Drops, sprays and inhalers Flashcards
3 types of drops solution
aqueous
organic
alcholic
Say the medial names of the following and how many drops in each
Eyes
Nose
Ears
occular 1-2 drops
nasal 2-3 drops
otic/aural 3-4 drops
How many drops in 1ml
20 drops
What kind of solvent is always used for eye drops?
Aqueous
How is sterility achieved with eye drops?
Sterile single use vials
Preservatives
Packaging for eye drops must be..
protective of contamination and produce accurate dosing
must be discarded 28 days after opening
Eye drops excipients (excluding preservatives) Tonicity= Viscosity= and why pH buffers to affect what? Examples Antioxidants
0.9%
hypromellose and polyvinyl alcohol to prolong contact with the eye
Buffers- stability, therapeutic activity, comfort of patient (pH 7.2-7.4)
Examples: boric acid, citric acid, sodium phosphate
Antioxidants: protect drug from oxidation e.g. sodium metabisulphate
Eye drops preservatives - name 3
Benzalkonium chloride
Chlorhexidine
Chlorobtanol
Most commonly used eye drop preservative? Why?
When isn’t it used?
Benzalkonium chloride
Broad spectrum of antibiotic properties
Incompatible with contact lenses
When are preservative free eye drops used?
Packaging?
After surgery or in hypersensitivity reactions
sterile single use vials i.e. minims
Name the 4 different types of packaging for eye drops. Describe them.
1) Sterile single use vials -injection moulded plastic with a sealed screw cap. Vials autoclaved to ensure sterility
2) Plastic bottles - sterilised before filling and filled using aseptic technique
3) Glass bottles - mostly for extemp products. 10ml ribbed amber bottles with dropper. Sterilised after filling
4) auto droppers to help patients administer the drops
Nose and ear drops and sprays are..
solutions
sometimes combination products
Nose drops and sprays pH
pH 5.5-6.5
Nose drops tonicity
0.9%
Nose drops local use for…
congestion, inflammation, infection
Nose drops systemic use example
Nicorette nasal spray
Nose drop vehicles are usually
aqueous
Ear drops/sprays local effect
softening ear wax
infection
inflammation
can be combination products
Vehicles for ear drops include
propylene glycol
oils
glycerol
water
Nose and ear drops have similar packaging to..
eye drops
Nose and ears sprays - consider 3 things
Age of patient
plastic vs glass
metered dose vs squeezy bottle
What is the main issue of the packaging of ear and nose drops and sprays?
Contamination hence short shelf life once opened
5 advantages of drops and sprays
convenient reduced systemic side effects fast local action sprays used for systemic use bypass 1st pass metabolism Drops can be administered in children
4 disadvantages of drops and sprays
inaccurate dosing of drops and squeezed bottles
manual dexterity
patient preference
short shelf life once opened
Inhalers are designed to what?
Local…
Systemic…
Deliver drug directly to lung
mostly local effect but potential for proteins and peptides to be delivered for systemic effect
How does particle size of drug effect how a drug from an inhaler acts?
Too small
Too big
Optimum
smaller the particle size, the further down the respiratory tract the drug will penetrate
<1 micrometer results in particle being exhaled
>10 micrometers results in drug remaining in oropharynx
best size 3-5 micrometres
Metered dose inhalers (MDIs) have what inside them?
Aerosol of drug and a propellant
Propellant types?
HFAs vs CFCs
i.e. hydroflouroalkanes vs chloroflourocarbons
Actuation of an MDI results in what?
evaporation of propellant to form droplets to be inhaled into the lung
Technique for MDI drug delivery?
Coordination between actuation and inspiration
Long steady inspiration
One inspiration per actuation
Why must you shake an MDI before use?
To disperse the propellant and the drug
When are breath activated MDIs most commonly used?
for patients with coordination issues
Name 2 brands of breath activated MDIs
Autohaler
Easi-breathe
Propellant for MDIs?
HFA/CFC
Gases at room temperature are maintained as liquids under pressure in the aerosol cannister
Surfactants for MDIs do what? example?
Aid wetting for suspension
e.g. oleic acid
Cosolvents for MDIs do what?
Example?
To aid dissolution
e.g. ethanol
Are dry powder inhalers breath actuated?
Yes but require stronger breath inwards
What is the drug form like in a dry powder inhaler? (DPI)
Doses compared to MDI?
Drug micronised powder for inhalation
Larger doses
Do DPIs need:
coordination?
propellant?
No and no
Name 4 brands of DPI
Accuhaler
Turbohaler
Handi-haler
Dischaler
Accuhaler DPI has a carrier for the drug. What is it?
Lactose
Why is lactose in accuhaler a problem?
It is the drug carrier and lactose remains in the mouth after drug is taken
patients complain of powder in the mouth
Turbohaler DPI.. the excipients?
Advantages?
It’s pure drug
Little or no taste residue
Packaging for MDIs
Advantageous or not?
either -tin plated steel -plastic coated glass -aluminium very stable as container protects from oxidation and microorganisms
Packaging for DPIs
Advantageous or not?
Powder can be contained in -preloaded chamber -foil blister discs -hard gelatin capsules Susceptible to moisture degradation
5 Advantages of inhalers
- Can use small does
- Reduced systemic side effects
- Fast onset of action
- Can use with drugs of poor oral bioavailability
- Cost of MDI (Cheap)
5 Disadvantages of inhalers
- difficult to coordinate
- Not suitable for all drugs
- only 20% of drug reaches lung
- Inflammation can reduce size of airways
- Cost of DPI (expensive)
