Just like many of his contemporary guitarists, Mauro Giuliani composed a number of studies to bring the pupils and guitar students to the level of virtuoso mastery. This certainly applies to the Studies Op. 48 and particularly to this example, Nr. 5. Developing speed in the sextuplets requires a special technique, called “planting”. Doing so, you place all your fingers on the strings at the moment you play with thumb, in preparation for the remainder of the arpeggio. The fingers are then closer to the strings they must play, which may provide an increase of speed.
For me, this technique was a bit uncomfortable in the beginning. Yet this study helps its development, provided you start very slooowly at first