Pulmonary Drug Delivery- Miroshnyk

Pulmonary drug delivery are drugs being delivered to the lungs via the __________ or ____________________.

via the NOSE or an ORAL INHALATION

All drug formulations being delivered to the lungs must be _______________.

aerosolized

Pulmonary drug delivery provides a local, systemic, or both effect?

both!

• local (to the lungs only)

• systemic

What are the 4 obstacles to pulmonary drug delivery?

• airway geometry (hard for drug to move between all the twists and turns of the airway system)

• mucus

• mucociliary clearance

• alveolar macrophages

What are the 3 mechanisms of deposition of inhaled particles?

1. inertial impaction

2. sedimentation

3. diffusion

What mechanism of deposition is this?

• mechanism for particles >5 um in diameter

• deposition increases w/ velocity, diameter, and density

• occurs in larger airways (highest airflow velocity)

inertial impaction

What mechanism of deposition is this?

• occurs when particles follow gravity

• deposition depends on particle diameter and density

• occurs in smaller airways (low airflow velocity)

sedimentation

What mechanism of deposition is this?

• SMALL particles

• independent of density

• deposition decreases with increasing particle size

• SMALL airways

diffusion

All mechanisms of deposition are dependent on what?

particle size

What is the relationship between physical diameter and aerodynamic diameter of particles?

physical diameter provides the straightforward size of the particle, aerodynamic diameter reflects how the particle interacts with the gas during its movement.

What is the effect of aerodynamic diameter on drug deposition in the lungs?

• you can look at the chart and see with each deposition mechanism, how diameter effects the deposition fraction or rate

• with diffusion: small diameter= more deposition

• with sedimentation and inertial impaction: large diameter= more deposition

What is the advantage of pulmonary drug delivery for local/ respiratory disease treatment?

• targeted delivery

• rapid onset of action

• avoid 1st pass metabolism

• avoid GIT

• minimized ADRs

• enables a similar/superior therapeutic effect at a fraction of the systemic dose

What is the advantage of pulmonary drug delivery for systemic disease treatment?

• non-invasive, needle free

• drugs can be self-administered

• patient compliance

• suitable for both small/large molecules

• enormous absorptive surface area and high permeable membrane in the lung region

• less harsh, low enzymatic environment that avoids 1st pass metabolism

• reproducible absorption kinetics

What are the 3 major types of pulmonary drug delivery devices?

1. nebulizers

2. pressurized metered dose inhalers (pMDI)

3. dry powder inhalers (DPIs)

Describe nebulizers:

• device that takes solutions/suspensions and turns them into aerosols

• 3 major kinds (air-jet, ultrasonic, and modern)

How do air-jet nebulizers create an aerosol?

• use a pressurized jet air stream delivered by a compressor

• this air is then forced through an opening called a “venturi”

• this air then hits the liquid and turns it into an aerosol

Think: air-jet nebulizer= air

What is the venturi effect?

fluid speed increases when the fluid is forced through a narrow or restricted area

How do ultrasonic nebulizers create an aerosol?

• piezo-electric crystals produce high frequency sound waves in the nebulizer solution

Think: ultrasonic nebulizer= sound waves

Advantage of ultrasonic nebulizers to air-jet nebulizers:

ultrasonic are lighter and quieter compared to air-jet

Disadvantage of air-jet nebulizers:

change in drug conc due to crystallization of drug or evaporation of solvent

Disadvantage of ultrasonic nebulizers:

• cannot nebulize high-viscosity liquids

• increase in temp causes degradation of thermolabile drugs

What should a patient using a nebulizer be counseled on?

• keep nebulizers upright!

• pt should breathe slow and deep for better med delivery

• do not mix any other meds with the nebulizer

What do metered dose inhalers depend on to deliver the medication?

• depend on the functioning of the container and propellant (gases) to deliver the medication

(you can see in the picture that the actual drug product is just a small portion)

How do pressurized metered dose inhalers work in general?

• drug is dispersed in propellants (like HFA)

• the device aerosols the drug

• “metering valves” allow for multiple dosing of the drug+propellant aerosol

FYI: this is what we commonly think of when someone has an inhaler

What is the role of metering valves in pressurized metered dose inhalers?

big picture: determine drug dose

• Function: to expel contents at the desired rate and in the proper amount

What is the role of HFA in pressurized metered dose inhalers?

propellant

What volume is dispensed from a pressurized metered dose inhaler (pMDI) each time it’s used?

30-100 uL

How should patients be counseled on how to use a pDMI?

• shake well

• wait 1 minute between if multiple dosing

• hold breath for 10 seconds

• explain importance between firing the device and breathing

  • like make sure they know to breath and hit the button releasing the drug at same time

Breath actuated MDIs are pDMIs that…

sense the patient’s inhalation through the actuator and fire the inhaler automatically

(like a vape)

What are some examples of propellant-free MDIs?

Respimat

Drug Formulations for Aerosol systems may be _______________ in the propellant system.

SATA

a. dissolved

b. suspended

c. emulsified

d. solutioned

a, b, c

A main issue with pMDIs is…

hand-breath coordination

What was developed to address the main issue of pMDIs?

dry powder inhalers (DPIs)

What is the major disadvantage of Dry powder inhalers?

efficient drug delivery depends on the patients own inspiratory effort (how hard they can breathe in)

Co-solvents used in inhaled products:

• water

• ethanol

• propylene glycol

Surfactants/Lubricants used in inhaled products:

• sorbitan

• lecithin

• magnesium stearate

Carrier Products used in inhaled products:

• lactose

• mannitol

• dextrose

preservatives/antioxidants used in inhaled products:

• parabens

• BAC

• EDTA

• ascorbic acid

Flavoring agents used in inhaled products:

menthol

Sweeteners used in inhaled products:

saccharin