What is the ruling on the salty secretions that a fasting person feels in their mouth, do they invalidate their fasting and prayer?

Tears that descend through the nasal canal do not invalidate the fast due to the difficulty of avoiding them. However, for tears that descend directly from the face into the mouth, intentionally swallowing them invalidates the fast if they are abundant. As for a small amount, like one or two drops, it does not break the fast.