The sterilizing grade polyethersulfone membrane cartridges are designed to produce product sterility. The filters are constructed of double layer hydrophilic polyethersulfone membrane in all polypropylene construction. It offers broad chemical compatibility, high flow rate at low pressure drop, and low extractables. The polyethersulfone is particular suitable for the filtration of products that contains substances absorb to the membrane itself. The low protein binding characteristics of polyethersulfone makes it a good choice for the filtration of valuable protein solutions such as vaccines and biologicals.