It is a wise mans part, rather to avoid sickness, than to wishe for medicines. ~Thomas More, Utopia

It is a wise mans part, rather to avoid sickness, than to wishe for medicines. ~Thomas More, Utopia
It is a wise mans part, rather to avoid sickness, than to wishe for medicines. ~Thomas More, Utopia

Saturday, 10 May 2014

EXPERIMENT 2 : EVALUATION OF THE IMPACT OF THE DIFFERENT CONTENTS ON THE CHARACTERISTIC OF THE SUSPENSION

Objective :
To determine the effect of using different amount of Tragacanth in suspension formulation.

Introduction :
           Suspension is a preparation containing finely divided, insoluble drug particles that are uniformly distributed throughout a vehicle. A suspension is a two phased system in which a finely divided solid is dispersed in a continuous phase of solid, liquid, or gas. The undissolved solid exists in equilibrium with a saturated solution of the solid in the continuous phase. Suspension is one of choice of formulation because certain drugs are chemically unstable in solution but stable when suspended and to administer an insoluble compound as a liquid.
Besides, it also has dosage flexibility and taste making properties, where it can mask the unpleasant taste of drugs by formulating a vehicle in which the drug is insoluble, using an insoluble form of the drug and adsorbing the drug onto an insoluble carrier. A good suspension must be therapeutically efficient, chemically stable, settle slowly but readily redispersed upon shaking. The suspended particle size should be small and uniformly sized in order to give a smooth, elegant product that is free from a gritty texture. In addition, suspended particle must remain constant for long periods and can be pour readily and evenly to achieve desirable suspension.
           The main problems with suspensions are, it settled rapidly at bottom of the container and may form hard cake. In order to minimize these problems, we add some ingredients, such as suspending agents, wetting agents and hydrophilic colloid besides from their main ingredients such as active ingredients, flavouring, colouring and preservatives. In this experiment, we are using Tragacanth as a wetting agent and it is viscous in nature, it provides thixotrophy to the solution. It acts by adsorbing at the suspensoid and reducing surface tension at the solid interphase.

Apparatus and Material :
I. Apparatus
Weighing balance                                           A set of pipette (1ml) and bulb-pipette
1 weighing boat                                              1 centrifugation tube 15ml
A set of mortar and pestle                              1 beaker 100ml
Plastic bottle 150ml                                         Centrifugation equipment
Measuring cylinder 50ml                                Viscometer                
A measuring cylinder 200ml                          Coulter Counter

II. Materials
Chalk                                                               Syrup BP
Tragacanth                                                      Double-strength Chloroform Water
Concentrated Peppermint Water                   Distilled water

Procedures :
1.      A suspension of Paediatric Chalk Mixture (150ml) is prepared using the formulation below:      
Chalk                                                                                       3g
Tragacanth                                                                    Refer to table 1
Concentrated Peppermint Water                                           0.6mL
Syrup BP                                                                               15mL
Double Strength Chloroform Water                                      75mL
Distilled Water, q.s.                                                              150mL

Table 1
Paediatric Chalk Mixture
Group
Tragacanth (g)
I
1, 5, 9
0.0
II
2, 6, 10
0.1
III
3, 7, 11
0.3
IV
4, 8, 12
0.5

2.      Some of the suspension formed (5ml) is poured into the weighing boat and labelled. State and compare the texture, clearness and colour of the suspension formed.
3.      50ml of suspension formed is poured into the 50ml measuring cylinder and the height of the solid phase sediment in the cylinder is measured at intervals of 0, 5, 10, 15, 20, 25, 30, 40, 50 and 60 minutes.
4.      The remaining suspension (95ml) is poured into a 100ml beaker and viscosity of the suspension formed is determined using a viscometer.
5.      The particle size of  ≥ 25µm in the suspension (from the remaining suspension) is determined using Coulter Counter.
6.      10ml of suspension is poured into a centrifugation tube and the height of the solid phase formed after centrifugation (1000rpm, 5 minutes, and 25°C) is determined.

