Development and validation of stability indicating analytical method for Ilaprazole

The objective of the present study was to develop and validate a rapid and simple stability indicating analytical method for estimating Ilaprazole. Ilaprazole was subjected to different stress conditions prescribed by International Conference on Harmonization (ICH) such as hydrolysis, oxidation, photolytic and dry heat degradation conditions. The drug was very susceptible to degradation under hydrolysis and photolytic conditions, less susceptible to oxidation and stable under dry heat degradation condition. An acceptable separation of drug and its degradants was achieved by using a C-18 column and mobile phase composed of ammonium acetate buffer (pH 3.2)—acetonitrile (55: 45, v/v). Flow rate was 1 mL/min and detection wavelength was set at 303 nm. Retention time of drug was found to be 6.6 min and analysis can be completed within 10 min. The method was validated with respect to linearity, precision, accuracy, robustness, LOD and LOQ as per ICH. The method was linear (R² = 0.996) in the range of 2.5–250 μg/mL. The recovery was in the range from 99.2–100.2%.     

Thermodynamics of binary mixtures: excess volumes of mixing of some binary 1,2-dichloroethane mixtures

The excess volumes, V^E, of some binary 1,2-dichloroethane mixtures have been determined at 30°C. The data have been examined for Cell model theory of Prigogine and Flory's theory. Both theories have been found to fail to fit the results with useful accuracy.     

Dielectric and optical rotatory power investigations of an antiferroelectric liquid crystal 12OF1M7 in a homeotropic cell: implications for models of the structure of ferrielectric phases

The antiferroelectric liquid crystal (AFLC) under investigation possesses different helical smectic phases. Measurements of the optical rotatory power (ORP) of these phases have elucidated the quality of this method for finding the phase transitions between several phases and for investigating their helical structure. The optical rotatory power as a function of temperature for seven wavelengths of light in the range 441 to 665 nm was measured for different phases of the AFLC material investigated, (R)-1-methylheptyl 4-(4'-n-dodecyloxybiphenyl-4-yl-carbonyloxy)-3-fluorobenzoate, with acronym 12OF1M7. The values of the pitch and the optical anisotropy in the plane of the smectic layers for the FiLC (SmC*_FI3) phase and SmC*_Aphase have been calculated from the ORP data. The results of the ORP rule out the simple clock model for describing the structure of the SmC* (SmC*_I1) and AF (SmC*_FI2) phases. The results for these phases can be explained either in terms of the modified Ising model or the highly distorted clock model. The ORP measurements establish the existence of SmC*_FI3 found already from dielectric, polarization and polarized IR spectroscopy.     

A pentaquinone-based 4-2 bit photonic encoder

A new pentaquinone-based chemosensor armed with phenolic moieties has been synthesized. The fluorescence behaviour of the chemosensor in the presence of different chemical inputs mimics the functions of a digital encoder.     

Di­chloro­bis(1,2‐phenyl­enedi­amine)­nickel(II)

The title compound, [NiCl₂(C₆H₈N₂)₂], contains centrosymmetric mol­ecules with two phenyl­ene­di­amine ligands coordinated in a bidentate fashion. The Ni—N distances are 2.088 (1) and 2.096 (1) Å, and the Ni—Cl distance of 2.4635 (4) Å. The plane of each phenyl­enedi­amine mol­ecule makes a dihedral angle of 26.53 (7)° with the NiN₄ plane. Extensive hydrogen bonding leads to distinct cleavage in the bc plane.     

A novel synthesis of hexakis(trifluoromethyl)cyclotriphosphazene. Single-crystal X-ray structures of N3P3(CF3)6 and N3P3F6

Reaction of hexafluorocyclotriphosphazene (N3P3F6) with trimethyl(trifluoromethyl)silane in the presence of a catalytic amount of cesium fluoride in THF produced hexakis(trifluoromethyl)cyclotriphosphazene [N3P3(CF3)6] in 90% isolated yield. N3P3(CF3)6 is fully characterized by melting point, IR, NMR (19F, 13C, 31p), MS, and elemental analysis data. Single-crystal X-ray structures of N3P3(CF3)6 and N3P3F6 are reported.     

Synthesis of p-tert-Butylcalix[4] Arenes with Diester Bridge Spanning the 1,3-(Distal) Positions on the Lower Rim

Abstract

p-tert-Butylcalix[4]crown ether esters have been synthesized in good yield using two synthetic methods.     

Biaxial order and a rotation of the minor director in the nematic phase of an organo-siloxane tetrapode by the electric field

Biaxiality in the nematic phase for a liquid crystalline tetrapode made up of organo-siloxanes mesogens is investigated using polarized infrared spectroscopy. An ordering of the minor director for the homeotropically aligned sample is found to depend on the amplitude of the in-plane electric field. On increasing the in-plane electric field, the minor director, lying initially along the rubbing direction, rotates to the direction of the applied field. The scalar order parameters of the second rank tensor are found to depend significantly on the strength of the electric field. A most significant increase is found in the nematic order parameter and in the parameter that characterizes the phase biaxiality.