NAPLEX Nonsterile Compounding Practice Questions with Answers

Preparing for the NAPLEX requires a deep understanding of the standards and techniques involved in preparing medications that do not require a sterile environment. Mastering NAPLEX Nonsterile Compounding is essential for ensuring patient safety and regulatory compliance in the pharmacy. This guide provides a comprehensive overview of USP <795> standards, compounding techniques, and calculations to help you excel on your exam.

To build a solid foundation for your board exams, you should also explore our NAPLEX Prep hub, which centralizes resources for all major testing categories. Whether you are calculating doses for NAPLEX Renal Therapeutics Practice Questions or managing complex regimens in NAPLEX Oncology Therapeutics Practice Questions, nonsterile compounding remains a core competency across various practice settings.

Concept Explanation

Nonsterile compounding is the process of combining, admixing, diluting, pooling, or otherwise altering a drug or bulk drug substance to create a medication tailored to the needs of an individual patient, as governed by USP Chapter <795>. Unlike sterile compounding, which is required for injections or ophthalmic preparations, nonsterile compounding is used for oral, topical, and rectal dosage forms. The primary goal is to provide a medication for a patient who cannot use a commercially available product, such as a child who needs a liquid version of a tablet or a patient with an allergy to an inactive ingredient.

Key components of nonsterile compounding include:

• USP <795> Standards: These regulations define the categories of compounding (Simple, Moderate, Complex), the requirements for the compounding environment, and the documentation needed, such as the Master Formulation Record (MFR) and the Compounding Record (CR).
• Beyond-Use Dates (BUD): These are dates after which a compounded preparation shall not be used. For nonsterile preparations, the default BUDs are determined by the water activity and formulation type:
  • Nonaqueous formulations: 6 months (180 days).
  • Water-containing oral formulations: 14 days (refrigerated).
  • Water-containing topical/dermal formulations: 30 days.
• Equipment and Techniques: Pharmacists must be proficient in using tools like mortars and pestles, ointment slabs, and electronic balances. Techniques such as trituration (grinding into a fine powder) and geometric dilution (mixing ingredients in equal portions) ensure a uniform distribution of the active ingredient.

For those looking to sharpen their skills under pressure, using an AI Exam Simulator can provide a realistic testing environment to practice these standards. Additionally, understanding the stability of medications is vital when reviewing NAPLEX Infectious Disease Practice Questions, where suspensions are frequently compounded.

Solved Examples

Example 1: Calculating Aliquots
A pharmacist needs to weigh 15 mg of a drug, but the balance has a Minimum Weighable Quantity (MWQ) of 120 mg. If the pharmacist uses 120 mg of the drug and dilutes it with lactose, how much lactose is needed to create a mixture where a 150 mg aliquot contains the 15 mg dose?

1. Identify the required dose: 15 mg.
2. Identify the amount weighed (MWQ): 120 mg.
3. Determine the dilution factor: $$\ \frac{120\ \text{ mg weighed}}{15\ \text{ mg needed}} = 8$$
4. Calculate the total weight of the mixture: $$150\ \text{ mg (aliquot)} \ \times 8 = 1,200\ \text{ mg total mixture}$$
5. Calculate the amount of diluent (lactose) needed: $$1,200\ \text{ mg (total)} - 120\ \text{ mg (drug)} = 1,080\ \text{ mg lactose}$$

Example 2: Determining Beyond-Use Date (BUD)
A pharmacist compounds a 1% hydrocortisone cream using a commercial moisturizing lotion and hydrocortisone powder. The preparation contains water. What is the default BUD according to USP <795>?

1. Identify the formulation type: Topical/dermal containing water.
2. Consult USP <795> guidelines: For water-containing topical nonsterile preparations, the BUD is 30 days.
3. Final answer: 30 days.

Example 3: Geometric Dilution
A pharmacist needs to mix 2 g of Active Pharmaceutical Ingredient (API) with 18 g of an ointment base. Describe the steps for geometric dilution.

1. Place the 2 g of API on the ointment slab.
2. Add an approximately equal amount (2 g) of the ointment base to the API and mix thoroughly.
3. Total weight is now 4 g. Add another 4 g of ointment base and mix.
4. Total weight is now 8 g. Add the remaining 10 g of ointment base and mix until uniform.

Practice Questions

1. According to USP <795>, what is the maximum BUD for a water-containing oral formulation stored at controlled cold temperatures?

2. A pharmacist is asked to compound 30 g of a 5% sulfur ointment. How many grams of sulfur powder and how many grams of petrolatum (the base) are required?

