scholarly journals Effect of Radiation Sterilization on Alprenolol in the Solid State Studied by High-Performance Thin-Layer Chromatography

2010 ◽  
Vol 93 (3) ◽  
pp. 792-797
Author(s):  
Barbara Marciniec ◽  
Magdalena Ogrodowczyk ◽  
Anna Kwiecien′
Keyword(s):  
High Performance ◽  
Good Accuracy ◽  
High Energy ◽  
Degree Of Crystallinity ◽  
Radiation Sterilization ◽  
Good Precision ◽  
Solid Form ◽  
Layer Chromatography ◽  
Higher Doses ◽  
The Degree Of Crystallinity

Abstract The possibility of radiation sterilization of alprenolol (AL) has been studied. Irradiation of AL in solid form with a 25 kGy beam of electrons caused only an insignificant change in color that became more intense with increasing irradiation dose. Moreover, with increasing dose a decrease in pH, the content of water, and the degree of crystallinity were observed. AL in solid form was radiated with a high-energy electron beam (9.96 MeV) at doses from 25400 kGy and analyzed by HPTLC using the mobile phase methanolammonia 25 (99 + 1, v/v). Densitometric analysis was carried out directly from chromatograms at 270 nm. The applied method was validated and characterized by good precision (RSD = 3.95); good accuracy (80 level 100.15, 100 level 99.99, and 120 level 104.44); and low LOD (LOD = 0.52 g/zone and LOQ = 1.55 g/zone). Chromatograms recorded for samples irradiated at the doses of 25 kGy were unchanged, but at higher doses (100400 kGy) additional peaks corresponding to the radiodegradation products appeared (Rf = 0.24 and Rf = 0.40). The decrease in the concentration of AL was proportional to the applied radiation dose, and for 400 kGy the concentration of AL was 90.23. The calculated radiolytic yield of the radiodegradation process was G(AL) = 7.12 107 mol/J.

The Influence of Reinforcing Fibers on the Morphology and Crystallization of Thermoplastic Polymer Composites

1991 ◽  
Vol 255 ◽  
Author(s):  
Ludwig Rebenfeld ◽  
Glenn P. Desio ◽  
Veronika E. Reinsch
Keyword(s):  
High Performance ◽  
Crystallization Process ◽  
Polarized Light ◽  
Fiber Surface ◽  
Weight Fraction ◽  
Degree Of Crystallinity ◽  
Surface Finishes ◽  
Reinforcing Fibers ◽  
Glass Carbon ◽  
The Degree Of Crystallinity

AbstractSemi-crystalline thermoplastic polymers are being used increasingly as matrices in high performance fiber reinforced composites. The crystallization kinetics and morphology of these polymers have been studied extensively, but relatively little attention has been given to the effects of the reinforcing fibers on the crystallization process.We have studied the effects of glass, carbon and aramid fibers on the rates of crystallization, the degree of crystallinity, and the glass transition temperature of such typical thermoplastics as poly(phenylene sulfide) and poly(ethylene terephthalate). Based on the isothermal crystallization studies using DSC, we find that, in general, reinforcing fibers increase the rates of crystallization and decrease the degree of crystallinity, the extent of these effects being dependent on the weight fraction of fiber in the composite, the specific type of fiber, and the nature of surface finishes (sizes) that may have been applied.The spherulitic morphology that develops in these polymers during the crystallization process, as characterized by polarized light microscopy, is also affected by the reinforcing fibers. In many cases, transcrystalline regions develop near the fiber surface due to nucleation effects.

scholarly journals Novel Organic Material Induced by Electron Beam Irradiation for Medical Application

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 306 ◽  
Author(s):  
Adrian Barylski ◽  
Krzysztof Aniołek ◽  
Andrzej S. Swinarew ◽  
Sławomir Kaptacz ◽  
Jadwiga Gabor ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Absorbed Dose ◽  
Medical Application ◽  
High Energy ◽  
Polymer Chains ◽  
Degree Of Crystallinity ◽  
Beam Irradiation ◽  
The Impact ◽  
The Degree Of Crystallinity

