"in a remark" is correct and usable in written English.
You can use it to refer to a comment or statement that someone has just made. For example: "I was surprised by his attitude," she said in a remark.
In a remark he will never live down, he once called iPods "repositories of stolen music".
John Lennon mentioned the move in a remark in an interview in San Francisco in 1964.
"I'm not the only one in this condition," she said, in a remark that typified Japanese selflessness.
"I don't have a soul," says Courage in a remark sure to resonate well beyond the curtain call.
"I'm the cheerleader in this," he added, laughing, in a remark that played a bit with gender stereotypes.
The reason for it is found in a remark made by a little boy to his mother last week.
In a remark clearly aimed at Sir Ken, he said: "We are still paying for some of those [mistakes].
"We can't not suffer," or so we are told in "The Living Room" in a remark that one could imagine belonging to Chekhov.
But these things interest Mr Wood only as they twinkle "in the beady eye of eternity"—the phrase comes in a remark about Saul Bellow's characters.
In a remark that irritated some stranded drivers, he also said abandoned cars were preventing the government from properly clearing the roads.
In a remark that could function as the subtext for all the history to come, Solly observes, "They never made emancipation what they say it was".
