Compression of enteric-coated pellets to disintegrating tablets

Enteric-coated sucrose pellets containing a layer of bisacodyl beneath the coating were compressed into tablets on an instrumented single-punch machine using four different filler-binders for direct compression. Different copolymers based on polymethacrylates were applied as coatings. Pellets of two different crushing strengths were used. The quality of the films before and after tableting was evaluated by determining the amount of bisacodyl liberated after treatment for 2 h in 0.1 M HCl according to the requirements of USP 23 for enteric-coated preparations. Results indicate that the most important parameters are the coating agent itself and the amount of coating applied to the pellets. Higher coating weights and coatings with better elastic properties lead to formulations, which liberate less bisacodyl after compression. Formulations are available that fulfil all requirements of USP 23 regarding enteric-coated preparations.