Development of a molecularly imprinted polymer for selective extraction followed by liquid chromatographic determination of sitagliptin in rat plasma and urine

A novel water-compatible molecularly imprinted solid-phase extraction (MISPE) combined with zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) method for selective extraction and determination of sitagliptin in rat serum and urine was developed and validated. The effects of progenic solvents, pH, cross linker and amount of monomer were studied to optimize the efficiency and selectivity. The adsorption kinetics and isotherms were measured. The molecularly imprinted polymer (MIP) showed good specific adsorption capacity with an optimum of 180 mg/g at pH 7.5 and selective extraction of sitagliptin from rat plasma and urine. The recovery of sitagliptin from rat urine and plasma was >98%. The limits of detection (LOD) and quantification (LOQ) were 0.03 and 0.10 μg/L respectively. The proposed method overcomes the matrix effects of phospholipids generally encountered while preparation of plasma samples by precipitation of proteins.     

Practical Synthesis of Pharmaceutically Relevant Pyrroles from α,β-Unsaturated Aldehydes and Phenacyl Azides

Structurally diverse pyrroles were synthesized by direct coupling of α, β-unsaturated aldehydes and phenacyl azides. The scope of the synthetic method was successfully demonstrated by synthesizing 28 different phenyl(5-phenyl-1H-pyrrol-2-yl)methanones in high yields (87–95 %). Derivatization of a few synthesized pyrroles was demonstrated which shows the potential application of the developed protocol in new functional materials. To get a mechanistic insight of the reaction, a typical reaction was performed in a deuterated solvent and the progress of the reaction was monitored by recording its ¹H NMR at regular time intervals.     

Modeling Wormholes Generated by Dark Matter Galactic Halos in f(R)$f(R)$ Modified Gravity

Wormholes (WHs) are hypothetical topologically non-trivial spacetime structures that can be freely traversed by observers and connect two asymptotic regions or infinities. From the current theoretical development, the prospect of their existence is challenging but cannot be excluded. In this paper, generalized Ellis–Bronikov (GEB) traversable WH geometries for static and spherically symmetric spacetime in the background of $f(R)$ gravity is explored. First, the Tsujikawa-like $f(R)$ model and the shape function for the GEB model is considered, which depend on a sequence of simple Lorentzian WHs with two parameters: a free even integer exponent, n, besides the throat radius, r₀. One also consider that these WHs are generated by dark matter galactic halos (DMGHs), based on the three most common phenomenological models, viz., Navarro–Frenk–White (NFW), Thomas–Fermi (TF), and pseudo-isothermal (PI). In this concern, the satisfaction of the energy conditions (ECs) which are dependent on the dark matter (DM) models, viz., dominant energy condition (DEC) and strong energy condition (SEC) and those which are not dependent viz., null energy condition (NEC) and WEC at the WH throat and its neighborhood is investigated. Finally, the presence of exotic matter is confirmed by the violation of the NEC in all cases, revealing the supremacy and physical acceptability to support the existence of the WHs and making them compatible and traversable in Tsujikawa's-like $f(R)$ model.     

Highly Efficient β-Functionalized Oxidomolybdenum(V) Corroles for Catalytic Oxidative Bromination of Phenols at Room Temperature

Two new β-functionalized oxidomolybdenum(V) corroles, oxido[3-formyl-5,10,15-triphenylcorrolato]molybdenum(V) ( Mo-1 ) and oxido[3-dicyanovinyl-5,10,15-triphenylcorrolato]molybdenum(V) ( Mo-2 ) were synthesized and characterized by various spectroscopic techniques and electrochemical studies. Mo-2 manifests splitted B bands due to x and y polarizations and highly red shifted longest B and Q bands due to the electron-deficient nature of the dicyanovinyl group. EPR data showed that these complexes exhibit an axial compression with d_xy¹ configuration. DFT studies revealed that HOMO and LUMO orbitals are stabilized in Mo-2 relative to Mo-1 . Mo-1 exhibits two successive reversible reductions and two oxidation potentials in cyclic voltammetry. Surprisingly, Mo-2 exhibits three successive reversible reductions and two oxidations; the one extra reduction could possibly be due to the reduction of the dicyanovinyl moiety. The catalytic activities of Mo-1 and Mo-2 for the oxidative bromination of various phenols using H₂O₂-KBr-HClO₄ mixture in water have been explored and exhibited excellent activity at a very low catalyst loading of 0.0030 and 0.0028 mol%, respectively. Both synthesized β-functionalized Mo(V) corroles manifest much higher conversion and TOF (59801–71174 h⁻¹) for oxidative bromination of phenols relative to earlier reported meso-functionalized Mo(V) corroles (20781–61646 h⁻¹). Hence, Mo-1 and Mo-2 mimic vanadium bromoperoxidase (VBPO) and act as functional models for these catalytic applications. These catalysts were reused upto 3 cycles and showed conversion rate upto 82 % indicating their excellent thermal and chemical stabilities.