scholarly journals The Influence of Ionizing Radiation, Temperature, and Light on Eplerenone in the Solid State

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Katarzyna Dettlaff ◽  
Magdalena Ogrodowczyk ◽  
Witold Kycler ◽  
Agnieszka Dołhań ◽  
Barbara Ćwiertnia ◽  
...  
Keyword(s):  
Electron Beam ◽  
Ionizing Radiation ◽  
Degradation Products ◽  
Standard Dose ◽  
High Energy ◽  
Hplc Method ◽  
Stress Factors ◽  
Great Resistance ◽  
High Doses ◽  
Dsc Curves

Eplerenone was subjected to the influence of ionizing radiation in the form of a high-energy electron beam (25–400 kGy), high temperature (90°C RH 0% and 60°C RH 76.4%), and light (6 mln lux h). An HPLC method was used to determine the content of eplerenone and to establish the impurity profile of all samples. As eplerenone was found to be a compound of great resistance to the above stress factors with the exception of high doses of ionizing radiation (≥200 kGy) when its degradation was above 1%, it is possible to sterilize eplerenone by radiation method with the standard dose of 25 kGy. Based on the analysis of impurities and degradation products, the mechanism of radiodegradation was demonstrated to differ from the mechanisms of photo- and thermodegradation. The observation that the DSC curves for the nondegraded and degraded samples of eplerenone were significantly different only under exposure to the electron beam confirmed the applicability of DSC for studies of radiolytic degradation of eplerenone.

Effects of High-Energy Ions on Synthetic Quartz

1972 ◽  
Vol 30 ◽  
pp. 544-545
Author(s):  
Joseph J. Comer ◽  
Charles Bergeron ◽  
Lester F. Lowe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Energy ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
High Energy Ions ◽  
Diffraction Patterns ◽  
Dauphiné Twinning ◽  
Beam Damage

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.

Synthesis and Characterization of Potential and Degraded Impurities of Regadenoson

2020 ◽  
Vol 16 (8) ◽  
pp. 1130-1139
Author(s):  
Singaram Sathiyanarayanan ◽  
Chidambaram Subramanian Venkatesan ◽  
Senthamaraikannan Kabilan
Keyword(s):  
Mass Spectra ◽  
Degradation Products ◽  
Hplc Method ◽  
Forced Degradation ◽  
Spectroscopic Techniques ◽  
A2a Adenosine Receptor ◽  
Degradation Study ◽  
Related Substances ◽  
Adenosine Receptor Agonist

Background: Regadenoson is an A2A adenosine receptor agonist that is a coronary vasodilator and commonly used as a pharmacologic cardiac stressing agents. Methods: HPLC method was used for the analysis of related substances. The degraded impurities during the process were isolated and characterized by IR, Mass and NMR spectral analysis. Results: Forced degradation study of regadenoson under conditions of hydrolysis (neutral, acidic and alkaline) and oxidations suggested in the ICH Q1A(R2) was accomplished. The drug showed significant degradation under all the above conditions. On the whole, five novel degradation products were found under diverse conditions along with process related impurities which were not reported earlier. Conclusion: All the degradation products were well characterized by using advanced spectroscopic techniques like IR, 1H NMR, 13C NMR and Mass spectra. The identification of these impurities will be productive for the quality control during the production and stability behavior of the regadenoson drug substance.

scholarly journals Development and Validation of Stability-Indicating RP-HPLC Method for the Estimation of Lenalidomide and its Impurities in Oral Solid Dosage Form

2019 ◽  
Vol 35 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Somana Siva Prasad ◽  
G. V. Krishna Mohan ◽  
A. Naga Babu
Keyword(s):  
Limit Of Detection ◽  
Degradation Products ◽  
Pharmaceutical Formulations ◽  
Hplc Method ◽  
Stability Robustness ◽  
Rp Hplc ◽  
Mobile Phases ◽  
Limit Of Quantitation ◽  
Successful Separation ◽  
Quality By Design Approach

In this study, a novel, simple and precise RP-HPLC method has been developed for the quantitative analysis of Lenalidomide (LLM) in pharmaceutical formulations using analytical quality by design approach. An X-bridge-C18 column (150 mm × 4.6 mm × 3.5 µ) with mobile phases containing a Potassium dihydrogen orthophosphate anhydrous buffer and methanol in the ratio of (90:10 v/v) and (35:65 v/v) are used for the estimation of LLM and its degradation products. The flow rate of 0.8 mL/min is maintained and all degradation studies are performed at 210 nm using photodiode array (PDA) detector. Method Validation is carried out according to International Council for Harmonisation (ICH) guidelines and the parameters namely; precision, accuracy, specificity, stability, robustness, linearity, limit of quantitation (LOQ) and limit of detection (LOD) are evaluated. The present developed RP-HPLC method shows the purity angle of peaks is less than their threshold angle, signifying that it to be suitable for stability studies. Hence, the developed method can be used for the successful separation of LLM and its impurities in the pharmaceutical dosage formulations.

scholarly journals The Structure and Mechanical Properties of Hemp Fibers-Reinforced Poly(ε-Caprolactone) Composites Modified by Electron Beam Irradiation

2021 ◽  
Vol 11 (12) ◽  
pp. 5317
Author(s):  
Rafał Malinowski ◽  
Aneta Raszkowska-Kaczor ◽  
Krzysztof Moraczewski ◽  
Wojciech Głuszewski ◽  
Volodymyr Krasinskyi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Beam ◽  
Impact Strength ◽  
Flexural Modulus ◽  
Natural Fibers ◽  
High Energy ◽  
Electron Radiation ◽  
Elongation At Break ◽  
Hemp Fibers

The need for the development of new biodegradable materials and modification of the properties the current ones possess has essentially increased in recent years. The aim of this study was the comparison of changes occurring in poly(ε-caprolactone) (PCL) due to its modification by high-energy electron beam derived from a linear electron accelerator, as well as the addition of natural fibers in the form of cut hemp fibers. Changes to the fibers structure in the obtained composites and the geometrical surface structure of sample fractures with the use of scanning electron microscopy were investigated. Moreover, the mechanical properties were examined, including tensile strength, elongation at break, flexural modulus and impact strength of the modified PCL. It was found that PCL, modified with hemp fibers and/or electron radiation, exhibited enhanced flexural modulus but the elongation at break and impact strength decreased. Depending on the electron radiation dose and the hemp fibers content, tensile strength decreased or increased. It was also found that hemp fibers caused greater changes to the mechanical properties of PCL than electron radiation. The prepared composites exhibited uniform distribution of the dispersed phase in the polymer matrix and adequate adhesion at the interface between the two components.

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