4 - Acetaminophen Flashcards
What is MOA of acetaminophen and what is it used for?
- Analgesic/ antipyretic that inhibits prostaglandin synthesis
- Elevates pain threshold
- Acts on hypothalamic heat-regulating center
- Used for MSK pain, earache, LBP, arthritis, dysmenorrhea, myalgia, infections
Is acetaminophen or ASA stronger in regards to analgesic and antipyretic effects?
Both are considered equipotent
Advantages of tablets over other dosage forms to manufacturers
- Economy
- Stability
- Convenience
Advantages of tablets over other dosage forms to consumers
- Accuracy
- Portability
- Convenience
What are some excipients found in tablets?
- Diluents
- Binders
- Lubricants
- Disintegrants
- Glidants
- Colorants
- Flavouring agents
Purpose and examples of diluents
- Increase tablet mass for compression
- Ex: lactose, cellulose, mannitol, starch
Purpose and examples of binders
- Improve free-flowing qualities of granules for desired hardness
- Ex: starch, gelatin, sugars (sucrose, glucose, dextrose), acacia
Purpose and examples of lubricants
- Prevent adhesion to dies/punches, reduce friction, facilitate ejection
- Ex: talc, magnesium stearate, PEG
Purpose and examples of disintegrants
- Absorb water rapidly to increase size afterwards, so tablets can disintegrate after administration
- Ex: starch, cellulose
Purpose of glidants
Improve flow characteristics of a powder mixture
Purpose of colorants
Provide appealing appearance
What is used in controlled release tablets that is unique?
Specific polymers or coating materials
What is the most popular tableting procedure?
Wet granulation
Describe wet granulation
- Weighing
- Mixing
- Granulating
- Wet screening
- Drying
- Dry screening
- Lubricating
- Compressing
Describe fluid-bed granulation
- Weighing
- Mixing, granulating, and drying processed in a single piece of equipment
What is special about dry granulation?
- No granulation fluid so no moisture
- High temperature is applied
What is special about direct compression?
- Most recent
- Mixing and compressing with shortened processing time/cost
What characteristics describe a tablet?
- Tablet size, shape, thickness, weight
- Hardness
- Drug content and uniformity
- Drug disintegration and dissolution
When is tablet hardness measured?
Throughout the tableting process
Why can’t a tablet be too hard or soft?
- Too hard = may not meet disintegration and/or dissolution requirements
- Too soft = won’t withstand handling conditions during subsequent processing
What determines tablet hardness?
Resistance to chipping, abrasion, or breakage during storage, transportation, and handling
What is tablet friability?
Ability of the tablet to withstand abrasion during packaging, handling, and shipping
When is tablet friability measured?
On finished products
Which tablets normally are tested for content uniformity?
Those w/ small amounts of active ingredients or have small tablet weight
What is disintegration?
How fast a tablet breaks into small particles once in contact w/ a medium
Does in vitro disintegration correlate w/ in vivo?
Not always
What is tablet disintegration used to measure?
Batch-to-batch reproducibility
Which tablets require disintegration testing?
- Compressed, film-coated, enteric-coated, buccal, sublingual, soft/hard gelatin caps
- Controlled release don’t require disintegration testing
Is dissolution or disintegration more important for solid dosage forms?
Dissolution
What is dissolution?
- Amount of time required for a given percentage of drug substance in a tablet to go into solution under specific conditions
- Determines availability of an active ingredient
What other formulations besides oral dosage forms can undergo dissolution testing?
Transdermal, suppositories, ointments
What excipients were used w/ acetaminophen for this experiment and what is the purpose of each?
- Lactose = diluent
- Avicel = binder
- Explotab = disintegrant
- Magnesium stearate and talc = lubricant
- Granulating solution (10% PVP solution or 10% starch paste) = binder
Which tests were performed on the tablets for this experiment?
- Hardness (10 tablets) using portable hardness tester
- Friability (10 tablets) in a tablet friability apparatus
- Weight uniformity (10 tablets) weighed them and recorded the average
- Tablet content (10 tablets)
- Dissolution
How was tablet content tested?
- Weigh 10 tablets and find average tablet weight and grind in mortar
- Weigh aliquot equivalent to 50 mg and dilute to 200 mL w/ distilled water
- Filter and pipette 1 mL of filtrate into 25 mL volumetric flask and dilute w/ distilled water
- Record absorbance at 249 nm w/ distilled water as blank
How was tablet dissolution measured?
- Place 1 tablet in 900 mL distilled water at 50 rpm for 30 min
- Withdraw 2 mL at 15 and 30 min and filter (replenish)
- Pipette 1 mL of the original dissolution solution into a 25 mL flask and dilute with water
- Measure absorbance at 249 nm and calculate content
