Extemporaneous Preparations Flashcards
When was the Medicines Act and The Human Medicines Regulation? What are their requirements?
What is the MHRA?
Medicines Act - 1968
The Human Medicines Regulation - 2012
- require that medicinal products be licensed before they are marketed in the UK
What is the MHRA?
What are medicinal products tested for before they can receive their marketing authorisation?
Medicines and Healthcare products Regulatory Agency
- government agency which directly approves medicines and issues Marketing Authorisation (MA) to the manufacturer.
medicinal products are tested for:
- efficacy
- quality
- safety
What are specials? When can they be prescribed?
A “special” is an unlicensed medicine and is supplied only when there is no available licensed medicine which fully meets the patient’s clinical needs.
specials can be prescribed only when suitable licensed medicines aren’t available
- the Medicines Act allows doctors to prescribe and specify the formulation of any medicine which they judge to be essential to meet the patient’s “special clinical need”
What is the difference between licensed medicines, specials and extemporaneous preparations in terms
- batch size
- safety, efficacy
- price
licensed medicines - large batches - rigorously tested for quality, safety and efficacy - cheap specials - small batches - tested for quality but not safety or efficacy - expensive extemporaneous preparations - single packs - not tested - very expensive
What is extemporaneous dispensing/compounding?
it is the mixing together of ingredients of a prescription or drug formula
- generally refers to a manual process performed for individual orders by a dispenser or pharmacist.
What are reasons for extemporaneous preparations?
The small size of the potential market is a key factor.
appropriate licensed formulation is unavailable
- liquid dosage forms when only tablets / capsules available
- dilution of creams/ointments when higher strength only available
- discontinued licensed medications
allergy to excipients in licensed preparations
sugar or alcohol content of liquid preparations too high for patient
What are the techniques for dispensing extemporaneous preparations?
mixing
- to ensure an even distribution of all the ingredients
mixing solids with liquids
- must know the solubility of the solid
- particle size reduction is important
mixing solids with solids
- must use mortar and pestle correctly
doubling up technique
- used if a small quantity of powder is to be mixed with large quantity of powder
- the smallest quantity must be added to the mortar, then a second ingredient is added in an approximately equal volume to the first. mix using pestle, then a further quantity of the second ingredient approx equal in volume to the mixture in the mortar is now added
mixing by trituration
- is the way a powder (or liquid ingredient) is incorporated into a base
- it is carried out with an ointment slab/tile and spatula to work in ingredients
- powder placed on one corner of tile, base on other. powder is gradually incorporated in a small quantity of base so as to form a smooth product to which the remainder of the base can then be added gradually to form a smooth homogenous preparation
What are the different expiry dates for extemporaneous preparations? What is the difference?
freshly prepared
- must not be made more than 24 hours before it is issued for use
- no preservative
- 2 week expiry = including the day of manufacture
recently prepared
- deterioration is likely if the preparation is stored for longer than about 4 weeks at 15°C to 25°C-
- has preservative
- four week expiry = including the day of manufacture
What is kept in the record for extemporaneous dispensing?
formula
ingredients and quantities
source of ingredients (i.e. manufacturer)
batch numbers and expiry dates of all ingredients where in existence
use by date of prepared product
What are excipients?
substances added to aid formulation and manufacture of dosage form for administration to the patient
What are the different types of excipient?
sweetening agents flavouring agents emulsifying agents stabilisers viscosity enhancers preservatives colouring agents suspending agents
What is the purpose of a flavouring agents? What are the properties? What are some examples?
their purpose is to make medicine more acceptable to take
- especially if drug has an unpleasant taste.
selected flavour must be
- non-toxic
- stable/compatible
age of the patient should be taken into account
- children prefer fruit or sweet flavours
flavour and colour should complement each other
examples
- juices, extracts, spirits, tinctures, syrups, aromatic waters
What is the purpose of a sweetening agents? What are the properties? What are some examples?
to enhance the medicines taste
- oral liquid preparations are sweetened with sugars = glucose, sucrose
prolonged use of liquid medicines with sugar will lead to increased incidence of dental caries
- especially in children
oral liquid preparations that do not contain fructose, glucose or sucrose are described as “sugar free “in the BNF.
sugar free preparations have
- hydrogenated glucose syrup, mannitol, maltitol, sorbitol or xylitol
What is the purpose of a colouring agents? What are the properties? What are some examples?
their purpose is to
- enhance appearance = often matched to colour
- increase acceptability to patient
- to prepare products of consistent colour
- aid identification = give medicine a distinct appearance
colouring agent must be
- non-toxic
- free of any therapeutic activity
natural colourants are derived from plants and animals. they include
- chlorophylls, saffron, red beetroot, caramel
synthetic dyes include
- azo compounds
What colouring agent is not suitable for use?
tartrazine known to cause allergic reactions and hyperactivity in children
