A syrup with noscapine tastes very acidic. How can I correct that sour flavour?

There is a composition for a noscapin syrup. You can set it as an example  

R/Noscapine HCl 160 mg;   Vaniilline 5 mg;   Mint spiritus   5 ml, alcohol 5 ml,   citric acid syrup PB V 80 g and sugar syrup AD 100 ml  

Citric acid syrup PB V: Citric acid 2 G; water 2 g; Lemon spiritus 2 g; sugar syrup 94 g