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Kirstys Flashcards > MDM: Tablets > Flashcards

MDM: Tablets Flashcards

1
Q

What are tablets?

A

A solid preparation manufactured by compressing uniform volumes of particles which contain a single dose of one of more active ingredients and excipients.

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2
Q

What are advantages of tablets?

A
  • Convient - to carry/ store
  • Good patinet compliance
  • Acurate dosing
  • chemical, physical and microbial stability
  • Generally cheap, robust and elegent
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3
Q

Disadvantages of tablets

A
  • Generally systemic delivery
  • poor bioavailability
  • must be swallowed
  • local irritation - GI mucosa
  • Extensive developmental work
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4
Q

What are the basic steps taken when forming a tablet?

A
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5
Q

When forming a tablet what are the ideal properties for a powder blend?

A
  • Homogenous - doesn’t segregate
  • Free flowing - freely flows through tablet machinary
  • Adheres and coheres
  • doesnt adhere to tablet tooling
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6
Q

What are examples of excipents included in tablets?

A
  • Binder
  • Distigrant
  • Lubricant
  • Diluent
  • Glidant
    *
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7
Q

What is the role of a diluent and some examples?

A

Increases tablets bulk density and acheive required strength

Lactose, sucrose, mannitol, glucose, Calcium hydrogen phosphate, MCC

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8
Q

What are examples of lubricants and their role

A

Reduce friction between tablet and machinary during manufacture

Magnesium sterate and sodium steryl fumarate

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9
Q

What are examples of binders and their roles

A

Improves mechanical strength by binding particles

PVP, gelatine, sucrose

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10
Q

What is the role of distigrants and some examples

A

Promote rapid tablet distigrant

Starch, cellulose, PVP,

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11
Q

What are example of glidants and their roles?

A

Improves powder flow by reducing intra-particular friction

silica, magnesuim sterate, talc

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12
Q

What are methods used to determine powder flow?

What do these methods tell you?

A
  • Flow through an orfice - flow rate
  • Angle of response - inter particular cohesion
  • Bulk density - percentage compressability and friction
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13
Q

What is powder flow dependent upon?

A
  • Particle size, shape and density
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14
Q

A powder has poor flow characteristics. What could be done to sort this?

A
  • Increase particle size and reduce size distribution
  • Change particle size and texture e.g. during spray drying, cyrstallisation
  • Change surface forces - e.g. add glidant
  • Alter process conditions e.g. vibration assisted hoppers
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15
Q

What are examples of equipments used to mix powders?

A
  • tumbling
  • high speed mixer granulators
  • fluidised bed mixers
  • agitator mixers
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16
Q

What is powder mixing depent on?

A
  • shape
  • size
  • density of particles
    *
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17
Q

What improvement could be done to improve powder mixing?

A
  • Granulation
  • Reduce particle size distribution - e.g. sieving or milling
  • controlled crystilisation - particular shape and sized crystals
  • Choose excipents with similar density to API
  • Reduce blending movement
  • Equipment - reduce time in hoppers, reduce transfer
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18
Q

When forming tablets what are the 2 methods that can be used?

Describe breifely these

A

Direct compression - drug and excipents mixed

or granulation - primary powder particles adhere to form granules

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19
Q

What are advantages and disadvantages of direct compression?

A

Advantages:

  • Faster drug dissolution
  • Reduction in manufactuing time and costs

Disadvantages:

  • powder segregation
  • poor compaction properties
  • poor colour uniformity
  • specialist fillers and binders required
  • powder must have good flow properties
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20
Q

Advantages and disadvantages of granulation

A

Advantages:

  • increases compactiabilty
  • improved colour uniformity
  • improves powder flow
  • increases bulk density
  • improves homogeneity and prevent segregation

Disadvantages:

  • increases in production time and costs
  • may cause hydrolysis of drug
21
Q

Describe 2 other granulating methods

A
  • Fluidised bed drier - spray drying using a binder solution
  • Dry granulating - using pressure to form compacts
22
Q

What are the benefits/ negatives of spray drying and dry granulating?

A

Spray drying - produces high quality granules - good homeogenity, flow and compactability. Time consusing

Dry granulation - no hydrolysis of drug

23
Q

What is powder compression?

A

Pushing particles into close proximaty to each other by using confined compression

24
Q

What are the 3 stages involved in powder compression to form a tablet?

A
  1. Die filling
  2. Tablet formation (compression of tablet from upper and lower die)
  3. Tablet ejection
25
Q

How does a tablet pressor work?

What are the differences between both?

What are they used for?

A
  1. Hopper filed with powder and and fills dies which are then compressed by upper and lower dies before being ejected
  2. Single punch tablet press - one set of tools and small output.
  3. rotary tablet press - multiple sets of tools and high out put
  4. Single tablet punch used to produce tablets for clinical trials and during formulation development
26
Q

Why would we coat a tablet?

A
  • Protect the drug
  • mask taste
  • ease of swallowing
  • improves appearance
  • rapid idnetificartion
  • increases bulk
  • modified release characteristics
  • ease of handling
27
Q

What are examples of types of tablet coatings?

A
  • film
  • sugar
  • compression
28
Q

Describe film coating

A
  • most common
  • ploymers, platisticizers, colourants
  • sprayed onto rotating tablet
  • immediate (non functional) - water soluble
  • functional - modified - PH 5 -6
29
Q

Describe sugar coating

A
  • sucrose based syrup
  • sugar coating pan (6 stages - sealing, subcoating, smoothing, colouring, polishing, printing)
  • readily water soluble - distigrant
  • generally immediate release
30
Q

Describe compression coating

A

compatction of granular particles around tablet core

31
Q

What are the desired attributes of a tablet?

