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Pharmacy Year 2 > Solid Dosage Forms > Flashcards

Solid Dosage Forms Flashcards

1
Q

What are examples of oral solid dosage forms

A

Tablets
Capsules
Oromucosal preperations

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2
Q

What are examples of non oral solid dosage forms?

A

Suppositories
Pessaries

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3
Q

What is an Oral Dosage Form?

A

Medicinal products delivered via the mouth
In the form of a solid
To be absorbed via the gastrointestinal system or oral cavity
Tablets and capsules

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4
Q

What are tablets?

A

Solid preperations each containing a single dose of one or more active ingredients
obtained by compressing uniform volumes of particles or by another suitable manufacturing technique, such as extrusion, moulding or freeze-drying (lyophilisation).
Intended for oral administration
swallowed whole, some after being chewed, some are dissolved or dispersed in water before being administered and some are retained in the mouth where the active substance is liberated.

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5
Q

What are capsules?

A

Solid preparations with either hard or soft shells of various shapes and capacities, usually containing a single dose of active substances.

produced by filling the active substance into one section, then closing the capsule by slipping the other section over it. The security of the closure may be strengthened by suitable means. (HGCs).

the capsules are generally made of gelatine and other materials, where necessary

capsule contents may be solid, liquid or of paste-like consistency.

the shell is attacked by digestive fluids and the contents released.

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6
Q

What are factors affecting the design of SDFs?

A

Medicines are mixtures of active pharmaceutical ingredient and excipients

The size, shape, density and material strength of medicine (API)

Powder flow - measure flow and after flow. powder flow can neg and pos alter medicine characteristics

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7
Q

How is powder classified?

A

Size
 1000 μm = coarse.
 100 μm < 1000 μm = intermediate
 5 μm < 100 μm = fine.
< 5 μm = ultrafine.

Shape
Spherical – good flow (seeds)
Acicular – poor flow (twigs)

Density
More dense – heavier (golf balls)
Less dense – lighter (table tennis balls)

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8
Q

How do you know if the API active pharmaceutical ingredients particles will move up or down?

A

Particles move up -
Large
Non-spherical
Low density

Particles move down -
Small
Spherical
High density

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9
Q

How is particle size analysis carried out using light based methods?

A

Microscopy
Light microscopy – easy, but multiple samples need to be measured, only useful for particles visible to the naked eye.
SEM or TEM – very small particles (ultrafine range). Useful for observing surface texture of particle.
Laser light diffraction (Malvern Mastersizer) – size range 0.5 – 3500 µm.
Photon correlation spectroscopy (Malvern Zetasizer) – size range 0.3 nm – 10 µm.

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10
Q

How is particle size analysis carried out using sieving methods?

A

Sieving – sample placed onto a top of a stack of sieves and the stack is agitated at a set amplitude for a specific period of time. All particles smaller than the sieve aperture pass through onto the next mesh. Method not used for API due to large volumes of sample required. Used extensively for blends, granulations etc.

Air jet sieving – using pulses of air and vacuum to alternately push and pull particles off and onto a screen. All the particle which pass through are removed and the remainder are transferred to a larger aperture screen where the whole process is repeated. Only used where very fine powders are being measured and is the product is brittle.

Inertial impaction – used extensively for inhalation based products due to similarity of method to how drugs would be delivered to the lungs.

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11
Q

What are the other methods for particle analysis?

A

Time of flight measurement (Malvern Aerosizer) – time of passage between two laser beams. Also used extensively for inhalation type products.

Electrical stream sensing zone method (Coulter counter) – monitoring change of electrical signal which occurs as a particle passes through the orifice. Not generally used for formulation type analysis as the light based methods are preferred.

Sedimentation methods – using Stokes’ Law and the Reynolds number (related to fluid flow) to determine particle size, based on the time taken to settle in a fluid of known viscosity. Only rarely used.

Equivalent Spheres - length of particle and volume of particles

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12
Q

What is dynamic sampling?

A

Dynamic – taking a proportion when the product is in motion (best). Take several samples at varying times when the powder is in motion.

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13
Q

What is Static sampling?

A

Static – taking a sample when the product is at rest. Must assume some level of segregation has occurred and so not as good as dynamic.

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14
Q

What is adhesion?

A

Adhesion – two chemically dissimilar materials stick together.

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15
Q

What is cohesion?

A

Cohesion – two chemically similar materials stick together.

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16
Q

What happens to van der waals forces when particle size increases?

A

Van der waals forces decreases the particle size increases

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17
Q

What causes a mechanical force?

A

Where particles become interlocked due to shape and surface roughness

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18
Q

What are frictional forces?

