CSPT Sterilization Methods and Filtration Technology

Question 1

What is the minimum membrane filter pore size required to achieve sterilization by filtration of a compounded sterile preparation?

Accepted Answer

0.22 micron

Answer

A pore size of ≤0.22 micron (also stated as 0.2 micron) is required for sterilizing-grade filtration because it retains bacteria. Larger pore sizes (0.45 micron) are used for clarification, not sterilization.

Question 2

What are the standard parameters for terminal sterilization of a preparation by moist heat (autoclave)?

Accepted Answer

121°C for a minimum of 15 minutes at 15 psi

Answer

The standard autoclave cycle is 121°C at 15 psi for at least 15 minutes. This combination of temperature and pressure is sufficient to achieve a sterility assurance level (SAL) of 10⁻⁶ for terminally sterilized preparations.

Question 3

Which sterilization method is MOST appropriate for a heat-sensitive aqueous drug that cannot withstand autoclave temperatures?

Accepted Answer

Membrane filtration through a 0.22-micron sterilizing-grade filter

Answer

Membrane filtration through a ≤0.22-micron filter is the preferred method for heat-sensitive aqueous preparations. It removes bacteria and fungi without exposing the drug to destructive temperatures. Ethylene oxide is used for devices, and dry heat/radiation are not practical for liquids.

Question 4

What is 'depyrogenation,' and which method is most commonly used to achieve it on glassware and equipment?

Accepted Answer

Removal of endotoxins; dry heat at ≥250°C for at least 30 minutes

Answer

Depyrogenation is the destruction or removal of pyrogens (primarily bacterial endotoxins). Endotoxins are heat-stable and survive standard autoclaving; dry heat at ≥250°C for ≥30 minutes is required to destroy them on glassware and stainless steel.

Question 5

After filtering a compounded sterile preparation through a 0.22-micron membrane filter, a bubble point integrity test is performed. What does this test confirm?

Accepted Answer

That the filter membrane is intact and was not compromised during filtration

Answer

The bubble point integrity test verifies that the filter membrane has not been punctured, torn, or otherwise compromised. A breached filter could allow microorganisms to pass through, invalidating the sterilization process. USP <797> requires post-filtration integrity testing for high-risk CSPs.

CSPT - Compounded Sterile Preparation Technician Practice Test

CSPT - Compounded Sterile Preparation Technician Practice Test

CSPT Sterilization Methods and Filtration Technology