P4: Inhaler Devices & Formulations

Question 1

what are some examples of pMDIs

Answer 1

standard inhalers, spacers, breath activated inhalers

Question 2

what are some examples of nebulisers

Answer 2

pneumatic, ultrasonic

Question 3

what are nebulisers

Answer 3

drug contained within a sterile solution of WFIs
they reproducibly and rapidly deliver correct dose to site of action with minimum waste; in reality, variations are observed
2/3 left in device, 2/3 lost during expiration, many particles too large/small
many nebulisers deliver as little as 10% of the target dose

Question 4

what are pneumatic nebulisers

Answer 4

dominant system in market with two fluid nozzle

Question 5

what are the components of a pneumatic nebuliser

Answer 5

unit doses, compressor, patient interface, valves/holding chamber, tubing

Question 6

what are the advantages of pneumatic nebulisers

Answer 6

cheap, small particle sizes (1-6 microns)

Question 7

what are some disadvantages of pneumatic nebulisers

Answer 7

variable performance, dead volume, lower output, portability

Question 8

what are the components of ultrasonic nebulisers

Answer 8

electronic power source, synthetic piezoelectric ceramic disc, liquid reservoir, air fan, mouthpiece

Question 9

what are the advantages of ultrasonic nebulisers

Answer 9

reproducible, small particle size (1-6microns), high output, small and quiet, low aerosol inertia

Question 10

what are the disadvantages of ultrasonic nebulisers

Answer 10

size increase at end of life/ fill volume dependence, expensive, heats solution to 40degreesC, poor for suspensions

Question 11

what are the recent advances in inhaler devices

Answer 11

breath assisted open vent, holding chambers, dosimetric, breath monitoring intelligent system, battery operated
enhances nebuliser output and/or shorten nebulisation time

Question 12

what does SMI stand for

Answer 12

soft mist inhalers

Question 13

what does LDI stand for

Answer 13

liquid dose inhalers

Question 14

what are SMIs and LDIs

Answer 14

emerging class of inhalers
based on drug dissolved in a non-volatile liquid (usually water)
volumetric dosing like in pMDIs
aerosolised in a single breath actuation
requires tight control of droplet size via a mechanism within device
aerosol is emitted as a slow moving cloud

Question 15

what is AERx LDI

Answer 15

hand held air-jet driven nebuliser system
utilises an electrochemical actuator to extrude drug, contained in unit dose liquid blisters, through an array of small micron sized holes
produces a uniformly fine aerosol for inhalation
uses microelectronics to guide patient into the optimum inspiratory flow rate for actuation and delivery

Question 16

how does a Respimat work

Answer 16

drug solution is forced through a micro nozzel assembly (uniblock) as the patient inhales

Question 17

what is the structure of Respimat

Answer 17

medication stored as a solution; avoids problems of moisture absorption and powder aggregation that occur with DPIs; use of solution ensures that the metered dose delivered with each actuation remains uniform; cartridge is a sealed container containing a collapsible bag