Assessing compressibility and compactibility of powder formulations with Near-Infrared Spectroscopy

The compressibility and compatibility of a powder formulation is usually determined by compaction and following destructive tensile strength and relative density measurement of the final compact.

In this study, a non-destructive method with Near-Infrared Spectroscopy (NIRS) was designed and evaluated for the measurement of powder compressibility and compactibility.

12 different formulations with a wide range of difference in properties were investigated by compaction and analysis of the resulting tablets. Two similar tablet batches were produced with every formulation. Relative density and tensile strength were measured with the traditional, destructive method on one tablet batch while a newly developed non-destructive chemometric NIRS method was applied for the second batch. The outcomes of the two approaches were compared to validate the developed method. All data sets were applied to three established mathematical equations to calculate equation factors, which are claimed to represent the formulation compressibility and compactibility. The study focus was set on the equation factor value comparison between the traditional and the newly designed method.

The results showed a high similarity between the outcomes of the two methods. An essential difference was noticed for the outcomes of the equation factors after application to the Leuenberger equation.

The approach with the NIRS is suggested as a promising tool for a reliable inline quality monitoring in the tablet manufacturing process.