Abstract: The invention provides a process for preparing a pharmaceutical composition comprising N-[(1-nbutyl-4-piperidinyl)methyl]-3,4-dihydro-2H-[1,3]oxazino[3,2-a]indole-10-carbixamide (pharmaceutical composition) (piboserod) or a pharmaceutically acceptable salt thereof in combination with one or more pharmaceutically acceptable excipients, the process comprising forming part or all of the (pharmaceutical composition) or the salt thereof into granules by a dry granulation process. The process is preferably a roller compaction process, preferably followed by milling to a suitable particle size. The granules are usually of increased particle size and/or compacted compared to the SB 207266 or the salt thereof. Preferably, the (pharmaceutical composition) or the salt thereof is present in the composition and/or in the granules in at least 4 weight % and/or up to 60 weight % by weight of the composition and/or by weight of the granules respectively. An intragranular lubricant, filler (e.g.