You can use the Export Clips as Files command to export audio clips to stereo or multichannel interleaved files for use in other applications. (Pro Tools cannot use interleaved files directly in the Timeline—these must be converted into multiple mono files.) For example, for this to work with a stereo file, the selected clips must have identical names with “.L” and “.R” suffixes (for instance, vocals_01.L and vocals_01.R). These clips appear as a stereo clip in the Clip List.
Pro Tools HD and Pro Tools with Complete Production Toolkit also let you bounce multichannel interleaved files of any supported file type.