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