LC-MS/MS and chiroptical spectroscopic analyses of multidimensional metabolic systems of chiral thalidomide and its derivatives

Simultaneous quantification of thalidomide, lenalidomide and pomadomide in plasma by LC-MS/MS

OBJECTIVE

To develop a new method for quantitatively analyzing three immunomodulators (thalidomide, lenalidomide and pomadomide) by liquid chromatography tandem mass spectrometry (LC-MS/MS).

METHODS

Using thalidomide-d4 as internal standard, the three analytes were separated on Agilent Zorbax SB-C18(2.1 mm × 100 mm, 3.5 μm, Agilent, USA) column and monitored in multiple reactions monitoring mode in Agilent G6460A triple quadrupole mass spectrometer operating in positive ionization mode. The sample was pretreated by protein precipitation using methanol at 3-fold volume to sample. The mobile phase was comprised of 0.1% formic acid in water (phase A) and acetonitrile (phase B) and was delivered in gradient elution program. The flow rate was 0.3 mL/min, and the injection volume was 5 μL.

RESULTS

The accuracy and stability of the method are within ±15.0%, and the precision is not >15.0%. The recoveries were 85.04% ∼ 119.07%, and the matrix effect was 73.68% ∼ 116.75%. Specificity, linearity, LLOQ, carry-over and dilution were all in line with the requirements of pharmacopeia and guidelines. The peak concentrations of thalidomide, lenalidomide shows huge inter-individual differences.

CONCLUSIONS

This newly developed method was sensitive, simple, and robust and can be used in therapeutic drug monitoring of three immunomodulators in multiple myeloma patients.

Research method of rapid determination of chiral pesticide fenpropathrin enantiomers in fruit and vegetable puree by supercritical fluid chromatography

A method is firstly established for the separation and determination of fenpropathrin enantiomer residues in apple puree, strawberry puree, and tomato puree considered as a supplementary food for infants by supercritical fluid chromatography. After the sample was extracted with acetonitrile and cleaned up by a solid phase extraction column, then it's separated by a CHIRALPAK AD-3 chiral column with a gradient elution at a flow rate of 1.0 mL/min using methanol and supercritical carbon dioxide as the mobile phase, detected by ultraviolet detector at 230 nm wavelength and quantified with the external standard method. The limits of quantification of the two fenpropathrin enantiomers were both 0.2 mg/kg, the linear ranges were 1.0-20.0 mg/L with linear correlation coefficients greater than 0.9992, the recoveries in the spiked samples at 0.2, 0.4 and 2.0 mg/kg were from 80.6% to 105%, and the relative standard deviation reached 2.6%-7.7%. This method has the advantages of convenient operation, good resolution and environmental protection, which can satisfy the requirement of determination for fenpropathrin enantiomer residues in fruit and vegetable puree as a supplementary food for infants. This article is protected by copyright. All rights reserved.

Strategies for designing proteolysis targeting chimaeras (PROTACs)

Proteolysis targeting chimaeras (PROTACs) is a cutting edge and rapidly growing technique for new drug discovery and development. Currently, the largest challenge in the molecular design and drug development of PROTACs is efficient identification of potent and drug-like degraders. This review aims to comprehensively summarize and analyse state-of-the-art methods and strategies in the design of PROTACs. We provide a detailed illustration of the general principles and tactics for designing potent PROTACs, highlight representative case studies, and discuss the advantages and limitations of these strategies. Particularly, structure-based rational PROTAC design and emerging new types of PROTACs (e.g., homo-PROTACs, multitargeting PROTACs, photo-control PROTACs and PROTAC-based conjugates) will be focused on.