Page 2 Sterile and Non-Sterile Compounding Study Guide for the PTCB Pharmacy Technician Certification Exam

Sterile Compounding Processes

Prior to completing any sterile compounding, the work area should be cleaned and the preparer should put on all their PPE as described previously. Once all equipment is set up, all the materials needed to make the product should be brought into the hood and placed as to not block the airflow across any sterile component.

These steps should be followed when using a vial to prepare a product:

  1. Remove the plastic cap and swab the vial stopper with 70% isopropyl alcohol.
  2. Swab all sterile surfaces being used during manipulation such as all vials and the injection port on the IV bag.
  3. Uncap needle and withdraw a volume of air equal to the desired volume of liquid to be extracted.
  4. Insert the needle into the vial at a 45-degree angle and the bevel side up (to avoid coring the vial) and then straighten out the needle. Do not block the airflow from the laminar flow hood.
  5. Push air into the vial and extract the desired volume.
  6. Remove the needle and inject contents into the IV bag through the specified port.
  7. Discard the needle in the sharps container and throw all other waste in the appropriate trash bin.

These steps should be followed when using an ampule to prepare a product:

  1. Swab the ampule with 70% isopropyl alcohol, especially in the neck (thinnest) area.
  2. Swab all sterile surfaces being used during manipulation such as all vials and the injection port on the IV bag.
  3. Covering the ampule with an alcohol swab, grip the top of the ampule and bottom of the ampule with the thumb and index finger of each hand (one hand on top, the other on the bottom).
  4. With a quick motion, snap the ampule at the neck being careful not to break it toward the HEPA filter (break toward the side of the hood).
  5. Uncap the filter needle and insert the needle into the ampule at a 45-degree angle. Do not block the airflow from the laminar flow hood.
  6. Extract the desired volume and remove needle.
  7. Remove the filter needle and attach a regular needle.
  8. Inject contents into the IV bag through the specified port.
  9. Discard the needle and ampule in the sharps container and throw all other waste in the appropriate trash bin.

Safety

To ensure safety, only one person should be involved in compounding a single product. All waste materials should be discarded in appropriate receptacles. Syringes with attached needles should be inserted into the sharps container with the needle facing downward. It is important to never recap the needle.

Calculations

Preparing IV products may require calculations to determine the exact volume that is needed from a vial to be injected into the IV bag for the required dose. Please consider these example calculations:

Example 1:

Vancomycin vials contain 50mg/ml. How many ml would be required to make a final product containing 750mg?

Answer: 750 mg x 1 ml/50 mg = 15 ml

Example 2:

Amiodarone vials contain 150 mg/3 ml. How many ml are required to make an IV bag containing 500 mg?

Answer: 500 mg x 3 ml/150 mg= 10 ml

Another key type of calculation is the determination of the rate of infusion of the final IV product. The rate is based on volume over time and may be expressed as ml/min or ml/hr. The infusion rate can be determined by dividing the total volume of the IV bag over the total time of the infusion to figure out the specific rate.

Example: What is the rate of infusion for a 1000 ml IV bag administered over 8 hours?

Answer:

1 hour/60 min X 1000 ml/8 hours
1 hour/60 min X 1000 ml/8 hours
1000 ml/60 min=16.66 ml/min

Nonsterile Compounding Processes

Nonsterile compounding refers to any preparation that does not meet the standards for sterile compounding and must follow USP 795 regulations.This includes wearing the proper PPE and ensuring a clean work area before beginning any preparations. Because of the diversity in types of compounds, the procedures can very drastically but follow some general steps:

  1. Using the prescription, create a formula for the intended product including any calculations and specific amounts of ingredients needed.
  2. Wash hands and put on all required PPE.
  3. Obtain any hardware supplies such as a balance or graduated cylinder.
  4. Weigh/measure out all ingredients using the proper measurement tools.
  5. Following the recipe, combine the ingredients in the correct ratios and in the proper order.
  6. Document the exact amounts used and label the final product including final strengths of ingredients.

Calculations

It is important to note that preparing nonsterile products also requires calculations to determine the exact amounts needed of each ingredient to make the final product in the correct strength. Many prescriptions are written in percentage strengths, which can sometimes be confusing depending on what type of preparation it is. There are three main types of percentage strengths:

Weight/weight (w/w%)—measured in grams of the ingredient/100 grams of the total product

Volume/volume (v/v%)—measured in ml of the ingredient/100ml of the total product

Weight/volume (w/v%)—measured in grams of the ingredient/100 ml of the total product

Example:

If 20 mg of aspirin powder is dissolved in 50 ml of water, what is the final weight/volume percentage strength?

Answer: 20 mg/50 ml x 100 ml = 10 mg/100 ml or 10% aspirin in water

Another type of calculation commonly seen is the allegation method, which allows you to prepare a concentration of solution from two other solutions of the same ingredients but in different strengths. One solution needs to be a higher strength and the other a lower strength than the desired concentration of the final product. Using the differences in % strengths, the number of “parts” of each can be determined, and the volume of each part can be calculated based on the total solution volume of the desired product. See the example calculations below:

  1. # of parts for higher % solution = Desired % in final product - lower % solution Answer = C - B
  2. # of parts for lower % solution = Higher % solution - Desired % in final product Answer = A - C
  3. Add the number of parts together to get a total number of parts.
  4. Divide the final volume of the desired product by the total number of parts to get ml/part.
  5. Multiply the number of parts for each % solution by the ml/part. To get the volume of each solution, you need to combine [how much of the high % and low % solution to add, respectively] to get the desired final product.

Example:

How many ml’s of a 60% solution and a 15% solution are needed to make 700 ml of 30% solution?

  1. # of parts for higher % solution = Desired % in final product - lower % solution
    Answer: 30 - 25 = 5
  2. # of parts for lower % solution = Higher % solution - Desired % in final product
    Answer: 60 - 30 = 30
  3. Add the number of parts together to get a total number of parts.
    Answer: 30 + 5 = 35 total parts
  4. Divide the final volume of the desired product by the total number of parts to get ml/part.
    Answer: 700/35 parts = 20ml/part
  5. Multiply the number of parts for each % solution by the ml/part. To get the volume of each solution, you need to combine [how much of the high % and low % solution to add, respectively] to get the desired final product.

Answer a: 20ml/part x 5 parts = 100ml of 60% solution
Answer b: 20ml/part x 30 = 600ml of 25% solution