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1
Q

Essential in powder technology and dosage form design. Expressed as particle diameter

A

Particle size

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2
Q

The diameter measured from the length of the particles at the point that divides a particle into two equal projected areas.

A

Martin’s diameter

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3
Q

The average size of collection of particles

A

Mean diameter

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4
Q

Diameter for which 50% of particles are small and 50% are large

A

Median diameter

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5
Q

Represents the most frequent particle size

A

Mode diameter

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6
Q

Distance between pairs of parallel tangents to the projected outline of the particle in some fixed direction

A

Feret’s diameter

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7
Q

Method for determining feret’s diameter (df)

A

Microscopic method

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8
Q

Method for determination of martin’s diameter (dm)

A

Microscopic method

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9
Q

Diameter of a circle having the same area as the projected area of the particle resting in a stable position

A

Projected area diameter (ds)

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10
Q

Method for determination of projected area diameter and perimeter diameter

A

Light extinction method

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11
Q

Diameter of a circle having the same perimeter as the projected outline particle

A

Perimeter diameter (dp)

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12
Q

Diameter of a sphere having the same volume as the particle

A

Equivalent volume diameter

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13
Q

Method of determination for equivalent volume diameter (dv)

A

Coulter counter method

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14
Q

Diameter of a sphere having the same surface area as the particle

A

Equivalent surface diameter

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15
Q

Method for determination of equivalent surface diameter (ds)

A

Surface method (absorption,permeability)

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16
Q

Width of the minumum square Aperture through which the particle can pass

A

Sieve diameter

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17
Q

Method for determination for sieve diameter (dA)

A

Sieving method

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18
Q

Diameter of a sphere having the same gravitational setting velocity as the particle

A

Equivalent light-scattering diameter

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19
Q

Method for determination of Equivalent light-scattering diameter (dIa)

A

Light scattering method

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20
Q

Diameter of a sphere having the same terminal settling velocity in the gas as the particle

A

Aerodynamic diameter

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21
Q

Method for determination of Aerodynamic diameter (dAero)

A

Impactor method

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22
Q

Expressed as the frequency distribution and the cumulative frequency distribution

A

Particle size distribution

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23
Q

Most precise particle size determination methods. Direct viewing of the particles. Sample size of atleast 300-600 particles. Analysis of two dimensional images of projected particles on a projection screen

