The kinetics of the decomposition of ammonium perchlorate (AP) in the presence of rare earth oxides, yttrium oxide (Y2O3) and lanthanum oxide (La2O3) as catalysts have been investigated. The Prout-Tompkins and contracting-cube equations have been found to fit the isothermal thermogravimetry data of catalysed AP decomposition. Gases evolved during catalytic decomposition of AP were analysed by infrared spectroscopy by matrix isolation technique. The mechanism of the catalysed thermal decomposition of AP has also been discussed in terms of an electron transfer process.
Authors:H. M. Patil, D. K. Sawant, D. S. Bhavsar, J. H. Patil and K. D. Girase
The growth of neodymium tartrate crystals was achieved in silica gel by single diffusion method. Optimum conditions were established for the growth of good quality crystals. Fourier transform infrared (FT-IR) spectroscopic study indicates the presence of water molecules and tartrate ligands and suggests that tartrate ions are doubly ionised. The thermal behaviour of the material was studied using thermogravimetry (TG), differential thermal analysis (DTA), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC). Thermogravimetric analysis support the suggested chemical formula of the grown crystal to be Nd2(C4H4O6)3·7H2O, and the presence of seven water molecules as water of hydration. It is shown that the material is thermally stable up 45 °C beyond which it decomposes through many stages till the formation of neodymium oxide (Nd2O3) at 995 °C. The decomposition pattern is reported to be typical of a hydrated metal tartrate.
Authors:D. K. Sawant, H. M. Patil, D. S. Bhavsar, J. H. Patil and K. D. Girase
In this study, calcium cadmium tartrate single crystals were grown in silica gel at ambient temperature. Effects of various parameters like gel pH, gel aging, gel density, and concentration of reactants on the growth of these crystals were studied. Crystals having different morphologies and habits were obtained. Transparent, diamond-like pyramidal-shaped crystals of calcium cadmium tartrate were obtained. Some of the crystals obtained were faint yellowish, with some milky white crystals being attched to them due to fast growth rate; faces are well developed and polished. The grown crystals were characterized by thermoanalytic techniques (TG, DTA, and DTG), and powder X-ray diffraction (XRD). The crystal system is confirmed to be orthorhombic having lattice parameters a = 7.9411 Å, b = 7.0396 Å, and c = 6.7271 Å as determined by powder XRD analysis. TG, DTA, and DTG analyses show a remarkable thermal stability. The results of these observations are described and discussed.
Authors:V. P. Rane, K. R. Patil, J. N. Sangshetti, R. D. Yeole and D. B. Shinde
A novel stability-indicating reversed-phase (RP) HPLC method has been developed and validated for quantitative analysis of eplerenone in the bulk drug and in a pharmaceutical dosage form. Use of a 250 mm × 4.6 mm, 5-μm particle, C18 column with 55:45 (v/v) 50 mM ammonium acetate buffer (pH 7)-acetonitrile as isocratic mobile phase enabled separation of the drug from its degradation products. UV detection was performed at 240 nm. The method was validated for linearity, accuracy (recovery), precision, specificity, and robustness. The linearity of the method was excellent over the range 10–100 μg mL−1 (correlation coefficient 0.999). The limits of detection and quantification were 0.019 and 0.053 μg mL−1, respectively. Recovery of eplerenone from the pharmaceutical dosage form ranged from 100.97 to 101.25%. Eplerenone was subjected to stress conditions (hydrolysis (acid, base), oxidation, photolysis, and thermal degradation) and the stressed samples were analysed by use of the method. Degradation was observed in acid, base, and 30% H2O2. The drug was stable under the other stress conditions investigated. The degradation products were well resolved from main peak. The forced degradation studies prove the stability indicating power of the method.
Authors:S. P. Patil, D. B. Kalgutkar, N. Jaychandran and V. K. P. Unny
An improved method for the preparation of [14C]thiourea of high radiochemical purity is described. [14C]thiourea is prepared by the barium cyanamide route and is purified by vacuum-sublimation. The labeled product showed ammonium
[14C]thiocyanate as a radiochemical impurity in the range of 2-4%. This was further purified by silica-gel column chromatography
to get the product having more than 99% radiochemical purity.
