CSPT Non-Sterile to Sterile Compounding 4 — Questions and Answers
Question 1: When converting a non-sterile bulk powder to a sterile injectable, which sterilization method is preferred for heat-stable compounds?
- Sterile filtration through 0.22 µm membrane
- Autoclaving (moist heat sterilization) (Correct answer)
- Dry heat oven at 250°C
- UV irradiation
Correct answer: Autoclaving (moist heat sterilization)
Autoclaving (moist heat) at 121°C for at least 15 minutes is the preferred terminal sterilization method for heat-stable compounded sterile preparations.
Question 2: A pharmacist determines that a non-sterile API cannot withstand heat sterilization. Which alternative sterilization method should be used?
- Gamma irradiation
- Ethylene oxide gas
- Sterile filtration through a 0.22 µm filter (Correct answer)
- Ultraviolet light exposure for 30 minutes
Correct answer: Sterile filtration through a 0.22 µm filter
Sterile filtration through a 0.22 µm (or smaller) membrane filter is the standard alternative sterilization method for heat-labile compounds.
Question 3: Which documentation must be completed BEFORE beginning a non-sterile to sterile compounding process?
- Post-preparation sterility test results
- Master formulation record review and compounding record initiation (Correct answer)
- Final product release certificate
- Patient administration log
Correct answer: Master formulation record review and compounding record initiation
The master formulation record must be reviewed and a compounding record initiated prior to starting any compounding process to ensure accuracy and traceability.
Question 4: What is the primary purpose of conducting a filter integrity test (bubble point test) after sterile filtration?
- To confirm the filter removed endotoxins
- To verify the filter membrane was not compromised during filtration (Correct answer)
- To measure the particle count in the filtrate
- To determine the osmolality of the final preparation
Correct answer: To verify the filter membrane was not compromised during filtration
A post-filtration bubble point test confirms the filter membrane remained intact and was not ruptured, ensuring the filtration achieved sterilization.
Question 5: When dissolving a non-sterile powder for subsequent sterile filtration, which quality attribute of the solvent is critical?
- The solvent must be at room temperature only
- The solvent must be sterile-grade or Water for Injection (WFI) (Correct answer)
- The solvent must be filtered through a 5 µm pre-filter only
- The solvent must be freshly autoclaved within 72 hours
Correct answer: The solvent must be sterile-grade or Water for Injection (WFI)
Sterile-grade solvents or Water for Injection must be used to minimize bioburden before final 0.22 µm sterile filtration.
Question 6: A compounding technician is preparing a sterile ophthalmic solution from a non-sterile API. What tonicity adjustment is typically required?
- The preparation must be hypotonic (below 0.9% NaCl equivalent)
- The preparation should be isotonic (approximately 0.9% NaCl equivalent) (Correct answer)
- The preparation must be hypertonic for increased drug absorption
- Tonicity is not relevant for ophthalmic preparations
Correct answer: The preparation should be isotonic (approximately 0.9% NaCl equivalent)
Ophthalmic preparations should be isotonic (equivalent to 0.9% NaCl) to prevent irritation and maintain patient comfort.
Question 7: Under USP <797>, which category of compounded sterile preparations (CSPs) requires the most stringent environmental monitoring and testing?
- Category 1 CSPs with short beyond-use dates
- Category 2 CSPs intended for longer storage periods (Correct answer)
- Radiopharmaceuticals compounded on-site
- Immediate-use CSPs prepared at the patient bedside
Correct answer: Category 2 CSPs intended for longer storage periods
Category 2 CSPs, which are assigned longer beyond-use dates, require the most stringent environmental monitoring, personnel qualification, and quality testing under USP <797>.