A

Electrical forces caused by friction between particles

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19
Q

What are capillary forces?

A

From absorbed liquids on the surface of particles.
Placing a straw into a glass of water. Dipping paper towels into water. The sap rising from roots in trees.

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20
Q

How does powder flow occur?

A

Occurs when an external force is applied, but will resist stress below a limiting value. low is permanent

Depends on the balance between Forces resisting flow, e.g. adhesion & cohesion and Forces promoting flow, e.g. gravity and applied stress.

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21
Q

how to measure powder flow?

A

Angle of repose – maximum angle to the horizontal made by a static heap of powder. Angle increased by smaller particle size, increased surface roughness and increased moisture content of the powder.
Bulk density – density of a powder taking into account its packing fraction (k). Percentage of the volume which is taken up by air is known as the bed porosity. An increase in bulk density and a consequent decrease in bed porosity is an indicator of how well the powder flows.

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22
Q

What is the Powder flow measurement? calculation

A

Calculations using bulk density (BD) measurements.

Hausner’s ratio = Tapped bulk density/poured bulk density.Values close to 1 indicated non-cohesive powder with good flow characteristics; > 1.5 indicates a cohesive powder with poor flow.

Carr’s compression ratio =(Tapped BD - poured BD) x 100(CC Index) Tapped BD CCI of < 10 indicates excellent flow , whereas > 20 indicates poor flow

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23
Q

What and why do we powder mix?

A

All medicines are mixtures.
Due to small quantities of drug OR
Poor processing characteristics of the drug OR
Special characteristics required of the medicine

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24
Q

What is powder mixing?

A

A unit operation that aims to treat two or more components initially in an unmixed or partly mixed state, so that each unit (particle, molecule, etc) of the component lies as nearly as possible in contact with a unit of each of the other components”.

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25
Q

What is powder mixing?

A

A unit operation that aims to treat two or more components initially in an unmixed or partly mixed state, so that each unit (particle, molecule, etc) of the component lies as nearly as possible in contact with a unit of each of the other components”.

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26
Q

What is segregation? What are the 4 types?

A

Segregation = demixing (separation of mixed particles).
Percolation segregation – separation of mixed particles according to size (smaller particles move down).
Trajectory segregation – mass based separation (heavier particles move further before stopping).
Elutriation segregation – density and size based (small and low density particles become entrained within the air flow when powders are moved. They then settle on the top of the powder bed).

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27
Q

What is trituration?

A

Trituration = mixing in a mortar with a pestle.

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28
Q

What is scale of scrutiny? What is the calculation?

A

How closely mix must be evaluated to determine whether the degree of mixing was sufficient.OR IN OTHER WORDS
What sample size must be taken to determine whether formulation has been mixed enough.
Equal to the weight / volume of dosage unit.

(unit dose/ conc of API in blend) x100

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29
Q

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 = S o S

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30
Q

What is particle size reduction? What is the term used for used for fine and ultrafine particles?

A

Reducing large solid masses into smaller units by mechanical means.
Micronization term used for fine and ultrafine particles.

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31
Q

Why do we need to reduce the particle size?

A

breakdown of cells to allow extraction
Biotechnologically produced drugs.
APIs extracted from plant sources.

Improve production efficiency.
Check screening.
Milling of granulations

Improve aesthetics and stability.
Ointments and creams.
Suspensions.

Provide appropriate size for drug targeting.
Respiratory medicines.

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32
Q

What does the Noyes Whitney calculation?

A

Noyes-Whitney states
dC / dt = DA (Cs – C) / h
where:
D = diffusion coefficient in GI fluids
A = surface area of drug
Cs – C = concentration difference between diffusion layer and bulk GI fluids.
h = thickness of diffusion layer

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33
Q

What is needed for particle size reduction?

A

Put energy in to initiate crack propagation (concentration of energy in weaknesses within crystals, which lead to bond rupture).
Know the type of starting material, its strength and hardness.
Type of material you are looking for (size distribution, shape, moisture content).
Equipment you have (what types and what are their characteristics).
What other losses you will incur (heat, noise damage etc).

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34
Q

What are the problems for particle size reduction?

A

Product aggregation.
Product degradation.
Polymorphic changes.
Alteration of moisture content
Hygroscopic materials. - absorb water from air
Deliquescent materials - ability to change into liquid
Contamination.

35
Q

What are excipients and what are they used for?

A

None active compounds.
Help convert API into dosage form.
Various specialised functions.
Bulk up the API.
Assist in production.
Improve stability.
Assist bioavailability.
Improve patient acceptability & compliance.
Aid identification.