Authors:S. P. Patil, D. B. Kalgutkar, N. Jayachandran and V. K. P. Unny
An attractive and simple method has been developed for the preparation of ammonium [14C]thiocyanate from [14C]thiourea which eliminates the necessity of handling highly hazardous potassium [14C] cyanide. [14C]thiourea was isomerized to ammonium [14C]thiocyanate by heating the aqueous solution of thiourea (12%) in a sealed tube at 160 °C for 24 hours. The product formed was purified by silica-gel column chromatography. A radiochemical yield of 92.7% was obtained based on [14C]thiourea. The specific activity of the product obtained was 53.3 mCi/mmol (1.97 GBq/mmol) and the radiochemical purity was greater than 99%. This method has not been reported so far for the production of this labeled compound.
Authors:D. H. Nagore, V. K. Ghosh, M. J. Patil and A. M. Wahile
This paper describes a new, simple, precise, and accurate HPTLC method for quantification of (−)-epicatechin in the leaves of Cassia fistula. The leaves were separately extracted with methanol and water by both maceration and hot extraction (Soxhlet apparatus). Chromatographic separation of the drug was performed on aluminium foil silica gel 60 F254 plates with toluene-ethyl acetate-formic acid-methanol 20:12:4:4 (v/v) as mobile phase. Densitometric evaluation of the separated zone was performed at 280 nm. Epicatechin in the extract was satisfactorily resolved with RF 0.22 ± 0.02. The accuracy and reliability of the method were assessed by evaluation of linearity (200–800 ng per band), precision (method precision RSD 1.42% and instrumental precision RSD 1.12%), accuracy (98.12%), and specificity in accordance with ICH guidelines.
Authors:S. L. Krishnamurthy, S. K. Sharma, D. K. Sharma, P. C. Sharma, Y. P. Singh, V. K. Mishra, D. Burman, B. Maji, B. K. Bandyopadhyay, S. Mandal, S. K. Sarangi, R. K. Gautam, P. K. Singh, K. K. Manohara, B. C. Marandi, D. P. Singh, G. Padmavathi, P. B. Vanve, K. D. Patil, S. Thirumeni, O. P. Verma, A. H. Khan, S. Tiwari, M. Shakila, A. M. Ismail, G. B. Gregorio and R. K. Singh
Genotype × environment (G × E) interaction effects are of special interest for identifying the most suitable genotypes with respect to target environments, representative locations and other specific stresses. Twenty-two advanced breeding lines contributed by the national partners of the Salinity Tolerance Breeding Network (STBN) along with four checks were evaluated across 12 different salt affected sites comprising five coastal saline and seven alkaline environments in India. The study was conducted to assess the G × E interaction and stability of advanced breeding lines for yield and yield components using additive main effects and multiplicative interaction (AMMI) model. In the AMMI1 biplot, there were two mega-environments (ME) includes ME-A as CARI, KARAIKAL, TRICHY and NDUAT with winning genotype CSR 2K 262; and ME-B as KARSO, LUCKN, KARSA, GOA, CRRI, DRR, BIHAR and PANVE with winning genotypes CSR 36. Genotypes CSR 2K 262, CSR 27, NDRK 11-4, NDRK 11-3, NDRK 11-2, CSR 2K 255 and PNL 1-1-1-6-7-1 were identified as specifically adapted to favorable locations. The stability and adaptability of AMMI indicated that the best yielding genotypes were CSR 2K 262 for both coastal saline and alkaline environments and CSR 36 for alkaline environment. CARI and PANVEL were found as the most discernible environments for genotypic performance because of the greatest GE interaction. The genotype CSR 36 is specifically adapted to coastal saline environments GOA, KARSO, DRR, CRRI and BIHAR and while genotype CSR 2K 262 adapted to alkaline environments LUCKN, NDUAT, TRICH and KARAI. Use of most adapted lines could be used directly as varieties. Using them as donors for wide or specific adaptability with selection in the target environment offers the best opportunity for widening the genetic base of coastal salinity and alkalinity stress tolerance and development of adapted genotypes. Highly stable genotypes can improve the rice productivity in salt-affected areas and ensure livelihood of the resource poor farming communities.