A stability-indicating liquid chromatographic method has been developed and validated for the determination of Diltiazem Hydrochloride (DTZ) together with its six related substances (Diltiazem sulphoxide, Imp-A, Imp-B, Imp-D, Imp-E, and Imp-F) in a laboratory mixture as well as in a novel tablet formulation developed in-house. Efficient chromatographic separation was achieved on a Hypersil BDS ...

in this paper, the electronic eigenstates and energy spectra of single and two-interacting electrons confined in a concentric double quantum rings with a perpendicular magnetic field in the presence of         on-center donor and acceptor impurities are calculated using the exact diagonalization method. for a single electron case, the binding energy of on-center donor and acceptor impurities ar...

INTRODUCTION Tobramycin is a water-soluble aminoglycoside antibiotic used in a variety of pharmaceutical applications, including ophthalmic and intravenous administrations. Tobramycin is purified from the fermentation of the actinomycete Streptomyces tenebrarius. Kanamycin B (also known as bekanamycin), nebramine, and neamine (also known as neomycin A) are three known impurities of tobramycin, ...

INTRODUCTION Tobramycin is a water-soluble aminoglycoside antibiotic used in a variety of pharmaceutical applications, including ophthalmic and intravenous administrations. Tobramycin is purified from the fermentation of the actinomycete Streptomyces tenebrarius. Kanamycin B (also known as bekanamycin), nebramine, and neamine (also known as neomycin A) are three known impurities of tobramycin, ...

We calculate the electronic structure of 3d impurities in niobium and molybdenum. Our calculations rely on the local density approximation of density functional theory. Assuming a muffin-tin description of the atomic potentials, the impurity potential and the ones of the nearest neighbours are calculated self-consistently while the embedding of this perturbed cluster into the host is described ...

First-principles calculations are used to explore the possibility of enhancing the Néel temperature T N of the magnetoelectric antiferromagnet Cr 2 O 3 by substitutional doping. We describe the electronic structure of transition metal (V, Ti, Mn, Fe, Co, and Ni) and anion (N and B) impurities and evaluate their effect on the exchange interaction. We find that, although transition-metal impuriti...

Lead tungstate (PbWO4) and cadmium tungstate (CdWO4) are dense, fast scintillator crystals which have achieved technological importance for high energy radiation detectors and medical imaging, respectively. Calcium tungstate (CaWO4, the mineral scheelite) is an important phosphor for lighting and displays. We recently compared the electronic structures of the four scheelite-structure materials ...

In the course of research and development of a new pharmaceutical formulation of azelaic acid in the liposomal form, we developed a rapid and accurate method for the detection of impurities using high-performance liquid chromatography. A chromatographic column from Merck (Purospher Star RP C18, 250-4 mm (5 μm) was used in the assay, and the mobile phase gradient consisted of three phases: A--me...

We study both monolayer and bilayer graphene transport properties taking into account the presence of correlations in the spatial distribution of charged impurities. In particular we find that the experimentally observed sublinear scaling of the graphene conductivity can be naturally explained as arising from impurity correlation effects in the Coulomb disorder, with no need to assume the prese...

We study how two magnetic impurities embedded in a solid can be entangled by an injected electron scattering between them and by subsequent measurement of the electron's state. We start by investigating an ideal case where only the electronic spin interacts successively through the same unitary operation with the spins of the two impurities. We find conditions for the impurity spins to be maxim...