A sensitive and stable High Performance liquid chromatographic method has been developed for the identification of three process related impurities viz impurity-A, impurity-B and impurity-C in Dapoxetine hydrochloride. The method was optimized based on the peak shape and resolution of impurity-A, impurity-B and impurity-C. Phenomenex Luna C18 column (250mm×4.6 mm, 5um) was used for optimization...

kevlar is one of the fbers which is used in heavy industrial productions such as, shipping, military and weaving for reinforcement of composites. initial polymer of kevlar or poly(para-phenylene terephthalamide) is an oriented liquid crystal polymer. existence of aromatic group in the main chain leads to formation of rigid-rod molecules in the polymer, high strength and high modulus in it is fb...

Local magnetic properties around a nonmagnetic impurity are investigated in high-Tc cuprate superconductors. We consider a model two-dimensional dx2−y2-wave superconductor with strong antiferromagnetic (AF) spin fluctuations and calculate the spin susceptibility around the impurity. We show that the uniform susceptibility (χ(0)), which is usually suppressed in spin-singlet superconductivity, is...

The high-pressure optical floating-zone method enables single crystal growth of the Pmnb high-temperature phase Li2FeSiO4. influence conditions on quality, homogeneity, and impurity formation in Li2FeSiO4 is studied. use different starting materials, i.e., either P121/n1 or Pmn21 polymorph, as well optimization various investigated. Several mm3-sized high-quality crystals are obtained by choice...

I N T RO DU C T IO N A company that manufactures drug product or drug substance has a vested interest in determining the impurities associated with their compounds. The analysis of impurities can be a very labor-intensive task involving method development, impurity synthesis, isolation techniques, and various analytical approaches to determine the unambiguous identification of the impurity of i...

This study details the isolation, identification, and characterization of ambroxol's unknown impurity. One unknown impurity of ambroxol was formed in the formulated drug under stress conditions [40°C /75% relative humidity (RH) for 6 months] with the relative retention time (RRT) 0.68 in RP-HPLC. The impurity was enriched by exposing it to heat and it was isolated by using preparative HPLC. The...

In perfect alkali halide crystals only the transverse optic phonons of zero wave vector absorb far infrared radiation in first order. The introduction of impurities in the lattice removes the translational invariance and almost all phonons become optically active. In addition to the absorption at the reststrahlen frequency, impurity induced absorption appears in the phonon band region and somet...

Although in vitro transport/inhibition studies are commonly performed on impure drug candidates to screen for pharmacokinetic properties in early development, quantitative guidelines concerning acceptable impurity levels are lacking. The broad goal was to derive models for the effect of impurity on transport and inhibition studies and identify the maximum allowable impurity level that does not ...

The method of obtaining pure polycrystalline silicon is described, followed by short accounts of how this material is converted into single-crystal form either by the Czochralski (cz) pulling method or the float-zone (FZ) method. It is shown that the silicon contains various impurities including oxygen, carbon, boron and possibly hydrogen. If a silicon nitride crucible is used instead of silica...