A green capillary zone electrophoresis method for the simultaneous determination of piperacillin,tazobactam and cefepime in pharmaceutical formulations and human plasma

A green, novel, rapid, accurate and reliable capillary zone electrophoresis method was developed and validated for the simultaneous determination of piperacillin, tazobactam and cefepime in pharmaceutical preparations. Separation was carried out using fused silica capillary (50 µm i.d. × 48.6 cm and 40.2 cm detection length) and applied potential of 20 kV (positive polarity) and a running buffer containing 15 m m sodium borate buffer adjusted to pH 9.3 with UV detection at 215 nm. Amoxicillin was used as an internal standard. The method was suitably validated according to International Conference on Harmonization guidelines. The method showed good linearity in the ranges of 10–100, 20–400 and 10–400 µg/mL with limits of quantitation of 1.87, 3.17 and 6.97 µg/mL and limits of detection of 0.56, 0.95 and 2.09 µg/mL for tazobactam, piperacillin and cefepime, respectively. The proposed method was successfully applied for the analysis of these drugs in their synthetic mixtures and co‐formulated injection vials. The method was extended to the in vitro determination of the two drugs in spiked human plasma. It is considered a ‘green’ method as it consumes no organic solvents. Copyright © 2015 John Wiley & Sons, Ltd.     

Single and binary catalyst systems based on nickel and palladium in polymerization of ethylene

The catalyst (N,N‐bis(2,6‐dibenzhydryl‐4‐ethoxyphenyl)butane‐2,3‐diimine)nickel dibromide, a late transition metal catalyst, was prepared and used in ethylene polymerization. The effects of reaction parameters such as polymerization temperature, co‐catalyst to catalyst molar ratio and monomer pressure on the polymerization were investigated. The α‐diimine nickel‐based catalyst was demonstrated to be thermally robust at a temperature as high as 90 °C. The highest activity of the catalyst (494 kg polyethylene (mol cat)^?1 h^?1) was obtained at [Al]/[Ni] = 600:1, temperature of 90 °C and pressure of 5 bar. In addition, the performance of a binary catalyst using nickel‐ and palladium‐based complexes was compared with that of the corresponding individual catalytic systems in ethylene polymerization. In a study of the catalyst systems, the average molecular weight and molecular weight distribution for the binary polymerization were between those for the individual catalytic polymerizations; however, the binary catalyst activity was lower than that of the two individual ones. The obtained polyethylenes had high molecular weights in the region of 10⁵ g mol^?1. Gel permeation chromatography analysis showed a narrow molecular weight distribution of 1.44 for the nickel‐based catalyst and 1.61 for the binary catalyst system. The branching density of the polyethylenes generated using the binary catalytic system (30 branches/1000 C) was lower than that generated using the nickel‐based catalyst (51/1000 C). X‐ray diffraction study of the polymer chains showed higher crystallinity with lower branching of the polymer obtained. Also Fourier transform infrared spectra confirmed that all obtained polymers were low‐density polyethylene.     

The Synthesis and Characterization of 2-Amino-3-methylpyridinium Dihydrogenmonophosphate: (C6H9N2)H2PO4

A new crystal of 2-amino-3-methylpyridinium dihydrogenmonophosphate has been prepared and characterized by X-ray crystallography, thermal analysis, and impedance and NMR spectroscopies. This compound crystallizes in the triclinic space group P with a = 7.343(2) Å, b = 7.987(2) Å, c = 8.116(4) Å, α = 77,62(3)°, β = 77,74(3)°, γ = 87,03(2)°, V = 454.3 (3)ų, and Z = 2. The crystal structure was solved and refined to R = 0.030 with 1602 independent reflections. The atomic arrangement can be described as (H₂PO₄ ^?)_n polymeric chains anchoring the 2-amino-3-methylpyridinium cations through short hydrogen bonds. All ring atoms of the organic entity are coplanar. The exocyclic N atom is an electron receiving center, which is consistent with features of imino resonance evidenced by bond lengths and angles. Solid state ³¹P, ¹³C, and ¹⁵N CP-MAS-NMR spectroscopies are in agreement with the X-ray structure. Ab initio calculations allow the attribution of carbons and nitrogen to the independent crystallographic sites.     

