D3 and D4: Medicine design and manufacturing- powder-based medicines Flashcards
what are the different types of powder-based medicines?
-bulk and wrapped powders
-capsules
-tablets
Describe powder medicines
-powders can be medicines themselves
-drug powder mixed with powder excipients
-packed as ‘single-dose’ or in ‘multi dose’ containers
Describe bulk powders
Several doses packed in a container suitable for the route of administration
advantages of oral bulk and wrapped powders?
-patients who struggle swallowing tablets or capsules
-more stable than liquids (less chemical degradation and very low risk of microbial growth)
-good way to give large doses of drug by mouth
-fast dissolution so fast action
Describe the issue with moisture with powders
-absorbs water (hygroscopic)
-can dissolve during processing and storage (deliquescent)
-can stick together (caking)
-Therefore must always be protected from moisture e.g using suitable packaging and store in dry conditions
Describe the issues with flow with powders?
-poor flow causes inaccurate/ inconsistent packaging
-Size, shape, moisture, surface charge affect ‘flowability’ → must be controlled
Describe the issue with mixing and separation with powders
-poor mixing can lead to inaccurate dosing
-powder mixes can unmix during movement (transport, pouring, mixing)
Describe oral bulk powders
-packed in jar or vial (spoonfuls of powder put in food or drink, easy to take)
-Reconstituted in water before dispensing (ex: antibiotics for children) – useful when drug is unstable in water
how do you solve mixing and separation issues with powders?
-equalise particle sizes (grinding and sieving)
-mix equal amounts of powders (geometric mixing)
-granulation; powders are bound together to form larger particles, usually spherical (‘granules’)
what is dry granulation
dry powders compressed by metal rollers
what is wet granulation
powder mixture is wetted with a solution of polymer (binder)
how do granules improve mixing and separation of powders?
Powders can not separate
Flow better due to large size
(sieve and dry)
Describe wrapped powders and sachets
-One single dose of powder mixture packed in a sealed small bag made of paper, foil or plastic.
-More accurate dosing and more convenient
-Better protection against moisture
what are the different excipients in bulk and wrapped powders?
Bulking agents (fillers/diluents), granulating agents (Binders), effervescent mixtures, flow aid (glidants), anti-caking agents, surfactants, flavours, colours
many polymers are used as…
excipients (can be natural of synthetic polymers)
Describe capsules
-Small ‘edible packages’ filled with one single dose unit
-hard polymer shell soluble in water (gelatin or HPMC)
-Filled with powder mixture, granules, small tablets or combination
why do we used hard capsules?
-easy to swallow
-different sizes available
-shell adds protection
-shell can be coloured (identification) or coated (delay release)
-some can be opened
-easier to manufacture than tablets
Describe soft capsules
-not as common
-shell made of gelatin, water and platicizer polymer
-used for oils, liquids, semi solids
-larger but easier to swallow
Function of bulking agent (fillers/dilutents) excipient?
add bulk as the drug may only be a few mg
Function of granulating agents (binders) excipient?
bind powders into granules
Function of effervescent mixtures excipient?
produce CO2, faster dissolution
Function of flow aid (glidants) excipients?
improve flow of powders
Function of anti-caking agents excipients?
adsorb water
Function of surfactants excipients?
Aids particle dispersion and drug dissolution
Function of flavours, colours excipients?
patient acceptability
Describe tablets
-single dose of compressed powder
-optional coat, drug and excipients within core (matrix)
-small, portable, convenient
-very stable
-shape and colour give distinctive
how are tablets made
granules or powder mixture by compression on a high speed tablet press
what are the excipients used in tablets
compression aids, binders, lubricants, tablet coat, disintegrants
function of compression aids, binders excipients?
bind particles under pressure to make tablets stronger
function of lubricants excipients?
help tablet machine eject tablet after compression
function of tablet coat excipient?
-protects contents (water, air, oxygen)
-taste masking
-identification
Function of disintegrants excipients
Break the tablet up in the stomach by attracting water and making it swell
Describe dispersible tablets
-dissolved in water or on tongue before taking
-very quick acting
-contain an effervescent mixture or are very thin porous tablets
Describe immediate release tablets
-conventional tablets
-disintegrate and release drug in the stomach
-fast acting (<1h) if drug is quickly absorbed
Describe delayed release tablets (gastro- resistant)
-intact in the stomach and disintegrate in the small intestine
-used if drug is degraded or irritates stomach
-coating is insoluble in acid (stomach) but soluble at neutral pH (intestine), called ‘enteric coating’
Describe extended release tablet
-slow release drug in the GI tract over 8-24hr
-used if once a day dosing if required or fast drug release causes side effects
-tablets designed with a coating that is insoluble but porous or a matrix that erodes slowly
Good working practice (GWP) must be followed to ensure what three things?
-accurate weighing of all ingredients
-no contamination
-accurate records of weighing on the BMR
(watch video on ppt for demo)
What are the problems with powders?
-powder ingredients might be coarse which can lead to poor medicine stability or patient discomfort
-powder ingredients might have diff particle sizes leading to separation
-powder ingredients might need to be mixed in very different amounts. Use geometric mixing technique.
What is the geometric mixing technique?
-grind a slight excess of the ingredients with bigger particles
-sieve
-weigh the powders
-Place the ingredient with the smaller volume in a mortar
-Add equal volumes of the other ingredients
-Using the pestle, mix gently until an even mixture is obtained.
-Repeat steps 5 and 6 until all ingredients are incorporated
what are the two types of labels
main label and ancillary label
general principles of labeling?
-clear
-printed, not handwritten
-english
-labels on medicine bottle and batch manufacturing doc
what is the main label?
main source of info and allows to track the product down
what is the ancillary label?
warning and advisory labels- legal requirement on all medicines
How do you name a product if the product has an official name
-use official name and include source at the end
-strength does not have to be included if the product can only be produced at a specific strength but must be included if more than one strength can be dispensed (check british pharmacopoeia)
How to name a product that does not have an official name?
use a general name and include the strength (strength for internal medicines is expressed as the amount of drug in one dose and in external medicines, it is expressed as a percentage)
What is dose and frequency?
dose- amount of medicine or drug taken on one occasion
frequency- how often dose is taken
(how to display this info on a label is on one note)
