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- Author or Editor: V. Deshmukh x
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Abstract
Bremsstrahlung spectral distributions have been experimentally measured for thick targets of lead and tantalum at 6 MeV electron energy, using Compton scattering technique. The experimental results are in agreement with the theoretical results.
Summary
A simple, precise, and accurate HPTLC method has been established for simultaneous quantification of aspirin, atorvastatin calcium and clopidogrel bisulphate in the bulk drug and in a capsule dosage form. Chromatographic separation of the drugs was performed on aluminium foil plates precoated with silica gel 60 F254, with toluene-methanol-formic acid 6.5:3.5:0.1 (v/v) as mobile phase. Densitometric evaluation of the separated zones was performed at 254 nm. The three drugs were satisfactorily resolved with R F ± SD values 0.26 ± 0.01, 0.47 ± 0.01, and 0.78 ± 0.01 for aspirin, atorvastatin calcium, and clopidogrel bisulphate, respectively. The method was validated for linearity, specificity, accuracy, precision, and robustness, in accordance with ICH guidelines. Results from recovery studies indicated acceptable recovery of the drugs from the capsule dosage form. The intra-day and inter-day relative standard deviations were in the ranges 0.17–0.73% and 0.46–1.03% for aspirin, 0.36–0.87% and 0.44–0.62% for atorvastatin calcium, and 0.25–0.69% and 0.35–0.94% for clopidogrel bisulphate. The method proved to be a rapid and cost-effective quality-control tool for routine simultaneous analysis of aspirin, atorvastatin calcium, and clopidogrel bisulphate in the bulk drug and in a capsule formulation.
Expression of antibodies or antibody fragments in plants is a useful tool for producing active antibody derivatives for diagnostic or pharmaceutical purposes as well as for immunomodulation. We investigated the effect of cellular expression site on the stability and yield of double-stranded RNA (dsRNA)-specific single-chain Fv-fragments (scFv) in transgenic tobacco. Two antibodies (J2 and P6) belonging to the V23(J558) heavy chain variable gene family but differing in the light chain variable domain were used. scFvs were targeted to the cytoplasm - with or without anchoring them in the plasma membrane -, into the endoplasmic reticulum (ER) and to the apoplast. Although high mRNA concentrations were detected in all cases, scFv proteins accumulated only when scFvs were made ER-resident by appropriate signal sequences. When the ER retention signal was removed to allow scFv-secretion to the apoplast, no scFv-proteins were detected. Despite the strong homology of the VH-sequences of J2 and P6 antibodies, only P6 provided a stable scFv scaffold for intracytoplasmic expression. J2-scFv could not be stabilised either by adding a C-terminal stabilisation signal or by anchoring the protein on the cytoplasmic side of the plasma membrane (PM). It was found that dsRNA-specific J2-scFvs are active in vivo and enhance Potato Virus Y induced symptoms in infected tobacco. This is the first report describing the expression and biological effect of RNA-specific antibodies in plants.
Summary
This paper includes the development of a novel, systematic, quality by design (QbD)-based high-performance thin-layer chromatography (HPTLC) method for the simultaneous estimation of torsemide and eplerenone. Chromatographic separation was carried out on aluminum-backed silica gel 60 F254 plates using toluene-ethyl acetate-glacial acetic acid (7:3:0.1, V/V) as the mobile phase. UV detection was carried out at 297 nm for torsemide and 247 nm for eplerenone. A 3-factor 17-run regular 3-level factorial design was applied to factor screening studies, and Box–Behnken design was utilized for optimization of the experimental parameters of HPTLC for obtaining anticipated chromatographic conditions. Risk assessment was executed to understand the basic method parameters. From the risk assessment, 3 independent parameters, such as band length, saturation time, and wavelength, were selected and studied for the impact of these 3 parameters on the responses. The method yields compact and well-resolved band at R F = 0.24 ± 0.02 for torsemide and R F = 0.50 ± 0.02 for eplerenone. In the linear regression analysis carried out for torsemide and eplerenone, the regression coefficient was found to be r 2 = 0.999 for torsemide and r 2 =0.995 for eplerenone. The method was validated for validation parameters like accuracy, precision, robustness, limit of detection, and limit of quantification as per the International Conference on Harmonization (ICH) guidelines.
