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Recent Advances in Drug Delivery and... 2022
Topics: Powders; Particle Size; Chemistry, Pharmaceutical; Pharmacy
PubMed: 35794746
DOI: 10.2174/2667387816666220704124635 -
The European Physical Journal. E, Soft... Jun 2022Size segregation will lead to stratification of a particle system. At present, people have not fully understood the segregation mechanism. In this work, we have studied...
Size segregation will lead to stratification of a particle system. At present, people have not fully understood the segregation mechanism. In this work, we have studied the size segregation behavior of two-component disk particles in chute flows. The effects of particle size ratio η, particle density ρ, static friction coefficient μ and chute angle α on size segregation are discussed. We use the discrete element method to simulate and calculate the force of disk large particles during segregation. Results show that the 'squeeze expulsion' mechanism plays a key role in the size segregation of a disk particle flow. We establish a physical model of 'squeeze expulsion' of disk particles and obtain the conditions for the formation of 'squeeze expulsion' mechanism.
Topics: Friction; Humans; Particle Size
PubMed: 35699803
DOI: 10.1140/epje/s10189-022-00207-0 -
Journal of Controlled Release :... Aug 2016Adequate characterization of NPs (nanoparticles) is of paramount importance to develop well defined nanoformulations of therapeutic relevance. Determination of particle... (Review)
Review
Adequate characterization of NPs (nanoparticles) is of paramount importance to develop well defined nanoformulations of therapeutic relevance. Determination of particle size and surface charge of NPs are indispensable for proper characterization of NPs. DLS (dynamic light scattering) and ZP (zeta potential) measurements have gained popularity as simple, easy and reproducible tools to ascertain particle size and surface charge. Unfortunately, on practical grounds plenty of challenges exist regarding these two techniques including inadequate understanding of the operating principles and dealing with critical issues like sample preparation and interpretation of the data. As both DLS and ZP have emerged from the realms of physical colloid chemistry - it is difficult for researchers engaged in nanomedicine research to master these two techniques. Additionally, there is little literature available in drug delivery research which offers a simple, concise account on these techniques. This review tries to address this issue while providing the fundamental principles of these techniques, summarizing the core mathematical principles and offering practical guidelines on tackling commonly encountered problems while running DLS and ZP measurements. Finally, the review tries to analyze the relevance of these two techniques from translatory perspective.
Topics: Nanoparticles; Particle Size; Scattering, Radiation; Surface Properties
PubMed: 27297779
DOI: 10.1016/j.jconrel.2016.06.017 -
Journal of Chromatography. A Jul 2021Microfluidics devices are widely used for particle separation. Deterministic Lateral Displacement (DLD) is a passive method for particle separation. DLD devices mainly...
Microfluidics devices are widely used for particle separation. Deterministic Lateral Displacement (DLD) is a passive method for particle separation. DLD devices mainly separate particles based on their sizes. There are two main modes of movement in DLD arrays; the small particles move in a zigzag path, and the larger particles separate in the displacement mode. It is therefore important to estimate the critical particle size for the transition of modes before the fabrication of DLD devices. Asymmetry in the design of the arrays can affect the fluid behavior and the critical particle size. In this study, we investigate the effects of the asymmetry caused by changing the downstream gap size to the lateral gap size ratio on the fluid behavior and particle trajectories in DLD devices. We used two dimensional (2D) Finite Element Method (FEM) to study the variations in the flow lane's widths and combined the fluid analysis with structural mechanics to model the contact between the particles and the posts in DLD arrays. We simulated the spherical particles' trajectories with diameters ranging from 1.4 to 19.2 μm in circular post DLD arrays with a lateral gap size of 20μm. In contrast to the previous works, in these simulations, the effect of particle movement on the fluid flow profiles was considered. We evaluated the particle movement mode in seven different values of the downstream gap size to the lateral gap size ratio (ranging from 0.5 to 2) and eight different row shift fraction (ranging from 0.025 to 0.3). Our simulations showed that increasing the value of the downstream gap while the lateral gap is fixed increases the veering flow rate and width. By finding the particle with the largest diameter in the zigzag mode and the particle with the smallest diameter in the displacement mode, we estimated the critical particle diameter for each value of shift fraction in different values of the downstream gap to the lateral gap size ratio. Using these data, a curve was fitted for predicting the critical particle diameter in each ratio. Finally, a more general form of the formula for the critical particle diameter was proposed, which considers an extra parameter compared to the previous ones. The results of this study can lead to a better understanding of DLD devices' functions and, thus, save time and costs for better designs and experiments.
