Distribution of Active Ingredients in Tablets

Apart from the active pharmaceutical ingredient (API), tablets contain a series of additional components ("excipients"). The distribution of APIs and excipients over the tablet is crucial for its effect. The analysis of tablet cross sections with Time-of-Flight Secondary Ions Mass Spectrometry (ToF-SIMS) imaging offers an excellent possibility to study these distributions.

In the present case, a tablet containing Ibuprofen was embedded in epoxy and cut with a microtome. The cross section was analysed with respect to its chemical composition. The results show that, apart from the API, various excipients could be detected. Sugar 1 forms the matrix for these ingredients. The Ibuprofen lies in this matrix in agglomerates with sizes between 50 and 100 µm. The second sugar component is agglomerated in particles with a size between 50 and 75 µm. The detected fatty acids are distributed relatively homogeneously over the cross sectioned surface. The finely spread Si containing material indicates the use of an excipient to improve the flow properties.