36
Q

What are Diluents used for? What are examples?

A

To fill/bulk out or aid processing.
E.g. in tablets diluents used to increase weight to acceptable level, or improve flow / compression characteristics.
Most common – lactose (natural disaccharide, produced from whey of cows milk).
Why is lactose most common.
Cheap
Easy to produce in large quantities.
Relatively inert
Safe
Two types – crystalline and amorphous
Other sugars :
Sucrose
Mannitol
Celluloses:
Microcrystalline cellulose (MCC)
Calcium phosphates

37
Q

What are binders? What are the 2 types?

A

Adhesives to bind powder particles during granulation and compression.
Solution binders – acacia mucilage, cellulose derivatives, gelatine solutions, polyvinylpyrrolidone, starch mucilage.
Dry binders – microcrystalline cellulose, crosslinked PVP.

38
Q

What are Disintegrants? How do they work?

A

To promote break-up of solid unit dosage forms following ingestion.
Three mechanism:
Facilitation of water uptake (Surface active agents, cationic exchange resins).
Rupture of tablet by swelling (MCC, sodium carboxymethylcellulose, PVP, starch, sodium starch glycolate).
Rupture of tablets by CO2 production (carbonate / bicarbonate salt and weak acid).

39
Q

What are Glidants? examples

A

Added to powders.
Improve flow properties.
Reducing inter-particulate friction.
Examples
Fumed or colloidal silica
Talc
Magnesium trisilicate

40
Q

What are lubricants and the two mechanisms?

A

Used in tableting and capsule filling
Ensure formation and smooth ejection of tablets
reducing friction
preventing adherence
Two mechanisms
Fluid – seldom used (liquid paraffin)
Boundary – have low resistance to shearing (magnesium stearate, polyethylene glycol, sodium lauryl sulphate, sodium stearyl fumarate

41
Q

Why and what colours are used for medicines?

A

Alter the appearance of medicines.
For differentiation, identification, patient acceptability.
Types of colour – natural (caramel, chlorophyll), synthetic organic dyes (tartrazine [E102], brilliant green [E142]), mineral pigments and lakes.
Only food regulation approved colours used.
Water insoluble (pigments) – used for solids.
pH may affect colour shade & intensity.
Psychology of colours

42
Q

What are flavours and what are the four basic taste sensations?

A

Impart a pleasant taste or mask an unpleasant one
More palatable, increase compliance and aid identification
In chewable, fast-melt, buccal or sublingual tablets, chewing gums or oral liquids.
Natural or synthetic, oil based, linked with colour.
Sweeteners
Four basic taste sensations
Bitter – use bitter flavour,
e.g. cherry, chocolate, mint, anise.
Sour – use sharp flavour,
e.g. citrus, liquorice, raspberry.
Salt – use sweet flavour,
e.g. butterscotch, maple, vanilla, apricot, liquorice, cinnamon.
Sweet – use fruity flavour,
e.g. berry type or vanilla.

43
Q

Where and why are solvents used and give examples?

A

Are used in capsules.
To carry the drug.
Must not react with gelatine (no water).
Often used to improve bioavailability.
Oils – corn, arachis, cottonseed.
Medium chain triglycerides (coconut)
Long chain triglycerides (castor)
PEGs, mineral oil etc.

44
Q

What do coatings improve?

A

improve appearance, control time or location of drug release.

45
Q

What do adsorbents improve?

A

to improve the uniformity of drug distribution.

46
Q

What do sorbents allow?

A

to allow OSDFs to be produced from liquid drugs.

47
Q
  1. Explain what is meant by the term ‘powder’.
A
48
Q
  1. Explain the difference between a drug and a medicine.
A
49
Q
  1. List the various excipients which may be included within both tablet or capsule formulations and their uses. Include an example of each excipient type listed and briefly describe additional points which may be useful for the material identified.
A
50
Q
  1. Explain the difference between hydrogen bonds and van der Waals forces in relation to solid particles.
A
51
Q
  1. State the Noyes-Whitney equation and briefly describe how particle size affects the dissolution of a drug substance.
A
52
Q
  1. Briefly describe what the term ‘equivalent diameter’ means when referring to the measurement of particle size.
A
53
Q
  1. Explain in your own words what the following ‘equivalent spheres’ are equivalent to:
    a. Free-falling diameter.
    b. Projected area diameter.
    c. Sieve diameter.
    d. Surface diameter.
    e. Surface volume diameter
    f. Volume diameter.
A
54
Q
  1. Briefly describe the following methods of particle size analysis:
    a. Sieve analysis.
    b. Microscopic analysis.
    c. Electrical stream sensing.
    d. Laser light-scattering (laser diffraction).
    e. Photon-correlation spectroscopy.
    f. Sedimentation methods
A
55
Q
  1. There are various factors which influence our ability to particle size reduce a powder. Briefly describe how the following factors affect this:
    a. The toughness of a material.
    b. Its surface hardness.
    c. The type of material (plastic, elastic or brittle).
A
56
Q
  1. State the various ways in which energy is lost from a particle size reduction process, other than that causing a reduction in size.
A
57
Q
  1. Briefly describe how the following mills achieve particle size reduction and indicate what type of material each one may be suitable for:
    a. Cutter mill.
    b. Hammer mill.
    c. Vibration mill.
    d. Ball mill.
    e. Fluid energy mill.
    f. Pin mill.
A
58
Q
  1. Explain why particle size separation methods may be required
A
59
Q
  1. Briefly describe sieving as a method for particle size separation.

