Learning Objective

• Advantages and disadvantages of aerosols

Advantages

1. A dose can be removed without contamination of the remaining contents. This factor is especially of importance when delivering sterile dosage forms. For example, sterile saline aerosol meant for the purpose of cleaning the wound.
2. Sufficient protection is provided for the medicaments that are susceptible to oxygen and moisture, thus increasing their stability.
3. The aerosol container closure system is tamper proof.
4. The medication can be delivered directly to the affected area in a desired form such as spray, stream, quick breaking foam or stable foam. Further handling of the medicament is not needed.
5. For medications requiring accurate dosage, a metering valve can be used.
6. The required particle size of the medicament can be delivered to the desired sites such as nasal or buccal.
7. Irritation produced by the mechanical application of topical medication is reduced or eliminated since manual application of the topical medicament onto the affected area is eliminated. The medication can be applied in a thin layer.
8. A pressure package is easy and convenient to use.

Disadvantages

1. Despite the various advantages, aerosols still carry some disadvantages most of which are associated with the propellant used.
2. The propellants used in an aerosol are highly inflammable in nature.
3. Proper care is required in disposing empty aerosol containers, which may still contain residues of the propellant in them. In case of MDI, a proper coordination is necessary between valve actuation and inhalation.
4. Inaccurate use leads to increased pharyngeal deposition, and in the case of inhaled corticosteroid will result in oral candidiasis, hoarseness and increased absorption into the systemic circulation.
5. Topical application of aerosols leads to sudden cooling, which may lead to discomfort on the injured skin.