Comparative Studies on Sedimentation Parameter of Aluminium Hydroxide and Sodium Bicarbonate, Magnesium Trisilicate, Magnesium Carbonate Suspension

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Asian J. Pharm. Tech. 2012; Vol. 2: Issue 4, Pg 133-134 [AJPTech.]


133


ISSN- 2231–5705 (Print) www.asianpharmaonline.org
ISSN- 2231–5713 (Online)


RESEARCH ARTICLE

Comparative Studies on Sedimentation Parameter of Aluminium
Hydroxide and Sodium Bicarbonate, Magnesium Trisilicate, Magnesium
Carbonate Suspension

Swati Paul*, Dibyajyoti Saha
Department of Pharmacy, BGC Trust University Bangladesh, Chittagong.
*Corresponding Author E-mail: saha.dibyajyoti@gmail.com ; swati946@gmail.com

ABSTRACT:
The sedimentation volume (F) is defined as the ratio of final or ultimate volume to the suspension volume. If the
volume of sedimentation in a flocculated suspension equal to the original volume of suspension, then F=1 is
pharmaceutically acceptable. When F=0 it means the total drug has sedimented and volume of sediment is negligible.
So, more the volume of F more will be therapeutic acceptance. In this study two types of suspension were studied
where aluminium hydroxide suspension classed as type-I and sodium-bi-carbonate, magnesium trisilicate, magnesium
carbonate suspension classed as ty pe-II suspension. It was observed that the sedimentation volume is more in case of
type-I suspension rather than type-II suspension.

KEYWORDS: Sedimentation volume, Aluminium hydroxide, Sodium bi carbonate, Magnesium trisilicate,
Magnesium carbonate.

INTRODUCTION:
The sedimentation volume, F, is the ratio of the equilibrium
volume of the sediment , Vu, to the total volume of the
suspension , Vo
1
. Thus,
F=Vu/Vo
A suspension is a heterogenous system containing dispersed
solids of such size that they settle. Whether a
pharmaceutical suspension is to be taken orally, applied
topically or injected, the dispersed phase should b e
uniformly distributed in order to ensure the administration
of a uniform dose. The rate of sedimentation or settling for
a suspended phase depends on several factors which are
under the control of the formulator or pharmacist
2
. Stokes
developed an equation which relates the rate of
sedimentation to the physical properties of the suspension.

dx/dt = [2r
2
(Rho
1
- Rho
2
)g]/[9 X Viscosity]

where r is the radius of the dispersed particle, Rho
1
is the
density of the particles and Rho
2
is the density of the
medium, and g is the gravitational constant
3
.

Received on 02.05.2012 Accepted on 12.08.2012
© Asian Pharma Press All Right Reserved
Asian J. Pharm. Tech. 2(4): Oct. - Dec. 2012; Page 133-134

Although the Stokes equation does not consider all
variables which affect a suspension, it gives an
approximation of the rate of settling and an appreciation of
the effect which controllable factors exert on the settling
rate. By reducing particle size, by increasing the viscosity,
and by increasing the density of the external phase, we may
retard settling. Suspending agents are physiologically inert
substances which increase viscosity when added to
suspensions
4
.On prolonged standing suspensions tend to
cake as some crystals knit together at point of contact at the
bottom of the container. Therefore, a second import ant
function for suspending agents is to facilitate redistribution
of a suspension on shaking. Particles in suspension can
come together to form either floccules or aggregate s.
Floccules form when weak Vander Walls forces are holding
the particles together. Floccules are easy to break apart. If
floccules sediment they trap solvent and are easier to
resuspend than if the particles settle into a tighter aggregate
without the trapped solvent. However, the large fluffy
clumps that characterize a flocculated system settle rapidly.
It is the goal of a good formulator to develop a system
which controls the rate of flocculation and sedimentation
5
.





Asian J. Pharm. Tech. 2012; Vol. 2: Issue 4, Pg 133-134 [AJPTech.]


134
0
0.2
0.4
0.6
0.8
1
1.2
0 2 4 6 8 10 12 14
Time (minutes)
Sedimentation volume(F)
Suspension I
Suspension II

Figure- 1: Graphical representation of Sedimentation volume Vs Time (for suspension I and II)

EXPERIMENTAL:
Weighed about 17.5 gm of aluminium hydroxide powder
and dispersed in 100 ml of water to produce suspension.
Then 5gm sodium-bi-carbonate, 5gm magnesium
trisilicate,5gm light magnesium carbonate were weighed,
mixed and dispersed in 100 ml of distilled water to produce
another suspension. These two types of suspension were
taken in two 100 ml of measuring cylinder and the volume
of sedimentation in 10ml interval up to 1 hour were noted.
Then sedimentation at various time were calculated and
sedimentation volume vs. time of these prepared
suspensions were plotted.

Table 1: Preparation Formula for both suspensions (For 100 ml)
Suspension-I Suspension-II
Aluminium hydroxide : 17.5 gm
Sugar : 5 gm
Methyl Paraben : 0.5-1 gm
Distill Water : Upto 100 ml
Sodium-bi-carbonate : 5gm
Magnesium trisilicate :5gm
Magnesium carbonate : 5gm
Sugar : 5 gm
Methyl Paraben : 0.5-1 gm
Distill Water : Upto 100 ml

RESULT AND DISCUSSION:
Table 2 represents the plot of sedimentation volume vs.
time for suspension I and table 3 represents the pl ot of
sedimentation volume vs. time for suspension II.

Table 2: For Suspension I (Tabulation for sedimentation Volume
vs. Time)
Time(minutes) Volume of
sediment(ml)
Sedimentation
volume(F)
10 99 0.99
20 96 0.96
30 92 0.92
40 89 0.89
50 84 0.84
60 80 0.80
70 74 0.74
80 72 0.72
90 70 0.70
100 70 0.70
110 70 0.70
Table 3: For Suspension II (Tabulation for sedimentation Volume
vs. Time)
Time(minutes) Volume of
sediment(ml)
Sedimentation
volume(F)
10 95 0.95
20 91 0.91
30 86 0.86
40 82 0.82
50 79 0.79
60 74 0.74
70 70 0.70
80 67 0.67
90 65 0.65
100 65 0.65
110 65 0.65

CONCLUSION:
It was observed that the sedimentation volume is more in
case of type-I suspension i.e. aluminium hydroxide
suspension and less in case of type-II suspension i.e.
sodium-bi-carbonate, magnesium trisilicate, magnesium
carbonate suspension. So, the suspension-I i.e. aluminium
hydroxide suspension is more therapeutically as well as
pharmaceutically acceptable.

REFERENCES:
1. A. Khusnoor, Physical Pharmacy. Tara Publishers, New Delhi,
1
st
Edition, pp61-69(2003).
2. G.P. Mohanta and P.K. Manna. Physical Pharmacy Practical
Text, Hyderabad, 1
st
Edition, pp72-75 (2008).
3. C.V.S. Subrahmanyam. Textbook of physical Pharmaceutics,
Vallabh Prakashani, New Delhi, 2
nd
Edition, pp 228-232(2007).
4. A.Martin, Physical Pharmacy, B.I. Waverly Pvt. Ltd, New Delhi,
4
th
Edition, pp 562-571(1996).
5. D.V. Derle, Essentials of Physical Pharmacy, Pharma Book
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st
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