D5 Making tablets Flashcards
(44 cards)
what does oral administration of medicines restrict, particularly tablets?
- formulation size and appearance
- tablet has to be of a reasonable size for patients to take or a liquid for children
- eg. size to swallow, taste and palatability
how fast must disintegration of tablets occur and how does this happen in terms of excipients and technology?
- formulation must disintegrate in GIT in appropriate time
- use of optimised excipients (disintegrants)
- use of fabrication technology (coating)
explain how formulations make drug available for absorption
- drug needs to be in dissolved state during its transit through the GIT for absorption to occur
- consider appropriate drug solubilisation approaches
what balance must drugs have?
- right balance of hydrophilicity and hydrophobicity
- too hydrophilic means it will stay in GIT and can’t cross membranes
- too hydrophobic means it will precipitate and not be in solution to be absorbed
what 2 things do medicine formulations need to address? give examples
- drug sensitivity to environment in GIT (eg. protection be enteric coating, local pH buffering or enzyme inactivation)
- drug absorption properties from GIT (use of absorption enhancers and gastroretentive formulations to overcome absorption window issues)
roughly, what percent of medicines are taken orally?
90%
what are the requirement for an ideal oral solid dosage form? give 6
- uniform drug content (reproducible dose)
- drug must remain stable during production and storage
- drug must be bioavailable (formulation reliably releases drug in GIT)
- formulation is robust during handling (by patient as well)
- easy and cost effective to mass produce
- pleasant to take (appropriate to patient group)
what can be achieved by tablets? give 6 things
- accuracy in dosing
- stability (in comparison to liquid formulations)
- release of drug in GIT
- robust on handling
- ease of manufacture (‘mature’ technology in pharmaceutical industry)
- convenient administration and high patient compliance
after drug discovery, what use occur in order to make tablets?
- drug powder needs to be made into a medicine
- powder must be compressed into a tablet that can then quickly disintegrated again
why do we bother making drug powders into tablets?
- easier to dose a tablet than a spoonful of powder (accuracy in dosing)
- most drugs are not very nice tasting or palatable
- tablets are much more convenient
why are fine particles needed for making tablets?
- fine powder dissolves faster and therefore absorption occurs faster
- molecules of the drugs are absorbed, not particles of drug
describe and explain this schematic of the tableting process
- powder you want to compress into a tablet is put through the hopper and flows into the die cavities
- each die must be filled equally
- upper punch compresses the tablet
- lower punch ejects the tablet
what excipient is important in the ejecting of tablets from the die cavities?
lubricant
why must each die be filled equally in the tableting process?
- the weight of the tablets are determined according to the volume of powder used in the die then compressed
- powder always equally and uniformly fills the die
why must powder mixes for tablets be homogenous?
so that all the tablets contain the same amount of active ingredient and excipients
5 requirements for tabletting process
- uniform flow of the powder
- no powder segregation
- die cavity uniformly filled
- powder compressibility
- lubricability
from the 5 requirements for the tabletting process, which is a prerequisite for uniform tablet weight?
uniform flow of the powder
from the 5 requirements for the tabletting process, which TWO are prerequisites for uniform drug content?
- no powder segregation
- die cavity uniformly filled
in the 5 requirements for the tabletting process, what is meant by powder compressibility?
for tablets to remain as tablets once the pressure is removed
in the 5 requirements for the tabletting process, what is meant by lubricability?
no sticking to the die cavity and punches under pressure
what determines the tablets weight and drug dose of tablets?
volume of powder filling die cavity
can all powders be compressed into tablets? explain
- no
- they do not possess the required properties (compressibility)
- after they are compressed they will just turn back into powder if they don’t possess compressibility properties
- excipients with compressibility properties are needed
what are the 3 methods of forming tablets?
- wet granulation
- dry granulation
- direct compression into tablet
what kinds of particles will have the best flow?
- larger particles
- this is because they have a smaller surface area to volume ratio
