MP324 - FORMULATIONS

Question 1

pulmonary delivery devices used to generate an aerosol

Answer 1

• pressured meter dose inhalers (pMDI)
• dry powder inhalers (DPIs)
• nebulisers

Question 2

definition of an aerosol

Answer 2

colloidal systems consisting of very finely subdivided liquid or solid particles dispersed in and surrounded by gas

Question 3

mass median aerodynamic diameter (MMAD)

Answer 3

diameter at which 50% of the particles of an aerosol by mass are larger and 50% are smaller than the median diameter

Question 4

fine particle fraction (FPF)

Answer 4

fraction of particles that can achieve deposition in the lower respiratory tract

Question 5

5 key components to pMDI

Answer 5

container
propellants
actuator
metering valve
formulation

Question 6

surfactants used in HFA inhalers (solution inhalers)

Answer 6

sorbitan trioleate
oleic acid
soya lecithin

Question 7

co-solvents used in HFA inhalers (solution inhalers)

Answer 7

ethanol
glycerol
propylene glycol

Question 8

why are co-solvents/surfactants used in HFA

Answer 8

drug solubility is limited

Question 9

inhalers for patients with good actuation-inhalation coordination and inspiratory flow >30L/min

Answer 9

pMDI
BA-pMDI
DPI
nebuliser

Question 10

inhalers for patients with good actuation-inhalation coordination and inspiratory flow <30L/min

Answer 10

pMDI
nebuliser

Question 11

inhalers for patients with poor actuation-inhalation coordination and inspiratory flow >30L/min

Answer 11

pMDI + spacer
BA-pMDI
DPI
nebuliser

Question 12

inhales for patients with poor actuation-inhalation coordination and inspiratory flow <30L/min

Answer 12

pMDI + spacer
nebuliser

Question 13

issues relating to the use of ethanol as a co-solvent

Answer 13

can exert multiple effects:
- changing the formulation density and thus changing the total mass of the formulation atomized during device actuation
- changing atomization of the formulation and the size of the atomized droplets
- changing the evaporation rate of the droplets towards their residual particle sizes

Question 14

formulation issues with pMDI suspensions

Answer 14

• particle interactions changing particle size distribution
• MMAD is dependent on aerosol droplet size and particle concentration
• larger particles have increased propensity to contain multiple drug particles

Question 15

4 features of DPIs

Answer 15

• dose-metering mechanism
• aerosolisation mechanism
• de-aggregation mechanism
• an adapter to direct the aerosol into the mouth

Question 16

5 types of DPIs and required inspiratory flow rates

Answer 16

turbohaler (min 30, optimal 60)
Handihaler (min 30)
easyhaler (effective at low inspiratory rates)
accuhaler (min 30)
novolizer (no drug release unless >35)