PCEUTICS quiz 2 (1)

Emulsions

• Components in Emulsions:

  • Drug (API)

  • Oil phase

  • Water phase

  • Emulsifying agents (e.g., surfactants)

  • Preservatives (prevent growth of microorganisms)

• Microorganism Susceptibility:

  • O/W (Oil in Water) emulsions are more susceptible to microorganism growth, as bacteria and fungi can decompose the emulsifier.

• Instability Mechanisms:

  • Breaking:

    • Coalescence: Droplets merge with each other to form large droplets (irreversible)

  • Creaming: Separation of the internal phase from the emulsion (irreversible)

  • Flocculation: Migration of droplets to the surface or bottom of emulsions (reversible)

• Stability Requirements:

  • Select correct emulsifying agents

  • Create small and uniform-sized droplets

  • Optimize phase-volume ratio

  • Optimize viscosity of the external phase

  • Minimize density difference between the internal and external phases

Aerosol Systems

• Major Components of an Aerosol System:

  • Canister

  • Propellant (expels the material)

  • API (active pharmaceutical ingredient) concentrate

  • Metering (valve)

  • Actuator (directs the API)

• Role of Propellant:

  • Supplies necessary pressure within an aerosol system to expel material from the container and, in combination with other components, converts the material into the desired physical form.

• Types of Propellants:

  • A chemical with vapor pressure greater than atmospheric pressure at 40°C is called a propellant.

  • Compressed Gases:

    • CO2

    • Nitrogen

    • Nitrous Oxide

  • Liquefied Gases:

    • CFC (Chlorofluorocarbons)

    • HFA (Hydrofluoroalkanes)

• Applications of Aerosols in Pharmaceutical Sciences:

  • Major application: Inhalation aerosols

  • Anti-infective agents and local anesthetic agents are known as topical aerosols.

  • Anti-inflammatory agents are classified as rectal aerosols.

• Advantages and Disadvantages of CFCs:

  • Advantages:

    • Low inhalation toxicity

    • Good solvent properties

    • High chemical stability

    • High purity

  • Disadvantages:

    • Reduce the amount of atmospheric ozone

    • Contribute to the greenhouse effect

    • High cost

• CFC Ban:

  • CFCs were banned on 12/31/2008

• Characteristics of HFA:

  • HFA spray is less forceful but creates a soft mist.

  • Advantages:

    • Low inhalation toxicity

    • High chemical stability

    • High purity

    • Does NOT impact the ozone layer

  • Disadvantages:

    • Minor greenhouse gas properties

    • High cost

    • Poor solubility

• Compressed Gasses vs. Liquid Propellants:

  • Disadvantage: Compressed gasses tend to lose pressure over time.

• Filling Processes:

  • Cold Filling: Uses the principle that some ingredients will liquefy when cooled.

  • Pressure Filling: Uses the principle that some ingredients will liquefy under high pressure.