Fine grinding and states of equilibrium

Opoczky, Ludmilla; Farnady, F.

doi:10.1016/0032-5910(84)85027-5

Cited by 15 publications

(3 citation statements)

References 1 publication

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“…Juhnke et al [ 63 ] developed a screening media mill equipped with up to 24 milling beakers which can perform up to 24 experiments in parallel to identify suitable drug stabilizers. Knieke et al [ 64 ] developed a method called dynamic equilibrium curves, based on step-wise addition of stabilizers at the end of milling [ 65 ] and the concept of dynamic equilibrium [ 66 ], for investigating the physical stability of drug nanoparticle suspensions. Via this approach, optimal surfactant concentration was obtained from a single wet media milling experiment, which resulted in 75% time saving and 83% drug saving.…”

Section: Formulation Aspects In the Preparation Of Stable Drug Nanmentioning

confidence: 99%

Nanomilling of Drugs for Bioavailability Enhancement: A Holistic Formulation-Process Perspective

et al. 2016

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Preparation of drug nanoparticles via wet media milling (nanomilling) is a very versatile drug delivery platform and is suitable for oral, injectable, inhalable, and buccal applications. Wet media milling followed by various drying processes has become a well-established and proven formulation approach especially for bioavailability enhancement of poorly water-soluble drugs. It has several advantages such as organic solvent-free processing, tunable and relatively high drug loading, and applicability to a multitude of poorly water-soluble drugs. Although the physical stability of the wet-milled suspensions (nanosuspensions) has attracted a lot of attention, fundamental understanding of the process has been lacking until recently. The objective of this review paper is to present fundamental insights from available published literature while summarizing the recent advances and highlighting the gap areas that have not received adequate attention. First, stabilization by conventionally used polymers/surfactants and novel stabilizers is reviewed. Then, a fundamental understanding of the process parameters, with a focus on wet stirred media milling, is revealed based on microhydrodynamic models. This review is expected to bring a holistic formulation-process perspective to the nanomilling process and pave the way for robust process development scale-up. Finally, challenges are indicated with a view to shedding light on future opportunities.

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Section: Formulation Aspects In the Preparation Of Stable Drug Nanmentioning

confidence: 99%

Nanomilling of Drugs for Bioavailability Enhancement: A Holistic Formulation-Process Perspective

et al. 2016

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“…Verma et al 33 demonstrated that the use of atomic force microscopy (AFM) in visualizing the morphology of various adsorbed polymers/surfactants on ibuprofen to gain surface coverage and adhesion information, and used this information as a means of selecting suitable stabilizers for the production of a stable drug nanosuspension. Knieke et al 23 developed a streamlined stabilizer optimization method based on step-wise addition of stabilizers at the end of milling 34 and the concept of dynamic equilibrium 35 . Lee 17 , Bilgili and Afolabi 22 , Knieke et al 23 and Panmai and Deshpande 36 constructed polymer adsorption isotherms to help the selection of polymer type and concentration.…”

Section: Introductionmentioning

confidence: 99%

Is the combination of cellulosic polymers and anionic surfactants a good strategy for ensuring physical stability of BCS Class II drug nanosuspensions?

Bilgili

Afolabi

2015

Pharmaceutical Development and Technology

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Ensuring the physical stability of drug nanosuspensions prepared via wet media milling has been a challenge for pharmaceutical scientists. The aim of this study is to assess the combined use of non-ionic cellulosic polymers and anionic surfactants in stabilizing multiple drug nanosuspensions. Particle size of five drugs, i.e. azodicarbonamide (AZD), fenofibrate (FNB), griseofulvin (GF), ibuprofen (IBU) and phenylbutazone (PB) was reduced separately in an aqueous solution of hydroxypropyl cellulose (HPC) with/without sodium dodecyl sulfate (SDS) via a stirred media mill. Laser diffraction, scanning electron microscopy, thermal analysis, rheometry and electrophoresis were used to evaluate the breakage kinetics, storage stability, electrostatic repulsion and stabilizer adsorption. Without SDS, drug particles exhibited aggregation to different extents; FNB and GF particles aggregated the most due to low zeta potential and insufficient steric stabilization. Although aggregation in all milled suspensions was reduced due to HPC-SDS combination, FNB and IBU showed notable growth during 7-day storage. It is concluded that the combination of non-ionic cellulosic polymers and anionic surfactants is generally viable for ensuring the physical stability of wet-milled drug nanosuspensions, provided that the surfactant concentration is optimized to mitigate the Ostwald ripening, whereas cellulosic polymers alone may provide stability for some drug suspensions.

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“…Later considerable works were published by Péter [14,15]. At present it is obvious the surface sizes, structures, activities and the internal chemical and crystal composition of materials can be modified by a controlled mechanical activation process [16][17][18][19][20][21][22][23] …”

Section: Introductionmentioning

confidence: 99%

Mechanochemical Phenomena during Fine Comminution of Clay Minerals for Ceramic Bricks and Roof-Tiles

Gömze

2010

MSF

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Abstract. During the fine comminution of clay minerals and layered silicate materials with relative large volume of specific surface area appreciable changes in chemical and minerological compositions can be observed. In this paper is described the mechanochemical investigation of conventional clay minerals from "Lenti" region (Hungary), having natural BET specific surface larger than 35-40 square metres per grams. The laboratory experiments made by author had shown an intensive reduction of specific surface volume at the beginning of grinding, further relatively slow growth and reduction of BET and Langmuir surfaces were observed. The content of mineral Muscovite-2M1 -(K, NH4Na)Al2(SiAl)4O10(OH)2 -has decreased and the contents of QuartzSiO2 -and Illite-1M (NR) -KO.7Al2(SiAl)4O10(OH)2 -have increased considerable depending on grinding time. Increasing the milling time the amount of Albite -NaAlO.91Si3O8 -and other mineral components were also not stable, but their content have varied not so strong as Muscovite-2M1 or Quartz and Illite-1M. The examined clay minerals had a certain proportion of amorphous particles as well, but in this contribution only the changes in proportions of crystalline particles are described.

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Fine grinding and states of equilibrium

Cited by 15 publications

References 1 publication

Nanomilling of Drugs for Bioavailability Enhancement: A Holistic Formulation-Process Perspective

Nanomilling of Drugs for Bioavailability Enhancement: A Holistic Formulation-Process Perspective

Is the combination of cellulosic polymers and anionic surfactants a good strategy for ensuring physical stability of BCS Class II drug nanosuspensions?

Mechanochemical Phenomena during Fine Comminution of Clay Minerals for Ceramic Bricks and Roof-Tiles

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