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DF08 Powder processing that influences product performance
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1Size reduction is important to [blank_start]increase[blank_end] surface area, that leads to [blank_start]increased[blank_end] dissolution rate & bioavailability. It is also important improve [blank_start]flow properties[blank_end] of powders that are needle shaped or irregular in shape and tend to form [blank_start]bridging[blank_end] (arching). It can also improve tablet-tablet [blank_start]content uniformity[blank_end] as there will be more particles per unit weight.
- Aincrease
- Bincreased
- Cflow properties
- Dbridging
- Econtent uniformity
2Trituration is size reduction using a mortar and pestle in the pharmacy.
- ATrue
- BFalse
3Order these methods of size reduction in increasing fineness of particles. (4 - most fine.)
[blank_start]2[blank_end]. Compression.
[blank_start]1[blank_end]. Cutting
[blank_start]3[blank_end]. Impact
[blank_start]4[blank_end]. Attrition (friction and pressure)- A2
- B1
- C3
- D4
4Problems (during or following dry milling) include formation of [blank_start]amorphous[blank_end] drug, which is not always desired, change to another [blank_start]polymorphic[blank_end] form, [blank_start]heat[blank_end] production, and so [blank_start]degradation[blank_end] due to heat build-up. Hygroscopic substances absorb [blank_start]moisture[blank_end] so this is something to take into account. Also [blank_start]static[blank_end] build-up, and [blank_start]plastic[blank_end] deformation may occur, rather than cracking.
- Aamorphous
- Bpolymorphic
- Cheat
- Ddegradation
- Emoisture
- Fstatic
- Gplastic
5Problems (during or following wet milling) & solutions may include production of [blank_start]nano-sized crystals[blank_end] and [blank_start]Ostwald[blank_end] ripening. Production of nano crystals depends on mill or homogeniser but crystal growth is [blank_start]likely[blank_end] once milling stops. Ostwald ripening is the phenomenon whereby smaller particles with [blank_start]higher[blank_end] surface energy give up [blank_start]mass[blank_end] to large particles with [blank_start]lower[blank_end] and more stable surface energy, so that small particles get [blank_start]smaller[blank_end] and large particles get [blank_start]larger[blank_end].
- Anano-sized crystals
- BOstwald
- Clikely
- Dunlikely
- Ehigher
- Fmass
- Glower
- Hsmaller
- Ilarger
6Size increase is important because several components can be combined to form granules or pellets, thus reducing risk of [blank_start]segregation[blank_end] of the individual components; [blank_start]improving[blank_end] flow properties for processing (filling tablet die or capsule). Also, uniformly sized wet granules can promote [blank_start]uniform drying[blank_end]. Controlled particle size can give [blank_start]better[blank_end] mixing & [blank_start]reduced[blank_end] segregation; particularly important for tablet die or capsule filling.
- Asegregation
- Bimproving
- Cuniform drying
- Dbetter
- Ereduced
7Size increase can be achieved by:
1. Spray [blank_start]Drying[blank_end] (bottom-up)
2. [blank_start]Precipitation[blank_end] (bottom-up)
- to make nano-sized particles (amorphous or crystalline)
3. [blank_start]Granulation[blank_end] & pelletisation (more later)
- components are mixed together, granulator may be used- ADrying
- BPrecipitation
- CGranulation
8[blank_start]Drying[blank_end] is the vaporisation and removal of water and other liquids from a sample to form a “dry solid”
[blank_start]Moisture content[blank_end] is the mass of moisture present in a sample. It is the loss in weight (%) after oven drying at 102°C until constant weight is obtained” %Moisture content = (Initial weight – dry weight)*100 /Initial weight
[blank_start]Relative humidity (RH)[blank_end] is the saturation level of the air with water vapour-normally expressed as a percentage. A higher percentage means that the air–water mixture is more humid. At 100% RH, the air is saturated. RH depends on moisture content and temperature.- ADrying
- BMoisture content
- CRelative humidity (RH)
9Pharmaceutical situations where drying of powders/solid occurs:
• to dry drug & excipients to [blank_start]reduce[blank_end] moisture content; thus [blank_start]increase[blank_end] stability; improve properties before [blank_start]milling or mixing[blank_end]
• to dry granules after a wet granulation process to [blank_start]improve handling, filling/flow/packaging[blank_end] (e.g. granulation)
• to prepare “vaccines” & other products which are marketed as [blank_start]moisture-free[blank_end] & able to be [blank_start]reconstituted[blank_end] before use (often freeze-drying)
• to prepare drug (or drug-excipient mix) in desired [blank_start]solid state/particle size distribution[blank_end] (often spray drying)- Areduce
- Bincrease
- Cmilling or mixing
- Dimprove handling, filling/flow/packaging
- Emoisture-free
- Freconstituted
- Gsolid state/particle size distribution
10Drying methods:
1. [blank_start]Convection[blank_end]
• air flows past solid &/or solid moves within the equipment (includes spray drying)
2. [blank_start]Conduction[blank_end]
• equipment is heated
• vapour may be removed by operation under vacuum or by air convection process
3. [blank_start]Radiation[blank_end]
• solids (plus moisture) are heated by infra-red radiation
• moisture within solids is heated by microwave- AConvection
- BConduction
- CRadiation
11Static-bed driers:
- Advantages: [blank_start]easy[blank_end] to clean, [blank_start]low[blank_end] cost, ease of [blank_start]mechanical[blank_end] operation
- Disadvantages: [blank_start]slow[blank_end] drying, heat gives [blank_start]decomposition[blank_end], [blank_start]non-uniform[blank_end] temperature
Fluidized bed driers:
- Advantages: [blank_start]rapid[blank_end] drying, [blank_start]uniform[blank_end] bed temperature, lower handling [blank_start]costs[blank_end], coprocessing
- Disadvantages: [blank_start]heated[blank_end] air gives decomposition, agitation gives particle size [blank_start]reduction[blank_end], material retention and care in [blank_start]cleaning[blank_end]- Aeasy
- Blow
- Cmechanical
- Dslow
- Edecomposition
- Fnon-uniform
- Grapid
- Huniform
- Icosts
- Jheated
- Kreduction
- Lcleaning
12Freeze drying avoids:
- AThe liquid-gas transition
- BThe solid-gas transition
- CThe liquid-solid transition
133 phases of freeze drying/lyophilisation:
