Medic, female, penning article in a brown study (8)
I believe the answer is:
dreamily
'in a brown study' is the definition.
(old-fashioned phrase meaning 'dreamily')
'medic female penning article' is the wordplay.
'medic' becomes 'dr'.
'female' becomes 'emily' (**).
'penning' is an insertion indicator.
'article' becomes 'a' (indefinite article).
'emily' placed around 'a' is 'eamily'.
'dr'+'eamily'='DREAMILY'
(Other definitions for dreamily that I've seen before include "As if in a reverie" , "Vaguely" , "in abstracted way" .)