Paul W S Heng 

GEA-NUS Pharmaceutical Processing Research Laboratory, Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore 

Multiparticulate delivery systems are increasingly popular but the encapsulation of multiparticulates in capsules is not an attractive option due to a variety of reasons. Thus, many pharmaceutical companies are keen to present multiparticulates as the highly popular tablet dosage form or commonly referred to as multi-unit pellet system (MUPS) tablets. As multiparticulates for controlled release would often involve barrier coated particulates for sustained drug release, the application of compaction force to fabricate MUPS tablets could also damage the barrier coats in the formulation. Thus, successful MUPS tableting would require good formulation design and the appropriate compaction attributes. While many proposals for formulation designs and compaction strategies have been reported in literature, the precise understanding of the consequences which occur when coated particulates are compacted is still not clearly understood. For a biaxial compaction cycle, the locality of a coated particulate in the compact may be important as the distribution of compaction pressure in a compact is non-uniform, creating a heterogeneous density map within the compact. Thus, understanding the locality of a coated particulate with respect to the extent of damage could help in the design of MUPS tablets, in terms of force application and tool design along with pellet and formulation attributes. This presentation will critically discuss the factors contributory to pellet coat damage, with experimental findings to support the discussion. The impact of compaction pressure on coat damage with respect to its barrier properties will also be discussed. This presentation will also discuss how compaction forces affect coated multiparticulates and the consequences of damage to barrier coatings. Studies were designed to specifically elicit the compaction related damage to barrier coat by single coated pellet compaction. Formulation designs and mechanical strategies to ameliorate compaction damage will also be examined. In particular, the design of sacrificial fillers. With a good understanding of compaction induced damage to barrier coats in MUPS tableting and the judicious selection of available technical options to fabricate MUPS tablets, good quality MUPS tablets can be produced with release properties close to that from coated particulates presented in capsule dosage form.