B. quercina from infected plant tissues. Pathogenicity tests performed with Brenneria and Serratia isolates showed that both were able to grow and cause cankers in oak trees

Biopartitioning micellar chromatoraphy to predict blood to lung, blood to liver, blood to fat and blood to skin partition coefficients of drugs

[EN] Biopartitioning micellar chromatography (BMC), a mode of micellar liquid chromatography that uses micellar mobile phases of Brij35 in adequate experimental conditions, has demonstrated to be useful in mimicking the drug partitioning process into biological systems. In this paper, the usefulness of BMC for predicting the partition coefficients from blood to lung, blood to liver. blood to fat and blood to skin is demonstrated. PLS2 and multiple linear regression (MLR) models based on BMC retention data are proposed and compared with other ones reported in bibliography. The proposed models present better or similar descriptive and predictive capability. (C) 2008 Elsevier B.V. All rights reserved.The authors acknowledge the Spanish Ministry of Science and Technology (MCYT) and the European Regional Development Fund (ERDF) for the financial support (Project SA2005-01435).Martin-Biosca, Y.; Torres-Cartas, S.; Villanueva-Camanas, RM.; Sagrado, S.; Medina-Hernandez, MJ. (2009). Biopartitioning micellar chromatoraphy to predict blood to lung, blood to liver, blood to fat and blood to skin partition coefficients of drugs. Analytica Chimica Acta. 632(2):296-303. doi:10.1016/j.aca.2008.11.004S296303632

Biopartitioning micellar chromatography to pedict mutagenicity of aromatic amines

[EN] Mutagenicity is a toxicity endpoint associated with the chronic exposure to chemicals. Aromatic amines have considerable industrial and environmental importance due to their widespread use in industry and their mutagenic capacity. Biopartitioning micellar chromatography (BMC), a mode of micellar liquid chromatography that uses micellar mobile phases of Brij35 in adequate experimental conditions, has demonstrated to be useful in mimicking the drug partitioning process into biological systems. In this paper, the usefulness of BMC for predicting mutagenicity of aromatic amines is demonstrated. A multiple linear regression (MLR) model based on BMC retention data is proposed and compared with other ones reported in bibliography. The proposed model present better or similar descriptive and predictive capability.The authors acknowledge the Spanish Ministry of Science and Technology (MCYT) and the European Regional Development Fund (ERDF) for the financial support (Project SA2005-01435).Torres-Cartas, S.; Martín-Biosca, Y.; Villanueva-Camañas, RM.; Sagrado, S.; Medina-Hernández, MJ. (2007). Biopartitioning micellar chromatography to pedict mutagenicity of aromatic amines. European Journal of Medicinal Chemistry. 42(11-12):1396-1402. doi:10.1016/j.ejmech.2007.02.022S139614024211-1

Direct chromatographic study of the enantioselective biodegradation of ibuprofen and ketoprofen by an activated sludge

[EN] The quantification of the enantiomeric fraction (EF) during the biodegradation process is essential for environmental risk assessment. In this paper the enantioselective biodegradation of ibuprofen, IBU, and ketoprofen, KET, two of the drugs most consumed, was evaluated. Biodegradation experiments were performed in batch mode using a minimal salts medium inoculated with an activated sludge (collected from a Valencian Waste Water Treatment Plant) and supplemented with the racemate of each compound. The inoculum activity was verified using fluoxetine as reference compound. The experimental conditions used (analyte concentration and volume of inoculum) were chosen according to OECD guidelines. In parallel, the optical density at 600 nm was measured to control the biomass growth and to connect it with enantioselectivity. Two RPLC methods for chiral separations of IBU and KET using polysaccharides-based stationary phases were developed. Novel calculations and adapted models, using directly the chromatographic peak areas as dependent variable, were proposed to estimate significant parameters related to the biodegradation process: biodegradation (BD) and EF values at given time, half-life times of (R)- and (S)-enantiomers, number of days to reach a complete BD and the minimum EF expected. The modelled BD and EF curves fitted adequately the data (R-2 > 0.94). The use of these new equations provided similar results to those obtained using concentration data. However, the use of chromatographic peak areas data, eliminates the uncertainty associated to the use of the calibration curves. The results obtained in this paper indicate that an enantiorecognition towards 1BU enantiomers by the microorganisms present in the activated sludge used in this study occurred, being the biodegradation of (R)-IBU higher than that of (S)-IBU. For KET, non-enantioselective biodegradation was observed.The authors acknowledge the Spanish Ministerio de Economia y Competitividad (MINECO) and the European Regional Development Fund (ERDF) for the financial support (Project CTQ2015-70904-R, MINECO/FEDER, UE).Escuder-Gilabert, L.; Martin-Biosca, Y.; Perez-Baeza, M.; Sagrado Vives, S.; Medina-Hernandez, MJ. (2018). Direct chromatographic study of the enantioselective biodegradation of ibuprofen and ketoprofen by an activated sludge. Journal of Chromatography A. 1568:140-148. https://doi.org/10.1016/j.chroma.2018.07.034S140148156