Separation and Determination of Diastereomers of λ-Cyhalothrin by Normal Phase-Liquid Chromatography Using a CN Column

Rao, R. Nageswara; Shankaraiah, B.; Sunder, Meenakshi

doi:10.2116/analsci.20.1745

Cited by 4 publications

(2 citation statements)

References 21 publications

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“…Pure g-cyhalothrin is a racemic mixture of isomers B and G. A normal phase Nucleosil Sherisorb CN column (Shimadzu, Kyoto, Japan) was used to separate this mixture. The mobile phase was n-hexane:tetrahydrofuran:2-propanol (99:0.9:0.1, v/v/v) (Rao et al 2004) (Table C4, Appendix C). The isomers chromatographed in the following order: B, G, H, and A.…”

Section: Analytical Methods For Pyrethroid Isomersmentioning

confidence: 99%

Parameters for Pyrethroid Insecticide QSAR and PBPK/PD Models for Human Risk Assessment

Knaak

Dary²,

Zhang

et al. 2012

Reviews of Environmental Contamination and Toxicology

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In this review we have examined the status of parameters required by pyrethroid QSAR-PBPK/PD models for assessing health risks. In lieu of the chemical,biological, biochemical, and toxicological information developed on the pyrethroids since 1968, the finding of suitable parameters for QSAR and PBPK/PD model development was a monumental task. The most useful information obtained came from rat toxicokinetic studies (i.e., absorption, distribution, and excretion), metabolism studies with 14C-cyclopropane- and alcohol-labeled pyrethroids, the use of known chiral isomers in the metabolism studies and their relation to commercial products. In this review we identify the individual chiralisomers that have been used in published studies and the chiral HPLC columns available for separating them. Chiral HPLC columns are necessary for isomer identification and for developing kinetic values (Vm,, and Kin) for pyrethroid hydroxylation. Early investigators synthesized analytical standards for key pyrethroid metabolites, and these were used to confirm the identity of urinary etabolites, by using TLC. These analytical standards no longer exist, and muste resynthesized if further studies on the kinetics of the metabolism of pyrethroids are to be undertaken.In an attempt to circumvent the availability of analytical standards, several CYP450 studies were carried out using the substrate depletion method. This approach does not provide information on the products formed downstream, and may be of limited use in developing human environmental exposure PBPK/PD models that require extensive urinary metabolite data. Hydrolytic standards (i.e., alcohols and acids) were available to investigators who studied the carboxylesterase-catalyzed hydrolysis of several pyrethroid insecticides. The data generated in these studies are suitable for use in developing human exposure PBPK/PD models.Tissue:blood partition coefficients were developed for the parent pyrethroids and their metabolites, by using a published mechanistic model introduced by Poulin and Thiele (2002a; b) and log DpH 7.4 values. The estimated coefficients, especially those of adipose tissue, were too high and had to be corrected by using a procedure in which the proportion of parent or metabolite residues that are unbound to plasma albumin is considered, as described in the GastroPlus model (Simulations Plus, Inc.,Lancaster, CA). The literature suggested that Km values be adjusted by multiplying Km by the substrate (decimal amount) that is unbound to microsomal or CYPprotein. Mirfazaelian et al. (2006) used flow- and diffusion-limited compartments in their deltamethrin model. The addition of permeability areas (PA) having diffusion limits, such as the fat and slowly perfused compartments, enabled the investigators to bring model predictions in line with in vivo data.There appears to be large differences in the manner and rate of absorption of the pyrethroids from the gastrointestinal tract, implying that GI advanced compartmental transit models (ACAT) need to be included in PBPK mo...

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Section: Analytical Methods For Pyrethroid Isomersmentioning

confidence: 99%

Parameters for Pyrethroid Insecticide QSAR and PBPK/PD Models for Human Risk Assessment

Knaak

Dary²,

Zhang

et al. 2012

Reviews of Environmental Contamination and Toxicology

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show abstract

“…ligands such as aminopropyl [8,9] or cyano [10] provide potential electron donor/acceptor, dipole-dipole or hydrogen bonding interactions available under normal phase conditions that may offer advantages for the separation of polar analytes due to significant intermolecular interactions with the polar stationary phase [7]. Hence, the retention mechanism of the SCIL phase under normal phase conditions is of interest.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a novel pyridinium bromide surface confined ionic liquid stationary phase for high-performance liquid chromatography under normal phase conditions via linear solvation energy relationships

Meter

Stuart

Carle

et al. 2008

Journal of Chromatography A

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Utilizing Linear Solvation Free Energy Relationship methodology, a novel pyridinium bromide surface confined ionic liquid (SCIL) stationary phase was characterized under normal phase High Performance Liquid Chromatographic conditions. A limited set of neutral aromatic probe solutes were utilized to rapidly assess the utility of the LSER model, using mobile phases of hexane modified with 2-propanol. The excellent correlation of the global fit across the mobile phase composition range used in this study for the experimental and calculated retention values (R 2 = 0.994) indicates that the LSER model is an appropriate model of characterizing this polar bonded phase under normal phase conditions. For a limited subset of compounds, retention on the pyridinium bromide SCIL stationary phase is more highly correlated with that obtained on a cyano column than on a diol column under NP conditions.

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Supercritical fluid chromatography separation of chiral pesticides: Unique capabilities to study cyhalothrin and metalaxyl as examples

Cutillas

García-Valverde

Gómez-Ramos

et al. 2020

Journal of Chromatography A

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Separation and Determination of Diastereomers of λ-Cyhalothrin by Normal Phase-Liquid Chromatography Using a CN Column

Cited by 4 publications

References 21 publications

Parameters for Pyrethroid Insecticide QSAR and PBPK/PD Models for Human Risk Assessment

Parameters for Pyrethroid Insecticide QSAR and PBPK/PD Models for Human Risk Assessment

Characterization of a novel pyridinium bromide surface confined ionic liquid stationary phase for high-performance liquid chromatography under normal phase conditions via linear solvation energy relationships

Supercritical fluid chromatography separation of chiral pesticides: Unique capabilities to study cyhalothrin and metalaxyl as examples

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