Intro to Solid Dosage Forms Flashcards
Why is there a need for dosage forms?
convenient and safe delivery of accurate dosage
avoiding degradation
improves palatability
form that can be administered
control drug release rate
What is a dosage form?
the means/form by which drug molecules are delivered to sites of action within the body
List off the many dosage forms.
tablet
capsule
solution
suspension
emulsion
powder
cream
ointment
What must all be considered for a drug delivery system?
physiochemical properties (solubility, stability, etc)
biopharmaceuticals (bioavailability, etc)
therapeutics (time of onset, duration of action, site of action,
age, illness)
What are the steps in formulation development?
- pre-formulation studies
-drug characterization
-drug/excipient, excipient/excipient interactions
-choice of excipients based on dosage form and drug - formulation
-process variables
-product paramters - testing in a biological system
-bioavailability
-bio distribution
-therapeutic response
-toxicological testing
What are the solid dosage forms?
powders
capsules
tablets
modified release
What are the advantages of solid dosage forms?
unit dose
cost of shipping
no breakage or leakage
masking taste is less difficult
more portable
require less space per dose
good physical and chemical stability
elegant distinctive appearance
What are the disadvantages of solid dosage forms?
potential bioavailability problems
potential irritant effect on GI mucosa
occasional difficulty in formulation
manufacturing can be technical/specialized
What are the three steps that drugs undergo?
disintegration
dissolution
absorption
What are the excipient categories of tablets and capsules?
diluent
binder
disintegrant
lubricant
glidant
coloring agent
plasticizer
What are the excipient categories of oral liquids?
pH modifier
wetting/solubilizing agent
antimicrobial preservative
chelating agent
antioxidants
sweetening agent
What are the excipient categories of semisolids, topicals, and suppositories?
suppository base
suspending or viscosity agent
ointment base
stiffening agent
emollient
What are the excipient categories of parenteral agents?
pharmaceutical water
diluent
tonicity agent
What are the excipient categories of aerosols?
propellant
What is bridging/arching?
material being discharged or fed forms a bridge/arch over the feed auger or discharge point in a cone or hopper
forces acting on the particles at the wall equal the internal strength of the mass of powder particles
no flow condition
What is the solution to arching?
larger discharge output
-success is limited with sticky fine powders
What is rat-holding?
material forms a hole or narrow channel above the feed auger or outlet in a hopper while the remaining material is stationary against the hopper wall
no flow condition
What is seggregation?
particulate solids and also quasi-solids tend to segregate by virtue of differences in size and physical properties
True or false: there is a direct relationship between particle size and chemical, physical, and pharmacological properties of a drug substance
true
What is dissolution rate?
the rate at which the particle dissolves
-smaller particles have a higher dissolution rate
How might one increase the bioavailability of a poorly soluble drug?
increase surface area
What is suspendability?
ability of a particle to remain undissolved but uniformly dispersed in a liquid vehicle
-larger particles settle faster
-smaller particles settle slower
What are all the possible characteristics that particle size can influence?
dissolution rate
suspendability
accuracy of dosage form
penetrability
non-grittiness
chemical stability
flowability
compressibility
What is penetrability?
the ability of a particle to reach their intended location
Why is non-grittiness important?
we dont want solid particles in dermal product to feel gritty
finer particles allow for smoother texture, appearance, and flow
What is chemical stability?
refers to degradation reactions
-smaller particles have larger surface area=vulnerable to
reactions with oxygen, water, and light
What is flowability?
effect on flow properties of powders and mixing of powders and granules
important in manufacturing of tablets and capsules
What is compressibility?
effect on adhesion when compressing granules into tablets
important in manufacturing of tablets and capsules
What are the advantages of sieving?
inexpensive
simple
fast
What are the disadvantages of sieving?
does not provide as much information as microscopy
What is the difference between monodisperse powders and polydisperse powders?
monodisperse: powders containing particles of uniform size (rare)
polydisperse: particle size varies a great deal
What is communition?
mechanical process of reducing particle size of a solid substance to a finer state of subdivision
-small scale or industrial
What is small-scale communition?
involves the use of a mortar and pestle by pharm or tech
-trituration, levigation, pulverization by intervention
Explain trituration.
the process of grinding a drug in a mortar to reduce its particle size
Explain levigation.
the process of mixing a powder with a liquid or semi-solid vehicle, in which the powder is insoluble, to form a smooth paste
Explain pulverization by intervention.
particle size reduction with the aid of an additional material, which can later be removed
What is milling?
industrial scale or mechanical process of reducing particle size
What are the three broad categories of milling equipment?
coarse crushers (jaw, roll, and impact crushers)
intermediate grinders (hammer, roller, rotary cutters)
fine grinding mills (ball, hammer, colloid, fluid energy mills)
Why is it important to thoroughly mix powders?
essential to ensure uniformity of drug throughout a batch and between batches
What are the three methods of small-scale extemporaneous mixing?
trituration: using mortar and pestle and mixing in a single op
spatulation: blending powders with a spatula on a tile or paper
sieving: used to help reduce loosely held agglomerates or to
increase effectiveness of blending
What is a powder?
mixture of dry, finely divided drugs and or chemicals that may be intended for internal or external use
-basic formulation
-mostly replaced by tablets or capsules
What are the uses of medicated powders?
oral: usually after mixing in water, preferred by people who
cant swallow other solid dosage forms
topical powders: external application to the skin, most powders
What are the advantages of powders?
flexibility in compounding
suitable for infants and young children
rapid onset of action (no disintegration)
can be applied to many body cavities
good chemical stability
What are the disadvantages of powders?
potential for misunderstanding for method of correct use
bitter or unpleasant taste
difficult to protect hygroscopic or aromatic material from degradation
time-consuming to prepare uniform wrapped doses
What are some “other” bulk powders?
dusting powders (usually topical)
dentifrices (denture powders, dental cleaning powders)
douche powders (dissolved in water prior to use as antiseptics)
Describe bulk powders for oral use.
convenient for dispensing non-potent, powdered drugs, which have doses that require large volumes
dose is measured volumetrically by patient or care-giver
not appropriate for drugs that require accurate dosing
