Pharmacy Technician Certification Exam (PTCE) Quiz: Drug Stability
19 questions · exam conditions
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Drug StabilityQuestion 1 of 19

According to United States Pharmacopeia (USP) guidelines, what is the maximum beyond-use date for a multi-dose injectable vial after it has been punctured for the first time, unless specified otherwise by the manufacturer?

14 days
28 days
60 days
Until the manufacturer's expiration date
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Pharmacy Technician Certification Exam (PTCE) Quiz

Pharmacy Technician Certification Exam (PTCE) Quiz: Drug Stability

Practice Drug Stability in Pharmacy Technician Certification Exam (PTCE) with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Drug Stability, giving you a quick way to practice the rules, question types, and explanations that matter most for Pharmacy Technician Certification Exam (PTCE).

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

According to United States Pharmacopeia (USP) guidelines, what is the maximum beyond-use date for a multi-dose injectable vial after it has been punctured for the first time, unless specified otherwise by the manufacturer?

  1. 14 days
  2. 28 days (correct answer)
  3. 60 days
  4. Until the manufacturer's expiration date
Explanation: USP Chapter <797> states that for a multi-dose vial, the beyond-use date is 28 days after the initial puncture, unless the manufacturer's package insert specifies a shorter duration. This helps prevent microbial contamination.

Question 2

A patient is prescribed Tresiba FlexTouch (insulin degludec). This long-acting insulin has a longer period of stability at room temperature after opening compared to many other insulins. What is its stability period?

  1. 28 days
  2. 42 days
  3. 56 days (correct answer)
  4. 90 days
Explanation: Tresiba FlexTouch pens are stable for 56 days (8 weeks) at room temperature after the first use. This is significantly longer than the typical 28-day stability of many other insulin products.

Question 3

An opened multi-dose vial of Humalog (insulin lispro) is being stored in a patient's home. What is the maximum number of days it can be used before it must be discarded, assuming it is stored correctly at room temperature?

  1. 14 days
  2. 28 days (correct answer)
  3. 31 days
  4. 42 days
Explanation: An opened vial of Humalog is stable for 28 days whether stored at room temperature or in the refrigerator. After 28 days, it should be discarded even if there is insulin remaining.

Question 4

A multi-dose vial of bacteriostatic water for injection, which contains an antimicrobial preservative, is punctured for the first time on March 1st. What is the correct beyond-use date to assign to this vial?

  1. March 2nd
  2. March 8th
  3. March 15th
  4. March 29th (correct answer)
Explanation: Multi-dose vials containing a preservative, such as bacteriostatic water, are stable for 28 days after the first entry. Therefore, the beyond-use date would be 28 days after March 1st, which is March 29th.

Question 5

An unopened vial of Humalog insulin, stored in the refrigerator, has a manufacturer's expiration date of November 30. If the vial is opened and first used on September 15 and kept at room temperature, what is the new beyond-use date for this vial?

  1. 28 days after September 15 (correct answer)
  2. 42 days after September 15
  3. September 30
  4. November 30
Explanation: Once an insulin vial is opened, its stability is determined by the in-use time frame, which is 28 days for Humalog. The manufacturer's original expiration date no longer applies, provided it is beyond the 28-day in-use period.

Question 6

A patient begins using a new Lantus SoloStar (insulin glargine) pen. After the first injection, how long is the pen stable when stored at controlled room temperature?

  1. 14 days
  2. 28 days (correct answer)
  3. 42 days
  4. 56 days
Explanation: Once in use, a Lantus SoloStar pen is stable for 28 days when stored at room temperature (up to 86°F or 30°C). It should not be refrigerated after the first use.

Question 7

A vial of Varivax (Varicella Virus Vaccine Live) is reconstituted. To ensure potency, the vaccine must be administered within what timeframe?

  1. 30 minutes (correct answer)
  2. 1 hour
  3. 8 hours
  4. 24 hours
Explanation: Reconstituted varicella vaccine is extremely unstable and must be discarded if not used within 30 minutes. Other vaccines, like MMR, have longer stability periods (e.g., 8 hours).

Question 8

A 1-gram vial of ceftriaxone is reconstituted with sterile water for injection in a hospital pharmacy. To maximize its stability, the solution should be refrigerated, which extends its usability to:

  1. 24 hours
  2. 48 hours
  3. 3 days
  4. 10 days (correct answer)
Explanation: While reconstituted ceftriaxone is stable for a shorter period at room temperature, its stability is extended to 10 days when stored under refrigeration, depending on concentration and diluent.

Question 9

A pharmacy must store its main supply of unopened insulin vials and pens. To maintain potency until the manufacturer's expiration date, these products must be stored in:

  1. a freezer
  2. a refrigerator (correct answer)
  3. a locked cabinet at room temperature
  4. a light-protected bin on a shelf
Explanation: Unopened insulin must be stored in a refrigerator (between 36°F and 46°F, or 2°C and 8°C) to ensure it remains stable until the manufacturer's expiration date. Freezing destroys insulin, and room temperature storage will shorten its shelf life.

