Regarding pka of Norepinephrine bitartarte

Question

Norepinephrine bitartrate has two Pka values pka1=8.85(strongest basic) and pka2=9.5 (Strongest acidic)

1. How a Pka value of 9.5 represents strongly acidic?
2. Does this Norepinephrine bitartrate is an acidic or basic drug?

Below is the link that I have searched about this pka value.

https://go.drugbank.com/salts/DBSALT001247.

Can anyone please help me to get clear about this doubt?

Answer 1

Norepinephrine itself is a base (free amine group).

1). pKa of 9.5 cannot represent a stronger acidic group than one with pKa of 8.85. This is incorrect.

2). The bitartrate salt of norepinephrine would be acidic because of the two acidic groups on tartaric acid and because tartaric acid is a stronger acid than NE is a base. Hydrolysis of this salt would result in a pH <7.