Membrane filtration is the Pharmacopoeia method of choice for sterility testing. Viscous products, such as creams and ointments, can be difficult to filter and are normally diluted in a sterile solvent, such as Isopropyl Myristate (IPM). Testing such products may be problematic if specific testing procedures are not implemented and appropriate devices are not used. The Steritest™ NEO device, TZHVSL210, is the perfect choice for testing solvents, creams, ointments and veterinary injectables due to the solvent-resistant nylon canister, Durapore® (PVDF) membrane, reinforced base structure and canister connection.
Steritest™ Symbio Pump: for Laminar Flow Hood or Isolator.
Note: In our experiments, poor rinsing was observed when the membrane filter was covered with liquid throughout the filtration steps. To avoid this, the entire volume of test article was allowed to filter through the Steritest™ NEO devices, followed by the entire volume (of each) Fluid K rinse.
According to Pharmacopoeias, method suitability must be tested for proper recovery. Inoculate the last Fluid rinse with not more than 100 CFU with the microorganisms recommended in the Pharmacopoeias. Environmental isolates can also be tested. When the filtration is complete, add media (SCDB and FTM) to the canisters and incubate for the proper time and temperature, following Pharmacopoeia recommendations. Then observe the canisters and see if growth Pharmacopoeia acceptance criteria are met.
Note: In case of direct inoculation of microorganisms into IPM, addition of 9% of NaCl Peptone buffer ensures recovery rate above 50%.