Papers by Gabriel Meesters
La invencion se refiere a un procedimiento de preparacion de un granulado que contiene una enzima... more La invencion se refiere a un procedimiento de preparacion de un granulado que contiene una enzima, en el que un liquido acuoso que contiene una enzima se mezcla con un excipiente solido con base de hidrato de carbono comestible, como almidon, transformandose la mezcla mecanicamente en granulados, ya continuacion estos se secan. Este granulado enzimatico esta indicado para la fabricacion de composiciones de alimentos para animales que consisten en mezclar ingredientes alimentarios con los granulados, tratarlos al vapor y granularlos. Las composiciones presentan una estabilidad mejorada de la enzima durante el procedimiento de granulacion.
Key Engineering Materials, 2002
ABSTRACT
International Journal of Pharmaceutics, 2006
Bouwman, A. M. (2005). Form, formation, and deformation: the influence of material properties and... more Bouwman, A. M. (2005). Form, formation, and deformation: the influence of material properties and process conditions on the shape of granules produced by high shear granulation. s.n.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2016
We have enhanced the radio-activation efficiency of SiC (silicon carbide) particles, which by nat... more We have enhanced the radio-activation efficiency of SiC (silicon carbide) particles, which by nature have a poor affinity towards F ions, to be employed as tracers in studies using PEPT (Positron Emission Particle Tracking). The resulting SiC-Al2O3 core-shell structure shows a good labelling efficiency, comparable to γ-Al2O3 tracer particles, which are commonly used in PEPT. The coating of the SiC particles was carried at 27 ± 3 °C and 1 bar in a fluidized bed reactor, using trimethyl aluminium and water as precursors, by a gas phase technique similar to atomic layer deposition. The thickness of the alumina films, which ranged from 5 to 500 nm, was measured by elemental analysis and confirmed with FIB-TEM (focus ion beamtransmission electron microscope), obtaining consistent results from both techniques. By depositing such a thin film of alumina, properties that influence the hydrodynamic behaviour of the SiC particles, such as size, shape and density, are hardly altered, ensuring that the tracer particle shows the same flow behaviour as the other particles. The paper describes a general method to improve the activation efficiency of materials, which can be applied for the production of tracer particles for many other applications too. Highlights • We deposited Al2O3 films on SiC particles at ambient conditions in a fluidized bed. • The affinity of 18 F ions towards Al2O3-SiC particle was improved compared to SiC. • We used the Al2O3-SiC activated particle as tracer in a PEPT experiment. • Tracer particles have suitable activity for accurate tracking. • The Al2O3 film is thin enough not to alter the particle size, shape and density.
Chemical Engineering Science, 2002
Population balance models have been used in chemical engineering since the 1960s and have evolved... more Population balance models have been used in chemical engineering since the 1960s and have evolved to become the most important tools for design and control of particulate processes. In this paper we show that the intrinsic particle parameter that determines changes in the process and should thus be included in the population balance is the particle volume. The basic population
The production of droplets in the micrometer range (1 to 5 micrometers) and the production of dro... more The production of droplets in the micrometer range (1 to 5 micrometers) and the production of droplets a few decades larger (70 micrometer to 2 mm) is considered. In the production of droplets in the micrometer range, the liquids are dispersed with the help of a strong electric field. A phenomenon known as the Taylor cone is used for dispersion of the liquid. A Taylor cone is a conically shaped liquid droplet from whose apex small droplets are emitted. The phenomena of these liquid cones were also investigated. In producing droplets of diameter 70 micrometers to 2 mm, the liquid jet is forced to break up by applying a vibration onto the jet causing it to break up with the imposed frequency. Two different pieces of equipment were set up to investigate the break up behavior of liquids of low and high viscosity. Using this apparatus it was possible to define a particle size distribution over a wide range of diameters and to tailor it.
