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 be 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 = [2r2(Rho1
- Rho2)g]/[9 X Viscosity]
where r is the radius of
the dispersed particle, Rho1 is the density of the particles and Rho2
is the density of the medium, and g is the gravitational constant 3.
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 suspensions4.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 important function
for suspending agents is to facilitate redistribution of a suspension on
shaking. Particles in suspension can come together to form either floccules or
aggregates. 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 sedimentation5.
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 plot 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, 1st Edition, pp61-69(2003).
2.
G.P. Mohanta and P.K. Manna. Physical
Pharmacy Practical Text, Hyderabad, 1st Edition, pp72-75 (2008).
3.
C.V.S. Subrahmanyam. Textbook
of physical Pharmaceutics, Vallabh Prakashani, New Delhi, 2nd Edition, pp
228-232(2007).
4.
A.Martin, Physical
Pharmacy, B.I. Waverly Pvt. Ltd, New Delhi, 4th Edition, pp 562-571(1996).
5.
D.V. Derle, Essentials of
Physical Pharmacy, Pharma Book Syndicate, Hyderabad,
1st Edition, pp209-218 (2006).
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