1. The first phase is [blank_start]freezing[blank_end].
2. Second phase is the [blank_start]primary drying[blank_end]: The chamber pressure is [blank_start]reduced[blank_end], and heat is applied to the product to cause the frozen mobile water to [blank_start]sublime[blank_end].
3. Third phase is [blank_start]secondary drying[blank_end]: The temperature is [blank_start]increased[blank_end] to desorb bound water such as water of crystallization.- Afreezing
- Bprimary drying
- Csecondary drying
- Dreduced
- Esublime
- Fincreased
14Select all the advantages of freeze drying.
- Alow temperatures so little degradation
- Bproduct is light and porous (ready solubility)
- Cno concentration of solution during drying
- Dno contact with air
- Ehygroscopic product
- Fprocess slow
- Gequipment expensive
- Hlimited to certain products
15Methods of mixing include diffusive, convective, and shear.
Diffusive mixing is where [blank_start]individual[blank_end] particles move to change position relative to neighbouring particles in a [blank_start]random[blank_end] way. An expanded bed allows particles to move. [blank_start]Free[blank_end]-flowing powders undergo diffusive mixing readily, and density & particle size [blank_start]differences[blank_end] promote diffusive mixing.
Convective mixing is [blank_start]transfer[blank_end] groups between adjacent locations. A portion of the mix is removed from one place & deposited in another; achieved by [blank_start]spatula, blades, or revolving screw[blank_end] (helix).
Shear mixing is where particles are [blank_start]forced[blank_end] to move past each other; slip [blank_start]planes[blank_end] are created by the mixing procedure. [blank_start]Large[blank_end] agglomerates are usually broken up by shear-mixing; [blank_start]small[blank_end] aggregates are often not broken up (cohesive forces determine if particles can be separated by this process). A more intense blending is required to break [blank_start]small aggregates[blank_end]. Energy is supplied to disrupt, and shear planes are within the mass.- Aspatula, blades, or revolving screw
- Btransfer
- CFree
- Dindividual
- Erandom
- Fdifferences
- Gforced
- Hplanes
- ILarge
- Jsmall
- Ksmall aggregates
16Achieving a good random mix can be extremely difficult in ome situations. For example, when the drug [blank_start]content[blank_end] is only a small proportion of the mix, when drug particles (or other ingredients) are [blank_start]aggregatedor agglomerated[blank_end] initially, when the mixing procedure tends to "[blank_start]compact[blank_end]" particles rather than separate them, when [blank_start]non-uniform non-spherical[blank_end] particle shape interferes with particles moving past each other easily, and when the average particle size & [blank_start]distribution[blank_end] of the different components are very [blank_start]different[blank_end] & demixing (segregation) tends to occur.
- Acontent
- Baggregatedor agglomerated
- Ccompact
- Dnon-uniform non-spherical
- Edistribution
- Fdifferent
17Demixing (segregation) can occur at the [blank_start]same time[blank_end] as mixing occurs. Segregation may occur when one component [blank_start]concentrates[blank_end] at one position in the mixer, especially where [blank_start]symmetric[blank_end] repetitive movement occurs. It can occur when the [blank_start]external[blank_end] mixing procedure [blank_start]stops[blank_end].
Factors promoting segregation are [blank_start]differences[blank_end] in particle size, shape and density—so [blank_start]gravity[blank_end] can lead to segregation. [blank_start]Asymmetric[blank_end] movement or [blank_start]abrupt reversal[blank_end] in movement helps to reduce this.- Asame time
- Bconcentrates
- Csymmetric
- Dstops
- Eexternal
- Fdifferences
- Ggravity
- HAsymmetric
- Iabrupt reversal
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- PHCY211 (Formulation) Quiz on DF08 Powder processing that influences product performance, created by Mer Scott on 28/04/2018.
- Author
- Mer Scott
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- English
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