Bulletin of the American Physical Society, 2015
L'invention concerne des granules en plastique enrobes d'une ou de plusieurs couches cont... more L'invention concerne des granules en plastique enrobes d'une ou de plusieurs couches contenant au moins un additif, le contenu additif a l'exterieur du granule enrobe etant inferieur a une partie situee plus a l'interieur des couches. Elle concerne egalement un procede de production de ces granules, qui consiste a appliquer au moins une couche contenant au moins un additif par contact des granules avec une composition contenant ledit additif et pulverisee au moyen d'un systeme de pulverisation, une couche exterieure sans additif etant appliquee par pulverisation d'une composition possedant un effet nettoyant sur le systeme de pulverisation.
La presente invention concerne une composition comprenant un premier granule avec un antibiotique... more La presente invention concerne une composition comprenant un premier granule avec un antibiotique et un second granule avec un inhibiteur de la β-lactamase, au moins l'un des granules etant un mini-comprime (une particule aux dimensions definies), une composition contenue dans un sachet, des compositions pharmaceutiques comprenant des mini-comprimes, l'utilisation de mini-comprimes et un procede de preparation de mini-comprimes.
La presente invention concerne un procede permettant de produire en continu des granules enzymati... more La presente invention concerne un procede permettant de produire en continu des granules enzymatiques, ledit procede se caracterisant en ce que : (h) une preparation enzymatique liquide contenant une ou plusieurs enzymes, est produite ; (i) des adjuvants sont eventuellement ajoutes a la preparation enzymatique obtenue en (a) ; (j) une ou plusieurs preparations enzymatiques liquides obtenues en (a) ou (b) sont pulverisees dans un lit fluidise au moyen de buses de pulverisation ; (k) la matiere fine qui s'echappe du lit fluidise avec le degagement gazeux est extraite et reintroduite dans le lit fluidise sous forme de noyaux a partir desquels se forment les granules ; (l) des granules ayant une taille predeterminee sont formees par regulation du flux de gaz de tamisage ; (m) les granules finies sont extraites par l'intermediaire d'un ou de plusieurs dispositifs de tamisage par gravite fonctionnant en meme temps, installes dans la plaque de flux entrant de l'appareil a l...
The invention relates to a process for preparing aqueous liquid containing a phytase, the process... more The invention relates to a process for preparing aqueous liquid containing a phytase, the process comprising cultivating microorganisms of the Aspergillus or Trichoderma type in a medium containing sources of assimilable carbon and nitrogen (eg glucose ions and ammonium) in the filter medium and subjecting the filtrate obtained to ultrafiltration to obtain an aqueous composition having at least 14,000 FTU / g. This aqueous liquid can be used to prepare granulates that can be incorporated into animal feed.
L'invention concerne un procede permettant de recuperer une proteine a partir d'une solut... more L'invention concerne un procede permettant de recuperer une proteine a partir d'une solution contenant des proteines dissoutes, par traitement de ladite solution avec un sel chaotropique. Ce procede comprend les etapes consistant: a ajouter le sel chaotropique a la solution contenant des proteines en quantite suffisante pour precipiter la proteine; et a recuperer ladite proteine sous forme de precipite.
Particles and Nanoparticles in Pharmaceutical Products
Producing Amorphous Active Pharmaceutical Ingredients offers an enhanced drug release that is cau... more Producing Amorphous Active Pharmaceutical Ingredients offers an enhanced drug release that is caused by the increase in its dissolution rate. This improvement enables higher bioavailability and bioactivity of such solid APIs. Possibilities to control the drug release and its bioactivity offer new opportunities to design more effective and stable medications. This chapter is a general introduction to Amorphous APIs and most commonly discussed production and characterization methods.