This study analyzed the effects of irradiation of polytetrafluoroethylene (PTFE) containing 40% of bronze using an electron beam with energy of 10 MeV. Dosages from 26 to156 kGy (2.6–15.6 Mrad) were used. The impact of a high-energy electron beam on the thermal, spectrophotometric, mechanical, and tribological properties was determined, and the results were compared with those obtained for pure PTFE. Thermal properties studies showed that such irradiation caused changes in melting temperature Tm and crystallization temperature Tc, an increase in crystallization heat ∆Hc, and a large increase in crystallinity χc proportional to the absorbed dose for both polymers. The addition of bronze decreased the degree of crystallinity of PTFE by twofold. Infrared spectroscopy (FTIR) studies confirmed that the main phenomenon associated with electron beam irradiation was the photodegradation of the polymer chains for both PTFE containing bronze and pure PTFE. This had a direct effect on the increase in the degree of crystallinity observed in DSC studies. The use of a bronze additive could lead to energy dissipation over the additive particles. An increase in hardness H and Young’s modulus E was also observed. The addition of bronze and the irradiation with an electron beam improved of the operational properties of PTFE.

Identification of Radiodegradation Products of Acebutolol and Alprenolol by HPLC/MS/MS

2015 ◽  
Vol 98 (1) ◽  
pp. 46-50 ◽  
Author(s):  
Magdalena Ogrodowczyk ◽  
Katarzyna Dettlaff ◽  
Piotr Kachlicki ◽  
Barbara Marciniec
Keyword(s):  
Physicochemical Properties ◽  
High Energy ◽  
Al Content ◽  
High Energy Electrons ◽  
Β Blockers ◽  
Solid Form ◽  
Derivatives Of ◽  
Higher Doses ◽  
Sterilization Dose ◽  
Additional Product

Abstract Two therapeutically active compounds from the group of β-blockers, acebutolol (AC) and alprenolol (AL), in solid form were subjected to ionizing radiation emitted by a beam of high energy electrons from an accelerator with a standard sterilization dose of 25 kGy and in higher doses of 50–400 kGy. The effects of irradiation were detected by chromatographic methods (TLC, HPLC) and a hyphenated method (HPLC/MS/MS). No significant changes in the physicochemical properties of both compounds studied irradiated with 25 kGy were noted, but upon irradiation with the highest dose (400 kGy) the loss of AC and AL content determined by HPLC was 2.79 and 9.12%, respectively. The product of AC decomposition and the two products of AL decomposition were separated and identified by HPLC/MS/MS. It has been established that radiodegradation of AC and AL takes place by oxidation, leading to formation of the products of radiolysis, most probably alcohol derivatives of the β-blockers studied. The additional product that appears on radiodegradation of AL is probably formed as a result of two simultaneous reactions: oxidation and CH2 group elimination.

scholarly journals An insight on the process–property relationships of melt spun polylactic acid fibers

2019 ◽  
Vol 89 (23-24) ◽  
pp. 4959-4966 ◽  
Author(s):  
AM Ali ◽  
HM El-Dessouky
Keyword(s):  
Polylactic Acid ◽  
High Performance ◽  
Polarized Light ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Diffractometry ◽  
Wide Range ◽  
Innovative Materials ◽  
The Degree Of Crystallinity

Polylactic acid (PLA) fibers are receiving growing interest as one of the recent innovative materials being developed for various applications. The inherent biodegradability of PLA makes it highly attractive for the biomedical and health care sectors. PLA fibers need to be partially and/or highly oriented to allow high performance and readiness for a wide range of manufacturability. In this study, the structure and properties of PLA fibers, manufactured at different spinning speeds, were studied. Laser diffractometry, polarized light microscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to determine the diameter, birefringence, molecular orientation, enthalpy and degree of crystallinity of as-spun and drawn PLA fibers. The results of DSC and XRD showed that the degree of crystallinity of the PLA fibers is significantly improved for the drawn PLA fibers compared to the as-spun fibers and leveled off in the case of changing the take-up speeds of drawn fibers.

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