Claudine's main Artifice is her Opening Act burn, which essentially removes 50% of your team's HP. Her secondary Artifice is her end-turn burn, which ticks immediately. Treat it as a 2% reduction in team HP every turn.
Using burn guard or cleanse. Mitigating the opening act is most important, as the subsequent burns are very weak and shouldn't do much.
Alternatively, you could simply burst her down quickly.
This boss has not appeared in an extended number of rotations and hence will not be further updated.
1) Budget Clearance Event
Two welfares! One of the wrong element, too. This clear hinges on getting Nurse Yachiyo's burn clear once, and then doing your best to chop down Claudine. Her low damage means that Lu Bu can, depending on US level, singlehandedly delete 60-75% of Claudine's HP if you send her in solo. With her occupying the backmost slot in such a team, victory is rather easy.
Other cleansers such as Sherlock Hikari, Oyuyu, or Salai Mahiru are usable as well.
Sample 1
1) Moooooooons.
Stacking up a decent amount of moon power is also more than enough to clear this boss. Zero to one tanks, everyone else on offense. If you have a US21 Musketeer Mahiru, use her.
2) The Kingdom of the Night
Tsukuyomi? yawns and solos the boss. 4AP-1AP-1AP your way to victory.