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:
These steps should be followed when using an ampule to prepare a product:
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.
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:
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
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?
1 hour/60 min X 1000 ml/8 hours
hour/60 min X 1000 ml/8 hours
1000 ml/60 min=16.66 ml/min
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:
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
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:
How many ml’s of a 60% solution and a 25% solution are needed to make 700 ml of 30% solution?
Answer a: 20ml/part x 5 parts = 100ml of 60% solution
Answer b: 20ml/part x 30 = 600ml of 25% solution