Physico‐Chemical and Technological Properties of Sodium Naproxen Granules Prepared in a High‐Shear Mixer‐Granulator

In the present work, authors produced tablets of anhydrous sodium naproxen by wet granulation using a high‐shear mixer‐granulator. Drug hydrated to the tetrahydrated form, as observed by X‐ray powder diffractometry. After wet granulation, authors then performed two different drying procedures, obtaining granules of different water content and crystallographic characteristics. The first procedure dried granules in the high‐shear mixer‐granulator by applying vacuum at room temperature (batch A), while the second employed the same apparatus and time, under vacuum at 40°C (batch B). X‐ray powder diffractometry revealed that the sodium naproxen (SN) contained in batch A granules was a mixture of dihydrated and tetrahydrated forms (as demonstrated by the coexistence of peaks typical of both hydrated forms), while that of batch B granules was a mixture of monohydrated and tetrahydrated forms. This means that differences in drying procedures could lead to products of different crystallographic properties. The behavior under compression was evaluated, revealing that batch A offered the best tabletability and compressibility. These results make it possible to conclude that differences in the crystallographic properties and water content of SN are such that different hydration/drying processes can alter the drug crystal form and thus the tabletability of the resulting granules. © 2008 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:5263-5273, 2008