Crystal structure, Hirshfeld surface and frontier mol-ecular orbital analysis of 10-benzyl-9-(4-hydroxy-3-meth-oxy-phen-yl)-3,3,6,6-tetra-methyl-3,4,6,7,9,10-hexa-hydro-acridine-1,8(2H,5H)-dione.

In the fused ring system of the title mol-ecule, C31H35NO4, the conformation of the central di-hydro-pyridine ring is inter-mediate between boat and envelope with the N and the opposite C atoms lying out of the basal plane. The conformations of terminal rings are close to envelope, with the atoms substituted by two methyl groups as the flaps. In the crystal, the mol-ecules are linked by O-H⋯O hydrogen bonds into helical chains. The Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (63.2%), O⋯H/H⋯O (20.1%) and C⋯H/H⋯C (14.4%) contacts. Quantum chemical calculations of the frontier mol-ecular orbitals were carried out to characterize the chemical reactivity of the title compound.

Crystal structure, Hirshfeld surface and frontier mol-ecular orbital analysis of 9-(3-bromo-4-hy-droxy-5-meth-oxy-phen-yl)-3,3,6,6-tetra-methyl-3,4,5,6,7,9-hexa-hydro-1H-xanthene-1,8(2H)-dione.

In the fused ring system of the title compound, C24H27BrO5, the mean plane and maximum deviations of the central pyran ring are 0.0384 (2) and 0.0733 (2) Å, respectively. The cyclo-hexenone rings both adopt envelope conformations with the tetra-substituted C atoms as flap atoms, whereas the central pyran ring adopts a flattened boat conformation. The central pyran and phenyl substituent rings are almost perpendicular to each other, making a dihedral angle of 89.71 (2)°. In the crystal, pairs of mol-ecules are linked via O-H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(20) ring motif. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (50.6%), O⋯H/H⋯O (22.9%) and C⋯H/H⋯C (11.1%) contacts. Quantum chemical calculations for the frontier mol-ecular orbitals were undertaken to determine the chemical reactivity of the title compound.

Crystal structure, Hirshfeld surface and frontier mol-ecular orbital analysis of 10-benzyl-9-(3-eth-oxy-4-hy-droxy-phen-yl)-3,3,6,6-tetra-methyl-3,4,6,7,9,10-hexa-hydro-acridine-1,8(2H,5H)-dione.

In the fused ring system of the title compound, C32H37NO4, the central di-hydro-pyridine ring adopts a flattened boat conformation, the mean and maximum deviations of the di-hydro-pyridine ring being 0.1429 (2) and 0.2621 (2) Å, respectively. The two cyclo-hexenone rings adopt envelope conformations with the tetra-substituted C atoms as flap atoms. The benzene and phenyl rings form dihedral angles of 85.81 (2) and 88.90 (2)°, respectively, with the mean plane of the di-hydro-pyridine ring. In the crystal, mol-ecules are linked via an O-H⋯O hydrogen bond, forming a helical chain along the b-axis direction. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (65.2%), O⋯H/H⋯O (18.8%) and C⋯H/H⋯C (13.9%) contacts. Quantum chemical calculations for the frontier mol-ecular orbitals were undertake to determine the chemical reactivity of the title compound.

Development and validation of a stability-indicating RP-HPLC method for estimation of atazanavir sulfate in bulk.

A stability-indicating reverse phase-high performance liquid chromatography (RP-HPLC) method was developed and validated for the determination of atazanavir sulfate in tablet dosage forms using C18 column Phenomenix (250 mm×4.6 mm, 5 µm) with a mobile phase consisting of 900 mL of HPLC grade methanol and 100 mL of water of HPLC grade. The pH was adjusted to 3.55 with acetic acid. The mobile phase was sonicated for 10 min and filtered through a 0.45 µm membrane filter at a flow rate of 0.5 mL/min. The detection was carried out at 249 nm and retention time of atazanavir sulfate was found to be 8.323 min. Linearity was observed from 10 to 90 µg/mL (coefficient of determination R2 was 0.999) with equation, y=23.427x+37.732. Atazanavir sulfate was subjected to stress conditions including acidic, alkaline, oxidation, photolysis and thermal degradation, and the results showed that it was more sensitive towards acidic degradation. The method was validated as per ICH guidelines.

Synthesis of 2,2,4-trimethyl-1,2-dihydroquinolinyl substituted 1,2,3-triazole derivatives: their evaluation as potential PDE 4B inhibitors possessing cytotoxic properties against cancer cells.

The 2,2,4-trimethyl-1,2-dihydroquinolinyl substituted 1,2,3-triazole derivatives were designed as potential inhibitors of PDE4B. These compounds were synthesized via a multi-step sequence consisting of copper-catalyzed azide-alkyne cycloaddition (CuAAC) as a key step in aqueous media. The required alkynes were prepared from nimesulide via N-propargylation and then nitro group reduction followed by a CAN mediated modified Skraup reaction of the resulting amine. All the synthesized compounds showed PDE4B inhibitory properties in vitro at 30µM with two compounds showing >50% inhibition that were supported by the in silico docking results of these compounds at the active site of PDE4B. Three of these PDE4 inhibitors showed promising cytotoxic properties against A549 human lung cancer cells in vitro with IC50 ∼8-9µM.

Effects of subchronic malathion exposure on the pharmacokinetic disposition of pefloxacin.

Malathion is one of the most extensively used organophosphorus pesticides applied in agriculture, mosquito eradication and in the control of animal ectoparasites and human body lice. The widespread use of malathion has raised concern over its potential to cause untoward health effects in humans, animals and birds. Malathion inhibits cytochrome P450 monooxygenases and has the potential to alter pharmacokinetic profiles of therapeutic agents that are metabolized in the liver. The present study was undertaken to evaluate the impact of subchronic exposure of malathion on the pharmacokinetic disposition of pefloxacin. Chickens were given either normal diet or malathion through food at a concentration of 1000ppm for 28 days. Subsequently, pefloxacin was administered either intravenously or orally (control) to birds fed normal diet and orally to malathion-exposed chickens at a dosage of 10mgkg(-1) body weight. Blood samples were drawn from the brachial vein at predetermined time intervals after drug administration. Plasma was separated and analyzed for pefloxacin by reverse-phase high performance liquid chromatography. The plasma concentration-time data were analyzed by non-compartmental techniques. Following intravenous administration of pefloxacin, elimination half-life (t(1/2ß)), area under the plasma concentration-time curve (AUC) and mean residence time (MRT) were 8.2±0.7h, 66±9µghml(-1) and 10.5±1.1h, respectively, and when the drug was administered orally, the respective values of pharmacokinetic parameters were 8.2±0.4h, 31±3.1µghml(-1) and 11.7±0.6h. Malathion exposure significantly increased maximum plasma drug concentration, t(1/2ß), AUC and MRT of pefloxacin to 54, 22, 117 and 37% of control, respectively. These findings provide evidence that subchronic malathion exposure markedly influences the elimination kinetics of pefloxacin which may be due to malathion-mediated inhibition of metabolism of pefloxacin.