Relationship between Hydrogen-bond Conditions of Surface Adsorbed Water and Interparticle Binding Force on Pharmaceutical Tablets

Abstract

 Influence of water contents to the pharmaceutical tablet strength is known empirically, and participation of hydrogen bonding force among adsorbed water molecules has been presumed. However, the detailed mechanisms of hydrogen bonding phenomena have not been reported. In this study, the hydrogen bonds states of the surface adsorbed waters on the excipient particles of the tablets were focused upon, and the relationship to the interparticle binding force determined by the Rumpf equation was discussed using a near-infrared spectroscopy (NIR). As for the results, NIR peaks of OH groups of surface water were shifted by a humidity change, and the degrees of the peak shifts correlated to interparticle binding force.