Scintillation Detectors
Michael Ljungberg in Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
The heavier LuAP:Ce (LuAlO3:Ce) is a material which, just like LSO and LYSO above, is of interest in PET. LuAP:Ce has the highest linear attenuation coefficient of all scintillator materials, even larger than BGO, and with a decay time of only 17 ns it could be a very attractive scintillator material in PET. The LuAP has however had difficulties competing with the other Lu-based scintillators. Possibly due to manufacturing problems, the performance of LuAP has varied between suppliers. While some have reported poor energy resolution, low light output in combination with self-absorption of its scintillation light, and non-uniform crystals, some have reported energy resolutions of around 7 per cent in combination with excellent nonproportionality [49]. The difficulty in producing high quality crystals has resulted in a high price for this material. The mixed LuYAP:Ce (Lu,Y)AlO3:Ce scintillator has been developed to improve phase stability during crystallization and thereby enable a commercial product [50].
The Chemical Environment
Vilma R. Hunt, Kathleen Lucas-Wallace, Jeanne M. Manson in Work and the Health of Women, 2020
A technician in a hospital, biology, or chemistry laboratory devotes considerable time to processes involving organic compounds. Basic methods in frequent use are distillation, crystallization, extraction, and chromatography. During the 1950s and early 1960s, extractions were performed with ethyl and diethyl ether, although their use was limited industrially because of the great fire-hazard potential. Common water-immiscible solvents were petroleum ether, benzene, carbon tetrachloride, chloroform, ethylene dichloride, butanol, and ligroin. In crystallization, a highly effective means of purifying a solid substance, the most common solvents used were the following: water, ligroin, methanol, benzene, ethanol (95%), chloroform, acetic acid, carbon tetrachloride, acetone, carbon disulfide, ether, toluene, petroleum ether, and aniline.
Nephrolithiasis: etiology, stone composition, medical management, and prevention
J Kellogg Parsons, E James Wright in The Brady Urology Manual, 2019
Crystallization: Stones are essentially salts that precipitate out of urineThe point of saturation of a salt in solution is called the solubility product (Ksp)When the product of the components of a salt (e.g. calcium and oxalate) exceeds Ksp, salt crystals will precipitate out of solutionCrystallization is based on Ksp, pH, and the presence of stone inhibitors and promotersSome stone inhibitors increase the concentration of stone components required for the crystals to precipitate out of solution (i.e. for the stone crystals to form).
Preparation and characterization of indomethacin loaded films by piezoelectric inkjet printing: a personalized medication approach
Published in Pharmaceutical Development and Technology, 2020
Muhammad Sohail Arshad, Aqeel Shahzad, Nasir Abbas, Ali AlAsiri, Amjad Hussain, Israfil Kucuk, M.-W. Chang, Nadeem Irfan Bukhari, Zeeshan Ahmad
Image analysis studies of IMC gave a clear description that how the drug was delivered. The phenomena of crystallization were clearly observed in this study. Images derived from electron microscopy, plane polarized microscopy, and light microscopy showed evident crystal growth. The change in number and shape of crystals at varying DPIs could also be observed here. This study explored the use of PVP to alter the rate of dissolution. Polyvinylpyrrolidone was used with type B ink which was printed in the same design (same DPIs and sheets). Image analysis showed that addition of PVP affected the crystals growth in these formulations and indicated that the PVP interacted with crystal growth. SEM, plane polarized, and light microscopy images clearly presented a pattern in which crystals of IMC were surrounded by polymer molecules and the phenomenon of caging could be observed.
Acoustic emission detection of crystallization in two forms: monohydrate and anhydrous citric acid
Published in Pharmaceutical Development and Technology, 2019
Xingjun Wang, Ying Huang, Thomas M. Michelitsch
As a key separation and purification process, crystallization is the first and probably the main unit operation dealing with solids in pharmaceutical industry. Crystallization is a complex process since many factors may affect the process of crystallization and the final quality of products. Apart from the reacting conditions, the properties of particulates, including the crystal size distribution (CSD), crystal habit, crystal structure, purity of particles, crystallinity and polymorphic state, have also significant impacts on the quality of crystallization (Wang et al. 2016). Due to the interdependence of these parameters, an online and real-time monitoring technique is required to collect representative data and provide further insight into process dynamics. This strategy coincides with the regimen of Process Analytical Technology (PAT) launched by Food and Drug Administration: the intrinsic quality of the product is achieved by critical quality-affecting attributes detection and avoiding any process deviations during the manufacturing (Poutiainen et al. 2012). In addition, some disadvantages of the product quality testing involving off-line laboratory analysis can be avoided such as expensive rework and disposal of out-of-specification products.
Particle engineering at the drug substance, drug product interface: a comprehensive platform approach to enabling continuous drug substance to drug product processing with differentiated material properties
Published in Drug Development and Industrial Pharmacy, 2019
Luke Schenck, Athanas Koynov, Aaron Cote
The routes outlined above involve maintaining purity of the isolated API. Other opportunities are created if allowances are made for introduction of additional materials to the crystallization process. The use of low levels (<1 wt%, and in some cases <0.1 wt%) of carefully selected additives to alter crystallization processes has been explored and shown to yield an array of options during crystallization. These additives would, of course, need to be pharmaceutically approved materials, generally involving polymers and surfactants. Additives have demonstrated the ability to alter crystal form [9,10] morphology [11–13], surface features [14], and growth rate [15,16]. Work has also been published showing changes in morphology between rods and rectangular plates along with potentially beneficial effects on compactability, and included spectroscopic evaluation of the component interactions that resulted in directed growth to alter particle morphology [17,18].
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