Crystal habit and tableting behavior.

The tableting behavior of drugs can be affected by changes in the crystal habit. Different crystal habits of the common analgesic drugs ibuprofen and acetaminophen were prepared. Their tableting behavior was characterized. In the case of ibuprofen, a plate-shaped crystal was compared with the common needle-shaped form. In the case of acetaminophen, plate-shaped and prismatic crystals of two different particle sizes were prepared. The aim was to find a crystal form that is suitable for direct compression with only a low amount of excipients. This requires a substance that forms stable compacts at low punch forces, having a good flowability and only a low tendency to stick to the punches. In order to compare the tableting behavior of different substances, a comparative factor (T-factor) was calculated, based on typical parts of the punch force/displacement-profile and properties of the resulting compact. This method works with low amounts of substance and allows a rapid reproducible determination of the tableting behavior. The method was evaluated by characterizing different typical excipients normally used for the production of tablets.