AAPS Advances in the Pharmaceutical Sciences Series
Most pharmaceutical products contain particles, as active ingredient (API) and/or as excipient. T... more Most pharmaceutical products contain particles, as active ingredient (API) and/or as excipient. The nature of these particles—e.g. particle size distribution (PSD), particle shape, morphology and powder flowability—is generally essential for product quality, during processing of powders and liquids to tablets, capsules, suspensions, emulsions and ointments as well as for the quality of the final product in terms of content uniformity, efficacy and stability. In view of their complex and particulate nature, pharmaceutical products and their manufacturing process require careful design and control. The quality of the final products should meet various strict requirements for e.g. content uniformity, tablet strength and stability and viscosity of dispersions, as well as for patient safety. Most often, quality aspects relate to the particle size distribution, particle shape, specific surface area and particulate concentration of the base materials. Since determination of these aspects is relatively easy, optimum relevant characteristic parameters are laid down in the form of specifications. In addition, some performance aspects of powders and dispersions, such as flow and viscosity behavior, are usually specified. This chapter describes the properties and characteristic features of particles, powders and dispersions and their relevance to pharmaceutical products. Also, it gives an overview of the main measurement methods that are relevant for pharmaceutical products. At the end of this chapter, the contents of this book are summarized. 1.1 Objective of This Book Most pharmaceutical products contain particles, both as active ingredient (API) and as excipient in formulations in the form of e.g. binder, filler, disintegrant, stabilizer, lubricant or colorant. The particles may be solid or liquid, occurring as powders in capsules or in tablets or dispersed in an immiscible liquid in the form of suspensions H. G. Merkus (&) Retired Associate Professor, Delft University of Technology, Park Berkenoord 30, 2641 CZ Pijnacker, The Netherlands e-mail: [email protected] © American Association of Pharmaceutical Scientists 2018 H. G. Merkus et al. (eds.), Particles and Nanoparticles in Pharmaceutical Products, AAPS Advances in the Pharmaceutical Sciences Series 29, https://doi.org/10.1007/978-3-319-94174-5_1 1 or emulsions or in air as sprays. Second to the chemical nature of the active ingredient, the nature of all of these particles—e.g. particle size distribution (PSD), particle shape, morphology and powder flowability—is essential for product quality, both during processing and for the final quality. The objective of this book is to highlight the role of particulate nature in the wide variety of pharmaceutical products, with focus on the very large range of particle sizes involved, as well as to give guidance in the choices of particle and powder characteristics and their measurement for setting product specifications, which have an optimum relationship with product quality. A further objective is to promote the approach of Quality by Design (QbD) and Process Analytical Technology (PAT) for pharmaceutical products and processes. Expert authors have contributed to the chapters on different types of pharmaceutical products, for which we are very grateful to them. In the next sections of this introductory chapter, particle and powder characteristics, measurement methods and their relevance for product manufacture, performance and quality are described. 1.2 Pharmaceutical Products Pharmaceutical products occur in many forms, viz. powders, capsules, tablets, solutions, emulsions, suspensions, ointments and sprays. Their composition may be very complex. The Active Pharmaceutical Ingredient (API) is the heart of the product. It should have optimum pharmaceutical activity for curing a specified disease in given surroundings with least negative side effects. It usually is a solid material, often crystalline, having a complex organic chemical structure. Among other things, adequate bioavailability requires that the substance is sufficiently soluble in the surrounding liquid. Following synthesis and purification, the active ingredient is typically combined with other components, each with its specific function, in a pharmaceutical formulation. These formulations may contain: – binders, to facilitate tabletting and granulation – lubricants or glidants, to aid flow of the powder – fillers, to give tablets the desired size, API concentration and strength – disintegrants, to facilitate break-up and dispersion of tablets into smaller particles for quick dissolution when in contact with water – polymer, to form a matrix for extended release of the drug – particle coatings, to promote liberation of the API in the desired region of the gastro-intestinal system, to promote extended release and/or to mask an unwanted taste – liquid, to form suspensions or emulsions – surfactants, to facilitate wetting of powders – dispersants, to…
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Papers by Gabriel Meesters