Question 10

A pharmacy technician is preparing an oral suspension of cefdinir. What are the correct storage and stability guidelines for this medication after it is reconstituted?

  1. Store at room temperature; stable for 10 days. (correct answer)
  2. Refrigerate; stable for 10 days.
  3. Store at room temperature; stable for 14 days.
  4. Refrigerate; stable for 14 days.
Explanation: Reconstituted cefdinir oral suspension is stable for 10 days when stored at controlled room temperature. Unlike many other antibiotic suspensions, it does not require refrigeration.

Question 11

A vial of M-M-R II (Measles, Mumps, and Rubella Virus Vaccine Live) is reconstituted at 10:00 AM. What is the latest time this vaccine can be administered before it must be discarded?

  1. 10:30 AM
  2. 12:00 PM (noon)
  3. 6:00 PM (correct answer)
  4. 10:00 PM
Explanation: Reconstituted M-M-R II vaccine is stable for 8 hours. Therefore, if reconstituted at 10:00 AM, it must be used by 6:00 PM (18:00) of the same day.

Question 12

A technician reconstitutes a vial of Zovirax (acyclovir) powder for IV infusion. Due to the risk of precipitation, the reconstituted solution should be administered within:

  1. 1 hour
  2. 6 hours
  3. 12 hours (correct answer)
  4. 24 hours
Explanation: Reconstituted acyclovir solution is stable at room temperature for 12 hours. Using it beyond this time frame increases the risk of crystal formation (precipitation), which can be dangerous if infused.

Question 13

A technician reconstitutes a 100 mg Act-O-Vial of Solu-Cortef (hydrocortisone sodium succinate). According to the manufacturer, how long is the resulting solution stable for use?

  1. 1 hour
  2. 24 hours
  3. 3 days (correct answer)
  4. 7 days
Explanation: The package insert for Solu-Cortef in an Act-O-Vial states that after reconstitution, the solution is stable and must be used within 3 days.

Question 14

The Shingrix vaccine is supplied as a lyophilized powder that must be reconstituted with the provided adjuvant suspension. Once mixed, the vaccine must be used within:

  1. 30 minutes
  2. 1 hour
  3. 6 hours (correct answer)
  4. 24 hours
Explanation: According to the manufacturer, the reconstituted Shingrix vaccine is stable for 6 hours when stored in the refrigerator or at room temperature. It must be discarded if not used within this timeframe.

Question 15

A 1-gram vial of ampicillin for injection is reconstituted with sterile water. This antibiotic is known to be very unstable after mixing. If stored at room temperature, it must be used within:

  1. 1 hour (correct answer)
  2. 4 hours
  3. 8 hours
  4. 12 hours
Explanation: Reconstituted ampicillin for injection degrades rapidly at room temperature. It is stable for only 1 hour and must be administered within this short window to ensure its effectiveness.

Question 16

A technician reconstitutes a bottle of azithromycin oral suspension. What is the correct stability information for this medication once mixed?

  1. Stable for 5 days at room temperature.
  2. Stable for 10 days at room temperature. (correct answer)
  3. Stable for 10 days only if refrigerated.
  4. Stable for 14 days only if refrigerated.
Explanation: Unlike many other antibiotic suspensions, reconstituted azithromycin is stable for 10 days at controlled room temperature and should not be refrigerated.

Question 17

After its first use, a Levemir FlexTouch (insulin detemir) pen can be kept at room temperature for a maximum of:

  1. 28 days
  2. 30 days
  3. 42 days (correct answer)
  4. 56 days
Explanation: Levemir FlexTouch pens are an exception to the common 28-day rule for many insulins. They are stable for 42 days (6 weeks) at room temperature after being opened.

Question 18

A patient using a NovoLog FlexPen (insulin aspart) asks for storage instructions for the pen currently in use. What is the correct advice regarding its storage and stability?

  1. Refrigerate for up to 42 days.
  2. Keep at room temperature for up to 14 days.
  3. Keep at room temperature for up to 28 days. (correct answer)
  4. Refrigerate for up to 28 days.
Explanation: Once a NovoLog FlexPen is in use, it should be stored at room temperature (not refrigerated, as this can affect dosing accuracy) and is stable for 28 days. Any unused insulin should be discarded after this period.

Question 19

A prescription for Augmentin (amoxicillin/clavulanate) oral suspension is prepared. What are the proper storage instructions and beyond-use date after reconstitution?

  1. Must be refrigerated; discard after 10 days. (correct answer)
  2. Store at room temperature; discard after 10 days.
  3. Must be refrigerated; discard after 14 days.
  4. Store at room temperature; discard after 14 days.
Explanation: Due to the clavulanate component, reconstituted Augmentin suspension is less stable than plain amoxicillin. It must be refrigerated and is only stable for 10 days.