Recycling of pharmaceutical waste gelatin for controlled-release applications. I. A 2,4-dicholorphenoxy acetic acid based system



Gelatin is a natural macromolecular protein. It contains a wide variety of amino acids in its polymer structure, and it is colorless to yellowish, water-soluble, and tasteless. It is used as a dispersing agent, sizing medium, and coating for photographic films and in pharmaceutical formulations. In this study, biodegradable mulching, based on waste gelatin from pharmaceutical gelatin scraps (derived from pharmaceutical soft gelatin capsule production), was formulated via the casting of water solutions or suspensions into flexible and consistent films. Gelatin was blended with synthetic materials such as poly(vinyl alcohol) and other natural wastes such as sugar cane bagasse and sawdust. To all formulations, 2,4-dichlorophenoxy acetic acid (2,4-D) was added as a herbicide. The morphology and mechanical properties of the samples were investigated with scanning electron microscopy and tensile testing, respectively. The results showed that the produced films had controlled-release properties. The effects of various additives and crosslinking on the films and the release of the herbicide 2,4-D from the films were also investigated. The introduction of synthetic and natural additives reduced the release rate of 2,4-D. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2313–2319, 2004