Non-destructive acoustic defect detection in drug tablets

Mechanical Property Characterization of Bilayered Tablets using Nondestructive Air-Coupled Acoustics

“…Thus, the relaxation of the individual layers will not occur uniformly through the whole bilayer tablet which results in mechanical property anisotropy (35,36) in the tablet. Nondestructive acoustic testing and characterization can provide insight to these kind of arising complications during compaction of BL-tablets and other complex-shaped tablets (e.g., multilayered, enteric-coated, multi-layer coated, and dry-coated tablets) as well as it can also provide the defect state information of the layers, since the transient vibrational response of the tablet is strongly affected by mechanical defects (e.g., cracks, lamination, and capping) (23). During mechanical characterization, close vicinity of a test point at the tablet is acoustically noisy, and the tablet is subjected to mechanical vibrations.…”

“…The PAT framework encourages and advises the use of modern measurement and monitoring approaches such as the acoustic emission method (18,19), acoustic and ultrasonic characterization techniques (20)(21)(22)(23)(24), the near-infrared sensing (25), light-induced fluorescence characterization (26), Terahertz pulsed spectroscopy (27), laser-induced breakdown spectroscopy (28), X-ray fluorescence method (15), and Raman spectroscopy (29) for characterization and monitoring of tablets to ensure product quality by using on-, in-, and/or at-line measurements and through timely measurements (i.e., during processing) of critical quality and performance attributes of raw and in process materials and unit operations. The effectiveness of air-coupled acoustic technique, using an aircoupled excitation source and laser interferometric detection, has been demonstrated for the nondestructive characterization of the critical mechanical properties and coating thickness of enteric-coated monolayer tablets (21,22).…”

Acoustic Testing and Characterization Techniques for Pharmaceutical Solid Dosage Forms

“…Tablet coating thickness is also an important criticalto-quality attribute of the final product and its performance [8][9][10][11]12]. Many coatings are simply for aesthetic or identification purposes, yet some serve critical therapeutic functions [12].…”

“…For an extended release drug, a cracked or damaged enteric coating could subject the patient to hypertherapeutic levels of drug [10,12]. Linear correlations have been observed between coating layer thickness and both in vitro and in vivo lag times of drug release [13].…”

“…Such procedures would be consistent with a new quality concept which is transforming "quality-by-inspection" to the desired "quality-by-design," and could reduce risks of quality and regulatory concerns while improving manufacturing efficiency [14]. PAT encourages the use of online techniques (e.g., acoustic emission [15,16], near-infrared spectroscopy [17], lightinduced fluorescence [18], terahertz spectroscopy [19], laser-induced breakdown spectroscopy [20], X-ray fluorescence [21], Fourier transform infrared spectroscopy [22] and acoustic techniques [8][9][10][11]23]) to monitor tabletting unit operations and to characterize final products with the goal of ensuring final product quality.…”