Micromeritics is the science of small particles, typically less than 1 mm in size. Key aspects include particle size, size distribution, shape, and surface area, which influence properties of powders and their performance in pharmaceutical dosage forms. Common methods to measure particle size include microscopy, sieving, sedimentation, and laser diffraction. Factors like size, shape, surface texture, moisture content and addition of glidants can impact flow properties which are important for manufacturing processes that require powder flow like tableting.
The document discusses micromeritics, which is the science and technology of small particles. It covers particle size and size distribution, methods for determining particle size such as microscopy, sieving, and sedimentation. It also discusses density and flow properties of powders. Particle size affects properties like drug release, absorption, stability, and dose uniformity. Methods are needed to characterize particle size distribution and average particle size. Flow properties tests include Carr's index and Hausner ratio. Factors like particle size, shape, surface forces, and additives impact flow.
This document discusses micromeritic properties of powders and granulation. It defines micromeritics and explains that particle size is important for physical and pharmacological properties. Common methods to determine particle size are described, including optical microscopy, sieving, sedimentation, and particle volume measurement. Derived powder properties like porosity, packing arrangement, and densities are covered. Factors affecting powder flow properties include particle size, shape, density, and surface texture. Applications of micromeritics in drug release, absorption, stability, and dose uniformity are presented. A case study on enhancing lovastatin dissolution uses methods like angle of repose, bulk density, tapped density, Carr's index, and Hausner's ratio to analyze
Micromeritics, the science of small particles, is important for drug formulation and delivery. Particle size influences properties like surface area, dissolution rate, absorption and drug action. It also impacts physical stability of suspensions and emulsions. Various methods can determine particle size, including microscopy, sieving, and sedimentation. Derived powder properties like porosity, density, bulkiness, and flowability depend on particle size, shape, and surface properties. Tests like Carr's index and angle of repose evaluate powder flowability. Altering particle features and adding glidants can improve powder flow in formulations.
Micromeritics is the science and technology of small particles. Knowledge of particle size and size distribution is important in pharmacy because it affects the physical, chemical, and pharmacological properties of drugs. Particle size can influence drug release from dosage forms and absorption. There are several methods to determine particle size, including optical microscopy (0.2-100 μm), sieving (40-9500 μm), and sedimentation (0.08-300 μm). Density and flow properties of powders are also important considerations that impact manufacturing processes.
This document discusses various aspects of micromeritics including particle size, shape, surface area, and methods to characterize these properties. It describes key terms like monodisperse and polydisperse systems. Common methods to determine particle size include optical microscopy, sieve analysis, sedimentation, and conductivity/Coulter counter methods. Each method has advantages and disadvantages and suitable size ranges. Particle properties influence important formulation and drug delivery factors like dissolution, absorption, stability, and dose uniformity.
The document discusses micromeritics, which involves characterizing individual particles and particle size distributions in powders. Key properties used to characterize particles include size, shape, volume, surface area, and density. Common methods to determine these properties include optical microscopy, sieving, sedimentation, and conductivity/Coulter counter methods. Particle size distribution and factors that influence powder properties like flow and density are also examined.
Micromeritics involves the study of small particles between 1-100 microns in size. It characterizes particles based on their size, shape, surface area, density, and other properties. Particle size is important for drug release, absorption, stability of formulations, and ensuring uniform drug doses. Methods to determine particle size include optical microscopy, sieving, sedimentation, and conductivity. No single method can directly measure all particle dimensions, so results may vary between methods depending on the intended application.
The document discusses micromeritics, which is the science and technology of small particles. It covers particle size and size distribution, methods for determining particle size such as microscopy, sieving, and sedimentation. It also discusses density and flow properties of powders. Particle size affects properties like drug release, absorption, stability, and dose uniformity. Methods are needed to characterize particle size distribution and average particle size. Flow properties tests include Carr's index and Hausner ratio. Factors like particle size, shape, surface forces, and additives impact flow.
