Drug delivery to the lungs Flashcards by Murielle Nsiela

what are the advantages of pulmonary delivery?

Avoids first pass hepatic metabolism
Fast onset of action
Non-invasive
Minimal side effects
Potential to deliver local and systemic i.e asthma - bronchioles, systemic alveoli

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what are the disadvantages of pulmonary delivery?

Poor inhalation technique can lead to deposition in the upper airway
Mucus fom infection can decrease deposition of drugs
Physical stability of aerosols can affect how much of it is absorbed
Ineffeciency of delivery

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Particles need to be hydrophilic enough to pass through the lung fluid and lipophilic enough to pass though the epithelia. TRUE OR FALSE?

TRUE

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Particles should be small enough to undergo endocytosis. TRUE OR FALSE?

TRUE

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The deposition of particles is dependent upon the particle size. TRUE OR FALSE?

TRUE

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Particle distribution is usually non-normal as described by the aerodynamics. TRUE OR FALSE?

TRUE

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Particle distribution is also non-normal in the lungs. TRUE OR FALSE?

TRUE

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ds is proportional to the settling velocity in the lungs. TRUE OR FLASE?

TRUE

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What is the aerodynamic diameter equation?

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Methods of sedimentation will depend upon particle size. TRUE OR FALSE/

TRUE

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What is inertia?

The property of a particle that allows it to remain at rest or in uniform motion

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The contribution of inertial compaction decreases as you move down the respiratory tract due to branching. TRUE OR FALSE?

TRUE

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what is gravitational sedimentation?

It is the downward movement of particles under gravity

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Gravitational sedimentation is important for drugs with small mass median aerodynamics. TREU OR FLASE?

TRUE

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Impaction of gravitational sedimentation is increased by holding breath. TRUE OR FLASE?

TRUE

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What is brownian diffusion?

The random movement of particles within a fluid

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What does browian diffusion do?

It enables small particles to move towards and bind to the walls of various tracts

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what is electostatic precipitation?

where the surface charge can affect deposition

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Electrostatic precipitation is not usually important when partcile size is less than >4um. TRUE OR FLASE?

TRUE

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What are the three types of pulmonary devices?

Nebulisers
pMDI
DPI

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why do Pulmonary devices need to be shaken before use?

Because the particle settle/sediment at bottom of the device
Need to shake to get equal dosing

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pMDI affects coordination. TRUE OR FLASE?

TRUE

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Side effects of orapharangeal impaction is greater in pMDI than DPI. true or flase?

true

What are the issues of stability with pMDI?

drug can leach out fro polymeric systems
Ingress of water through valve avtuation
Drug adherence to the metal canister

what does propellants used in pMDI have?

- Must have low viscocity - Must be stable on storage - Must disperse freely - Evaporate quickly - have low surface tension

what are propellants used for?

- They provide the driving force to push the drug into the patients respiratory tract

what type of propellanst are msotly used?

- CFCs | - No HFCs better fo rthe environment

What happens when vapour pressure is high?

- Causes impaction | - Reduces efficacy of the drug leading to reduced clincila performance

what happens when vapour pressure is too low?

- This makes propellant less volatile meaning that less of the drug can reach the downward respiratory tract

What does breath-actuation in MDI helps to improve?

- It improves the coordination of firing which can increase clinical benefits

Aerosol particle size define the dose deposited and the distribution of drug aerosols int he lungs. TRUE OR FALSE?

TRUE

smaller particles distribute drugs perpherally but distribute smaller concentration to surface area, while larger particles distribute larger concentrations but disrtibute drugs centrally. TRUE OR FALSE?

TRUE

Most pharmaceutical aerosols are heterodispersed. TRUE OR FLASE?

TRUE

Where are B receptors mostly found in the lungs?

- In the alveolar wall

where are B2 recptors loctaed in the lungs?

- in the airway epithelium

Particle size affects lung deposition of aerosol as well as the clinical efficacy. TRUE OR FALSE?

TRUE

Particle size and efficacy is not neccesarily linearly correlated. TRUE OR FLASE?

TRUE

Larger particles deposite in the trachea. TRUE OR FALSE?

TRUE

What is minimum fluid velocity?

- When upward flow exceeds gravitational pull

Drug particles less than 5um must then detach from cohesive and adhesive via impact based detachment and fluid based detachment. TRUE OR FLASE?

TRUE

Pneumocyst carinii pneumonia is found predominetly within the alveolar spaces. TRUE OR FALSE?

TRUE

How does espiratory diseases such as bronchietasis change the nature of the lung?

- Through alteration in bifurcation angles - Obstruction of the airways due to mucus accumulation - These factors may modify depositon and distribution of patterns of aerosols

How are drugs deposited in normal vrs obstructed airway?

- Obstrcuted airways drug is distributed centrally usually due to inertial impaction - Normal - drug is deposited unformally

Spacer MDIs have been developed to reduce the coordination requirements. TRUE OR FLASE?

TRUE

Spacer devices reduce the amount of drug deposited in the oropharynx by decreasing the particle size distribution and slowing the aerosols velocity. TRUE OR FLASE?

TRUE

What does spacer devices do?

- Improve deposition better than pMDI - Allows propellant ot evaporte - Coordiantes breath with actuation - Clinically efficious dose after 2 breaths - No need for coordination

what are the disadvantages of spacer devices?

- Patient compliance with portability

Why have dry powder inhalers been developed?

- Reduces issues of coordination that is seen with MDIs | - No propellant is required

Poor drug distribution with DPIs is usaully as a result of inefficient dis-aggregation of fine drug particles. TRUE OR FALSE?

TRUE

Temperatre and high humidity affects drug dis-aggregation. TRUE OR FALSE?

TRUE

What are the formulation considerations need ot tkae with DPIs?

- Therapeutic agent - Excipiens used to improve production - Excipient used to imrpove flow porperties - Polymorphism

Nebulisers use sterile solutions. TRUE OR FALSE?

TRUE

Nebulisers can use co-solvents. TRUE OR FALSE?

TRUE

Acidic solutions o fless than 5 can cause bronchoconstriction. true or false?

true

What are the two type of nebulisers?

- Jet nebulisers which are use compressed system (most comon type) - Ultrasonic nebulisers which may damage certain drugs

What are the advantages of nebulisers?

- Can be used at any age - No propellant used - easy to teach how to use - no cordination required - Can be used with supplemetal oxygen

What are the disadvantages of nebulisers?

- Portability is an issue - device can take 5-10 minutes to work - formulation limitations