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Yalkowsky, Samuel H.; Bolton, Sanford

doi:10.1023/a:1015958209643

Cited by 67 publications

(6 citation statements)

References 1 publication

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“…The size of the particles in a solid powder is a critical property to monitor and control in many industries, especially in the pharmaceutical industry. Particle size directly impacts properties such as dissolution rate, mixing uniformity, and compaction behavior. − Methods commonly used to measure particle size include laser diffraction techniques and microscopy . Laser diffraction is typically used to measure particles nominally ranging from 0.2 to 2000 μm in size.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Particle Size and Polydispersity of Dicumarol Using Solid-State NMR Spectroscopy

Dempah

Lubach²,

Munson

2017

Mol. Pharmaceutics

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A variety of particle sizes of a model compound, dicumarol, were prepared and characterized in order to investigate the correlation between particle size and solid-state NMR (SSNMR) proton spin-lattice relaxation (H T) times. Conventional laser diffraction and scanning electron microscopy were used as particle size measurement techniques and showed crystalline dicumarol samples with sizes ranging from tens of micrometers to a few micrometers. Dicumarol samples were prepared using both bottom-up and top-down particle size control approaches, via antisolvent microprecipitation and cryogrinding. It was observed that smaller particles of dicumarol generally had shorter H T times than larger ones. Additionally, cryomilled particles had the shortest H T times encountered (8 s). SSNMR H T times of all the samples were measured and showed as-received dicumarol to have a T of 1500 s, whereas the H T times of the precipitated samples ranged from 20 to 80 s, with no apparent change in the physical form of dicumarol. Physical mixtures of different sized particles were also analyzed to determine the effect of sample inhomogeneity on H T values. Mixtures of cryoground and as-received dicumarol were clearly inhomogeneous as they did not fit well to a one-component relaxation model, but could be fit much better to a two-component model with both fast-and slow-relaxing regimes. Results indicate that samples of crystalline dicumarol containing two significantly different particle size populations could be deconvoluted solely based on their differences in H T times. Relative populations of each particle size regime could also be approximated using two-component fitting models. Using NMR theory on spin diffusion as a reference, and taking into account the presence of crystal defects, a model for the correlation between the particle size of dicumarol and its H T time was proposed.

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Section: Introductionmentioning

confidence: 99%

Characterization of the Particle Size and Polydispersity of Dicumarol Using Solid-State NMR Spectroscopy

Dempah

Lubach²,

Munson

2017

Mol. Pharmaceutics

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“…The size of the tablet core met the requirements of the Indonesian Pharmacopoeia [6]. Furthermore, the diameter of the tablet core was not more than three times and not less than fourthirds of the thickness of each tablet [6,22,23]. The tablet hardness test was conducted to measure the compactness of the pressure, i.e.…”

Section: Discussionmentioning

confidence: 99%

The Anti-Inflammatory Tablet Formulation of Coleus (Plectranthus Scutellariodes) Leaves Extract Using Kollicoat®protect Coating

Mustarichie

Ramdhani²,

Saptarini³

2022

Int J App Pharm

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Objective: The purpose of this study was to find the concentration of weight gain on the use of Kollicoat®Protect to produce coleus leaf extract film-coated tablets with good physical properties. Methods: Coleus extract was obtained by maceration using 70% ethanol. Tablet cores were prepared using the wet granulation method, then evaluated (uniformity of weight, size, hardness, friability, and disintegration time). Coated tablets were made in four variations of polymer weight gain, i.e. 5, 6, 7, and 8%. To determine the effect of the weight gain concentration of Kollicoat®Protect an evaluation of the coated tablets was carried out, i.e. the uniformity of weight, size, hardness, disintegration time, and physical appearance of the film-coated tablets. Results: The four variations (Film Coated Tablet, FCT 5, 6, 7, and 8%) in weight gain of film-coated tablets showed the physical appearance results per the applicable requirements. However, the physical observation test at room temperature showed the instability of the film-coated tablet. The qualitative analysis of thin-layer chromatography showed that the productive substances in the extracts, tablet cores, and film-coated tablets were still contained even though they had undergone several formulation stages. Conclusion: Film-coated tablets met the standards of the Indonesian Pharmacopoeia and the United States Pharmacopeia. After two weeks, there was slight instability in film-coated tablets at room temperature storage. The extract, tablet core, and film-coated tablet contain flavonoids.

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“…The Nador bentonite analyzed show a wide variation in particle size distribution; four particle size fractions were identified: clay (17.3%), silt (38.7%), sand (43.9%) and gravel (0.1%). The grain sizes of clay characterize by the uniformity coefficient or Hazen coefficient allows to express the spread of the curve granulometric, and the curvature coefficient is used to describe the shape of the particle size curve [30]. The particle size curves of the bentonite investigated is well spread out (Fig.…”

Section: Particle Distributionmentioning

confidence: 98%

Simultaneous adsorption behaviour of heavy metals from Oil Mill Wastewater onto natural clay

et al. 2021

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The present work reports the synergistic and inhibitory adsorption effects involved in the multicomponent adsorption of heavy metal ions (Fe (II), Pb (II)), and major elements from oil mill liquid waste (OMW) using natural bentonite as adsorbent cames from Nador (North-East Morocco). Morocco is one of the most olive oil producing Mediterranean countries. This industry, which is so beneficial to the national economy, leaves two toxic and non-biodegradable residues (liquid/solid). OMW or margin is a current liquid pollutant that has been listed by the United States Environmental Protection Agency (EPA). The classical methods used for phenol removal are expensive or limited to large-scale applications such as biological and thermal decomposition methods. The margins used in the studies were collected from a semimodern oil mill (Nador-Morocco). The results of the physicochemical analyses showed that the effluents of the oil mills showed that they are highly polluted, in particular the suspended solids, COD, and iron contents of around 154.82 (mg/l) and copper 31.72 (mg/l). Samples of OMW mixed with raw bentonites at different percentages vary between 10 % and 80 %. Different interactions between bentonite and metal ions dealing with the decrease of the concentrations. This study proves that this bentonite is an effective adsorbent for the elimination of heavy metals from OMW.

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Cited by 67 publications

References 1 publication

Characterization of the Particle Size and Polydispersity of Dicumarol Using Solid-State NMR Spectroscopy

Characterization of the Particle Size and Polydispersity of Dicumarol Using Solid-State NMR Spectroscopy

The Anti-Inflammatory Tablet Formulation of Coleus (Plectranthus Scutellariodes) Leaves Extract Using Kollicoat®protect Coating

Simultaneous adsorption behaviour of heavy metals from Oil Mill Wastewater onto natural clay

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