Results :
2. Compare the texture, clarity and colour of suspension(0.1g of tragacanth)
Texture: Diluted smooth
Clarity: Cloudy
Colour: Chalky white
3.
Time/ min
0
5
10
15
20
25
30
35
40
45
50
55
60
Height/ mm
11.8
11.6
11.5
11.3
11.2
11.1
11.1
11.0
11,0
11,0
10.9
10.9
10.8

4.
Readings
1
2
3
4
5
6
Viscocity/ cP
47.00
217.50
150.00
135.00
82.50
150.00
Average + SD
130.33 ± 59.37

6.

Height/ mm
Before centrifuge
8.0000
After centrifuge
6.7000
Ratio of height
0.8375

Discussion :
Suspension is a heterogeneous mixture containing solid particles that are sufficiently large for sedimentation.  In this experiment, the suspension made is diluted smooth, cloudy and chalky white.  However, when 50 ml of suspension is poured into the cylinder for observation, it shows that there is sedimentation.  Besides, it has also been shown that the viscosity   of the suspension is not uniform. 
Tragacanth is widely used in pharmaceutical products as a binding agent.  It is an especially important substance in the production of suspension.  In this experiment, only 0.1 g of Tragacanth is used.  Therefore, it was observed that the suspended particle (which in this case is the chalk) settled with time.  Apart from that, it is also shown that this suspension cannot achieve uniform viscosity. The use of too little Tragacanth has contributed to these.
There are some errors that may have occurred throughout the experiment that had lead to different results when compared with others groups of the same amount of tragacanth used.  Firstly, it may be parallax error. While measuring the materials, the eye level is not parallel to the meniscus of the the ingredients.  Besides, there might also be impurities in the suspension.  This is because all the apparatus are not washed beforehand the experiment. 
All the excipients used in this experiment have its own function.  For tragacanth, it is used as a binding agent. Concentrated peppermint water and syrup BP are used as a flavouring agent in pharmaceuticals.  The Double Strength Chloroform Water BP is included in this product as the preservative and also as the vehicle as per the product formula. Distilled water in this case is used as a raw material, ingredient, and solvent in the processing, and formulation of this suspension.
Tragacanth is used to suspend heavy insoluble powder in the production of suspension.  The appropriate quantity of Tragacanth to be used to form suspension is 0.2 g Tragacanth BP powder for 100 ml suspension.  Therefore, to prepare for a 150 ml suspension, the most suitable amount is 0.3 g of Tragacanth.

Conclusion:
Suspension dosage form is a preferred and widely accepted dosage forms for insoluble or poorly soluble drugs for various therapeutic applications. In this practical, the texture (0.1 g of tragacanth) is smooth and dilute in its form. The suspension formed is cloudy and chalky white in colour. Formations of precipitate, clarity for solutions, pH, viscosity, extractable, level of microbial contamination are those to be emphasizing during formulation of suspension.
The height of suspension which excludes the clear part of it (at upper part of test tubes) is decreases due to precipitation that occurs as time increases. Viscosity of suspension also is different from one formulation to another because it depends on the type of suspending and stabilizing agents used. The height of suspension before centrifuge is 8.000 mm while 6.700 mm after centrifuge because the process causes more sedimentation of particles in suspension to occur. This process is used to separate solid substances from highly concentrated suspension.

References:
1.      http://www.springer.com/biomed/pharmacology+%26+toxicology/book/978-1-4419-1086-8
Retrieved on: April 28, 2014.

2.      http://www.amazon.com/Pharmaceutical-Suspensions-Formulation-Development-Manufacturing-ebook/dp/B008BA5S9E
Retrieved on:April 28, 2014.

3.      http://www.lenntech.com/library/clarification/clarification/centrifugation.htm
Retrieved on: April 29, 2014.



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