Filtration Of Viscous Materials For Microbial QC

Membrane filtration is the preferred method for sterility testing. Viscous products, such as oils, creams and ointments can prove difficult to filter. As per USP <71> viscous oils may be diluted as necessary with a suitable sterile diluent such as isopropyl myristate shown not to have antimicrobial activity in the conditions of the test. Sterile isopropyl myristate (IPM), has been shown to have no anti-microbial activity in test conditions. This study investigates the effectiveness of IPM as a diluent by comparing filtration times with unfiltered oils.