Files and links (1)
PDFOpen Access (License Unspecified), Open Access
Thesis
Characterization of the viscoelastic behavior of pharmaceutical powders
Master of Science (M.S.), Drexel University
Jun 2009
DOI:
https://doi.org/10.17918/etd-3051
Abstract
Currently, the leading means of drug delivery is by oral administration, and tablets produced by powder compaction are the most widespread form of oral dosage. Understanding the mechanical behavior of powders allows for a rational design of complex compacts (bilayer, core in tablet, etc.). Pharmaceutical formulation development difficulties often arise during the scale up process, due to significant increase in production rate and local strain rates, when problems are the most detrimental, in terms of time and money. Viscoelasticity is one of the rate dependent characteristics of powder compaction. The main goal of this research is to evaluate the role of viscoelasticity on the powder compaction process. Current literature concerning viscoelastic behavior of powder compacts focuses on the modulus of elasticity. Equally, or even more important is the viscoelasticity of the bulk modulus, since few would argue that powder compaction is a bulk phenomenon which is not equivalent to simple tension or simple compression. Additionally, the experimental techniques used in the literature involve primarily out of die viscoelastic testing mechanisms. In die viscoelastic tests would provide a more complete explanation of the viscoelastic role in powder compaction. For the aforementioned reasons, this work is primarily focused on characterizing the viscoelastic behavior of compacts by dynamic mechanical analysis inside of a cylindrical die. This thesis includes a review of the existing literature, experimental results for Starch and MCC compacts, and some numerical simulation to support the experimental results. The results include the evaluation of the role of friction in the accuracy of the measurements, the limits of linear behavior, and the effect of relative density. Contrary to prior references in the literature the bulk modulus is viscoelastic but the corresponding dissipation factor is less than that of the Young's modulus.
Metrics
27 File views/ downloads
21 Record Views
Details
- Title
- Characterization of the viscoelastic behavior of pharmaceutical powders
- Creators
- Barbara Jane Robinson - DU
- Contributors
- Antonios Zavaliangos (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Materials (Science and) Engineering (Metallurgical Engineering) [Historical]; College of Engineering (1970-2026); Drexel University
- Other Identifier
- 3051; 991014632423604721