A washpipe cartridge for carrying drilling mud in a top drive of a drilling assembly, the washpipe cartridge comprising: a housing adapted to fit between a stationary goose neck pipe of the top drive and a drill string, wherein the drill string is rotatable about a rotational axis, the housing comprising: a sleeve; and, a housing; wherein the sleeve is configured to provide the drilling mud to the drill string; and, wherein the housing is configured to receive drilling mud from the goose neck pipe; wherein disposed between the sleeve and the housing is a first seal, a second seal and a first gallery between the first seal and the second seal, and wherein the cartridge further comprises: a first gallery inlet for providing a first supply of barrier fluid to the first gallery; a second gallery inlet for providing a second supply of barrier fluid to the second seal, wherein the second gallery inlet is separated from the first gallery by the second seal.