This document discusses micromeritic properties of powders and granulation. It defines micromeritics and explains that particle size is important for physical and pharmacological properties. Common methods to determine particle size are described, including optical microscopy, sieving, sedimentation, and particle volume measurement. Derived powder properties like porosity, packing arrangement, and densities are covered. Factors affecting powder flow properties include particle size, shape, density, and surface texture. Applications of micromeritics in drug release, absorption, stability, and dose uniformity are presented. A case study on enhancing lovastatin dissolution uses methods like angle of repose, bulk density, tapped density, Carr's index, and Hausner's ratio to analyze
Micromeritics, the science of small particles, is important for drug formulation and delivery. Particle size influences properties like surface area, dissolution rate, absorption and drug action. It also impacts physical stability of suspensions and emulsions. Various methods can determine particle size, including microscopy, sieving, and sedimentation. Derived powder properties like porosity, density, bulkiness, and flowability depend on particle size, shape, and surface properties. Tests like Carr's index and angle of repose evaluate powder flowability. Altering particle features and adding glidants can improve powder flow in formulations.
Micromeritics is the science and technology of small particles. Knowledge of particle size and size distribution is important in pharmacy because it affects the physical, chemical, and pharmacological properties of drugs. Particle size can influence drug release from dosage forms and absorption. There are several methods to determine particle size, including optical microscopy (0.2-100 μm), sieving (40-9500 μm), and sedimentation (0.08-300 μm). Density and flow properties of powders are also important considerations that impact manufacturing processes.
This document discusses various aspects of micromeritics including particle size, shape, surface area, and methods to characterize these properties. It describes key terms like monodisperse and polydisperse systems. Common methods to determine particle size include optical microscopy, sieve analysis, sedimentation, and conductivity/Coulter counter methods. Each method has advantages and disadvantages and suitable size ranges. Particle properties influence important formulation and drug delivery factors like dissolution, absorption, stability, and dose uniformity.
The document discusses micromeritics, which involves characterizing individual particles and particle size distributions in powders. Key properties used to characterize particles include size, shape, volume, surface area, and density. Common methods to determine these properties include optical microscopy, sieving, sedimentation, and conductivity/Coulter counter methods. Particle size distribution and factors that influence powder properties like flow and density are also examined.
Micromeritics involves the study of small particles between 1-100 microns in size. It characterizes particles based on their size, shape, surface area, density, and other properties. Particle size is important for drug release, absorption, stability of formulations, and ensuring uniform drug doses. Methods to determine particle size include optical microscopy, sieving, sedimentation, and conductivity. No single method can directly measure all particle dimensions, so results may vary between methods depending on the intended application.
Micromeritics is the study of particle size, shape, and other characteristics of small particles. Key methods to determine particle size include optical microscopy, sieving, sedimentation, and conductivity. Particle size affects properties like density, surface area, and flow. True density measures only the particle material, while bulk and tapped density account for interparticle voids. Flow properties like angle of repose, Carr's index, and Hausner ratio are important for uniform dosing in manufacturing.
Powder Technology
Particle analysis in pharmaceuticals
Determination of particle size and surface area
Large scale equipment for powders
Types of powders
This document discusses micromeritics and its applications in pharmaceutical solid dosage forms. Micromeritics is defined as the science and technology of small particles, dealing with fundamental and derived properties of individual and collections of particles. In pharmacy, micromeritics influences parameters like research and development, manufacturing of dosage forms such as suspensions, tablets, and capsules. Particle size and size distribution impact properties like flow, dissolution, absorption and stability. Various methods for determining particle size are also summarized, including microscopy, sieving, sedimentation, and Coulter counter techniques.
Micromeritics refers to the science and technology of small particles. It deals with particle size, size distribution, shape, surface area, and pore size. Knowledge of these properties is important in pharmacy because particle size affects drug release from dosage forms and stability of suspensions, emulsions, and tablets. It also influences flow properties and uniformity of drug fill in tablets and capsules. Smaller particle sizes increase dissolution and absorption rates for some drugs. Common methods to determine particle size include sieving, sedimentation, light scattering, and electrical sensing using a Coulter Counter.
This document discusses particle size distribution (PSD), including defining PSD, the significance of PSD, sampling and measurement techniques like sieve analysis and sedimentation methods, and graphical representation of PSD using histograms. Particle size and shape are first defined to understand PSD. Sieve analysis separates particles by size but is limited to larger particles, while sedimentation methods produce fractional analysis for finer particles below 100 μm.
