A validated stability-indicating RP-HPLC assay method for Amsacrine and its related substances

A validated specific stability indicating reversed-phase high-performance liquid chromatography method was developed for the quantitative determination of Amsacrine as well as its related substances determination in bulk samples, in presence of degradation products, and its process related impurities. Forced degradation studies were performed on bulk samples of Amsacrine as per International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human use (ICH) prescribed stress conditions using acid, base, oxidative, thermal stress, and photolytic degradation to show the stability indicating power of the method. Significant degradation was observed during basic hydrolysis, slight degradation was observed in oxidative and thermal stress, and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies and the impurity spiked solution. Good resolution between the peaks corresponds to process-related impurities and degradation products from the analyte were achieved on Inertsil ODS column using the mobile phase consists a mixture of 1.0% triethyl amine in 20 mM potassium dihydrogen orthophosphate, with pH adjusted to 6.5, with ortho phosphoric acid in water and acetonitrile using a simple linear gradient. The detection was carried out at wavelength 248 nm. The mass balance in each case was in between 99.4% to 99.9%, indicating that the developed method was stability-indicating. Validation of the developed method was carried out as per ICH requirements. The developed method was found to be suitable to check the quality of bulk samples of Amsacrine at the time of batch release and also during its stability studies.     

Photocatalytic reduction of CO2 over Cu-TiO2 /molecular sieve 5A composite

TiO(2) and different Cu wt% loaded TiO(2) (TC(0.5-5.0)), 10 wt% TC(2.0) supported on molecular sieve 5A (10 wt% TC(2.0)/MS) were prepared by impregnation and solid-state dispersion methods. The photocatalysts prepared were characterized using XRD, SEM, and UV-Vis DRS, TEM, XPS spectroscopy techniques. Photocatalytic reduction of CO(2) in water and alkaline solution are investigated in a batch reactor. The yield of oxalic acid increased notably when TC was supported on molecular sieve. The Cu-TiO(2) supported on molecular sieve catalyst promotes the charge separation that leads to an increase in the selective formation of oxalic acid in addition to methanol, acetic acid and traces of methane. The product formation is due to the high adsorption of CO(2), water and product shape selectivity of the composite photocatalyst. The maximum yield of oxalic acid was found to be 65.6 μg h(-1) g(-1) per cat using 0.2 N NaOH containing solution over 10 wt% TC(2.0)/MS photocatalyst. The difference in the photocatalytic activity is related to its physicochemical properties.     

Radiation-Induced Copolymerization of Acrylonitrile with Methyl Acrylate: Synthesis and Characterization

Radiation-induced copolymerization of acrylonitrile with methyl acrylate was carried out in aqueous medium at room temperature. Different compositions of the copolymer were prepared and characterized by IR, ¹H-NMR, thermal, and dielectric studies. NMR spectroscopy was used to determine the composition and stereochemistry of the copolymer. Glass transition temperature values (T_g ) were determined by DSC. Dielectric studies were carried out to understand the segmental motions and the effect of composition on dielectric loss.     

Stability and Scalarization of Weak Efficient, Efficient and Henig Proper Efficient Sets Using Generalized Quasiconvexities

The aim of this paper is to establish the stability of weak efficient, efficient and Henig proper efficient sets of a vector optimization problem, using quasiconvex and related functions. We establish the Kuratowski?CPainlevé set-convergence of the minimal solution sets of a family of perturbed problems to the corresponding minimal solution set of the vector problem, where the perturbations are performed on both the objective function and the feasible set. This convergence is established by using gamma convergence of the sequence of the perturbed objective functions and Kuratowski?CPainlevé set-convergence of the sequence of the perturbed feasible sets. The solution sets of the vector problem are characterized in terms of the solution sets of a scalar problem, where the scalarization function satisfies order preserving and order representing properties. This characterization is further used to establish the Kuratowski?CPainlevé set-convergence of the solution sets of a family of scalarized problems to the solution sets of the vector problem.     

Duality in ε-variational inequality problems

In this paper a general analysis of duality for an extended ε-variational inequality problem based on the notions of ε-convexity and ε-conjugacy is performed. Optimal solutions of both the primal and dual problems are also related to the saddle point of an associated Lagrangian. Gap functions for these problems are proposed. An existence theorem for the extended ε-variational inequality is also established by means of the KKM lemma.     

Levitin–Polyak well-posedness for parametric quasivariational inequality problem of the Minty type

In this paper, we introduce the notions of Levitin?CPolyak (LP) well-posedness and Levitin?CPolyak well-posedness in the generalized sense, for a parametric quasivariational inequality problem of the Minty type. Metric characterizations of LP well-posedness and generalized LP well-posedness, in terms of the approximate solution sets are presented. A parametric gap function for the quasivariational inequality problem is introduced and an equivalence relation between LP well-posedness of the parametric quasivariational inequality problem and that of the related optimization problem is obtained.     

Hardness of Crystals with NaCl Structure and the Significance of the GILMAN-CHIN Parameter

The microhardness of PbTe, PbSe, EuS and EuSe has been determined. The microhardness vs lattice constant plot for chalcogenides is a curve similar to the one for alkali halides. The Gilman-Chin parameter (H/C₄₄) has been calculated for a large number of crytals with NaCl structure. There is no unique value representing the entire group of crystals, the values ranging from 0.01 to 0.20. The Gilman-Chin parameter broadly correlates with the effective ionic charge (e) indicating that it is a measure of the ionicity. Empirically, it is observed that the product (H/C₄₄) · (e)² is approximately constant.     

Growth and selective etching studies on NaBrO3 crystals

Surface studies on (111) faces of sodium bromate crystals grown from aqueous solution show the presence of growth steps. A new etchant consisting of a mixture of 8 parts of glacial acetic acid and 2 parts of formic acid, to which 3 mg/cc of cupric nitrate is added, reveals the dislocation sites on (111) faces of these crystals. The etching action on (111) and (111 ) faces is different. Different microhardness values are recorded on (111) and (111 ) faces of these crystals. The difference in etching action as well as in microhardness values on (111 ) and (111) faces is discussed.