New enantioselective liquid chromatography method development and validation of dipeptidyl peptidase IV inhibitors using a macrocyclic glycopeptide (vancomycin) chiral stationary phase under polar ionic mode condition.

The direct separation of dipeptidyl peptidase IV (DPP-4) inhibitors such as Sitagliptin (STG), Linagliptin (LIG), and Saxagliptin (SAG) enantiomers in normal phase conditions have been achieved on immobilized polysaccharide-based chiral stationary phases (CSPs), as well as on the macrocyclic glycopeptide vancomycin chiral stationary phase (Chirobiotic V2) under polar ionic mode. The enantiomers of these targets could be separated completely (resolution factor Rs > 2) using the Chirobiotic V2 column in polar ionic mode with the mobile phase (MeOH/AcOH/TEA 100/0.3/0.1 v/v/v) in an isocratic elution at 1.0 ml min-1 . The effect of the mobile phase composition on separation, including buffer salts, acid-base modifiers, and analyte structures, was evaluated. The developed technique was validated in the polar ionic mode according to the International Conference on Harmonization (ICH) Q2R1 guidelines in terms of accuracy, precision, selectivity, linearity, limit of detection (LOD), and limit of quantification (LOQ). The calibration curve was linear in a concentration range from LOQ to 3.75 µg/ml. The LOD and LOQ of STG, LIG, and SAG were 0.15 and 0.45, 0.15 and 0.50, 0.16 and 0.50, respectively. The proposed method is said to be selective, accurate, and precise. Finally, the validated method was used successfully for the quantitative determination of DPP-4 enantiomers in pharmaceutical analytes.

Synthesis of 2-aryl-5-(arylsulfonyl)-1,3,4-oxadiazoles as potent antibacterial and antioxidant agents.

Ten novel 2-aryl-5-(arylsulfonyl)-1,3,4-oxadiazoles were produced and assessed for their in vitro antibacterial and antioxidant activities. Diverse spectroscopic methods like 1H NMR, 13C NMR, IR, and LCMS were used for the characterization of the prepared samples and all the data was in good agreement with the anticipated structures. The prepared compounds 6a-j were screened for their in vitro antibacterial activity against bacterial strains Pseudomonas aeruginosa, Enterobacter aerogenes, Escherichia coli (gram-positive), and Bacillus cerus, Staphylococcus aureus, Bacillus subtilis (gram-negative). The antimicrobial screening outcome revealed that the prepared 2-(3,4-dimethylphenyl)-5-tosyl-1,3,4-oxadiazole (6j), 2-(3-isopropylphenyl)-5-tosyl-1,3,4-oxadiazole (6c), and 2-(2-ethylphenyl)-5-tosyl-1,3,4-oxadiazole (6i) are most potent among all the examined compounds. Furthermore, the antioxidant activity of the prepared compounds was also investigated by DPPH radical scavenging method and the results showed that some of the compounds were moderately active.