iGC Symposium Online 2021
Featuring leading experts in iGC from across the academic and industrial spectrum, the Conference Agenda will explore the latest findings and insights for iGC, as well as the innovative applications you can use in your own work.
| Responsible | Daniel Villalobos |
|---|---|
| Last Update | 16/02/2023 |
| Completion Time | 7 hours 25 minutes |
| Members | 112 |
POSTER: The Importance of Surface Chemistry in the Flow Behaviour of Pharmaceutical Powders
Speaker: Alina Dumitru, Imperial College London Abstract: Achieving optimal powder flow in pharmaceutical powder processing is often a challenge due to handling fine, cohesive excipients and APIs (Valverde, et al. 2000). Generally, poor flow behaviour is encountered with small particles due to the strong interparticle interactions associated with such systems (Zhou, et al. 2011). Although particle size contributes greatly to explaining powder flow patterns, it is thought that surface chemistry can play a significant role in underpinning powder flow behaviour for many formulations in the pharmaceutical sector. This study was designed to systematically focus on the effects of surface chemistry, and in turn surface energy, on the powder flow performance of four model systems prepared through controlled surface functionalisation of D-mannitol powders. IGC was used as a physical characterisation method to assess the surface energy and thus chemical alterations undertaken on D-mannitol, as well as the surface area. Powder flow performance was assessed using the FT4 Powder Rheometer, where dynamic, bulk and shear properties have been analysed. It was found that the surface chemistry can be responsible for altering the flow properties of these powders, whilst other key material attributes such as particle size distribution or particle morphology remain unchanged. Increasing the hydrophobic character of the samples, a positive correlation was observed in the total flowability energy, where less energy was required to instigate powder flow for lower surface energy functionalisations, such as phenylated-mannitol and methylated-mannitol. A key finding which can surely present broader implications for many pharmaceutical powders was seen with the fluorinated powders developed, where the electrostatic charge associated with this superhydrophobic sample, overwhelmed the low surface energy character of the fluorinated sample. This work emphasises the importance of investigating a broader range of powder surface chemistries as well as developing a deeper understanding of the electrostatic behaviour of powders which have fluorinated surface groups.
Speaker: Dr. Douglas Gardner, University of Maine The production of cellulose nanofibers by disk refining lignocellulosic feed stocks as aqueous suspensions results in particles exhibiting dimensions ranging from nano- to micron-scale with surface chemistry and morphological attributes that are challenging to study. Obtaining dry cellulose nanofibers for study is also challenging because of the propensity of the fibers to agglomerate during the drying process. So, particles that exist as nanoscale in aqueous suspensions may end up as micron scale agglomerates. Surface characterization techniques that have proven to be quite useful in studying cellulose nanofibers include inverse gas chromatography, nuclear magnetic resonance and atomic force microscopy. It is the objective of this presentation to provide information on the surface characteristics of cellulose nanofibers as a function of energy input during the disk refining process. Understanding how surface chemistry and morphology change as a function of processing time and energy will help guide future work on the application of cellulose nanofibers in various products.
... Surface Free Energy Distribution Profiles Speaker: Dr. Vibha Puri, Bristol-Myers Squibb Unanticipated changes in the surface properties of mechanically-activated micronized drugs are a leading cause of variability in drug product performance. To address this issue, a post-micronization annealing step is often introduced. However, there is limited understanding of the material changes that occur during annealing. We present a case study on the use of surface free energy (SFE) measured by inverse gas chromatography to monitor surface-specific changes during annealing. We also use other orthogonal techniques (atomic force microscopy, RH perfusion microcalorimetry) to conduct additional analysis. Further, the SFE descriptor enabled us to differentiate the extent of mechanical activation of the neat micronized drug and co-micronized drug-excipient blends. This study’s primary contribution is to identify SFE as a tool for characterizing post-micronization material changes over storage. Vibha Puri1, Jagdeep Shur2, and Ajit S. Narang3 1Drug Product Development, Bristol-Myers Squibb, USA, 2Nanopharm Ltd, an Aptar Pharma Company, U.K., 3Small Molecule Pharmaceutics, Genentech, Inc., USA
Speaker: Dr. Kristian Waters, McGill University