Effect of Kollidon VA^®64 particle size and morphology as directly compressible excipient on tablet compression properties

Abstract

The study evaluates use of Kollidon VA^®64 and a combination of Kollidon VA^®64 with Kollidon VA^®64 Fine as excipient in direct compression process of tablets. The combination of the two grades of material is evaluated for capping, lamination and excessive friability. Inter particulate void space is higher for such excipient due to the hollow structure of the Kollidon VA^®64 particles. During tablet compression air remains trapped in the blend exhibiting poor compression with compromised physical properties of the tablets. Composition of Kollidon VA^®64 and Kollidon VA^®64 Fine is evaluated by design of experiment (DoE). A scanning electron microscopy (SEM) of two grades of Kollidon VA^®64 exhibits morphological differences between coarse and fine grade. The tablet compression process is evaluated with a mix consisting of entirely Kollidon VA^®64 and two mixes containing Kollidon VA^®64 and Kollidon VA^®64 Fine in ratio of 77:23 and 65:35. A statistical modeling on the results from the DoE trials resulted in the optimum composition for direct tablet compression as combination of Kollidon VA^®64 and Kollidon VA^®64 Fine in ratio of 77:23. This combination compressed with the predicted parameters based on the statistical modeling and applying main compression force between 5 and 15 kN, pre-compression force between 2 and 3 kN, feeder speed fixed at 25 rpm and compression range of 45–49 rpm produced tablets with hardness ranging between 19 and 21 kp, with no friability, capping, or lamination issue.

Keywords:

• Kollidon VA^®64
• morphology
• particle size
• direct compression
• compression speed
• compression force
• tablet hardness
• friability
• capping

Acknowledgments

The author acknowledges the support of this work by BASF Corporation, Florham Park, NJ by sharing the SEM-images of different Copovidone grades and by providing various Copovidone samples as gifts. Furthermore, the fruitful discussions with Dr. B. Fussnegger of BASF SE, Ludwigshafen, Germany on the morphological appearance of various Copovidone grades is highly appreciated.

Disclosure statement

The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of this article.