Occurrence of Capping Due to Insufficient Air Escape during Tablet Compression and a Method to Prevent It

Abstract

A study was made on the capping of tablets containing d-α-tocopheryl acid succinate. The study determined that capping occurs due to insufficient air escape from the granules during high-speed tablet compression. To prevent this, removal of air in the granules was necessary before tableting, and thus a degassing method by compaction was studied. In consideration of the long time required for the air to escape from the granules by compaction, a slow but continuous compacting force is thought to be more effective for degassing than an instantaneous high compression force. Consequently, a system to expel the air from the lubricated granules by compaction due to the weight of the upper punch itself was established before the pre-compression roller stage, and its effect was evaluated. This system achieved efficient degassing of the granules before tableting and completely prevented the capping of tablets containing d-α-tocopheryl acid succinate at a high concentration.