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BACKGROUND
Angle of repose is defined as the maximum angle possible between the surface area of the pile of powder and horizontal plane. The angle of repose is given by1
(o) = tan-1 h/r
Where, h = height of pile
r = radius of the base of the pile
Bulk density is defined as the ratio of weight of powder to the bulk volume is the volume occupied by certain weight of powder when gently poured into the measuring cylinder.
Bulk density = weight / bulk volume
Tapped density is the ratio of weight of powder to the tapped volume.Tapped volume is the volume occupied by certain weight of powder after standard no. of tapping.2,3
Tapped density = weight / tapped volume
Carr’s index may be defined as
Carr’s index = (Tapped density – bulk density / tapped density)× 100
Hausner’s ratio is the no. i.e co-related to flowability of the powder.
Hausner’s ratio = Tapped density / bulk density
Aim: To determine bulk density,tap density,angle of repose,carr’sindex,hausmer’s ratio and flow rate of powder.
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REQUIREMENTS
Chemical: Lactose,
Calsium carbonate,
ZnO,
Talc
Apparatus: Measuring cylinder,
Funnel,
Using balance,
Burette stand.
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PROCEDURE
1. Determination of bulk density and tap density
10gm of powder sample was weight accurately. Then it was transferred in to a 100ml measuring cylinder.The volume was noted as bulk volume V1. Then the measuring cylinder was tapped 100 times. The volume noted as tapped volume.
Bulk Density=Weight/Bulk Volume
Tapped Density=Weight/Tapped Volume
2. Determination of carr’s index and housner’s ratio:-
Carr’s Index= {(Tapped Density –Bulk Dencity) /Tapped Density } ×100
Housmer’s Ratio=Tapped Density/Bulk Density.
3. Determination of angle of repose:-
A clean and dry funnel was taken and attached to a burette stand.A white paper site was placed 5cm below the tip of the funnel in a dry plat form. Gently this sample was pore in to the funnel. Using a pencil circle was drawn around the tip of powder .The height of the hip also measured. The same procedure was followed 3 times to obtain average reading.
Angle of repose (θ)=tan-1h/r
Where h = Average height of heap
R = Average radius of heap
4. Determination of flow rate
Flow Rate=Weight of Powder/Time Required To Flow
Result interpitation
CARR’S INDEX |
TYPE OF FLOW |
5-15 |
EXCELLENT |
12-16 |
GOOD |
18-21 |
POOR |
>23 |
VERY POOR |
ANGLE REPOSE |
TYPE OF FLOW |
<25 |
|
25-30 |
|
30-40 |
|
>40 |
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CONCLUSION
The flow property of the given sample is _______________.
POWDER NAME |
BULK DENSITY |
TAPPED DENSITY |
CARR’S INDEX |
H.R |
ANGLE OF REPOSE |
FLOW RATE |
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REFERENCES
- More HN, Hajare AA. Practical Physical Pharmacy. Career Publications. 2010: 120-122
- Gaud RS, Gupta GD. Practical Physical Pharmacy. CBS Publisher and Distributors. 2009: 55-56.
- Mohanta GP. Physical Pharmacy Practical Text, Pharma Book Syndicate. 2006: 49-50.