Eye dropper bottles is made with LDPE polymer, and LDPE usually sensitive for temprature, before blowing easy to shrink and make bottom weak, especially side cavities. So usually make eye dropper bottles on small IBM machine for easy quality check.
Victor use speical temprature control for machine and mold, make multi cavity mold temperature even, then can make 5 to 15ml eye dropper bottles in 18 cavities on IBM machine MSZ70/MSZ70S.

Material: suggest PP material good tensile, not breaking the cap topside.
Mold design
A.Ejection by force
Character: mold cost is cheaper , but easily slip on the bottle neck .
B.Unscrewing jection
Character: mold price is higher, but good fitment for the bottle without any slipping on the bottle neck area.
C.Cap mold, suggested to make hot runner, save raw material, excellent cap products.
Material :LDPE
Mold structure: cold runner or semi-hot runner
Nozzle mold , suggested semi-hot runner, save raw material cost.