The phrase "it is important to note however" is correct and usable in written English. You can use it when you want to emphasize a point or introduce an alternative point of view. For example: Taking public transportation is a great way to reduce your environmental impact; it is important to note however, that carpooling is also a great option.
It is important to note, however, that the cappuccino is a breakfast food.
It is important to note, however, that this new label does not mean extinction is a foregone conclusion.
It is important to note, however, that the game isn't 2D.
It is important to note, however, that the connection of required interfaces is optional.
It is important to note however, that Lammers study excluded patients with intra-oral lacerations [6].
It is important to note however that their higher potency makes them better than commercial surfactant.
It is important to note, however, that these responses can be affected by sex [100, 101].
Awesome tool! I started using it one year ago and I never had to look for another app
Ha Thuy Vy
MA of Applied Linguistic, Maquarie University, Australia