Powders are mixtures of finely divided drugs and chemicals that can be used internally or externally. Powders consist of particles that can range in size from 10 mm to 1 μm. The particle size distribution and properties influence how powders can be used. Before using powders to make pharmaceutical products, their chemical and physical characteristics like morphology, purity, solubility, and stability are analyzed. Proper blending and avoiding segregation of powder mixtures is important for ensuring uniform and consistent dosing.
This document provides an introduction to a course on particle technology. It discusses key topics that will be covered, including characterization of solid particles by size, shape, and density. Particle size is an especially important property, as it influences many material behaviors. Size can be analyzed through techniques like screen analysis to determine distributions. Average particle sizes are defined in several ways. The course will also cover topics like particle motion, separation methods, and more.
The document discusses particle size distribution (PSD). It defines PSD and explains that it refers to the relative amounts of particles sorted by size. The significance of PSD is that it affects properties like flow, reactivity, and stability. Common techniques to measure PSD include sieve analysis, sedimentation methods, and laser diffraction. Sieve analysis separates particles by passing them through sieves of different sizes, while sedimentation methods measure settling rates of dispersed particles to determine sizes.
This document discusses powders used in pharmaceutical preparations. Powders are mixtures of finely divided drugs and chemicals that can be used internally or externally. Powders are characterized based on properties like particle size, morphology, purity, solubility, and stability. Powder particle size ranges from 10 mm to 1 μm. Powders are analyzed using sieving, sedimentation rate, microscopy, and other methods. Proper particle size influences dissolution, suspension, distribution in mixtures, and other factors. Segregation during blending can be an issue and is influenced by particle size, shape, density, and other properties. Powders are used to prepare various dosage forms like tablets, capsules, liquids, and semisolids through processes like blending,
Powders are mixtures of finely divided drugs and chemicals that can be used internally or externally. Powders consist of particles that can range in size from 10 mm to 1 μm. The particle size distribution and other properties of powders are important and must be characterized. Powders are commonly used to make other dosage forms or are administered directly after mixing with water or other liquids. Some powders are intended for inhalation while others are reconstituted before oral or injectable use.
Particle technology involves the handling and processing of particles. Some key aspects covered in the document include:
1) Characterization of particles involves measuring their size, shape, and density. Size is an especially important property and can be measured using techniques like screen analysis.
2) Particles in industrial processes come in many forms and sizes, from hard abrasive particles to soft cohesive powders. Proper handling and processing requires understanding particle properties.
3) The course will cover topics ranging from particle characterization to separation techniques. It will provide useful knowledge for industries involving particulate solids like chemicals, minerals, foods, and more.
The word Micromeritics refers to a discipline of science and technology that deals with studies related to the fundamental as well derived properties of particles. The knowledge and control of the size of particles is of importance in pharmacy and materials science.
This document provides information about micromeritics, which is the science and technology of small particles. It discusses several key concepts in micromeritics including particle size, shape, density, and surface area. The document then describes several important applications of micromeritics in the pharmaceutical field related to drug release, absorption, stability, and dose uniformity. Several examples are provided to illustrate how reducing particle size can impact solubility and bioavailability. Different methods for measuring particle size distribution are also summarized, including microscopic, sieving, sedimentation, and conductivity techniques.
The document discusses micromeritics, which is the study of physicochemical properties of small particles. It describes various fundamental properties of powders like particle size, shape, surface area, as well as derived properties including density, flow properties, and porosity. Common methods for analyzing particle size are discussed, including optical microscopy, sieving, and sedimentation techniques like the Andreasen pipette method. Understanding micromeritics is important for preformulation and formulation development as particle properties influence aspects like drug release, absorption, stability, and dose uniformity.
This document discusses various properties related to micromeretics and powder technology. It begins by explaining the importance of understanding particle size, shape, surface area and other properties in preformulation and formulation development. Various methods for determining these properties are described, including optical microscopy, sieving, sedimentation, and conductivity methods. The document also discusses fundamental properties like size, shape and surface area as well as derived properties of powders including density, porosity and flow properties. Understanding these properties is important for developing solid dosage forms with consistent and uniform drug content.
