CVS Caremark, the company that operates CVS retail pharmacies, will lay off up to 230 employees and close its mail-order pharmacy operation in Largo. The shutdown, effective March 31, affects the Caremark Pharmacy Services operation at 8275 Bryan Dairy Road in Largo. CVS Caremark sent notice to the state of the upcoming cuts but said it will try to place as many workers as possible in area CVS stores. CVS, based in Rhode Island, so far has suffered little impact from the recession. Earlier this month it raised its quarterly dividend 10.5 percent to 7.625 cents from 6.9 cents.