A

Microscopic method

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24
Q

Used to characterize particle size between 1-150 microns in diameter

A

Light microscopy

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25
Can aquire a three dimensional image of particles, particle shape and thickness.
Scanning electron microscopy
26
Used in particle size less than 1 micron in diameter
Transmission electron microscopy (TEM) scanning electron microscopy (SEM)
27
Rely on measuring the percentage by number or mass of the extracted size group corresponding to the feed concentration from the powder sample
Separation method
28
Most conventional and simplest separation method. Low cost and ease of operation. Arrange form coarser mesh opening to smaller mesh, top to bottom
Sieving
29
Wet sieving is designed for micron particle usually
6-150 um2
30
Defined as the width of minimum square aperture through which particle can pass through
Sieve diameter
31
Sources of error for sieving method
- shape of the particles - weight of the sample loaded unto the sieve - vibration intensity - the phenomenon of static electricity cause by friction.
32
Measure the aerodynamic diameter of aerosols.
Impaction
33
An expression of a particle's aerodynamic behavior and diameter. Way to characterize aerosols
Aerodynamic diameter.
34
Settling of a single particle in a liquid medium under the influence of gravitational and centrifugal forces
Sedimentation method
35
Particle settling in a liquid medium can be describe by
Stokes law
36
Commonly used instrument for sedimentation method
Andreasen pipette
37
Used to measure the particle size between 5-10um in diameter
Centrifugal sedimentation
38
Measures 0.6-120um particle size
Coulter counter method or electrical sensing zone
39
Based on facts that particles scatter light. Measure both large and small particles.
Laser light-scattering methods or laser diffraction
40
Low angle light scattering is also referred as
Fraunhofer diffraction
41
Fundamental theory of photo correlation spectroscopy (PCS)
Brownian motion
42
The surface area of particles expressed per unit weight or volume. Surface area increases as particle size decreases.
Specific surface
43
Determination of surface area
``` Gas adsorption ( 0.03-1um) Permeability (1-100um) ```
44
Developed the equation of sorption isotherms
Brunauer, emmett, and teller or the BET method
45
Factors that affect the resistance of flow
Surface area of the powder Surface area of the bed Pore size Viscosity of the fluid
46
Slender, needle-like particle of similar width and thickness
Acicular
47
Long,thin particle with a width and thickness that are greater than acicular
Columnar
48
Thin, flat particle of similar length and width
Flake
49
Flat particles of similar length and width but with greater thickness than flakes
Plate
50
Long, thin, and blade like particles
Lath
51
Particles of similar length, width and thickness, includes cubical and spherical particles
Equant
52
Ratio of mass to volume
Density
53
Types of particle shapes
``` Acicular Columnar Flake Plate Lath Equant ```
54
Types of density
True density Particle density Bulk density
55
The ratio of the mass of the particle to its actual volume, excluding pore volume and the volume gap between particles.
True density
56
Determination of true density
Helium pycnometer
57
Ratio of particle mass to the particle volume, including pores within the particle. Excluding gaps between particles
Particle density
58
Determination method of particles density
Mercury intrusion method
59
The ration of powder bed mass to volume of powder bed, includes both pore and gap volume
Bulk density
60
Typical apparatus for liquid replacement method
Pycnometer
61
Other method for particle density
Laser interferometer Differential mobility analyzer Sedimentation Diffraction method
62
Defined as fused or cemented particles
Agglomerate
63
Mass of adhered particles
Aggregate
64
Essential property for a powder.represents the void on the surface of individual particles or agglomerates of particles.
Specific surface area
65
Method to determine surface are
``` Gas adsorption Permeability Flow microcalorimeters Estimation of surface area from size distribution data Turbidity method Chemisorption ```
66
The ratioof the volume of the pore interior and the space between particles to the total volume of the powder, including the pore interior, the gaps between the particle, and the inherent volume of the particle
Porosity
67
Affects porosity
Particle shape Particle size Surface properties ( fine particles -> porous -> faster disintegration time)
68
Push a non-wetting liquid and cause it to enter into an extremely small volume, which requires extremely high pressure.
Capillary rise phenomenon
69
State of powders
Crystalline | Amorphous
70
Molecules in the solid are arranged in a fixed order. Exhibits melting point
Crystalline
71
The outer appearance of a crystal
Crystal habit
72
Molecules in a substance are packed in a non-fixed, random order. No melting point. Easy to disintegrate and dissolve.
Amorphous state
73
The temperature at which of the solid transforms between rubbery to glassy.
Glass transition temperature
74
Crystals with different packing orders. Obtained by changing the crystallization conditions. Like different solvent or changing direction of stirring
Polymorphism | stable form has high melting point and low dissolution rate.
75
Has high dissolution rate and might be a candidate for enhancing the bioavailability of poorly soluble drugs.
Metastable polymorphic forms
76
>Has been widely used to determine the crystallinity of solid powders. >Measurement of identical intensity patterns, composed of peaks at different scattering angle
Xray diffraction
77
Also widely used to evaluate the crytallinity of solid powders.
Thermal analysis
78
Frequently used. Plotted by differentiating the rate of heating versus temperature.
Differential scanning calorimetry
79
Essential property that has a great impact on pharmaceutical process, like blending, transfer, storage, compression, and handling
Powder flowability
80
Widely used to describe powder flowability. | The angle between the free surface of the powder body and the horizontal plane.
Angle of repose | Smaller angle of repose -> smaller frictional forces -> greater flowability
81
Angle of repose less than 30 degrees
Free-flowing powder
82
Less than 40 degrees
Satisfactory flowability
83
Greater than 40 degrees
Does not flow freely
84
A direct method to determine powder flowability, by measuring the rate of powder discharging from the hopper.
Hopper rate flow
85
Particle size larger than 200um
Smaller angle of repose
86
100-200um
Cohesion and friction increase . Angle of repose increases
87
Less than 200um
Agglomeration occurs, particles exhibit tackiness or stickiness
88
Particle size
Particle size increases -> less angle of repose -> better flowability
89
Particle shape
Irregular particle shape -> rougher surface -> poor powder flowability
90
Water content
Cohesive forces are related to the amount of water contained in the powder. Increase angle of repose -> increase moisture content -> increase cohesive forces -> flowability decreases
91
Like molecules are attracted to each other
Cohesive forces
92
Different molecules are attracted to each other
Adhesive force
93
Are Powders consisting of very fine particles. Fill the hollow parts on the powder surfaces. To much of it can cause poor powder flowability.
Lubricants and glidants
94
Phenomenon where Molecules or ions are transferred from solid into solution
Dissolution
95
Extent of dissolved substance | Amount of substance in a solution when equilibrium is achieved between the dissolved and non-dissolved substance.
Solubility
96
Dissolution rate, independent of agitation speed, surface area, diffusion layer thickness, and the volume of solvent
Intrinsic dissolution rate

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