Pulmonary Drug Delivery Flashcards
Why is pulmonary administration used?
- treatment or prophylaxis of ariway diseases
- asthma
- cystic fibrosis
- COPD
- infection
- rapid onset of action
- smaller doses required
- useful if drug poorly absorbed orally or rapidly metabolised
- avoids FPM
- easily accessible
- non invasive
- lower proteolytic activity than GI tract
What are disadvantages of pulmonary drug delivery?
- poor reproducibility - smokers
- ability of lung marophages to engulf particles
- metabolic capacity of lung
- inefficiency of drug delivery devices
What kind of drugs are administered pulmonarily?
- bronchodilators
- corticosteroids
- anti-allergy
- mucloytics
- anti-infectives
- oxygen
What are the lungs coordinated with for oxygenation of blood?
- CNS
- diaphragm
- chest wall musculature
- circulatory system
What is the respiratory system divided into?
- nasopharynx region - nose, mouth, pharynx, larynx
- tracheobonchial region - trachea, bronchi, bronchioles - conductory region
- pulmonary region - respiratory bronchioles - respiratory bronchioles, alveoli - respiratory region
What cells are in the alveoli?
- ciliated columnar epithelial cells
- goblet cells
- submucosal glands - mucus moistens inspired air, prevents drying of walls and traps marticulate matter
What cells are the alveoli lined with?
- type 1 pneumocytes - highest SA
- type 2 pneumocytes - most cells
What is the drug delivered as pulmonarily?
aerosol: dispersion of solid or liquid in a gas
What are the three types of pulmonary drug devices?
- nebulisers - liquid or solid
- DPI dry powder inhalers - solid
- pMDI pressurised metered dose inhalers - liquid or solid
Summarise the use of nebulisers
- delivers large volumes of drug solutions and suspensions
- drug administartion during normal tidal breathing - useful for children, elderly and unconcious but
- LARGE DOSE LOST
How does an airjet nebuliser work?
compressed air carries a liquid medication through a narrow hole at high velocity turning it into an aerosol which is inhaled
How does an ultrasonic nebuliser work?
ultrasonic wave generated which vibrates a diaphragm at high frequency that is in contact with a liquid medication
high frequency vibrating converts the liquid into a vapour mist
the higher the frequency = smaller droplets
What are advantages and disadvantages of nebulisers?
+
- can aerosolise most liquid medications
- allow for delivery of large doses, with limited skill by patient
-
- expensive and time consuming (long periods of time)
- most drug retained in nebuliser or released into environment
- approx 10% acc reaches lungs
Summarise the use of dry powder inhalers
- metered quanitity of powder delivered
- devices are breath actuated - powder dispensed into stream of air drawn through the device by the patients own inspiratory effect
- no coordination required between activation and inhalation
- air is forced through a powder containing the drug
- turbulent air created inside powder container breaks down large particles into smaller
What is a single dose DPI?
- drug plus lactose packed in gelatin capsule
- capsules individually loaded into DPI by patient
- priming of device pierces capsule
- inhaled air flow disperses the powder from the capsule
allows the patients to remember how many doses theyve had
