Micro-computed tomography and brightness-mode ultrasound show air entrapments inside tablets

Abstract

Controlled disintegration of pharmaceutical tablets has been of interest for consistency checks and drug delivery. Under sonication, tablet disintegration is accelerated. This acceleration has been attributed to the existence of microscopic air pockets inside compacted tablets. In this study, we investigated the existence of such pockets by subjecting tablets to micro-computed tomography. In addition, we subjected tablets from the same batch to sonography. The tablets were measured to have an ultrasonic swelling rate of 162±16 μms−1. The micro-computed tomography images showed air pockets of up to 9 μm in diameter, some of which were visibly connected to each other. The brightness-mode images showed scattering from inside the tablets, suggesting cavitation activity. We conclude that, inside the tablets investigated, microscopic air entrapments exist, whose pulsations are detectable with brightness-mode ultrasound.

Keywords

• μct
• b-mode
• air pockets
• scattering
• tablet swelling
• tablet disintegration