Physioco -Chemical Processes Flashcards

1
Q

Precipitation
Methods

A
  1. Organic solvent nethod
  2. pH change method
  3. Double decomposition reaction
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2
Q

Precipitation

A

Ppt maybe amorphous or crystalline

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3
Q

Crystal

A

A solid with an ordered internal arrangement of molecules

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4
Q

Evaporation

A

Affected by
1. Temperature
2. Atmospheric pressure
3. Surface area
4. Agitation

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5
Q

Distillation

A

Process of separating a liquid from a solid

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6
Q

Distillation is useful in

A
  1. Preparation of aromatic water.
  2. Preparation of distilled water.
  3. Preparation of water for injection.
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7
Q

Efflorescence

A

Lose of water from a hydrate

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8
Q

Vapour pressure

A

Pressure that results in the release of vapour

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9
Q

Hydrates

A

Exert vapour pressure because of water of hydration or water of crystallisation

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10
Q

Hydrates

A

Exert vapour pressure because of water of hydration or water of crystallisation

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11
Q

Vapour pressure > atmospheric pressure =

A

Efflorescence

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12
Q

Delinquensce = opposite of efflorescence

A

Vapour pressure < atmospheric pressure

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13
Q

Atmospheric pressure

A

Pressure that will lead hydration, deliquescence

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14
Q

Exsication

A

International accelerated efflorescence

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15
Q

Applications if exsication

A
  1. Carried out to reduce the bulk and weight of certain drugs for administration.
  2. Production of anhydrous product required in the formulation of another drug
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16
Q

Exsication

A

Usually produce fine powder

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17
Q

Dessication

A

Removing water molecules from a substance using a dessicant

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18
Q

Desiccant

A

Hygroscopic material that induces or sustains a state of dryness . It is usually an adsorbent .

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19
Q

Examples of desiccant

A
  1. Phosphorus pentoxide
  2. Conc. H2SO4
  3. Exsicated CaCl2
  4. Silica gel
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20
Q

Substances that sublime

A

1.Carbon dioxide
2. Ammonium chloride
3. Naphthalene

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21
Q

Sublimation

A
  1. Cp- critical point
  2. Tp- triple point
  3. SCF- Super critical fluid
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22
Q

Sublimation

A

Occurs when vapour pressure is equal to that of the gas phase

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23
Q

Sublimation

A

Can only occur at temperature below critical point temperature
But at a pressure above critical point pressure.
Eg. CO2 sublimes at pressure 517kPa and tep.-78.5°C

24
Q

Applications of sublimation

A
  1. Purification
  2. Freeze drying
25
Q

Freeze drying (lypholisation)

A

Works as sublimation.

26
Q

Stages of freeze drying

A
  1. Freeze the solution
  2. Reduce atmospheric pressure to below that of the TP.
  3. Add heat of sublimation
27
Q

Advantages and of freeze drying

A
  1. Heat sensitive materials are not damaged
  2. Freeze-dried materials are porous and facilitate easy re-dispersing in water.
  3. Denaturation of proteins is avoided.
  4. Sterility may be maintained during process.
28
Q

Disadvantages of freeze drying

A

The product is prone to oxidation due to high porosity
2. Some materials are not cryo- stable and may require cryo protectants.

29
Q

Examples of cryo protectant

A
  1. Mannitol
  2. Sucrose
  3. Glucose
  4. Trehalose
30
Q

Elutriation

A

Process of moving water in the opposite direction of sedimentation

31
Q

Methods of elutruation

A
  1. Gravitational
  2. Centrifugal
32
Q

Advantages of elutriation

A
  1. It’s a continuous process
  2. It’s faster than sedimentation.
33
Q

Disadvantage of elutriation

A

Dilute products may be required for the process .

34
Q

Applications of elutriation

A
  1. Separation of particles into different sizes. Eg. Light and heavy kaolin
35
Q

Ignition

A

Burning substances at elevated temperatures to cause escape of carbonaceous component( organic component) leaving behind ash(inorganic component).

36
Q

Application of ignition

A

Used in determining the quality and purity of a product

37
Q

Fusion

A

Putting 2 subs together and applying heat to melt them.

38
Q

Fusion

A

Used in the preparation of ointment ( especially when they contain solids and semi-solids)
Used in preparing suppositories
Used in purification of some solid and semi solid subs. Eg. Paraffin (hard and soft, wool fat and beeswax)

39
Q

Calcination

A

Intensely heating inorganic substances to eliminate their volatile components and produce a fixed residue
Usually carried out for 3 hrs.

40
Q

Calcination ( the oxides man)

A

Useful in producing MgO( both hesvy and light)
, ZnO, CaO

41
Q

Adsorption

A

Accumulation at an interface
Occurs when liquid or gas accumulates on the surface of a solide for an adsorbate.

42
Q

Absorption

A

Movement of water or gas into a solide to form a mixture or solution.

43
Q

Types of adsorption

A
  1. Physisorption - adsorbate adheres to the surface only through Van der Waals forces
  2. Chemisorption - adsorbate adheres to the surface through chemical bonds
44
Q

Applications of adsorption

A

1.Decolouration - use of activated charcoal to remove colour from water.
2. Desiccation and freeze drying.
3. Medical application
4. Purification of water
5. Adsorption chromatography.

45
Q

Centrifugation
Factors that affect it

A
  1. Viscosity of medium
  2. Rotor speed.
46
Q

Centrifugation

A

Separation occurs due to differences in size and shape of substances in the mixture

47
Q

Application of centrifugation

A
  1. Evaluation of suspension and emulsions
  2. Production of bulk drugs.
  3. Production of biological drugs.
  4. Determination of molecular weight of colloids
48
Q

Dialysis

A

Separation is based on unequal rates of passage btwn substances through a pore

49
Q

Application of dialysis

A
  1. Purification of protein
  2. Medical application
  3. Drug permeation studies
50
Q

Maceration

A

Occasional agitation.

51
Q

Infusions( cold)

A

Menstrum may be cold or boiling water.
They produce dilute solutions.
Prepared by steeping the drug into a cold or boiling water.

52
Q

Decoction ( concotion)

A

Produces concentrated solutions.
Useful for extracting water soluble or heat soluble substances

53
Q

Digestion ( gentle heat)

A

Gentle heat is applied in the process of extraction.
Used when moderate temperature is unquestionable and solvent efficiency is increased thereby.

54
Q

Percolation

A

Continuous downward displacement of menstrum through drug in a percolator

55
Q

Steps in percolation ( SIPMP)

A
  1. Size reduction
  2. Imbibition
  3. Packing
  4. Maceration
  5. Percolation