Spectroscopic Estimation of Doxylamine Succinate in Tablets and Human Plasma by Formation of Ion-pair Complex

Aim: To develop a simple spectroscopic method for estimation of doxylamine (DOX) succinate in its tablet dosage form and human plasma with the aid of an ion-pair complex formation. Methods: In this method, methyl orange (0.05 % w/v) dye was used to form an ion-pair complex in acetate buffer (1M; pH: 5.00) at 300 C ± 20C. The ion-pair complex formed was extracted with chloroform. The maximum absorbance for the ion-pair complex was measured at 420 nm. Results and discussion: The method conditions were obeyed Beer's law in the concentrations ranging from 5-25 µg/mL of DOX succinate with a correlation coefficient (r2) of 0.992. The ion-pair (drug-dye) complex was formed in a 1:1 ratio which was demonstrated by Jobs' method of continuous variation. The method was satisfied the validation criteria as per ICH (Q2R1) guidelines. Accuracy studies showed 99.06-100.9 % recovery of the analyte. The responses of the precision and robustness were found within acceptable limits (<2% RSD). The LOD and LOQ values were found as 0.31 and 0.939 µg/mL, respectively. Conclusion: The developed method was simple, specific, and economical and requires a short analysis time. Therefore it could be considered for precise analysis of DOX succinate in biological matrices.

GREEN SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL STUDIES OF MIXED LIGAND COMPLEXES OF Co (II), Ni (II) and V(III) METALS USING SOME AMINO ACIDS AS LIGANDS

Co (II), Ni (II) and V (III) metal complexes were synthesized mechanochemically using L-Leucine, L-Tyrosine and Creatinine as mixed ligands. The metals and the ligands were grounded using an agate mortar with a pestle. The compounds formed were characterized using their melting/decomposition temperature, solubility, magnetic susceptibility, conductivity measurement, Infrared analysis and scanning electron microscope (SEM). The Metal – ligand ratios were investigated via Job’s method of continuous variation. The shifts of bands (for instance 1693-1677 cm-1 to 1674-1607 cm-1) in C=O and the appearance of new bands in the complexes (683-669 and 713-750 cm-1 indicates the complexation. The lower conductivity measurement values (15.00 to 32.40) µS.cm-1 suggested the non-electrolytic nature of the complexes. The magnetic effective value of the metal complexes showed that all the three complexes are paramagnetic and octahedral. It was concluded that the amino acids (ligands) coordinated in a bidentate way through the nitrogen from the amino group and oxygen from carboxylate. The complexes were screened for their antimicrobial activities against two bacterial isolates (Streptococcus pneumoniae and Klebsiella pneumoniae). All the complexes exhibited good activity against the organisms

Synthesis, Characterization and corrosion Inhibition Studies on Mn (II) and Co (II) Complexes Derived from 1-{(Z)-[(2-hydroxyphenyl) imino]methyl}naphthalen-2-ol in 1M HCl Solution

Schiff base derived from the reaction of 2-amino phenol and 2-hydroxy-1-naphthaldehyde and its Co (II), and Mn (II) complexes have been synthesized and characterized by solubility test, melting point/ decomposition temperatures, molar conductance, IR and magnetic susceptibility. The number of ligands coordinated to the metal ion was determined using Job’s method of continuous variation. Their molar conductance values indicate that all the complexes are non-electrolytes. Magnetic moment values of the complexes showed that both Mn (II) and Co (II) are paramagnetic. The spectroscopic data of metal complexes indicated that the metal ions are complexed with azomethine nitrogen and deprotonated oxygen atom. Corrosion inhibition of the schiff base and Mn (II) and Co (II) complexes were evaluated using the weight loss method in a 0.1MHCl solution for copper metal. The inhibition efficiency increased with increasing inhibitors concentration. The negative values of Gibb’s free energy of adsorption (ΔGads) confirmed the spontaneity and physical adsorption of the inhibition process which is inconsistent with Langmuir adsorption isotherm.

Investigation of the Interaction of Gadolinium with Several Organic Ligands and Humic Acid by Ligand Competition Using 4-(2-Pyridylazo)-Resorcinol (PAR)

Gd3+ forms a strongly colored complex with 4-(2-pyridylazo)-resorcinol (PAR) in aqueous solutions. We characterized the Gd3+-PAR complex in order to use it as a probe of Gd3+ speciation in the presence of environmentally relevant ligands. The formation of the Gd3+-PAR complex was investigated from pH 5 to 8 in the presence of excess PAR. The absorbance of the Gd3+-PAR complex dramatically increased from pH 5 to 8 and application of the method of continuous variation indicates that the complex was primarily 1:2 Gd(PAR)2 at pH 8. Stability constants for Gd3+ with other ligands can be quantified by competitive displacement of the PAR ligand. To establish the viability of this approach, we measured the stability constants between Gd3+ and several organic acids and carbonate. Our measurements show reasonable agreement with the literature values. We used the competitive displacement approach to establish that humic acids can competitively displace PAR from the Gd(PAR)2 complex.

