Biomedical Engineering Reference
In-Depth Information
Trachea
Bronchi
FIGURE 11.3
Illustration of the alveoli. (Reproduced from
Pediatric Critical Care
. 14 ed. D'Angelis CA
et al., Structure of the respiratory system. Lower respiratory tract. Copyright 2011, with permission from
Elsevier Saunders.)
passages. Hence, drugs delivered to the lower airways can enter the systemic circulation through
the absorption into the systemic circulation or into the alveolar capillaries of the pulmonary vas-
cular bed [20,27].
Traditionally, drug delivery has been carried out in the form of injections, infusions, ingestions,
and inhalations, with additional variations in each category. The challenge for both drug and drug
delivery companies is to deliver both existing and emerging drug technologies in a manner that
improves the benefits to patients and the healthcare system. An ideal drug therapy must bear the
following attributes:
•
Improved efficacy
•
Reduced side effects
•
Sustained dosing (continuous release)
•
Increased ease of use
•
Reduced pain from administration
•
Increased patient compliance
•
Improved mobility
•
Decreased involvement of healthcare workers
•
Improved safety
•
Safe elimination
To provide these benefits, a number of approaches are being explored to determine which of the
approaches best meets the needs; this is a complex problem. Although ingestion is probably the
most widely accepted form of delivery, it presents difficulties for a number of important classes
of drugs. In the case of proteins and peptides, oral formulations can only deliver bioactives with
a fewer bioavailability. Even though oral delivery meets the need for self-administered drugs, tar-
geted, sustained releases and increased bioavailabilities represent the areas of difficulty in meeting
the emerging value proposition. To address this difficulty, nano-fabricated drug delivery systems
are being explored.
