Agree.
I would introduce the following categories:
Systemic
subsumes
Systemic Parenteral , Systemic Enteral , Systemic Topical (Nicotine patches are probably the systemic topical).
Local
Subsumes
Local topical, local intra-organ
And link SNOMED concepts to them
Injection without notion of systemic or local doesn’t make sense for me as, for example, intravenous and intraarticular injections have totally different clinical meaning.