Evaluation of a novel sugar coating method for moisture protective tablets

A novel method of manufacturing one-step dry-coated (OSDRC) tablets, which we recently invented, was used to produce sugar-coated tablets protected from moisture without the need for a conventional complicated sugar coating process. Amorphous sucrose was selected for the outer layer of the OSDRC tablets as sugar-coated layer. The isothermal crystallization behavior and characteristics such as water vapor permeability, tensile strength, and disintegration time of compressed amorphous sucrose were investigated. Water vapor adsorption measurements showed the crystallization behavior of amorphous tablets to be similar to that of amorphous powder, although it was affected by compression pressure. We found that the crystallized amorphous sucrose after compression at 200 MPa was moisture protective, and the water vapor permeability coefficient was decreased to 1/2000 or less compared with a tablet prepared with a lactose-microcrystalline cellulose (MCC) mixture, hydroxypropylmethylcellulose (HPMC), and sucrose crystal. The water vapor permeability and physicochemical characteristics were influenced by the amorphous content or additive content. It was confirmed that a new sugar-coated tablet using amorphous sucrose and OSDRC technology was moisture protective, therefore, it was concluded that the novel sugar coating method was very useful to obtain a moisture protective tablet. (C) 2007 Elsevier B.V. All rights reserved.