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Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
Micromeritics is the study of particle size, shape, and other characteristics of small particles. Key methods to determine particle size include optical microscopy, sieving, sedimentation, and conductivity. Particle size affects properties like density, surface area, and flow. True density measures only the particle material, while bulk and tapped density account for interparticle voids. Flow properties like angle of repose, Carr's index, and Hausner ratio are important for uniform dosing in manufacturing.
Powder Technology
Particle analysis in pharmaceuticals
Determination of particle size and surface area
Large scale equipment for powders
Types of powders
This document discusses micromeritics and its applications in pharmaceutical solid dosage forms. Micromeritics is defined as the science and technology of small particles, dealing with fundamental and derived properties of individual and collections of particles. In pharmacy, micromeritics influences parameters like research and development, manufacturing of dosage forms such as suspensions, tablets, and capsules. Particle size and size distribution impact properties like flow, dissolution, absorption and stability. Various methods for determining particle size are also summarized, including microscopy, sieving, sedimentation, and Coulter counter techniques.
Micromeritics refers to the science and technology of small particles. It deals with particle size, size distribution, shape, surface area, and pore size. Knowledge of these properties is important in pharmacy because particle size affects drug release from dosage forms and stability of suspensions, emulsions, and tablets. It also influences flow properties and uniformity of drug fill in tablets and capsules. Smaller particle sizes increase dissolution and absorption rates for some drugs. Common methods to determine particle size include sieving, sedimentation, light scattering, and electrical sensing using a Coulter Counter.
This document discusses particle size distribution (PSD), including defining PSD, the significance of PSD, sampling and measurement techniques like sieve analysis and sedimentation methods, and graphical representation of PSD using histograms. Particle size and shape are first defined to understand PSD. Sieve analysis separates particles by size but is limited to larger particles, while sedimentation methods produce fractional analysis for finer particles below 100 μm.
Powders are mixtures of finely divided drugs and chemicals that can be used internally or externally. Powders consist of particles that can range in size from 10 mm to 1 μm. The particle size distribution and properties influence how powders can be used. Before using powders to make pharmaceutical products, their chemical and physical characteristics like morphology, purity, solubility, and stability are analyzed. Proper blending and avoiding segregation of powder mixtures is important for ensuring uniform and consistent dosing.
This document provides an introduction to a course on particle technology. It discusses key topics that will be covered, including characterization of solid particles by size, shape, and density. Particle size is an especially important property, as it influences many material behaviors. Size can be analyzed through techniques like screen analysis to determine distributions. Average particle sizes are defined in several ways. The course will also cover topics like particle motion, separation methods, and more.
The document discusses particle size distribution (PSD). It defines PSD and explains that it refers to the relative amounts of particles sorted by size. The significance of PSD is that it affects properties like flow, reactivity, and stability. Common techniques to measure PSD include sieve analysis, sedimentation methods, and laser diffraction. Sieve analysis separates particles by passing them through sieves of different sizes, while sedimentation methods measure settling rates of dispersed particles to determine sizes.
This document discusses powders used in pharmaceutical preparations. Powders are mixtures of finely divided drugs and chemicals that can be used internally or externally. Powders are characterized based on properties like particle size, morphology, purity, solubility, and stability. Powder particle size ranges from 10 mm to 1 μm. Powders are analyzed using sieving, sedimentation rate, microscopy, and other methods. Proper particle size influences dissolution, suspension, distribution in mixtures, and other factors. Segregation during blending can be an issue and is influenced by particle size, shape, density, and other properties. Powders are used to prepare various dosage forms like tablets, capsules, liquids, and semisolids through processes like blending,
Powders are mixtures of finely divided drugs and chemicals that can be used internally or externally. Powders consist of particles that can range in size from 10 mm to 1 μm. The particle size distribution and other properties of powders are important and must be characterized. Powders are commonly used to make other dosage forms or are administered directly after mixing with water or other liquids. Some powders are intended for inhalation while others are reconstituted before oral or injectable use.