A
  • contains correct dose
  • consistant size, weight and appearance
  • drug release controlled and reproducable
  • sufficent mechanical strength
  • physical, chemiacal and microbiologically stable
  • formulated for patient acceptance
  • packaged appropriately
    *
32
Q

Why is tablet testing required?

A
  • To ensure the patient receives a tablet which contains the required amount of drug substance in a form in which it can exert its full pharmacological action.
  • to ensure it is microbiologically stable
  • to ensure the AI is released over a specified time
  • ensure mechanical strenght is sufficent to avoid it crumbling/ breaking on handling
33
Q

What are examples of drug tests carried out?

A
  • Uniformity of weight
34
Q

Describe uniformity of weight testing

A
  • equal to or greater than 25mg or 25% drug coc
  • individually weigh 20 tablets and determine the mean
  • Not more than 2 tablets should deviate from the mean by particular % and no tablets should deviate by twice the %
  • More acurate with higher drug conc
  1. ≤ 80mg - 10%
  2. > 80mg /< 250mg - 7.5%
  3. ≥250mg - 5%
35
Q

Describe uniformity of content

A
  • Done if less than 25mg or less than 25% drug content
  • using appropriate analytical technique determine drug content of 20 tablets
  • Drug content of each tablet should fall between 85% - 115% of average content
  • One tablet allowed to be between 75% - 125% of avergae content
  • if one tablet falls out with limits re test another 20
36
Q

Describe friability testing

A
  • Friabilitor used - Mimics forces encountered during handling
  • tablets must resist friability to ensure appearance and dose is maintained
  • if less or equal to 650mg - 6.5g of whole tablets tested
  • if more than 650mg - 10 tablets tested
  • No more thn 1% mass loss allowed and no chips or cracks allowed
37
Q

Describe fracture resistance testing

A
  • The resistance to crush tablet - measured by force.
  • Tablet placed against platen, load applied along diameter by movable platen. Tablet cracks along diameter into two pieces of similar size and force recorded.
  • Record mean, minimum and maximum forces (Newtons). RGU: Mean force - 40 – 100 Newtons
38
Q

Describe distigratin testing

A
  • Determines if tablets disintigrate in prescribed time
  • 6 tablets in purified water at 37°C +/- 2 for 15 mins
  • if 1 or 1 fail test further 12. 16/ 18 must distigrate in required time
  • depends on type of tablet e.g. coated - 60 mins
    *
39
Q

Describe dissolution testing

A
  • Tablet placed in dissolution medium in stirred vessle at 37 +/- 0.5
  • more than 70/ 75% of drug released after 45 mins
40
Q

What are problems that can occur during tableting?

A
  • low mechanical strength
  • weight/ dose variations (granulate?)
  • capping - top of tablet fractures/ breaks
  • lamination - tablet breaks into more than 2 distinict horizontal layers
  • sticking - powder sticks to punch
  • picking - particular sticking where powder sticks wihtin letters/ logos of punch
  • chipping - breaking of edge of tablet
41
Q

What tablet classes is there?

A
  • immediate release: rapid drug release
  • modified release: slower/ varied drug release
  • prolonged release: released slowly over a long period of time
  • ­Pulsatile release: Released in two or more pulses
  • Delayed release: Released some time after administration
42
Q

What are types of immediate release tablets?

A
  • distigrating
  • chewable
  • effervescent
  • compressed lozingers
  • sublingual and buccal tablets
43
Q

Describe distigratning tablets

A
  • Most common tablet type - intended for swallowing whole.
  • Drug release: disintegration -> dissolution -> absorption
  • Disintegration rate: dependant on several formulation and production factors.
  • Dissolution rate: limited by drug factors such as solubility and particle size.
  • Absorption rate: lipophilicity
  • Examples: Paracetamol, Ibuprofen.
44
Q

Describe chewable tablets

A
  • Mechanical disintegration – no disintegrant
  • Drug dissolves in stomach
  • Rapid effect, no water required, for patients with difficulty swallowing
  • Flavourings and colourings commonly used
  • Vitamins, Gaviscon
45
Q

Describe effervscengt tablets

A
  • Releases carbon dioxide – facilitating disintegration and dissolution (reaction between carbonate / bicarbonate and acid such as citric or tartaric acids)
  • Rapid drug action
  • Analgesics, vitamins
46
Q

Describe compressed lozengers

A
  • Slow drug release - No disintegrant
  • Systemic and local drug delivery
  • Filler and binder – water soluble and acceptable taste e.g. carbohydrates / sugars
  • Colouring and flavouring
  • High pressure – increased hardness and low porosity.
  • e.g Strepsils, Nicotine
47
Q

describe buccal/ sublingual

A
  • Rapid systemic delivery avoiding first pass liver metabolism
  • Subligual – under tongue / Buccal – side of cheek / between upper lip and gum.
  • Small, porous, disintegrant (buccal).
  • Slow release – polymers 1 – 2 hrs
  • e.g. Nitroglycerin, Loratadine, Nicotine (Nicotinell), Nytroglycerin (Nitrostat).
48
Q
  1. Tablets too soft?
  2. Tablets not disintegrating?
  3. Tablets breaking apart after manufacture?
  4. Active not being released from tablet during dissolution test?
  5. Powder will not flow correctly?
A
  1. binder or less distigrant
  2. add distigrant
  3. Add binder
  4. Distigrant
  5. glidant
  6. granulation

Kirstys Flashcards (116 decks)

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