In this article i am sharing some practical experiences as well as few calculations on syrup preparation with my readers.
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| John Pemberton |
Introduction on syrup
Syrup
is a concentrated aqueous solution of sugar or its’ substituent, with or
without medication and flavouring agent .It is usually used as a vehicle for
drugs and used for making simple stock of drugs. Syrup is also used as taste
masking for bitter drugs .A high proportion of around 60-80 % sucrose can give
a desirable sweetness, preservation, viscosity and stability to syrup. There
are several types of medicated syrups used in daily life, such as cough and
cold remedies The non -medicated drug involves simple syrups , gomme syrups ,
maple syrups.
Despite that
syrup is self -preserved due to the presence of highly concentrated sucrose
solution, in some preparation preservative is still added. Examples of
preservatives for syrups are Benzoic acid, 0.1 – 0.2%,Sodium benzoate 0.1 –
0.2% and combinations of methyl-, propyl-, and butyl parabens (totaling 0.1%).
Alcohol is also used as preservative but does not exceed the required amount by
15-20% in the final product.
The precautions
taken for the preparation of syrups is we have to fold the 4 sharp edges of the
paper before place it on the top of measuring pan, this is to prevent the paper
for being supported by the table when the edges touch the table. This can
reduce the experiment error. We should rinse the apparatus with the reagent
first before we start adding the reagent into the particular apparatus. Rinse
also the glass rod during filtration. While reading the measuring cylinder we should
ensure that our eyes level is in line with the meniscus of the solution or
liquid.
Materials and apparatus you may need:
Sucrose,
glycerine, ethanol (95%), drug solution, density bottle, 100mL VF, 200mL
beaker, funnel, glass rod and cotton plug.
Here are some practical procedures and calculations you may follow during your syrup preparation
You are required to prepare 50 mL simplex
syrup base, (USP) which should
contain 85%w/v of sucrose in purified
water.
1 Place about half the amount of sucrose
required in a 100 mL beaker.
2 Measure
23.15g of distilled water
3 Add about 10mL of the distilled water
onto the sucrose and insert the
magnetic bar.
4 Using the magnetic stirrer, stir the
above mixture until the sucrose begins to
dissolve.
5 Add the remaining water and continue
stirring until complete dissolution
(stirring may take up to 25 minutes).
6 Place a moistened cotton plug in the neck
of a funnel and secure the
funnel using a 50mL measuring cylinder.
7 Slowly pour the syrup into the funnel and
allow dripping into the
measuring cylinder.
The specific
gravity of simple syrup is about 1.313gmL-1
1mL syrup → 1.313g
syrup
50mL syrup → 65.65g
syrup
In 100ml (131.3g)
of syrup, there are 85g of sucrose and 46.3g( 131.3-85g) of water.
100mL syrup → 85g sucrose
50mL syrup → 42.5g sucrose,
The weight of
water found in 50mL of syrup = 46.3g/2
=
23.15g
Part 2: calculation of specific gravity
1.Mix the collected syrup with a glass rod
and measure the density using a
density
bottle.
Calculations
of weight and density of the syrup base
Weight
of density bottle + syrup base, W2
|
50.04g
|
Initial
weight of density bottle, W1
|
17.91g
|
Weight
of syrup base, W2 – W1
|
32.13g
|
Table
1 shows the weight of syrup base.
The density of
the syrup base = W2 – W1
V
density bottle
= 32.13
25
=
1.285gmL-1
The actual
specific gravity of simple syrup is 1.313gmL-1.The difference may be
due to some systemic error during the experiment.
Part 3: preparation of medicated syrup
1.Prepare the following medicated using the following procedure:
Add glycerine, syrup
base and the drug in a beaker and then stir with a
glass rod. Add the
required quantity of alcohol (see notes).
2. The calculations detailing the amount of
ethanol required is shown.
Preparation of medicated syrup which contains Ethanol (95%
v/v)
Drug
|
8mL
|
Glycerine
|
30mL
|
Ethanol (95%v/v)
|
5.59mL
|
Syrup base containing
|
18.13mL
|
Purified water
|
100mL
|
Table 2 shows the amount of
ingredients needed to make the drug.
(a) -In 100mL of syrup, there are 85g of sucrose
and 46.3g of water.
( density of water is
1gmL-1),
-85g of sucrose
preserves 46.3mL of water,
-1g of sucrose preserves
0.54mL of water and thus
-Volume of water that 25g of
sucrose preserves = 25 X 0.54 = 13.5mL
(b)
-85g of sucrose occupies 53.7mL,
-1g of sucrose occupies
0.63mL of volume
-Therefore, volume of 25g of
sucrose occupied = 25 X 0.63
= 15.75mL
(c)
-The active drug is equal to 8mL.
(d)
-Each mL of glycerine preserves one equivalent
quantity of volume, twice, so it is
= 2 X 15mL
= 30mL
(e)
-The volume
taken so far = 13.5mL + 15.75mL + 8mL + 30mL
= 67.25mL
(f)
-The quantity
of free water remaining (to make upa total of 100ml) = 100mL – 67.3mL= 32.7mL
(g)
18% of alcohol is required to preserve water,
Volume of alcohol that
32.7mL of water preserves = 32.75mL X 0.18
= 5.9ml
(h)
100% of Ethanol à 5.9mL of Ethanol
95% of Ethanol à (18/95) x32.75=6.21,ml of
Ethanol
Therefore, 6.21ml of Ethanol
is added to sufficient water to make 100mL of medicated syrup.
Conclusion
- The density of my syrup
base is 1.285gmL-1.
2. The
volume of Ethanol 95% needed for the medication is 6.21 mL.
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