The document is a seminar presentation on powder flow properties relevant to pharmaceutical manufacturing, discussing factors that affect flowability such as particle size, shape, texture, and surface forces. Key methods for characterizing powder flow include Carr's compressibility index, Hausner's ratio, and angle of repose, with recommendations for using flow activators to enhance flow. The presentation also highlights the importance of optimizing powder characteristics for improved manufacturing processes.

1. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 1
POWDER FLOW
A seminar as a part of curricular
requirement for I year M. Pharm I semester
Presented by
K. Tarun (20L81S0805)
Dept. of Industrial Pharmacy
Under the guidance/Mentorship of
Dr. Hindustan Abdul Ahad M. Pharm, Ph.D, FAGE
Life member of IPA & APTI
Professor & Head, Dept. of Industrial Pharmacy

2. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 2
The information provided in this PPT for
Education purpose only.

3. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 3
• Powders may be free-flowing or sticky.
• Many common manufacturing problems are attributes to
powder flow.
• Powder transfer through large equipment such as hopper.
Uneven powder
flow
Excess entrapped air
within powders
Capping
or
lamination

4. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 4
The powder flow properties can be characterized by the
following methods:
a. Carr’s compressibility Index
b. Hausner’s Ratio
c. Angle of repose ()

5. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 5
• A volume of powder is filled into a graduated glass cylinder
and repeatedly tapped for a known duration.
Carr’s Index(%) =
𝑇𝑎𝑝𝑝𝑒𝑑 𝑑𝑒𝑛𝑠𝑖𝑡𝑦−𝐵𝑢𝑙𝑘 𝑑𝑒𝑛𝑠𝑖𝑡𝑦
𝑇𝑎𝑝𝑝𝑒𝑑 𝑑𝑒𝑛𝑠𝑖𝑡𝑦
x100
Carr’s Compressibility Index

6. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 6
• Hausner’s Ratio=
𝑇𝑎𝑝𝑝𝑒𝑑 𝑑𝑒𝑛𝑠𝑖𝑡𝑦
𝐵𝑢𝑙𝑘 𝑑𝑒𝑛𝑠𝑖𝑡𝑦
x100
Hausner’s Ratio
Flowability Carr’s Index
(%)
Hausner’s
Ratio
Excellent 0-10 1.00-1.11
Good 10-15 1.12-1.18
Fair 16-20 1.19-1.25
Possible 21-25 1.26-1.34
Poor 26-31 1.35-1.45

7. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 7
It is the maximum angle between the
surface of a pile of powder &
horizontal plane.
The sample is poured onto the
horizontal surface and the angle of the
resulting pyramid is measured.
The user normally selects the funnel
orifice through which the powder flows
slowly and reasonably & constantly.
Angle of Repose ()

8. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 8
tan-1 =
ℎ
𝑟
• The rougher & more irregular the surface of the particles,
the higher will be the angle of repose.
• Lower values indicate better flow characteristics.
Flowability Angle of repose
Excellent <25
Good 25-30
Moderate flow 30-40
Poor flow >40

9. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 9
Improvement of powder
flowability
Particle size
&
Distribution
Particle
Shape &
texture
Surface
forces
Flow
Activators
Factors affecting the flow properties of
powder

10. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 10
• 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.
Alteration of Particle size & Distribution

11. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 11
Particle Shape:
 Generally, more spherical particles have better flow
properties than more irregular particles.
 Sphericalparticles are obtained by spray drying, or by
temperature cycling crystallization.
Particle texture:
Particles with very rough surfaces will be more
cohesive and have a greater tendency to interlock
than smooth surfaced particles.
Alteration of Particle shape & texture

12. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 12
 Reduction of electrostatic charges can improve powder
flowability.
 Moisture content of particle greatly affects powder’s
flowability.
 Drying the particles will reduce the cohesiveness and
improve the flow.
 Hygroscopic powder’s stored and processed under low
humidity conditions.
Alteration of Surface Forces

13. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 13
o Flow activators are commonly referred as a
glidants.
o Flow activators improve the flowability of
powders by reducing adhesion and cohesion.
e. g. Talc, maize starch and magnesium stearate
Flow Activators

14. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 14
1. Prescott JK, Barnum RA. On powder flowability.
Pharmaceutical technology. 2000 Oct;24(10):60-85.
2. Amidon GE, Ausburger LL, Brittain HG, Byrn SR, Fox
CD, Peck GE, Wurster DE. Physical test methods for
powder flow characterization of pharmaceutical
materials: A review of methods. InPharmacopeial Forum
1999 May (Vol. 25, No. 3, pp. 8298-8308).
References

15. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 15