A thermoplastic composition that is water-sensitive (e.g., water-soluble, water-dispersible, etc.) in that it loses its integrity over time in the presence of water that can also be injection molded is provided. The composition contains a cellulose derivative, a synthetic water-soluble polymer, and a plasticizer. The desired water-sensitive and moldable attributes of the composition may be achieved in the present invention by selectively controlling a variety of aspects of the composition, such as the nature of the components employed, the relative amount of each component, the manner in which the composition is formed, and so forth.