Special Issue "Powder Processing in Pharmaceutical Applications"

A special issue of Pharmaceutics (ISSN 1999-4923).

Deadline for manuscript submissions: 29 February 2020.

Special Issue Editors

Prof. Dr. Arno Kwade
E-Mail Website
Guest Editor
Institute for Particle Technology, Technische Universität Braunschweig, Braunschweig, Germany
Interests: research on production, tailoring, formulation of nano and micro sized particles and their use for the design of structured products like battery electrodes, drugs and nano composites
Dr. Jan Henrik Finke
E-Mail Website
Guest Editor
Institute for Particle Technology, Technische Universität Braunschweig, Braunschweig, Germany

Special Issue Information

Dear Colleagues,

In all production processes of solid dosage forms, powders with a multitude of distributed properties must be processed. Starting with the handling for dispensing and weighing, over blending, dosing, comminution, and granulation, up to capsule filling or tableting, powder properties crucially determine the process performance and product quality. In any case, each powder in pharmaceutical formulations brings along distributions of various microscopic properties such as particle size, morphology, and surface energies as well as macroscopic properties such as flow behavior and bulk densities. Along the process chain, multiple powders are blended or more fundamentally change their properties, e.g. by granulation, causing complex changes that will affect their behavior in subsequent processes. Additionally, transportation and packaging of intermediates and final products can cause changes due to aeration, abrasion, or compaction. The determination of powder properties such as particle, surface, and flow properties require sophisticated, methodologic approaches to measure meaningful parameters under representative conditions. The deep knowledge of powder properties and quick and reliable measurement techniques become a prerequisite in the context of continuous process chains that need to immediately respond to material property changes to keep processes and product quality stable within specified ranges. To achieve this, well-developed model approaches need to be derived to predict and control any complex powder processing operation.

This special issue is dedicated to in-depth studies and reviews, presenting fundamental advancement in the scientific field of powder processing in pharmaceutical applications. Contributions addressing thorough insight into unit operations, innovative measurement methods for powder properties, model approaches providing prediction of effects such as demixing, segregation, overmixing, abrasion, deagglomeration, particle breakage, and residence time distribution based on material properties and process parameters, as well as research on continuous process chains are especially encouraged.

Prof. Dr. Arno Kwade
Dr. Jan Henrik Finke
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Pharmaceutics is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Powder processing/handling
  • Process modelling
  • Powder properties
  • Flow behavior
  • Process performance
  • Continuous processes
  • Demixing/Segregation
  • Granulation
  • Tableting
  • Capsule filling

Published Papers (3 papers)

