Development and Validation of Stability Indicating RP-HPLC Method for the Determination of Process and Degradation-Related Impurities in Sugammadex Sodium Drug Substance

The aim of this study is to develop and validate a sensitive and specific stability-indicating reversed-phase high-performance liquid chromatographic (RP-HPLC) method for the quantitative determination of Sugammadex sodium together with its process and possible degradation impurities. The pKa value is 2.82. The chromatographic conditions have been optimized by the Hypersil Gold 250 mm X 4.6 mm, 3 µ RP-18 columns with gradient elution using a mobile phase composed of 0.1% phosphoric acid, acetonitrile, and methanol. The eluents were monitored at 205 nm with a flow rate of 1.0 mL/min with an injection volume of 20 µL. The optimized method produced symmetrical and sharp peaks with good separation between the process and degradation impurities. The forced degradation study was carried out under acid, base, oxidation, and thermal conditions to demonstrate the stability-indicating capability of the method. The method was validated as per the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Q2 (R1) and showed excellent specificity, precision, linearity, accuracy, and robustness. The developed HPLC method was precise with a value of 0.25%. The relative standard deviation of accuracy represented by the recovery studies ranged between 89.5% and 104.6%. Linearity analyses indicated a correlation coefficient value of greater than 0.996 for Sugammadex and its known impurities. The LOD and LOQ values for Sugammadex ranged from 0.017% to 0.050%, and for its related impurities, they ranged from 0.015% to 0.055%. The stability of the analytical solution was evaluated and was stable for 75 h when stored at 5 °C. No chromatographic interference was observed during the degradation studies and also in the blank chromatogram.

     

The chromatographic separation of a mixture of the chlorides of calcium,strontium, barium and magnesium

The chlorides of calcium, strontium, bitnum and magnesium have been separated on circular paper, using mixed alcohols, containing mcthanol as one of the constituents, as solvents. Approximate R_F values obtained by using ethanol containing 50%, methanol, have been reported     

Partial linearization for noninvertible mappings

A Hartman-Grobman result for noninvertible mappings is proved. It is assumed that the spectrum of the linearized mapping contains zero but is disjoint from the complex unit circle. In the infinite-dimensional case, additional spectral conditions are assumed. These additional conditions are satisfied if the linearized mapping is completely continuous. The proof combines Hartman'sC ¹ linearization method for contractive mappings [10] with our previous result [1] on linearization of the expanding part.The paper was written while the second author was an Alexander-von-Humboldt Research Fellow in the Mathematical Institute of the University of Augsburg, Germany.     

Plasmonic Hotspots in Air: An Omnidirectional Three‐Dimensional Platform for Stand‐Off In‐Air SERS Sensing of Airborne Species

Molecular‐level airborne sensing is critical for early prevention of disasters, diseases, and terrorism. Currently, most 2D surface‐enhanced Raman spectroscopy (SERS) substrates used for air sensing have only one functional surface and exhibit poor SERS‐active depth. “Aerosolized plasmonic colloidosomes” (APCs) are introduced as airborne plasmonic hotspots for direct in‐air SERS measurements. APCs function as a macroscale 3D and omnidirectional plasmonic cloud that receives laser irradiation and emits signals in all directions. Importantly, it brings about an effective plasmonic hotspot in a length scale of approximately 2.3 cm, which affords 100‐fold higher tolerance to laser misalignment along the z‐axis compared with 2D SERS substrates. APCs exhibit an extraordinary omnidirectional property and demonstrate consistent SERS performance that is independent of the laser and analyte introductory pathway. Furthermore, the first in‐air SERS detection is demonstrated in stand‐off conditions at a distance of 200 cm, highlighting the applicability of 3D omnidirectional plasmonic clouds for remote airborne sensing in threatening or inaccessible areas.     

Bifurcation analysis of an oscillatory CNN model with two cells

The aim of this paper is to carry out the full bifurcation analysis of the two-parameter two-dimensional oscillatory cellular neural network (CNN) model (3)–(4) in Chap. 8 of the recent monograph of Chua and Roska (Cellular Neural Networks and Visual Computing, Cambridge University Press, [2002]). The main tool is an averaged divergence inequality implying that—regardless the dimension of the phase space—compact invariant sets are of zero Lebesgue measure.     

A Novel Stability-Indicating Method for Determination of Related Substances of Montelukast Sodium in a Pharmaceutical Dosage Form Using RP-HPLC

Chromatographia - The main aim is to develop a simple, rugged, and sensitive method for determining the Montelukast Sodium-related impurities in a tablet dosage form using reverse-phase...     

The earliest known record of California Indian numbers

The earliest written record of a numeral system for any California Indian tribe has been ascribed to Padre José Señán, O.F.M., missionary at Mission San Buenaventura. It is now known that the earliest is in The First Spanish Entry Into San Francisco Bay 1775, the diary of Fr. Vicente Maria, O.F.M., chaplain of a Spanish expedition. He recorded the Indian words for the numbers one to fourteen. The first eight of these correspond with the same numbers used by the Costanoans of Mission Santa Clara. The differences are credited to the influence of other tribes who visited Angel Island in San Francisco Bay where Padre Vicente made his record.     

Multipole expansion of non-local coupling potentials for cluster transfer and application to 16O(16O, 12C)20Ne

When the transfer of clusters and the symmetrization (antisymmetrization) of scattering wave functions is described by cluster models within the coupled-channel formalism, non-local coupling potentials arise. We suggest a procedure to calculate these potentials by a multipole expansion of all potentials and wave functions which depend on sums of vectors. The expansion coefficients are found by least-squares fit. The method is applied to the ¹⁶O(¹⁶O, ¹²C)²⁰Ne reaction, which is treated in the cluster model with two inert ¹²C- and α-clusters as constituents.