Real-time Acoustic Elastic Property Monitoring of Compacts During Compaction

Abstract

A nondestructive, real-time acoustic technique for determining elastic properties of compacts during compaction is presented. An acoustic time-of-flight study was conducted, and the extraction of the linear elastic properties of calcium carbonate compacts was demonstrated. To verify the results of the acoustic experiments, a uniaxial compaction investigation was also carried out using a computer-controlled press with an instrumented die. Good agreement between linear elastic properties determined using both acoustic experiments and compaction force-displacement data was observed. This technique has the potential to be used as a real-time compaction monitoring tool.

A Quantitative Correlation of the Effect of Density Distributions in Roller-Compacted Ribbons on the Mechanical Properties of Tablets Using Ultrasonics and X-ray Tomography

“…The mechanical and physical properties of a tablet such as elastic properties, mechanical strength, and mass density are closely related to the unit operations employed in its production (e.g., roller compaction and tableting). Over the decades, volume reduction mechanism, bond formation and compaction characteristics of pharmaceutical powders (21)(22)(23), and the mechanical and physical property characterization of tablets either with destructive (15,16,24,25) or with nondestructive (17,(26)(27)(28)(29) methods have been intensely studied. Relatively few studies (11,(30)(31)(32) have focused on the determination of the density distributions in rollercompacted ribbons and the impact of the localized ribbon density on the performance of the final pharmaceutical solid dosage form using nondestructive methods.…”

“…Relatively few studies (11,(30)(31)(32) have focused on the determination of the density distributions in rollercompacted ribbons and the impact of the localized ribbon density on the performance of the final pharmaceutical solid dosage form using nondestructive methods. Nondestructive ultrasonic testing has been recently utilized to characterize the elastic properties of the coat and the core materials of tablets (26)(27)(28). Ultrasound differs from X-rays because the propagation speed is much lower and thus it is possible to measure the exact pressure of the wave as a function of time.…”

Measurements of Elastic Moduli of Pharmaceutical Compacts: A New Methodology Using Double Compaction on a Compaction Simulator

“…To measure the elastic properties, it is necessary to focus on the phase of the compaction process where only elastic deformation occurs. Authors generally choose the unloading part of the curve 16–18. However, the use of this part of the compaction curve may lead to problems.…”

Real-time in-die compaction monitoring of dry-coated tablets

“…Considering the millisecond (ms) time-scale dwell time of a typical commercial compaction press (from ∼5 ms to 80+ ms) (Levin, 2002) and the micro-seconds of pulse duration and time-of-flight (TOF) of an acoustics pulse in typical tablets, the results reported in Akseli et al (2008a) and later Leskinen et al (2010) indicates that the ultrasonic approach has potential to be employed for real-time in-die online monitoring of the geometric and mechanical properties of drug tablets. It is widely known that dwell-time is a key parameter defining the end-mechanical properties of the compacted tablet, such as hardness and porosity.…”