Solid dosage forms Flashcards

1
Q

What is an oral dosage form?

A

Medicinal products in the solid form to be administered in the mouth and absorbed by the GI system or oral cavity

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2
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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3
Q

What are capsules?

A

solid preperations with either hard or soft shell gelatine capsules containing a single dose of API

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4
Q

What classifications of powders?

A

size:

  • >1000um = coarse
  • >100<1000um = intermediate
  • >5<100um = fine
  • <5um = ultra fine

Shape:

  • Spherical - good flow
  • acicular - poor flow

Density:

More dense - heavier (better)

Less dense - lighter

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5
Q

What are light techniques used to measure particle size

A
  • Microscopy: easy, multiple samples needed, only useful for particles visiable to naked eye
  • SEM ot TEM (scanning/ transmission electron microscopy): ultrafine range of particles. Can observe surface texture
  • Laser light difraction
  • Proton correlation spectroscopy
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6
Q

What sieving techniques are used to determine particle size?

A
  • Sieving: sample placed on top of stack of seives and aggitated. Smaller particles that sieve apeture pass through onto next mesh.
  • Air jet sieving: Using pulses of air and vacuum to push and pull particles off and onto a screen. Particles which pas through are transferred onto a larger apeture screen and the process repeated.
  • Inertial impacation: used for inhalation products
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7
Q

What alternaive methods can be used to measure particle size?

A
  • Time of flight measurement: TIme of passage between 2 laser beams
  • Electrical stream sensing zone method: Monitors charge of electricsl signal which occurs as a particle passes through an orfice
  • Sedimentation method: Using stokes law and reynolds number to determine particle size based on time take to settle in a fluid of known viscosity
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8
Q

What is particle size analysis the equivalvent sphere?

A

Make an equivalent sphere if particle not spherical to measure it. Equivalent sphere of length and volume of particle

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9
Q

What are the 2 types of methods of powder sampling?

A

Dynamic: take proportion of sample when in motion (better). Take several samples at varrying times

Static: Take sample when product at rest

Important to take whole sample at one time

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10
Q

What is adhesion and what is cohesion?

A

Adhesion: 2 chemically disimilar materials stick together

Cohesion: 2 chemically similar materials stick together

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11
Q

What are examples of cohesive and adhesive forces?

A
  • Van der Waals: decrease as particle size increases
  • mechanical forces: When particles become interlocked due to shape and roughness
  • Frictional forces: electrical forces caused by friction between particles
  • Capillary forces: from adsorbed liquid on the surface of a particle
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12
Q

When will a powder flow?

A

When an external force is applied by will resist stressed below a limiting value.

Depends upon forces resisting flow e.g. adhesion/ cohesion and forces promoting flow e.g. gravity and applied stress

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13
Q

What techniques are used to measue powder flow?

A
  • Angle of repsonse
  • bulk density
  • critical orfice diameter

(See powders and granulation for more depth)

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14
Q

Why are all medicines mixtures?

A
  • Due to small quantities of the drug

Or

  • Poor processing characteristics of the drug

Or

  • Special characteristics requirements of the medicine
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15
Q

What does mixing and segregation mean?

A

Blending

Demixing

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16
Q

What does Pecolation segregation mean?

A

Seperation of mixed particles according to size (smaller particles move down)

17
Q

What does trajectory segregation mean?

A
  • mass based seperation (heavier particles move further before stopping)
18
Q

Elutriation segregation

A

density and size based segregation

19
Q

What does trituation mean?

A

mixing in a motor with a peatle

20
Q

What types of mixtures are there?

A
  • Positive mixtures: diffusion, irreversible (no problems)
  • Negative: Density, shape, size differences. Spontaneously seggregates
  • Neutral: no movement without addition of energy
  • Types that can change: Not neg to pos. Neg to Neu possible
21
Q

What is scale of scutiny in relation to powder mixing?

A

What sample size is required to determine if the formulation has been mixed enough/ has correct dose of drug

e.g. if need 300mg of drug take 300mg sample

equal to weight/ volume of dosage unit

22
Q

calculate scale of scruntiny:

Blend contains 10% API, 25 % Excipient X and 65% Excipient Y. Each dose needs to contain
25 mg. What is the scale of scrutiny?

A

(25 / 10) x 100 = 250 mg

(unit dose / conc. in blend) x 100 = SOS

23
Q

What is particle size reduction?

A

Reducing larger solid masses into smaller units by mechanical means

24
Q

Why is particle size reduction required?

A
  • Optimise dissolution rate
  • Improve aesthetics and stability
  • improved production efficiency
  • breakdown of cells to allow extraction of APIs from plants
  • Provide appropriate size for drug targeting (respiratory med)

Energy needs to be put in to initate crack propagation

25
Q

What are problems associated with particle size reduction?

A
  • Product degradation
  • Product aggregation
  • Polymorphic change
  • Alternative moisture content ( hygroscopic/ deliquecent)
  • Contamination
26
Q

What are excipent functions?

A
  • Bulk up API
  • Assist in production
  • Improve stability
  • Assist Bioavailability
  • improve patient complicance
  • Aid identificatino
27
Q

What is the purpose of a dilutent and examples?

A

Used to fill/ bulk out or aid processing

  • Lactose: cheap, inert, safe
  • Sugars: Mannose, Sucrose
  • Celluloses: MCC, Calcium Phosphate

LMMSC

28
Q

What does a Binder do? Examples?

A

Adhesives to bind powders together during granulation and compression

  • MCC, PVP, Starch
29
Q

What is the purpose of distinigrants? Examples?

A

Breaks up solid unit dosage form following ingestion

  • MCC, PVP, Starch, (Bi)Carbonate

Three mechanisms:

  • Facilitation of water uptake
  • Rupture of tablet by swelling
  • Rupture of tablet by CO2 production
30
Q

What is the purpose of a glidant? Examples?

A

Improves powder flow and reduces intra-particular friction

  • Silica, Talc
31
Q

What is the purpose of lubricants? Examples?

A

Used in tablet/ capsule filling. Ensures formation and smooth ejection of tablets. - reduces friction and prevents adherance

  • Magnesium sterate, sodium lauryl sulphate

2 methods:

Fluid, boundary

32
Q

What is the purpose of colouring?

A

AIds identification and alters appearance

33
Q

What is the purpose of flavourings?

A
  • Masks unplesant taste
  • More palatable
  • identification
  • compliance
34
Q

Purpose of solvents? examples?

A

Used in capsules to carry drugs. PEGS

35
Q

Purpose of coating, adsorbents, sorbents

A
  • Improve appearance, control time, location of drug release
  • Improve uniformity of drug distribution
  • Allows OSDFs to be formed from liquid drugs