An improvement of separation and response applying post-column compensation and one-step acetone protein precipitation for the determination of coenzyme Q10 in rat plasma by SFC-MS/MS

Comprehensive evaluation of novel fungicide benzovindiflupyr at the enantiomeric level: Bioactivity, toxicity, mechanism, and dissipation behavior

Racemates in the environment can lead to inaccurate risk assessment. To obtain the enantiomeric level information of benzovindiflupyr for accurate risk assessment, the absolute configuration of benzovindiflupyr was first confirmed, and the enantioseparation method was developed by supercritical fluid chromatography tandem mass spectrometry. The enantioselectivity for bioactivity and toxicity was investigated, and the mechanism was explored by molecular docking and detecting succinate dehydrogenase (SDH) activity and content of succinate acid. 1S,4R-(-)-benzovindiflupyr was identified as the most active against the six targeted phytopathogens, which showed higher 1.7-54.5 times than 1R,4S-(+)-benzovindiflupyr. Additionally, 1S,4R-(-)-benzovindiflupyr (LD₅₀: 21.54 μg L^-1) was 103.7 times more toxic than 1R,4S-(+)-benzovindiflupyr against Daphnia magna. 1S,4R-(-)-benzovindiflupyr had a stronger affinity for SDH and significantly inhibited SDH activity, resulting in an increase in succinate acid in the tricarboxylic acid cycle, while its downstream products, fumaric and L-malic acid were significantly reduced. Moreover, the dissipation behavior of benzovindiflupyr on three vegetables was evaluated. 1S,4R-(-)-benzovindiflupyr was preferentially degraded in tomato, but opposite in leaves. The enantioselectivity in pepper and cucumber leaves was the same as in tomato, while there was no enantioselectivity in pepper and cucumber. The study provides a basis for accurate risk assessment and the development of high-effective and low-risk fungicides.

Application of a HPLC-Q/TOF method with post-column compensation for separation and identification of polar impurities in Cytidine disodium triphosphate for injection

Background:

Cytidine Disodium Triphosphate (CTP-2Na) for injection is mainly used for treating nervous system diseases. Currently, there are few studies focused on the separation and identification of polar impurities in CTP-2Na for injection, which is important for ensuring drug safety and efficacy.

Objective:

The study aimed to establish an HPLC-Q/TOF method for the separation and identification of polar impurities in CTP-2Na for injection.

Methods:

Chromatographic separation was achieved on a Waters Atlantis T3 column using 5 mM aqueous ammonium acetate solution as the mobile phase in an isocratic elution mode. A postcolumn compensation technology was used to improve the ionization efficiency of impurities in the spray chamber.

Results:

Three polar impurities (disodium cytidine tetraphosphate, disodium cytidine diphosphate, disodium cytidine monophosphate) were detected in CTP-2Na for injection. The former one is probably the overreaction product during the production of CTP-2Na, the latter two were reported as degradation products. The fragmentation patterns of cytidine phosphate compounds in negative ion mode are summarized.

Conclusion:

This study provides a good reference for the separation and identification of polar impurities in nucleotide drugs.

SFC-MS/MS method for simultaneous determination of nimodipine and 3-n-butylphthalide in beagle plasma: application to pharmacokinetic interaction study

Aim: Nimodipine and 3-n-butylphthalide are co-administered to treat vascular dementia, but the pharmacokinetic interaction between the two drugs is still unknown. Therefore, a robust, high-throughput and economical supercritical fluid chromatography-ESI-MS/MS method has been initially developed to simultaneously determine nimodipine and 3-n-butylphthalide in beagle plasma, in order to study the safety of co-administration. Materials & methods: After a simple protein precipitation procedure, isocratic elution with mobile phase of CO₂ and methanol (containing 0.3% formic acid and 2 mM ammonium acetate) was applied to minimize run time and facilitate sensitive and high-throughput bioanalysis. The method was fully validated according to US FDA Guidance. The validated method was then successfully applied in a pharmacokinetic interaction study. Results: The results indicated there is no significant pharmacokinetic interaction between the two drugs.

Supercritical fluid chromatography: a promising alternative to current bioanalytical techniques

During the last years, chemistry was involved in the worldwide effort toward environmental problems leading to the birth of green chemistry. In this context, green analytical tools were developed as modern Supercritical Fluid Chromatography in the field of separative techniques. This chromatographic technique knew resurgence a few years ago, thanks to its high efficiency, fastness and robustness of new generation equipment. These advantages and its easy hyphenation to MS fulfill the requirements of bioanalysis regarding separation capacity and high throughput. In the present paper, the technical aspects focused on bioanalysis specifications will be detailed followed by a critical review of bioanalytical supercritical fluid chromatography methods published in the literature.

Enantioselective supercritical fluid chromatography–tandem mass spectrometry method for simultaneous estimation of risperidone and its 9-hydroxyl metabolites in rat plasma

Aim: Objective of the current work was to develop a ‘green chemistry’ compliant selective and sensitive supercritical fluid chromatography–tandem mass spectrometry method for simultaneous estimation of risperidone (RIS) and its chiral metabolites in rat plasma. Methodology & results: Agilent 1260 Infinity analytical supercritical fluid chromatography system resolved RIS and its chiral metabolites within runtime of 6 min using a gradient chromatography method. Using a simple protein precipitation sample preparation followed by mass spectrometric detection achieved a sensitivity of 0.92 nM (lower limit of quantification). With linearity over four log units (0.91–7500 nM), the method was found to be selective, accurate, precise and robust. Conclusion: The method was validated and was successfully applied for simultaneous estimation of RIS and 9-hydroxyrisperidone metabolites (R & S individually) after intravenous and per oral administration to rats.