Particle technology involves the handling and processing of particles. Some key aspects covered in the document include:
1) Characterization of particles involves measuring their size, shape, and density. Size is an especially important property and can be measured using techniques like screen analysis.
2) Particles in industrial processes come in many forms and sizes, from hard abrasive particles to soft cohesive powders. Proper handling and processing requires understanding particle properties.
3) The course will cover topics ranging from particle characterization to separation techniques. It will provide useful knowledge for industries involving particulate solids like chemicals, minerals, foods, and more.
The word Micromeritics refers to a discipline of science and technology that deals with studies related to the fundamental as well derived properties of particles. The knowledge and control of the size of particles is of importance in pharmacy and materials science.
This document provides information about micromeritics, which is the science and technology of small particles. It discusses several key concepts in micromeritics including particle size, shape, density, and surface area. The document then describes several important applications of micromeritics in the pharmaceutical field related to drug release, absorption, stability, and dose uniformity. Several examples are provided to illustrate how reducing particle size can impact solubility and bioavailability. Different methods for measuring particle size distribution are also summarized, including microscopic, sieving, sedimentation, and conductivity techniques.
The document discusses micromeritics, which is the study of physicochemical properties of small particles. It describes various fundamental properties of powders like particle size, shape, surface area, as well as derived properties including density, flow properties, and porosity. Common methods for analyzing particle size are discussed, including optical microscopy, sieving, and sedimentation techniques like the Andreasen pipette method. Understanding micromeritics is important for preformulation and formulation development as particle properties influence aspects like drug release, absorption, stability, and dose uniformity.
This document discusses various properties related to micromeretics and powder technology. It begins by explaining the importance of understanding particle size, shape, surface area and other properties in preformulation and formulation development. Various methods for determining these properties are described, including optical microscopy, sieving, sedimentation, and conductivity methods. The document also discusses fundamental properties like size, shape and surface area as well as derived properties of powders including density, porosity and flow properties. Understanding these properties is important for developing solid dosage forms with consistent and uniform drug content.
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Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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2. Micromeritics
• Definition: It is the science and technology of
small particles. The name is given by
Dalla Valle
• The unit of particle size used in the
micrometer (µm), micron (µ) and equal to 10
m.
-6
• As particle size decreases ↓ , area increases ↑
3
3. Micromeritics
• Micromeritics is the science and technology of small
particles. Knowledge and control of the size and the
size range of particles are of significant importance in
pharmacy because the size and surface area of a
particle related to the physical,
pharmacologic properties of a drug.
chemical and
• The particle size of a drug can affect its release from
dosage forms that are administered
parenterally, rectally and topically.
orally,
5
4. Micromeritics
• In the area of tablet and capsule manufacture,
control of the particle size is essential in
achieving the necessary flow properties and
proper mixing of granules and powders.
6
5. Particle Size and
Size Distribution
• In a collection of particles of more than one size, two
properties are important, namely.
1. The shape and surface are of the individual particles.
2. The particle size and size distributions (The size
range and number or weight of particles).
7
6. Monodisperse Polydisperse
Two properties of polydisperse particles are important.
a) Shape and surface area of the individual particles
b) Size range & number/weight of particles present & total surface area
Particle size and size distribution
7. Particle Size
• The size of a sphere is readily expressed in terms of its
diameter.
• The Surface diameter, d , is the diameter of a sphere
s
having the same surface area as the particle.
• The Volume diameter, d , is the diameter of a sphere
v
having the same volume as the particle.
• The Projected diameter, d , is the projected diameter of a
p
sphere having the same observed area as the particle.
• The Stokes diameter, d , is the diameter which describes an
st
equivalent sphere undergoing sedimentation at the same rate
as the asymmetric particle.
8
8. A general diagram providing definitions of the Martin (1), Feret (2),
and projected diameters (3).
9. Particle Size
• Any collection of particles is usually polydisperse. It
is therefore necessary to know not only the size of a
certain particle, but also how many particles of the
same size exist in the sample.
• Thus, we need an estimate of the size range present
and the number or weight fraction of each particle
size.
• This is the particle-size distribution and from it we
can calculate an average particle size for the sample.