 

A
60
Q
  1. Describe briefly why the process of mixing is necessary when making medicines.
A
61
Q
  1. Give a definition of the following types of mixtures:
    a. Positive mixtures.
    b. Negative mixtures.
    c. Neutral mixtures.
A
62
Q
  1. Briefly describe the terms ‘perfect mix’ and ‘random mix’.
A
63
Q
  1. Explain what the term Scale of Scrutiny (SoS)means.
A
64
Q
  1. Calculate the SoS for the following formulations:

Example: Product A contains 35% w/v API. What is the SoS if a solid dosage form containing 140 mg is required?

Amount of API
required per dose x 100 = SoS
concentration of
API in formulation

(140/35) x 100 = 400 mg

a. Product B contains four components (Excipient A at 20% w/w, Excipient B at 35 % w/w, Excipient C at 1 % w/w and the API at 44 % w/w). What is the SoS if a dosage form containing 150 mg is required?

b. Calculate the SoS for a powder blend where the unit dose is required to contain 200 mg and the granulation being used to prepare it contains 67 % w/w.

A
65
Q
  1. Briefly describe the rationale behind conducting a mixing time experiment and give two reasons for its use.
A
66
Q
  1. Provide a brief definition of the following powder mixing mechanisms:
    a. Convective mixing.
    b. Shear mixing.
    c. Diffusive mixing.
A
66
Q
  1. Provide a brief definition of the following powder mixing mechanisms:
    a. Convective mixing.
    b. Shear mixing.
    c. Diffusive mixing.
A
67
Q
  1. Provide a brief definition of the following liquid mixing mechanisms:
    a. Bulk transport.
    b. Turbulent mixing.
    c. Molecular diffusion.
A
68
Q
  1. Explain the term segregation.
A
69
Q
  1. Explain how segregation can be avoided and outline six methods by which this can be achieved.
A
70
Q
  1. Describe briefly how the following particle characteristics affect their ability to mix and segregate, including the specific term used to describe each segregation type:
    a. Particle size effects.
    b. Particle shape effects.
    c. Particle density effects.
A
71
Q
  1. Explain how segregation can be avoided and outline six methods by which this can be achieved.
A
72
Q
  1. Briefly describe the term ‘ordered mixing’.
A
73
Q
  1. Explain in what situations segregation can still occur in ordered mixes.
A
74
Q
  1. Explain some of the practical considerations required when thinking about the type of mixer to use in a production process.
A
75
Q
  1. Briefly describe the following types of mixers useful for the mixing of powders:
    a. Tumbler mixers.
    b. High-speed mixer-granulators.
    c. Fluidised-bed mixers.
    d. Agitator mixers.
A
76
Q
  1. State three reasons why powders need to be free-flowing in the production of medicines.
A
77
Q
  1. Define the Angle of Repose and briefly describe one method for its measurement.
A
78
Q
  1. Briefly describe how the following particle characteristics affect powder flow and packing:
    a. Particle size.
    b. Particle shape.
    c. Particle density.
A
79
Q
  1. Define the bulk density of a powder and how this value differs from the true density of a solid.
A
80
Q
  1. Describe briefly how the following factors affect the rate at which powders flow through an orifice:
    a. Orifice diameter.
    b. Hopper width.
    c. Head size.
    d. Hopper wall angle.
A
81
Q
  1. Briefly describe mass flow and funnel flow from a hopper.
A
82
Q
  1. Explain how the bulk density of a powder would be measured and how the results may be interpreted?
A
83
Q
  1. Describe five ways in which powder flowability could be improved.
A

Pharmacy Year 2 (33 decks)

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