3. Which piece of equipment is most appropriate for mixing a liquid into a semi-solid cream to ensure a smooth, uniform texture?

4. Define the term "trituration" in the context of nonsterile compounding.

5. A Master Formulation Record (MFR) must include which of the following: the name of the compounder, the specific lot numbers of ingredients used, or the instructions for preparing the compound?

6. Calculate the Sensitivity Requirement (SR) of a balance if the Minimum Weighable Quantity (MWQ) is 150 mg and the acceptable error is 5%.

7. A pharmacist is compounding a nonaqueous capsule using only dry powders. What is the maximum BUD for this preparation?

8. Which type of mortar and pestle is best suited for mixing liquids or chemicals that may stain?

9. A prescription calls for 100 mL of a 2% (w/v) solution. If the pharmacist only has a 10% (w/v) stock solution, how many mL of stock solution and how many mL of diluent are needed?

10. What is the purpose of a "levigating agent" in the preparation of an ointment?

Answers & Explanations

1. Answer: 14 days.
   USP <795> states that water-containing oral formulations (such as suspensions or solutions) have a maximum BUD of 14 days when stored in a refrigerator.
2. Answer: 1.5 g sulfur and 28.5 g petrolatum.
   Calculation: $$30\ \text{ g} \ \times 0.05 = 1.5\ \text{ g sulfur}$$. The remaining weight is the base: $$30\ \text{ g} - 1.5\ \text{ g} = 28.5\ \text{ g}$$.
3. Answer: Glass Mortar and Pestle or an Ointment Slab (with spatula).
   Glass mortars are preferred for liquids and chemicals that can stain or for ensuring smooth mixing of semi-solids.
4. Answer: Grinding a substance to a fine powder.
   Trituration is the process of reducing the particle size of a solid by grinding it in a mortar.
5. Answer: Instructions for preparing the compound.
   The MFR is the "recipe" and includes instructions. The Compounding Record (CR) includes patient-specific info and lot numbers.
6. Answer: 7.5 mg.
   The formula is $$\ \text{MWQ} = \ \frac{\ \text{SR}}{\ \text{Error}}$$. Rearranging: $$\ \text{SR} = 150\ \text{ mg} \ \times 0.05 = 7.5\ \text{ mg}$$.
7. Answer: 6 months (180 days).
   Nonaqueous formulations (like powders or oils) have a maximum BUD of 6 months at room temperature.
8. Answer: Glass Mortar and Pestle.
   Glass is non-porous and does not absorb chemicals, making it ideal for staining agents or liquids.
9. Answer: 20 mL stock solution and 80 mL diluent.
   Using $$C_1V_1 = C_2V_2$$: $$10\% \ \times V_1 = 2\% \ \times 100\ \text{ mL} \ \rightarrow V_1 = 20\ \text{ mL}$$. Diluent = $$100 - 20 = 80\ \text{ mL}$$.
10. Answer: To reduce the particle size of a solid and aid in its incorporation into a base.
    Levigating agents (like mineral oil or glycerin) act as a "wetting agent" to create a smooth paste before adding the bulk base.

1. Which USP chapter provides the standards for nonsterile compounding?

• AUSP &lt;795&gt;
• BUSP &lt;797&gt;
• CUSP &lt;800&gt;
• DUSP &lt;71&gt;

Frequently Asked Questions

What is the difference between a Master Formulation Record and a Compounding Record?

The Master Formulation Record serves as the official "recipe" or template for a specific compound, while the Compounding Record is the log of a specific batch prepared for a specific patient, including lot numbers and expiration dates of ingredients.

Can I use a porcelain mortar for all nonsterile compounding?

While porcelain is excellent for reducing the particle size of dry crystals, it is porous and may absorb certain medications or stains, so glass is preferred for liquids and oily substances.

How is the beyond-use date determined if an ingredient expires sooner than the USP default?

The BUD can never exceed the earliest expiration date of any individual component used in the compound; you must always use the shorter of the two dates.

What is the purpose of using a levigating agent?

A levigating agent is used to wet a powder and reduce its particle size to create a smooth paste, preventing a "gritty" texture in the final ointment or cream.

When is a preparation classified as "Complex" compounding?

Compounding is classified as complex when it requires specialized training, facilities, or equipment, such as the preparation of transdermal patches or modified-release dosage forms.

Are nonsterile compounds required to be prepared in a laminar airflow workbench?

No, nonsterile compounds do not require a sterile environment or a laminar airflow workbench, but they must be prepared in a designated, clean area that meets USP <795> standards.