Topics: Computer Simulation; Lab-On-A-Chip Devices; Microfluidic Analytical Techniques; Particle Size
PubMed: 34034107
DOI: 10.1016/j.chroma.2021.462216 -
Nature Feb 1948
Topics: Particle Size
PubMed: 18904448
DOI: 10.1038/161313a0 -
Pharmaceutical Research Dec 2022Spray dried dispersion particle size is a critical quality attribute that impacts bioavailability and manufacturability of the spray drying process and final dosage...
Spray dried dispersion particle size is a critical quality attribute that impacts bioavailability and manufacturability of the spray drying process and final dosage form. Substantial experimentation has been required to relate formulation and process parameters to particle size with the results limited to a single active pharmaceutical ingredient (API). This is the first study that demonstrates prediction of particle size independent of API for a wide range of formulation and process parameters at pilot and commercial scale. Additionally we developed a strategy with formulation and target particle size as inputs to define a set of "first to try" process parameters. An ensemble machine learning model was created to predict dried particle size across pilot and production scale spray dryers, with prediction errors between -7.7% and 18.6% (25th/75th percentiles) for a hold-out evaluation set. Shapley additive explanations identified how changes in formulation and process parameters drove variations in model predictions of dried particle size and were found to be consistent with mechanistic understanding of the particle formation process. Additionally, an optimization strategy used the predictive model to determine initial estimates for process parameter values that best achieve a target particle size for a provided formulation. The optimization strategy was employed to estimate process parameters in the hold-out evaluation set and to illustrate selection of process parameters during scale-up. The results of this study illustrate how trained regression models can reduce the experimental effort required to create an in-silico design space for new molecules during early-stage process development and subsequent scale-up.
Topics: Chemistry, Pharmaceutical; Particle Size; Powders
PubMed: 35986124
DOI: 10.1007/s11095-022-03370-3 -
PloS One 2022We experimentally created a particle size dataset that is based on reduction sequences and raw materials typical of the Middle and Later Stone Age in southern Africa....
We experimentally created a particle size dataset that is based on reduction sequences and raw materials typical of the Middle and Later Stone Age in southern Africa. The reason for creating this new dataset is that current particle size frameworks are based, almost exclusively, on flint and western European knapping methods. We produced the dataset using knapping methods and raw materials frequently encountered in the southern African archaeological record because we wanted to test whether it has the same distribution as particle size datasets experimentally created in Europe, and to initialise the production of a database for use in the analysis of lithic assemblages from southern African Late Pleistocene deposits. We reduced 117 cores of quartz, quartzite, jasper, chalcedony, hornfels, and rhyolite. The knapping methods selected were unidirectional, discoidal, Levallois recurrent and bipolar flaking. In this article we compare this new particle size distribution dataset with the results obtained from previous experiments. We found that the southern African dataset shows a wider size range distribution, which seems to be explained by differences in knapping methods and raw materials. Our results show that there is overlap between the distribution of the southern African experimental knapping dataset and the sorting experiment conducted by Lenoble on flint artefacts in a runoff context. This article shows that a particle size analysis is not sufficient on its own to assess the perturbation of an archaeological assemblage and must be coupled with other analytical tools.
Topics: Particle Size; Technology; Europe; Archaeology; Africa, Southern; Fossils
PubMed: 36584160
DOI: 10.1371/journal.pone.0278867 -
Molecules (Basel, Switzerland) Apr 2022The assessment of active pharmaceutical ingredient (API) particle size and morphology is of great importance for the pharmaceutical industry since it is expected to...
