Which route of administration involves inhalation of aerosolized particles?

• A. aerosol
• B. oral
• C. topical
• D. intravenous

Answer: (A)

Inhalation of aerosolized particles describes delivering substances via the aerosol route. This involves breathing in tiny droplets or solid particles suspended in gas, which deposit in the respiratory tract. Particle size matters: larger particles tend to settle in the upper airways, while smaller ones can reach the bronchioles and alveoli, where absorption into the bloodstream occurs rapidly. This route is used to study or utilize substances that act locally in the lungs or systemically after absorption through the lung surface. In contrast, oral administration involves swallowing and absorption through the gastrointestinal tract, topical delivery is to the skin or mucous membranes, and intravenous administration delivers directly into the bloodstream.