PTFE syringe filter is hydrophobic and so is not recommended for the filtration of aqueous solution. For filtering aqueous solution PTFE requires pre-wetting with alcohol to establish flow with reasonable pressure differentials.
The Millex® Filter Unit, designed for small-volume sterilization and clarification of pharmacy solutions. Like all Millipore filters, Millex units are built with quality in mind. Raw materials are carefully inspected before being used and stringent control is exercised over the manufacturing process.