Drug delivery to the lungs Flashcards
(42 cards)
Particles must be hydrophilic enough to dissolve in the lung fluid lining and be lipophilic enough to crosss the epithelia. TRUE OR FALSE?
TRUE
Drug should be small enough to undergo andocytosis to navigate the intercellular route through tight junctions. TRUE OR FALSE?
TRUE
What are the advantages of pulmonary drug delivery?
- Avoids hepatic first pass metabolism
- Non-invasive
- RAPID ONSET OF THERAPEUTICS
- Local and systemic delivery (bronchioles - asthma/systemic alveoli)
- Minimises side effects
What is exhubera?
Hexameric form of insulin developed by inhaled therapeutics
What are the disadvantages for drug delivery to the lungs?
- Co-ordination in use, activation of an inhlaer and actuation may lead to deposition in the upper airway
- Mucus from infection can reduce deposition
- Efficiency of delivery
- Physical stability of aerosols i.e suspensions
What is minimum fluid velocity?
-An inspiration rate where the upward flow of air exceeds gravitational pull is required.
How is powder flow aided?
- Impact based detachment
- Fluid based detachment
- Particle must then nagigate the oropharngeal bend and bronchial network
What is inertia?
-The property of a particle that allows it to remain at rest or in uniform mition until exposed to an external force
after particle is inhaled it often changes direction due to i.e flow of air. TRUE OR FALSE?
TRUE
The probability of initial impaction increases as the angle and velocity of airflow increases. TRUE OR FALSE?
TRUE
Probability of inertial impaction reduces in airways of larger radius.TRUE OR FLASE?
TRUE
As airlfow velocity decreases within the lower sections of the respiratory tract, due to factors such as branching or resistance to air flow, the contribution of inertial impaction on particle deposition is lower. TRUE OR FALSE?
TRUE
What is gravitational sedimentation?
-The downward movement of particles under gravity
Impaction by gravitational sedimentation is increased by a steady rate of breathing or holding the breath. TRUE OR FALSE?
TRUE
What is brownian diffusion?
-The random movement of particles within a fluid
In the respiratory tract brownian motion enbles small particles to move towards and be deposited on the walls of the various sections of the tract. TRUE OR FALSE?
TRUE
What is electrostatic precipitation?
-Where the surface change may affect deposition
What are the three ways in which electrostatic precipitation causes particles to deposite?
- As an aerosol cloud of particles charged with the same polarity is generated, then like charge swill repel each other which will cause the particles to move apart from each other
- As a charge particle approaches an uncharged surface within the respiratory system, an image charge of opposite polarity may be induced onto that surface which will enhance that attraction between the two, increasing the probability of deposition by electrostatic deposition
- Negative charge soccur naturally on the surface of the cell membranes and so if a positively charged aerosol particles appraoches, the electrostatic attraction will thus increase the amount of deposition
Particle size effects the lung deposiiton of aerosol, and as such it also can influence the clinical efficcay of a drug. TRUE OR FALSE?
TRUE
Particle size and efficacy are necessarily lineraly correlated. TRUE OR FALS?
FALSE
The optimal site of deposition in the respiratory tract for aerosolisation antibiotics depends on the conditon being treated. TRUE OR FALSE?
TRUE
Respiratory diseases such as OF and bronchoiectasis, change the nature of the lung though what?
- Alterations in bifurcation angles
- Obstruction of the airways due to mucus accumulation
Obstruction of the lungs decreases cross-sectional area and results in an increase in air velocity and turbulence. TRUE OR FALSE?
TRUE
Obsrtuction divert air to unobstructed airways and very little drug gets deposited in obstucted areas, and these are often the areas that need to be reached by the drugs being inhaled. TRUE OR FALSE?
TRUE
