Development of Coprocessed Chitin-Calcium Carbonate as Multifunctional Tablet Excipient for Direct Compression

Abstract Due to the increasing interest in multifunctional excipients for tableting, coprocessing of individual excipients is regularly used to produce excipients of improved multifunctionality superior to that of individual excipients or their physical mix. The use of chitin as an excipient in tablet formulation is limited due to certain drawbacks such as poor flowability and low true density. The objective of this work is to improve these properties through coprocessing of chitin with calcium carbonate (CaCO 3 ) by precipitating CaCO 3 on chitin particles using different methods. In addition, optimization of the coprocessed chitin was carried out to improve the excipient's properties. Physico-chemical (CaCO 3 content, true density, X-ray diffraction, infrared spectroscopy and scanning electron microscopy) and functional testing (swelling force, flowability, tensile strength, deformation mechanism and disintegration time) were used to characterize the coprocessed product. Results showed that the calcite CaCO 3 polymorph is precipitated on the chitin surface, and that it interacts with chitin at carbonyl and amide groups level. In addition, the coprocessed excipient has an improved true density and powder flowability with CaCO 3 forming single layer on the chitin particles surface. Tableting studies showed that the coprocessed powder exhibited an intermediate deformation behavior between that of CaCO 3 (most brittle) and chitin (most plastic). Tablets showed acceptable tensile strength and rapid disintegration (2-4s). These results show the potential use of coprocessed chitin-CaCO 3 as a multifunctional excipient for fast disintegrating tablets produced by direct compression.