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Gary's lecture (Pharmaceutics) > Drug delivery to the lungs > Flashcards

Drug delivery to the lungs Flashcards

1
Q

Particles must be hydrophilic enough to dissolve in the lung fluid lining and be lipophilic enough to crosss the epithelia. TRUE OR FALSE?

A

TRUE

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2
Q

Drug should be small enough to undergo andocytosis to navigate the intercellular route through tight junctions. TRUE OR FALSE?

A

TRUE

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3
Q

What are the advantages of pulmonary drug delivery?

A
  • Avoids hepatic first pass metabolism
  • Non-invasive
  • RAPID ONSET OF THERAPEUTICS
  • Local and systemic delivery (bronchioles - asthma/systemic alveoli)
  • Minimises side effects
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4
Q

What is exhubera?

A

Hexameric form of insulin developed by inhaled therapeutics

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5
Q

What are the disadvantages for drug delivery to the lungs?

A
  • 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
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6
Q

What is minimum fluid velocity?

A

-An inspiration rate where the upward flow of air exceeds gravitational pull is required.

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7
Q

How is powder flow aided?

A
  • Impact based detachment
  • Fluid based detachment
  • Particle must then nagigate the oropharngeal bend and bronchial network
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8
Q

What is inertia?

A

-The property of a particle that allows it to remain at rest or in uniform mition until exposed to an external force

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9
Q

after particle is inhaled it often changes direction due to i.e flow of air. TRUE OR FALSE?

A

TRUE

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10
Q

The probability of initial impaction increases as the angle and velocity of airflow increases. TRUE OR FALSE?

A

TRUE

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11
Q

Probability of inertial impaction reduces in airways of larger radius.TRUE OR FLASE?

A

TRUE

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12
Q

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?

A

TRUE

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13
Q

What is gravitational sedimentation?

A

-The downward movement of particles under gravity

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14
Q

Impaction by gravitational sedimentation is increased by a steady rate of breathing or holding the breath. TRUE OR FALSE?

A

TRUE

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15
Q

What is brownian diffusion?

A

-The random movement of particles within a fluid

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16
Q

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?

A

TRUE

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17
Q

What is electrostatic precipitation?

A

-Where the surface change may affect deposition

18
Q

What are the three ways in which electrostatic precipitation causes particles to deposite?

A
  1. 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
  2. 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
  3. 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
19
Q

Particle size effects the lung deposiiton of aerosol, and as such it also can influence the clinical efficcay of a drug. TRUE OR FALSE?

A

TRUE

20
Q

Particle size and efficacy are necessarily lineraly correlated. TRUE OR FALS?

A

FALSE

21
Q

The optimal site of deposition in the respiratory tract for aerosolisation antibiotics depends on the conditon being treated. TRUE OR FALSE?

A

TRUE

22
Q

Respiratory diseases such as OF and bronchoiectasis, change the nature of the lung though what?

A
  • Alterations in bifurcation angles

- Obstruction of the airways due to mucus accumulation

23
Q

Obstruction of the lungs decreases cross-sectional area and results in an increase in air velocity and turbulence. TRUE OR FALSE?

A

TRUE

24
Q

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?

A

TRUE

25
Q

How is drug deposited in an obstructed lung?

A

-Drug is deposited more centrally in the lungs caused by inertial impaction, compared to the uniform distribution achieved in the normal lung

26
Q

Patienst with COPD have a significantly lower aerosol penetration than helthy volunteers. TRUE OR FALSE?

A

TRUE

27
Q

Name three devices used for pulmonary delivery?

A
  • pMDI
  • DPI
  • Nebuliser
28
Q

How can pMDI, DPI and nebuliser and its use affect dosing?

A
  • pMDI coordination
  • High tidal capacity required
  • Side effects of oropharangeal impaction
  • Internubiliser variation
29
Q

What is included in the formulation in drugs delivered in the lungs?

A
  • Propellant
  • Therapeutic agent (solution or suspension)/excipients
  • Actuation mixes drug and propellant which is released
30
Q

The particles/droplets must have the right particle size and polydispersity for the target site. TRUE OR FALSE?

A

TRUE

31
Q

What is a propellant used for?

A
  • Provides driving force to expel drug/formulation from the device to the upper respiratory tract
  • To evaporate quickly enough to facilitate delivery to the required region of the lung
32
Q

What occurs when the vapor pressure is too high?

A
  • Excessive impaction on the surfaces in the upper respiratory tract
  • Reduces effectiveness of drug delivery and clinical performance
33
Q

What occurs when vapour pressure is too low?

A

-May resolve the limittations mentioned above if lowered, but if too low then the propellant is less volatile which may reduce the perectange of actuated dose reaching the lower airways

34
Q

What are the features of a good propellant?

A
  • Must have low viscosity
  • Have low surface tension
  • Be stable on storage
  • Disperse freely
  • Evaporate quickly
35
Q

What does a spacers on FP10 do?

A
  • Improves deposition from pMDI
  • Coordinates breath with actuation
  • Clinically efficacious dose after two breaths
  • Drug is inhaled fromspacer device
  • Size is a disdavantage - reduces portability
36
Q

Drugs that enter the lungsare only distributed in the proximal airways. TRUE OR FALSE?

A

TRUE

37
Q

wHAT ARE CONTAINED DRY POWDER INHALERS?

A
  • No propellant - no CFC’s or HFA’s
  • Easier to use, fewer side effects
  • Few patients develop poor inhilation technique with contiued use of DPIs
  • They achieve a similar degree of bronchodilation to the MDI
38
Q

What are the two different types of dry powder inhalers?

A
  • Inhalers in which the formulation(the drug and excipients) are present within a hard gelatin capsule
  • Inhalers in which the drug and excipients are present within a blister pack
39
Q

With most DPIs , drug delivery to the lungs is augmented by fast inhilation. TRUE OR FALSE?

A

TRUE

40
Q

What are used in nebulisers?

A

-Sterile solutions with a Ph greater than 5

41
Q

What are the two different types of nebulisers and which one is most commonly used?

A
  • Jet nebulizer/ compressor system (most commonly used)

- Ultrasonic nebuliser (not suitable for viscous solutions/may damage certain drugs/particles

42
Q

As hydrophilic particle enters the lung it becomes a saturated droplet. TRUE OR FALSE?

A

TRUE

Gary's lecture (Pharmaceutics) (7 decks)

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