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Research

Open AccessArticle
Along the Process Chain to Probiotic Tablets: Evaluation of Mechanical Impacts on Microbial Viability
Pharmaceutics 2020, 12(1), 66; https://doi.org/10.3390/pharmaceutics12010066 - 15 Jan 2020
Abstract
Today, probiotics are predominantly used in liquid or semi-solid functionalized foods, showing a rapid loss of cell viability. Due to the increasing spread of antibiotic resistance, probiotics are promising in pharmaceutical development because of their antimicrobial effects. This increases the formulation requirements, e.g., [...] Read more.
Today, probiotics are predominantly used in liquid or semi-solid functionalized foods, showing a rapid loss of cell viability. Due to the increasing spread of antibiotic resistance, probiotics are promising in pharmaceutical development because of their antimicrobial effects. This increases the formulation requirements, e.g., the need for an enhanced shelf life that is achieved by drying, mainly by lyophilization. For oral administration, the process chain for production of tablets containing microorganisms is of high interest and, thus, was investigated in this study. Lyophilization as an initial process step showed low cell survival of only 12.8%. However, the addition of cryoprotectants enabled survival rates up to 42.9%. Subsequently, the dried cells were gently milled. This powder was tableted directly or after mixing with excipients microcrystalline cellulose, dicalcium phosphate or lactose. Survival rates during tableting varied between 1.4% and 24.1%, depending on the formulation and the applied compaction stress. More detailed analysis of the tablet properties showed advantages of excipients in respect of cell survival and tablet mechanical strength. Maximum overall survival rate along the complete manufacturing process was >5%, enabling doses of 6   ×   10 8 colony forming units per gram ( CFU   g total 1 ), including cryoprotectants and excipients. Full article
(This article belongs to the Special Issue Powder Processing in Pharmaceutical Applications)
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Open AccessArticle
Improved Understanding of the High Shear Wet Granulation Process under the Paradigm of Quality by Design Using Salvia miltiorrhiza Granules
Pharmaceutics 2019, 11(10), 519; https://doi.org/10.3390/pharmaceutics11100519 - 09 Oct 2019
Abstract
Background: High shear wet granulation (HSWG) is a shaping process for granulation that has been enhanced for application in the pharmaceutical industry. However, study of HSWG is complex and challenging due to the relatively poor understanding of HSWG, especially for sticky powder-like herbal [...] Read more.
Background: High shear wet granulation (HSWG) is a shaping process for granulation that has been enhanced for application in the pharmaceutical industry. However, study of HSWG is complex and challenging due to the relatively poor understanding of HSWG, especially for sticky powder-like herbal extracts. Aim: In this study, we used Salvia miltiorrhiza granules to investigate the HSWG process across different scales using quality by design (QbD) approaches. Methods: A Plackett–Burman experimental design was used to screen nine granulation factors in the HSWG process. Moreover, a quadratic polynomial regression model was established based on a Box–Behnken experimental design to optimize the granulation factors. In addition, the scale-up of HSWG was implemented based on a nucleation regime map approach. Results: According to the Plackett–Burman experimental design, it was found that three granulation factors, including salvia ratio, binder amount, and chopper speed, significantly affected the granule size (D50) of S. miltiorrhiza in HSWG. Furthermore, the results of the Box–Behnken experimental design and validation experiment showed that the model successfully captured the quadratic polynomial relationship between granule size and the two granulation factors of salvia ratio and binder amount. At the same experiment points, granules at all scales had similar size distribution, surface morphology, and flow properties. Conclusions: These results demonstrated that rational design, screening, optimization, and scale-up of HSWG are feasible using QbD approaches. This study provides a better understanding of HSWG process under the paradigm of QbD using S. miltiorrhiza granules. Full article
(This article belongs to the Special Issue Powder Processing in Pharmaceutical Applications)
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Open AccessArticle
A Mathematical Approach to Consider Solid Compressibility in the Compression of Pharmaceutical Powders
Pharmaceutics 2019, 11(3), 121; https://doi.org/10.3390/pharmaceutics11030121 - 15 Mar 2019
Cited by 1
Abstract
In-die compression analysis is an effective method for the characterization of powder compressibility. However, physically unreasonable apparent solid fractions above one or apparent in-die porosities below zero are often calculated for higher compression stresses. One important reason for this is the neglect of [...] Read more.
In-die compression analysis is an effective method for the characterization of powder compressibility. However, physically unreasonable apparent solid fractions above one or apparent in-die porosities below zero are often calculated for higher compression stresses. One important reason for this is the neglect of solid compressibility and hence the assumption of a constant solid density. In this work, the solid compressibility of four pharmaceutical powders with different deformation behaviour is characterized using mercury porosimetry. The derived bulk moduli are applied for the calculation of in-die porosities. The change of in-die porosity due to the consideration of solid compressibility is for instance up to 4% for microcrystalline cellulose at a compression stress of 400 MPa and thus cannot be neglected for the calculation of in-die porosities. However, solid compressibility and further uncertainties from, for example the measured solid density and from the displacement sensors, are difficult or only partially accessible. Therefore, a mathematic term for the calculation of physically reasonable in-die porosities is introduced. This term can be used for the extension of common mathematical models, such as the models of Heckel and of Cooper & Eaton. Additionally, an extended in-die compression function is introduced to precisely describe the entire range of in-die porosity curves and to enable the successful differentiation and quantification of the compression behaviour of the investigated pharmaceutical powders. Full article
(This article belongs to the Special Issue Powder Processing in Pharmaceutical Applications)
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