Is zakat obligatory on a sum of 97,0 Saudi Riyals (50,0 Riyals as a loan and 47,0 Riyals as a donation) that was not used for the treatment for which it was collected, and a full year has passed since its collection?

There is no zakat on borrowed money unless there is non-zakatable money sufficient to cover the debt. Zakat is obligatory on donated money if it reaches the nisab and a full year has passed over it, even if it is saved for medical treatment.