Chitosan is not a common excipient for direct compression due to poor flowability and inadequate compressibility. Co-processing of chitosan and kaolin is a challenging method to overcome the limitations of the individual excipients. The purpose of the present study was to develop co-processed chitosan-kaolin by the spray drying technique (rotary atomizer spray dryer) and to characterize the excipient properties. The formation of chitosan nanoparticles was the major factor for desirable tablet hardness. The ratio of chitosan/tripolyphosphate of 10:1 and 20:1 had a significant effect on hardness. The successful development of co-processed chitosan-kaolin as a novel tablet excipient was obtained from a feed formulation composed of chitosan and kaolin at a ratio of 55:45 and the optimum chitosan/tripolyphosphate ratio of 20:1. Co-processing altered the physical properties of co-processed chitosan-kaolin in such a way that it enhanced the flowability and tableting performance compared to the physical mixture.
Keywords: chitosan; co-processing; kaolin; nanoparticles; spray drying.