Inhalation Therapy: Dry Powder Devices and Nebulizers from University of Portsmouth

Inhalation Therapy Overview

Inhalation Therapy (Lecture 2) wiseGEEK Professor Paul Cox School of Pharmacy & Biomedical Sciences UNIVERSITYOF PORTSMOUTH•

Lecture 2: Dry Powder Devices and Nebulizers

• Dry Powder devices
• Nebulizers

Dry Powder Inhalers (DPI)

Drug inhaled as cloud of fine particles. Either pre-loaded or loaded by patient. Formulation usually just consists of addition of 'carrier'

DPI Strengths and Weaknesses

Advantages of DPIs

• Breath activated.
• Larger doses

Disadvantages of DPIs

• Deaggregation depends on patient's inhalation.
• Drug often sometimes exposed to atmosphere .Cost

General Technique for Dry Powder Inhalers

Remove the inhaler cap, if there is one. If required, load a dose of medicine. Tilt your head back a little, and breathe out slowly and completely. - Hold the inhaler away from your mouth while you breathe out. - Do not breathe out into the inhaler. This can blow some of the powder medicine out of the inhaler. The moisture in your breath also can cause the dry powder to clump together and clog the inhaler. Place the inhaler's mouthpiece in your mouth. -Close your lips tightly around the mouthpiece. Inhale quickly and deeply through your mouth for 2 or 3 seconds. After you have inhaled the powder, take the inhaler out of your mouth. Hold your breath for 10 seconds. Slowly breathe out through pursed lips. - Make sure not to breathe out into the inhaler. Repeat these steps if you need to take a second dose.

DPI Formulation

Microionized (5 um particle size) `Carrier' particles added (30-60 um) `Carrier' helps ensure more drug enters inhaled air. Requires carrier-drug adhesion (mix/fill) but carrier-drug desorption when liberated. " Morphology/surface energies critical.

Single Dose Inhaler - Cyclohaler

CYCLOHALER Mouthpiece Spinning Chamber Filter 'Piercing' Buttons 'Piercing' Chamber Cover Flange Air Inlet Port Flange Air Inlet Port 40 Piercing Buttons

• Single capsule is inserted into piercing chamber.
• User must press the blue buttons in order to pierce the capsule.
• Strong, steady breath is required in order to 'spin' the capsule and release the powder.

Multidose Inhalers

(a) Diskhaler Device

Drug/lactose carrier loaded into foil blister disc. Disc contains 4/8 doses Needle pierces blister Air flow through blister leads to dispersion. No. of doses displayed. Diskhaler Mouthpiece Diskhaler Support Wheel Cover Rotadisk drug Needle Mouthpiece Tray Mouthpiece

(b) Accuhaler Device

Drug preloaded in device 60 foil covered blister pockets Foil lid 'peeled' as dose is advanced. Protection for drug. Discarded after use. No of doses displayed. Accuhaler Drug exit port Mouthpiece Manifold Strip lid peeled from pockets Index wheel Body PRESCRIPTION ONLY MEDICINE KELP- OUT OF REACH OF CHILDREN 50/ 100 Seretide" ACCUHALER 50/100 Powder for itution Lath blute contains 50 micrograms If SALINTIROL (AS XINAFCATE) IMG 100 micrograins af FLUTICASONE PROPIONATE 60 bìnhhg A J106635 Empty strip - Contracting wheel Lever Base wheel Dose indicator whee Thumbgrip Outer case Coiled strip Pockets containing drug

(c) Turbohaler Device

Large no of doses (~200) Microionized drug, stored in reservoir. Drug fills fine holes on disc, when rotated by patient. Drug more exposed. required. Closure Turbohaler PION ONLY MEDICINE EACH OF CHILDREN turbuhaler® 12µg wurde dihydrate itlocation. 12uig per inhalation gions A farmaceuticoli Py LNd Tin kà Ni Byde NSW 2112 Autók Mouthpiece with insert Turbohaler Inhalation channel Scraper One metered dose Storage unit fordrug compound Dosing unit Air inlet Turning grip

d) Easyhaler Device

• Drug held in a reservoir.
• Dose preparation with the Easyhaler requires shaking, with the inhaler kept in an upright position; this manoeuvre is needed to aid the dose being deposited into the metering cylinder.
• Pressing once on the overcap of the inhaler deposits the drug and its carrier into the inhalation channel.
• Turbulent airflow, generated by patient inhalation, breaks the inhaled product into breathable particles, which are then deposited into the lungs

Easyhaler Overcap Bulk chamber cover Bulk chamber Metering cylinder Dust cap Mouthpiece Oasis-Stad.com 200 doses Easyhaler Beclomet Easyhaler 200 microg/ dose inhalation powder Easy BECLOMETASON DIPROPION 200 miciog Lactos monohydr.q.s 200 Easyhaler Beclomet

Nebulizers

• Generates an aerosol vapour of medicine.
• Deliver large volumes of drug solutions. (severe attacks).
• Inhaled during normal breathing via mask or mouthpiece.
• Modern spacer devices now considered 'almost as good'.

Three Types of Nebulizers

Three types: Jet/Ultrasonic/Mesh

Jet Nebulizer

Jet nebuliser To mouthpiece Air Baffle Medication -Venturi K Feeding tube Compressed air .Compressed air cylinder used (liquid to spray) .Gas passes through narrow opening (0.3-0.7 mm) .Liquid drawn up feed tube. ·Fine droplets formed via surface tension. . Recycling mechanism.

Ultrasonic Nebulizers

Ultrasonic nebuliser To mouthpiece Air Medication Baffle Ultrasonic waves -Piezoelectric crystal High frequency source Power supply .Crystal vibrating at high frequency atomises liquid ·Liquid 'fountain formed'. Small 'mist' at top. ·Fan often used to blow droplets to patient.

Mesh Nebuliser

Metal alloy mesh plate Horn device Mesh 0 0 2 0 · Liquid passed through vibrating plate · Creates very fine spray • Rapid Delivery

Formulation for Nebulizers

Formulated in water Cosolvent often used (surfactant for suspension formulation. Anti-oxidants (sulphites) and preservatives. Can be avoided by presenting as a single sterile dose, High pH necessary to avoid bronchoconstriction. " Doses of 1-2.5 mL.

New Advances: Thermally Generated Inhalation Aerosols

A B Back Housing Battery Drug Coating Front Housing Air Inlet Breath Activation Circuit Heat Package Thin film of drug is heated rapidly (~400°C). Inhalation is detected by breath sensor. Generates vapours that condense rapidly into respirable particles of approximately 1-3um. Thermal aerosol is inhaled through airway housing.

Summary of Powdered Dose Inhalers

Powdered Dose Inhalers require a sharp breath in when they are used. This is needed to deaggregate carrier and drug particles. The need for a sharp breath limits their use for people with compromised airways. There are three main types; (a) Single . dose, (b) Multi-dose and (c) Reservoir- types.

Summary of Nebulizers

Nebulizers can be used to deliver high doses of drug quickly. There are three types of nebulizer; (a) Jet, (b) Ultrasonic and (c) Mesh. These devices are becoming much more portable.

Any Questions

If you have any questions then please feel free to contact me on paul.cox@port.ac.uk