Determination of Carbadox and Olaquindox Residues in Chicken Muscles, Chicken Liver, Bovine Meat, Liver and Milk by MLC with UV Detection: Application to Baby Formulae

A simple and sensitive method was optimized and validated for the analysis of carbadox and olaquindox residues in chicken muscles, chicken liver, bovine meat, liver and milk. Analytical separation was performed in less than 4 min using a C₁₈ column with UV detection at 373 nm and a micellar solution of 0.1 M sodium dodecyl sulphate, 10 % acetonitrile and 0.3 % triethylamine in 0.02 M phosphoric acid buffered at pH 4 as the mobile phase. The method was fully validated in accordance with ICH guidelines. The micellar method was successfully applied to quantitatively determine carbadox and olaquindox residues in spiked chicken muscles, chicken liver, bovine meat, liver and milk. It was also extended to the determination of carbadox and olaquindox residues in baby formulae. The recoveries obtained were in the 89.2–93.6 and 93.0–107.2 % ranges for carbadox and olaquindox, respectively. High extraction efficiency for carbadox and olaquindox was obtained without matrix interference in the extraction process and in the subsequent chromatographic determination. No organic solvent was used during the pretreatment step.     

Gravitational Spin Entropy Production

Spin entropy production for particles with arbitrary spin moving in a curved spacetime is discussed. There is a Wigner rotation due to both the acceleration an the curvature, which causes an initial pure state to transform into a final mixed state. Depending on the spacetime characteristics, one may find paths on which there is no Wigner rotation and the state remains pure.     

Some remarks on residually algebraic pairs of rings

In this paper we continue the study of residually algebraic pairs begun in [10], and we give other characterizations of such pairs. As a consequence, we study the interaction between residually algebraic pairs and pairs of rings when all intermediate domains satisfy some properties P {\cal P} .     

Convex hull and extreme points of two families of univalent functions

Closed convex hull and extreme points are obtained for the classR (α) of univalent functions ? inU = {z:¦z ¦< 1}. satisfying inU the conditions ?(0) = 0, ?′(0) = 1Re {f(z)/z} >α, 0 ≤ α < 1. We also obtain the closed convex hull for the classR (α, β) of univalent functionsg inU, satisfying inU the conditionsg (0) = 0,g (0) = 1 and Re{g(z)/F(z)} > β, 0 ? β< 1, wheref ∈ R (α). Integral representations are given for the hulls of these two classes in terms of probability measures on suitable sets. These results are used to solve extremal problems. For example the upper bounds are determined for the coefficients of a function subordinate to some function in R(α) when 1/2 ≤ α < 1.

     

Synthesis,crystal structure,magnetic properties and second harmonic generation of a new noncentrosymmetric coordination compound:Triaqua(4-amino-6-methoxypyrimidine) cuprate(Ⅱ)sulfate

The chemical preparation, crystal structure and infrared spectroscopic characterization of the triaqua(4-amino-6-methoxypyrimidine) cuprate(II) sulfate, [Cu(C_5H_7N_3)(H_2O)_3]SO_4, is reported. The compound crystallizes in the noncentrosymmetric orthorhombic space group P2_12_12_1 with lattice parameters a = 7.9025(3), b = 11.1189(4), c = 12.9720(4) , V = 1139.81(7) ~3 and Z = 4. The Cu(II) cation is fivecoordinated, in an early half-way between square pyramidal and trigonal bipyramidal fashion, by two nitrogen atoms of the 4-amino-6-methoxypyrimidine ligand and three water oxygen atoms. In the atomic arrangement, the organic ligands and the 5-connected Cu centers are linked with each other to give a 1-D corrugated hybrid chain running along the b-axis direction. The chains are interconnected by the SO_4~(2-) anions via O–H...O, O–H...S, C–H...O and N–H...O hydrogen bonds to form layers spreading parallel to the(011) plane. The vibrational absorption bands were identified by infrared spectroscopy. Quantitative measurements of the second harmonic generation(SHG) of a powdered sample at 1064 nm were performed and a relative efficiency of 5.2 times the KDP standard was observed. Magnetic properties were also defined to characterize the complex. Magnetic measurements revealed that this material had a onedimensional antiferromagnetic character. The magnetic parameters were g = 2.11 and 2J/k B = -36 K.