9
10. Particle Size Distribution
• When the number or weight of particles lying within
a certain size range is plotted against the size range or
mean particle size, a so-called frequency distribution
curve is obtained.
• This is important because it is possible to have two
samples with the same average diameter but different
distributions.
10
12. Release and dissolution
• Particle size and surface area influence the
release of a drug from a dosage form.
• Higher surface area allows intimate contact of
the drug with the dissolution fluids in vivo and
increases the drug solubility and dissolution.
12
13. Absorption and drug action
• Particle size and surface area influence the
drug absorption
therapeutic action.
and subsequently the
• Higher the dissolution, faster the absorption
and hence quicker and greater the drug action.
13
14. Physical stability
• The particle size in a formulation influences
the physical stability of the suspensions and
emulsions.
• Smaller the size of the particle, better the
physical stability of the dosage form.
14
15. Dose uniformity
• Good flow properties of granules and powders
are important in the manufacturing of tablets
and capsules.
15
16. Methods for determining
particle size
• Many methods available for determining particle size
such as optical microscopy, sieving, sedimentation
and particle volume measurement.
1. Optical microscopy (range: 0.2-100 µm).
2. Sieving (range: 40-9500 µm).
3. Sedimentation (range: 0.08-300 µm).
4. Particle volume measurement (range: 0.5-300 µm).
16
17. Range of particle sizes
A guide to range of particle sizes applicable to each
method is
17
Particle size Method
1 µm Electron microscope,
ultracentrifuge, adsorption
1 – 100 µm Optical microscope,
sedimentation, coulter
counter, air permeability
>50 µm Sieving
18. Optical microscopy
(range: 0.2-100 µm)
The microscope eyepiece is fitted with a micrometer by
which the size of the particles may be estimated.
18
19. Optical microscopy
(range: 0.2-100 µm)
• According to the optical microscopic method,
an emulsion or suspension is mounted on ruled
slide on a mechanical stage.
• The microscope eyepiece is fitted with a
micrometer by which the size of the particles
can be estimated.
• The ordinary microscope used for
measurement the particle-size in the range of
0.2 to about 100 µm.
19
20. Disadvantage of
microscopic method
1. The diameter is obtained from only two
dimensions of the particle.
2. The number of particles that must be counted
(300-500) to obtain a good estimation of the
distribution makes
slow and tedious.
the method somewhat
20
21. Sieving
(range: 40-9500 µm)
• Standard size sieves are
available to cover a wide
range of size.
• These sieves are designed to
sit in a stack so that material
falls through smaller and
it
smaller meshes until
reaches a mesh which is too
fine for it to pass through.
21
22. Sieving
(range: 40-9500 µm)
• The stack of sieves is
mechanically shaken to promote
the passage of the solids.
• The fraction of the material
between pairs of sieve sizes is
determined by weighing
residue on each sieve.
the
• The result achieved will depend
on the duration of the agitation
and the manner of the agitation.
22
23. Sedimentation
(range: 0.08-300 µm)
• By measuring the
terminal settling velocity
of particles through a
a
liquid medium in
gravitational centrifugal
environment using
Andreasen appartus.
23
24. Particle volume measurement
(range: 0.5-300 µm)
• In this type of machine the powder is suspended in an
electrolyte solution.
• This suspension is then made to flow through a short
insulated capillary section between two electrodes
and the resistance of the system is measured.
• When a particle passes through the capillary there is a
momentary peak in the resistance, the amplitude of
the peak is proportional to the particle size.
• Counting is done by a computer.
24
26. Density of powders
• Density is defined as weight per unit volume
(W/V).
• During tapping, particles gradually pack more
efficiently, the powder volume decreases and
the tapped density increases.
26
27. Types of Density
1. True density: The true density or absolute
density of a sample excludes the volume of
the pores
sample.
and voids within the powder
2. Bulk density: The bulk density value
includes the volume of all of the pores within
the powder sample.
27
28. Flow properties of powders
• Powders may be free-flowing or cohesive (Sticky).
• Many common manufacturing problems are attributes to
powder flow.
1. Powder transfer through large equipment such as hopper.
2. Uneven powder flow → excess entrapped air within
powders → capping or lamination.
