Health Net Inc. plans to sell its Medicare Part D prescription drug plan business to a subsidiary of retail drug store operator CVS Caremark Corp. for $160 million.

The Woodland Hills managed care provider on Monday said the drug plan has about 400,000 members in 49 states and the District of Columbia, and produces roughly $490 million in annual revenue. It expects to net $140 million cash from the deal.

In addition to its drug stores, CVS Caremark is one of the nation’s largest pharmacy benefits managers. It’s the second such acquisition for the Woonsocket, R.I. company in the past year.

“We believe this proposed transaction is in the best interests of our Medicare (Part D Plan) members and our stockholders,” said Chief Executive Jay Gellert in a statement.

“Our Medicare PDP members, who have received certain services from CVS Caremark for five years, will now be affiliated with one of the nation’s largest Medicare PDP sponsors.”

The deal must be reviewed by antitrust regulators and is expected to close in the second quarter.

Health Net shares were down 4 cents, or less than 1 percent, to $32.74 in midday trading on the New York Stock Exchange.