Aerosol Device Dr Manal

7/31/2019 Aerosol Device Dr Manal

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The respiratory tract


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Common route for entry of

Gases, vaporsand Aerosol

particles


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Inhalational route of administration

Used for :

Administration of drugs to be absorbed into blood

stream to produce systemic effects Administration of drugs to produce localized

effects


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The lung is an excellent

route for systemic drug absorption

wide surfacearea

of alveolarsurface

Bronchoalveolar

bloodsupply


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Drugs systemically absorbed from alveoli are

usefulgases

inhalationanesthetics


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General inhalation anesthesia


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usefulgases

Oxygen

Hypoxia

Highattitude Pulmonary

edemapneumonia


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Administration at one atmosphere

Hyperbaric oxygen inhalationusually at two atmosphere


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1- Mask


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2- Tent


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3-Nasal cannula


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AEROSOLIZED MEDICATIONS

to produce localized effects

Advantages of aerosolized medications

Onset of action is rapidDirect delivery of the drug to the respiratory

system (efficacy)Systemic side effects are fewer and lesssevere than oral or parenteral therapy(safe)


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Aerosol particles deposition in

the respiratory system

Aerosol particles produced by inhalant

devices include a range of sizes The site of deposition depend on particle size


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>10 orally deposited & swallowed

1-5 m deposited in small airways (therapy)

5-10 m deposited in major airways

10 m


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Bronchial asthma

Topical application of drugs

COPD

SalbutamolTerbutalineFormoterol

Inhaledcorticosteroids

budesonidefluticasone

Inhaledipratropium

bromid


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Disposition of inhaled drugs

Mouth deposition90%

10%

Reach airwaysSwallowed drug

reach intestine and absorbed

1st pass metabolismDrug metabolite

Blood stream

Drug systemic effect + inactive metabolite

Lung pulmonary

absorption


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Aerosol devices for drug delivery

Metered dose inhalers

NebulizersDry powder inhalers


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Metered dose inhalers: MDIs

Five major components in MDI

Drug Propellant / excipient mixture

Canister

Metering valve/spray orifice

Mouthpiece /actuator

Requires ... pt cooperation

.. proper instruction and supervision by practitioner


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Components of MDIs Drug is a suspension of micronized powder or

solution

Propellant

Liquified gas under pressure

Chloroflurocarbons (CFCs)

Excipient: e.g. Oleic acid to preventaggregation of drug particles therebymaintaining suitable particle size in theaerosol plume produced

Metering valve: it contains metered dose ofdrug-propellant mixture

Canister depressed into actuator the drug-propellant mixture in metering valve is released

under pressure


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Guidelines for administering MDI

Removecap

Shake

Exhale

Hold MDISlow deep inspiration (3-

4s)

+actuating canister

Hold breath for up to 10 s

Exhale

Shake

Wait 1 min

Repeat


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Advantage and disadvantage of MDI

Advantages MDIs are portable Treatment time is short

Disadvantage They require hand /face breathing co-ordination CFCs are released into environmentpotential

for damage to protective ozone layer in the earthsatmosphere


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New MDI technology

Breath -actuated MDI ( autohaler)The metered dose is released when thepatient inhale

Use No CFCs propellantsUsehydrofluroalkanes Environment friend No cold Freon effect to cause bronchospasm or

inhibit full inspiration


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Metered dose inhalerspacer device

Extension Add-on attached to MDIs for administration

Advantage

1. Simplify coordination required for good use of MDI

2. Reduce oropharyngeal drug deposition

With inhaled corticosteroids decrease oropharyngeal deposition

1. Decrease opportunistic throat infection

2. Decrease dysphonia

3. Limit swallowed drug amount

Spacer


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MDI content

Full (sink, nozzle down) full (float, nozzle down) Empty (float on side)


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POWDER AEROSOLS

AerolizerDiscus

Turbuhaler


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Advantage of powdered aerosol

Breath-actuated: remove the need for co-ordinate inhalation and actuation of the inhaler

Count of remaining drug doses is simple No CFCs propellant gas

Disadvantages

1. A high airflow is required to disperse the powder

2. Dry powder may be irritant to airways


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Nebulizers

Devices used to administer aerosol from adrug solution kept inside a reservoir


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What is meant by the term dead volume in

an SVN?

Residual amount of drug solution left in

a nebulizer when the nebulizer is nolonger able to generate aerosol

Vary according to the brand between 0.5-1 ml


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How do you solve the problem of dead

volume

So diluent must be added to nebulizersolution

Minimum volume in SVN=3 ml

Optimum volume in SVN= 5ml


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Advantage & disadvantage of nebulizer Advantages

Ability to aerosolize drug mixture(>1 drug) Useful in very young & very old patients or patient

in acute severe asthma exacerbations who can not slow breathing & inspiratory pause is not

obtainable

Disadvantages Equipment required for use is expensive

Treatment times are lengthy (Treatment time 10

minutes ) Contamination is possible with inadequate

cleaning


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Question


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Hyperbaric oxygen inhalation means:

a. Inhalation of pure Oxygen.

b. Inhalation of Oxygen with CO2.

c. Inhalation of 50% Oxygen.

d. Inhalation of O2 at two atmospheres


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True or False:

Dry powder inhaler needs hand facebreathing coordination. F

Non chlorinated propellants are preferredthan chlorinated MDIs. T

Budesonide and fluticasone inhalation are

examples for systemic absorption fromlungs. F

General anesthesia may be applied

through inhalation T


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Fill in the spaces :

Two typical methods of Oxygen delivery

------------------, -----------------------

Two types of dry powder inhalers----------------------------, -----------------------


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Two advantages of nebulizer

---------------------------------,---------------------

Two disadvantages of dry powderinhalation

-------------------------,---------------------


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Rank the following steps for the use Of

MDIs

- Remove the dust cap, and shaking thecanister

- Inhale.- Press down opening a valve at its base

and releasing a jet of air and medicine

- Hold it in the hand by the housing

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Aerosol Device Dr Manal