The assessment of active pharmaceutical ingredient (API) particle size and morphology is of great importance for the pharmaceutical industry since it is expected to significantly affect physicochemical properties. However, very few methods are published for the determination of API morphology and particle size of film-coated (FC) tablets. In the current study we provide a methodology for the measurement of API particle size and morphology which could be applied in several final products. Bismuth Oxide 120 mg FC Tabs were used for our method development, which contain bismuth oxide (as tripotassium dicitratobismuthate (bismuth subcitrate)) as the active substance. The sample preparation consists of partial excipient dissolution in different solvents. Following this procedure, the API particles were successfully extracted from the granules. Particle size and morphology identification in Bismuth Oxide 120 mg FC Tabs was conducted using micro-Raman mapping spectroscopy and ImageJ software. The proposed methodology was repeated for the raw API material and against a reference listed drug (RLD) for comparative purposes. The API particle size was found to have decreased compared to the raw API, while the API morphology was also affected from the formulation manufacturing process. Comparison with the RLD product also revealed differences, mainly in the API particle size and secondarily in the crystal morphology.
Topics: Bismuth; Excipients; Particle Size; Tablets
PubMed: 35458800
DOI: 10.3390/molecules27082602 -
International Journal of Pharmaceutics Aug 2023The effect of particle size on the sublimation behavior of butylhydroxytoluene (BHT) was investigated when BHT was included as antioxidant in tablets. Sublimation of...
The effect of particle size on the sublimation behavior of butylhydroxytoluene (BHT) was investigated when BHT was included as antioxidant in tablets. Sublimation of pure BHT was found to be independent of its particle size, with pore formation on the surface of all tablets after storage at room temperature and above. Moreover, a higher residual BHT content after storage was detected in tablets containing a larger size fraction. X-ray µCT scans revealed the formation of peripherally larger pores at higher BHT particle sizes, implying a slower sublimation rate in the tablet core. A stability study indicated an increase in the extent of BHT sublimation at higher temperature and longer exposure time for all size fractions. The influence of BHT particle size was more pronounced when the tablets were stored at higher temperature, but the effect receded with longer exposure time. Similar trends were seen in film-coated tablets. Due to the short exposure time to elevated temperatures, a gradient in pore size was also observed at smaller particle sizes, with peripheral pores being larger in uncoated tablets. Superficial pores disappeared when a film coating was deposited onto the tablets. After storage of the film-coated tablets, less BHT had sublimated compared to the uncoated tablet. The coating layer did not prevent sublimation, but the process was slowed down.
Topics: Antioxidants; Butylated Hydroxytoluene; Particle Size; Tablets; Tablets, Enteric-Coated
PubMed: 37488059
DOI: 10.1016/j.ijpharm.2023.123264 -
PDA Journal of Pharmaceutical Science... 2021Traditional statistical analyses of subvisible particle data are usually based on either descriptive statistics, normal-based methods, or standard Poisson models. These...
Traditional statistical analyses of subvisible particle data are usually based on either descriptive statistics, normal-based methods, or standard Poisson models. These methods often do not adequately describe the counts or particle size distribution. They usually ignore relevant information represented in the data, such as count correlation. Therefore, any meaningful analyses of subvisible particle data require a reasonable representation of counts and particle size distribution and the correlation in the data. Such comprehensive approaches are not widely available or used when analyzing subvisible particle data. In this article, we propose the use of generalized linear mixed models to analyze the counts and the particle size distribution of subvisible particle data. These models make optimal use of the information in the data and allow flexible approaches for the analyses of a wide range of data structures. They are readily accessible to practitioners through the use of modern statistical software. These models are demonstrated with two numerical examples using two different data structures.
Topics: Linear Models; Models, Statistical; Particle Size
PubMed: 33199515
DOI: 10.5731/pdajpst.2020.011510