The purpose of this research is to determine several characteristics of chitosan lactate in tablet form such as dimensional changes, gel evolution, swelling (liquid uptake), and erosion using an image analysis method. The examination of these characteristics will be helpful in the design of oral drug delivery systems with this polymer. It has been demonstrated that image analysis is a valuable technique, allowing the study of quantitative measurements of dimensional and core changes and gel evolution. The dimensional expansion changes of the chitosan lactate tablets were greater in water, and the crushing strength and the stirring effect affected these attributes to a limited extent. The fastest and greatest liquid uptake was observed in water, whereas the greatest erosion was observed in HCl. The thickness of the gel layer increased considerably with time up to the eighth hour, indicating the formation and development of a thick and durable gel, particularly in water. This is an essential characteristic for potential sustained drug release delivery. Consequently, this polymer appears to be a versatile material and a promising vehicle for the preparation of various oral sustained release medications and relevant devices. (C) 2009 Wiley Periodicals, Inc. Adv Polym Techn 28: 32-39, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20147