Role of an isomorphic desolvate in dissolution failures of an erythromycintablet formulation

The investigation of dissolution failures for erythromycin dihydrate tablet formulation over a 12-month period using a near-infrared spectroscopy tech nique revealed the role of a desolvated dihydrate in the retardation of dis solution. Near infrared spectroscopy (NIR) indicated a dehydrated dihydrate of erythromycin is produced during formulation and gradually binds with MS (OH)(2). The binding delays the process of dissolution. NIR was used to suc cessfully predict that humidifying the tablets would reverse the binding an d increase the dissolution rate.