Formulation and in vivo imaging evaluation of colonic targeting tablets prepared by a simple dry powder coating technique

Purpose: The study aimed firstly to determine the release behavior of the model drug (berberine chloride) from the dry coated tablets. The second objective of this study was to evaluate the exact location of the dry coated tablets in in vivo. Methods: The colon targeting tablets were developed by dry powder coating technique on pan coater. The drug release behavior was determined in the three continuous mediums: pH 1.2; 7.4 and 6.8 plus pectinase. The location of the dry coated tablets in the gastrointestinal tract of human volunteers was observed through the X-ray imaging of the dry coated tablets containing the optimized radiocontrast agents. Results: The release kinetics of berberine chloride from the dry coated tablets was mainly controlled by erosion and enzyme sensitive mechanism. The optimum dry coated tablets having the coating powders of pectin 102:HPMC K4 M (2:1) with the coating level of 200%, and the tablet core with BaSO4 10% and iobitridol 30% as radiocontrast agents were observed in the caecum and ascending colon of human volunteers after 5–6 h of oral administration. Conclusion: The successful development of these dosage forms is believed to have a high potential in precisely monitoring the release of highly potent drugs such as anti-inflammatory drugs in bowel diseases. © 2019, The Korean Society of Pharmaceutical Sciences and Technology.