10 Chapter 10: Preparing Different Types of Compounds

In this chapter, we will discuss general procedures on how to make various different types of preparations.  All Pharmacy compounding should follow a Master Formulation Record.

How to incorporate a powder or liquid into an ointment or cream

1. Gather all ingredients and appropriate equipment
2. Weigh, measure and label all ingredients
3. If necessary, triturate solid ingredients into a fine powder using a mortar and pestle
4. Levigate a small amount of the base ointment or cream with the powder or liquid to form a uniform, smooth paste
5. Using the principles of geometric dilution, gradually add more base to the paste, levigating after each addition to ensure uniform distribution
6. Weigh empty ointment pot, transfer into ointment pot and calculate yield
7. Package and label, including BUD

How to incorporate a powder into an ointment to create a paste:

1. Gather all ingredients and appropriate equipment
2. Weigh, measure and label all ingredients
3. If necessary, triturate solid ingredients into a fine powder using a mortar and pestle
4. Transfer powder  to the middle of the glass slab. If there are more than one powder, the powders can be combined together.
5. Transfer the white petrolatum to the top corner of the glass slab.
6. Levigate a small portion of ointment into the powder with a spatula. Spatulate until smooth thick paste is formed.
7. Once all of the powder is incorporated into the ointment, incorporate any remaining ointment by geometric dilution.
8. Weigh empty ointment pot
9. Transfer the paste into the ointment pot
10. Weigh final product and calculate yield and complete quality assurance checks
11. Label and ensure pharmaceutical elegance

How to make a solution:

1. Gather all ingredients and appropriate equipment.
2. Calibrate prescription oval if necessary
3. Measure the solvent. Add solutes such as APIs, preservatives, sweeteners, and flavoring agents to the solvent in the correct order.
4. Stir to ensure complete dissolution. Heat may be necessary, for instance, gently warming for poorly soluble drugs. Some drugs may require pH adjustment for solubility or stability.
5. Once all solutes are fully dissolved, bring the solution to final volume.
6. Mix thoroughly to ensure homogeneity.
7. Filter solution if needed to remove undissolved particles or to clarify the solution.
8. Package and label, including storage and beyond use dating.

How to Compound a Suspension

1. Gather all ingredients and equipment required.
2. Calibrate prescription oval to final volume.
3. Triturate the active ingredient if required using mortar and pestle.
4. Place powder into mortar. Wet the powder with a small amount of wetting agent or vehicle. Levigate to make a smooth, homogenous paste.
5. Add a small amount of vehicle (suspending agent) to the paste and mix thoroughly. Geometric dilution is applicable here but only until liquid is formed. Continue adding the suspending vehicle slowly until mixture is pourable.
6. Transfer mixture to the calibrated oval.
7. Rinse mortar with small amounts of vehicle and pour rinsings into oval (two to three rinsings is standard practice to ensure all drug is transferred into final suspension).
8. Qs to final volume with the vehicle.
9. Mix well by shaking to ensure uniform distribution.
10. Label. Apply appropriate auxiliary label “Shake well before use”, BUD, and storage instructions.

NOTE: 

Common vehicles used in suspensions traditionally include simple syrup and methylcellulose. While simple syrup can be made at the pharmacy from sugar and water, it is readily available and usually bought as a ready-made product. Today, it’s more commonplace to use commercially available suspending agents such as Ora-Plus, Ora-Sweet, Ora-Blend and SuspendIt. These commercially available suspending agents are pre-formulated to simply preparation and enhance consistency, stability, and palatability of the final compound and are widely used to create stable, uniform suspensions of insoluble drugs.

Watch video:

https://online.saskpolytech.ca/d2l/le/content/314498/viewContent/12733170/View

How to make a Eutectic Mixture:

A eutectic mixture is a combination of two or more solid substances that, when mixed, melt at a lower temperature than either component alone. This occurs due to molecular interactions that disrupt the crystalline structure of the individual components, leading to a decrease in the melting point.

• Forms a liquid or soft mass upon mixing, even at room temperature.
• Common in powder or topical compounding, where careful handling is needed to prevent liquefaction.
  • Example:  Camphor & Menthol → Used in topical analgesic preparations.

1. Gather all ingredients and equipment required
2. Weigh all ingredients
3. Using a glass slab, press crystals together with a spatula (spatulate) to reduce particle size
4. The components will gradually liquefy as their melting points are depressed
5. Continue spatulation until a homogeneous, smooth liquid is formed
6. Using the principles of geometric dilution, incorporate liquid into a base for patient use
7. Transfer to ointment pot and label, including BUD and storage

NOTE:

Forming a eutectic mixture requires a certain ratio (by weight) of the individual ingredients. For instance, camphor and menthol form a eutectic mixture in approximately a 1:1 ratio. Lidocaine and prilocaine form a eutectic mixture in a 1:1 ratio (available in the commercially available EMLA cream).

How to make an emulsion:

 1. Select the Emulsification Method

There are three main methods for preparing emulsions:

1. Dry Gum (Continental) Method (Common for O/W emulsions)

• • Ratio: 4 parts oil : 2 parts water : 1 part emulsifier (e.g., acacia).
  • Procedure:
    1. Weigh and mix the emulsifying agent (e.g., acacia) with the oil phase in a dry mortar.
    2. Add all the water at once and triturate rapidly until a creamy white emulsion forms.
    3. Dilute with additional water while continuing to mix.

2. Wet Gum (English) Method (Common for O/W emulsions)

• • Ratio: Same as Dry Gum (4:2:1).
  • Procedure:
    1. Mix the emulsifier with water first to form a mucilage.
    2. Slowly add oil in small portions, triturating after each addition until a stable emulsion forms.
    3. Continue mixing while adding more liquid as needed.

3. Bottle (Forbes) Method (For volatile oils or small-volume emulsions)

• • Procedure:
    1. Place emulsifying agent and oil in a dry bottle.
    2. Shake vigorously, then gradually add water in portions, shaking well after each addition

2. Homogenization and Mixing

• • Once the primary emulsion is formed, further homogenization can be done using:
    • Mechanical blenders (for large-scale emulsions).
      • Key Considerations
        • Choose the correct emulsification method based on ingredients and stability needs.
        • Ensure proper emulsifier selection to maintain stability.
        • Monitor for signs of instability, such as creaming, phase separation, or coalescence.
        • Store emulsions properly to prevent degradation.

       

       

    • Hand stirring (for small-scale pharmacy preparations).

3. Adjusting Stability

• • Add stabilizers or viscosity enhancers (e.g., gelatin, tragacanth) if needed.
  • Adjust pH with appropriate buffers to enhance stability.

4. Finalizing the Emulsion

• • Transfer to a suitable container (e.g., amber bottle for light-sensitive emulsions).
  • Label with storage conditions (e.g., “Shake well before use”).
  • Determine Beyond-Use Date (BUD) according to USP guidelines.

Why is formatting weird??