3. Uneven powder flow → increase particle’s friction with
die wall causing lubrication problems and increase dust
contamination risks during powder transfer.
28
30. Flow properties of powders
5. Powder storage, which for example result in
caking tendencies within a vial or bag after
shipping or storage time.
6. Separation of small quantity of the powder
from the bulk-specifically just before the
creation of individual doses such as during
tableting, encapsulation and vial filling which
affect the weight uniformity of the dose (under
or over dosage).
30
32. Flow properties of powders
• Tests to evaluate the flowability of a powder.
1. Carr’s compressibility index.
2. Hausner ratio.
3. The angle of repose (θ).
32
33. Carr’s compressibility
index
• A volume of powder is filled into a graduated glass
cylinder and repeatedly tapped for a known
duration. The volume of powder after tapping is
measure.
Bulk density= weight/bulk volume
Tapped density=weight/true volume
33
100 1 b
t
D
Carr sindex C
D
34. Carr’s compressibility index
Flow description % Compressibility
Excellent flow 5 – 15
Good 16 – 18
Fair 19 – 21
Poor 22 – 35
Very Poor 36 -40
Extremely poor > 40
Relationship between powder flowability and % compressibility
34
35. Hausner ratio
Hausner ratio was related to interparticle friction:
Value less than 1.25 indicates good flow (=20% Carr).
35
𝐻𝑎𝑢𝑠𝑛𝑒𝑟 𝑟𝑎𝑡𝑖𝑜 𝐻 =
𝐷𝑡
𝐷𝑏
36. Hausner ratio
• The powder with low interparticle friction, such as
coarse spheres.
• Value greater than 1.5 indicates poor flow (= 33%
Carr’s Compressibility Index)).
• More cohesive, less free-flowing powders such as
flakes.
• Between 1.25
improves flow.
and 1.5 added glidant normally
• > 1.5 added glidant doesn’t improve flow.
36
37. The angle of repose (θ )
• The sample is poured onto the
horizontal surface and the angle
of the resulting
measured.
pyramid is
• The user normally selects the
funnel orifice through which the
powder flows slowly
reasonably constantly.
and
37
38. The angle of repose (θ )
1. Angle of repose less than 20 (Excellent flow).
2. Angle of repose between20-30 (Good flow).
3. Angle of repose between 30-40 (Pass flow).
4. Angle of repose greater than 40 (Poor flow).
• The rougher and more irregular the surface of
the particles, the higher will be the angle of
repose.
38
40. Factors affecting the flow
properties of powder
Alteration of Particle’s size & Distribution
• There is certain particle size at which powder’s flow
ability is optimum.
• Coarse particles are more preferred than fine ones as
they are less cohesive.
• The size distribution can also be altered to improve
flowability by removing a proportion of the fine
particle fraction or by increasing the proportion of
coarser particle’s such as occurs in granulation.
41
41. Factors affecting the flow
properties of powder
Alteration of Particle shape & texture
Particle’s Shape
• Generally, more spherical particles have better flow
properties than more irregular particles.
• Spherical particles are obtained by spray drying, or
by temperature cycling crystallization.
42
42. Factors affecting the flow
properties of powder
Alteration of Particle shape & texture
Particle’s texture
• Particles with very rough surfaces will be
more cohesive and have a greater tendency to
interlock than smooth surfaced particles.
43
43. Factors affecting the flow
properties of powder
Alteration of Surface Forces
• Reduction
flowability.
of electrostatic charges can improve powder
• Electrostatic charges can be reduced
conditions to reduce frictional contacts.
by altering process
• Moisture content of particle greatly affects powder’s flowability.
• Adsorbed surface moisture films tend to increase bulk density
and reduce porosity.
• Drying the particles will reduce the cohesiveness and improve the
flow.
• Hygroscopic powder’s stored and processed under low humidity
conditions.
44
44. Factors affecting the flow
properties of powder
Formulation additives (Flow activators)
• Flow activators are commonly referred as a
glidants.
• Flow activators improve the flowability of
powders by reducing adhesion and cohesion.
e. g. Talc, maize starch and magnesium stearate.
45