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


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 – 15 kN, pre-compression force between 2 – 3 kN, feeder speed fixed at 25 rpm and compression range of 45 – 49 rpm produced tablets with hardness ranging between 19 – 21 kp, with no friability, capping or lamination issue.


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