Disparaging after extracting iodine around ring of bark? (8)

I believe the answer is:

cortical

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'disparaging after extracting iodine around ring of bark?' is the definition.
I can't judge whether this defines the answer.

'disparaging after extracting iodine around ring' is the wordplay.
'disparaging' becomes 'critical' (I've seen this in another clue).
'after extracting' indicates named letters should be taken away.
'iodine' becomes 'I' (chemical symbol).
'around' is an insertion indicator.
'ring' becomes 'O' (letter resembling a ring).
'critical' with 'i' removed is 'crtical'.
'crtical' placed around 'o' is 'CORTICAL'.

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I've seen this clue in The Times.

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