Synthesis and characterization of Al(III) complex with paracetamol

The complex of Al (111) with paracetamol have synthesized and characterized using UV–Vis, Infrared spectroscopies and melting point. The ligand has been found to behave as tridentate chelating agents. Paracetamol complex coordinate through the carboxylate oxygen, phenolate oxygen atom, and amine group. The complex solubility was evaluated for several solvents and it was found the compound was more soluble in DMSO. Job’s method of continuous variation suggested 1 : 2 metals to ligand stoichiometry for paracetamol complex

Extractive Spectrophotometric Method for the Determination of Glibenclamide by Ion-Pair Complex in Pure Form and Pharmaceutical Formulation

Simple, rapid and sensitive extractive spectrophotometric method is presented for the determination of glibenclamide (Glb) based on the formation of ion-pair complex between the Glb and anionic dye, methyl orange (MO) at pH 4. The yellow colored complex formed was quantitatively extracted into dichloromethane and measured at 426 nm. The colored product obeyed Beer’s law in the concentration range of (0.5-40) μg.ml-1. The value of molar absorptivity obtained from Beer’s data was found to be 31122 L.mol-1.cm-1, Sandell’s sensitivity value was calculated to be 0.0159 μg.cm-2, while the limits of detection (LOD) and quantification (LOQ) were found to be 0.1086 and 0.3292 μg.ml-1, respectively. The stoichiometry of the complex created between the Glb and MO was 1:1 as determined via Job’s method of continuous variation and mole ratio method. The method was successfully applied for the analysis of pharmaceutical formulation.

Di-Palladium Complexes are Active Catalysts for Mono-N-Protected Amino Acid Accelerated Enantioselective C-H Functionalization

The role of mono-protected amino acid (MPAA) ligands in accelerating enantioselective cyclopalladation and palladium catalyzed C-H func-tionalization was investigated using kinetic, spectroscopic, and computational methods. Single crystal X-ray diffraction and NMR spectroscopy demonstrate that MPAA ligands bind catalytically competent di-palladium complexes as bridging carboxylates. The catalytic relevance of the observed di-palladium species was evaluated by kinetic analysis. The kinetic method of continuous variation demonstrated that a complex contain-ing a single MPAA-bridged di-palladium core (Pd2(MPAA)1) is an active catalyst for the reactions studied. The experimental studies are con-sistent with density functional theory calculations that indicate enantioinduction can be achieved by a single MPAA ligand bridging a di-palladium catalyst through secondary sphere hydrogen-bonding interactions that lower the barrier to C-H activation of the major enantiomer.<br>

Di-Palladium Complexes are Active Catalysts for Mono-N-Protected Amino Acid Accelerated Enantioselective C-H Functionalization

The role of mono-protected amino acid (MPAA) ligands in accelerating enantioselective cyclopalladation and palladium catalyzed C-H func-tionalization was investigated using kinetic, spectroscopic, and computational methods. Single crystal X-ray diffraction and NMR spectroscopy demonstrate that MPAA ligands bind catalytically competent di-palladium complexes as bridging carboxylates. The catalytic relevance of the observed di-palladium species was evaluated by kinetic analysis. The kinetic method of continuous variation demonstrated that a complex contain-ing a single MPAA-bridged di-palladium core (Pd2(MPAA)1) is an active catalyst for the reactions studied. The experimental studies are con-sistent with density functional theory calculations that indicate enantioinduction can be achieved by a single MPAA ligand bridging a di-palladium catalyst through secondary sphere hydrogen-bonding interactions that lower the barrier to C-H activation of the major enantiomer.<br>

Di-Palladium Complexes are Active Catalysts for Mono-N-Protected Amino Acid Accelerated Enantioselective C-H Functionalization

The role of mono-protected amino acid (MPAA) ligands in accelerating enantioselective cyclopalladation and palladium catalyzed C-H func-tionalization was investigated using kinetic, spectroscopic, and computational methods. Single crystal X-ray diffraction and NMR spectroscopy demonstrate that MPAA ligands bind catalytically competent di-palladium complexes as bridging carboxylates. The catalytic relevance of the observed di-palladium species was evaluated by kinetic analysis. The kinetic method of continuous variation demonstrated that a complex contain-ing a single MPAA-bridged di-palladium core (Pd2(MPAA)1) is an active catalyst for the reactions studied. The experimental studies are con-sistent with density functional theory calculations that indicate enantioinduction can be achieved by a single MPAA ligand bridging a di-palladium catalyst through secondary sphere hydrogen-bonding interactions that lower the barrier to C-H activation of the major enantiomer.<br>