– These are colloidal dispersions (very finely subdivided liquid droplets or solid particles dispersed in and surrounded by a gas)

– A suspension of small solid particles or liquid droplets

– It also refers to product that depends on pressure of a compressed or liquefied gas

Metered Dose Inhalers

MDIs or aerosol drug delivery system provides systematic or pulmonary drug delivery

These devices allow a drug to be inhaled as a fine mist of drug or drug-containing particles

These use special metering valves to regulate the amount of formulation & drug that is dispensed at each dose

Particle size/Liquid Droplet Requirements:
  • Space sprays - 50 millimicrons
  • Inhalation aerosols - less than 6 millimicrons, will reach the respiratory bronchioles, while less than 2 microns will reach the alveolar ducts and alveoli.
  • Dermatological sprays/aerosols - coarse droplet/ particle size.
Principle of Aerosol Technology
  • Product concentrate – the active/s combined with the required adjuvants to prepare a stable and efficacious product.
  • Propellant – may be liquefied gas or a mixture of liquefied gasses. It is responsible for developing pressure within an aerosol container.
Aerosols Packaging Components
  1. Plastic Coated Glass
    • allows level of contents to be seen
    • compatible with most formulations
    • plastic coating absorbs “neck shock” during crimping, provides barrier to broken glass
    • poor aesthetic finish, difficult to label, heavy
    • used for inhalation aerosols, containing dissolved drugs
  2. Aluminum
    • light weight and seamless
    • can be screen printed, therefore visually appealing
    • easy to crimp and fill
    • incompatible with some propellants and solvents (can be anodized or epoxy coated)
    • opaque
    • used for inhalation and topical aerosols
  3. Three-piece Tin Plate
    • corrosion inhibitors typically included in the formulation (not suitable for all products)
    • incompatible with some propellants and solvents
    • visible seams make it less appealing
    • can be pressurized from the base with compressed gasses