Prelab6

Pharmaceutics I
Prelab 6

Presented by
Ahmed Magdy

Prelab contents
1. Preparations
 Cough Syrup.
 Black draught (infusion).
 Heavy magnesium oxide suspension.
2. Problems
 Dose calculations
 Percent preparation
 Percent error

Cough syrup
Rx
Codeine phosphate
Cpd Tartarazine solution
Benzoic acid solution
Water
Lemon syrup
Syrup to
Send
Fiat: Cough Syrup
Sig: Ʒi t.d.s.p.c.

X 0.5
0.3 g 0.15 g
Cough Suppressant
0.5 ml
1 ml
Coloring agent
1 ml
Preservative
2 ml
2 ml
1 ml
Solvent for drug
10 ml Sweetening and flavoring agent
20 ml
100 ml 50ml
Vehicle
50 ml

Calculation:

Factor = 50/100 = 0.5
Vehicle = 50 – (10+1+1+0.5) =37.5 ml
¾ vehicle = ¾ X 37.5 = 28.125 ml =

Use: Cough Syrup for treatment of
dry cough

28 ml

1 ml water

0.5 ml
Compound
tartarazine
solution

1 ml benzoic
acid solution
Cup measure

0.000 g

Cup measure

0.15 g Glass-rod
codeine
phosphat
e

Cup measure

10 ml lemon
syrup

Cup measure

Adjust
volume to
50 ml with
syrup

Fiat: Cough Syrup
Sig: Ʒi t.d.s.p.c.

The Cough Syrup

Label

One teaspoonful to
be taken three times
daily after meals.

Infusion preparation
Black draught
Rx
Magnesium Sulphate
Compound tincture of cardamom
Aromatic spirit of ammonia
Fresh infusion of senna
to
Fiat :mist–send 100 ml
Sig : 30 ml O.m.

250 gm 2.5 gm
10 ml
100 ml
5 ml
50 ml
1000 ml 100 ml

F = required / prescribed = 100/1000 = 0.1

Use: purgative in chronic constipation.

Saline laxative.
Carminative.
Antacid and carminative.
Irritant laxative.

Procedure:
Prepare 120 ml of 5 % senna infusion ??
5% Senna infusion means
5g
100 ml
??
120 ml
6 g senna
 Boil 120 ml H2O in kettle or flask and funnel.
 Then remove from flame.
 Crush 6 g of senna leaves and add to the boiled water.
 Leave for 15 min with occasional shaking (keep the
kettle beside the flame and keep it covered).
 Filter on small wet piece of cotton (Don’t press it).
1)

Procedure :
2) Transfer 50 ml of the infusion to a cup measure

3) Dissolve MgSO4 in the infusion while warm.

4) Cool then add tincture of cardamom and
ammonia spirit.

5) Adjust the volume to 100 ml with cold infusion

The label:
Fiat :mist
Sig : 30 ml O.m.
Shake The Bottle

The Mixture
One coffeecupful to be
taken in the morning.

Decoction

Infusion

Boil Water with ammi
visnaga for 15 min.

Boil Water only and add senna
leaves to water after boiling

Cool before filtering.

Don’t cool before filtering.

After filtration press the cotton

After filtration Don’t press the
cotton
After filtration Don’t
complete volume (to avoid
dilution)

After filtration complete volume to
100 ml in cup measure to replace
water lost by evaporation.
Calculate for 20% excess
water to guard against loss by
evaporation during boiling

Calculate for 20% excess
infusion to guard against
loss by filtration.

Used for heat stable drugs.Ex:

Used for heat sensitive drugs. Ex:

woody plants or seeds (as ammi
visnaga)

leaves (as senna leaves).

Heavy magnesium oxide suspension

Rx
Heavy magnesium oxide ჳii
Magnesium sulphate
ჳvii
Glycerin
ჳi
Acacia mucilage
℥i
Peppermint water ad
℥iii
Fiat: mist.
Sig.: m.d.s.

Use: Laxative

2x4=8 g
7x4=24 g
1x4=4ml
1x30=30ml
3x30=90ml

Laxative and antacid.
Saline purgative
Wetting agent
Suspending agent
vehicle

1-grind MgSo4 with pestle

3-add Mg oxide
4- mix the two
powders together

5-add glycerin and
levigate

8-Rinse the mortar
with small portion
of peppermint water
9-Adjust
volume to
90ml with
peppermint
water.

7- Transfer to cup
measure.

6-add acacia mucilage
portion wise with
levigation

Fiat: mist.
Sig.: m.d.s.

Label
Shake The Bottle

The Mixture
To be taken as directed.

CALCULATION of DOSES
Sig.

Label

Ʒi

5 ml

One teaspoonful

℥ss

15 ml

One tablespoonful

℥i

30 ml

One coffeecupful

℥ii

60 ml

One wineglassful

CHILDREN DOSE
Young’s rule  CHILD DOSE =
Cowling’s rule  CHILD DOSE =

Fried’s rule  CHILD DOSE =
Clark’s rule  CHILD DOSE =

Using BSA (body surface area)  CHILD DOSE =

% Preparation
Percent weight-involume (%w/v):

expresses the number of grams
of a constituent in 100 ml .of
solution or liquid preparation

Percent volume-in- expresses the number of
volume (%v/v):
milliliters of a constituent in
100 ml. of solution or liquid
preparation
Percent weight-in- expresses the number of grams
weight(%w/w):
of a constituent in 100 g. of
solution or liquid preparation.

The term % used without qualification
means……??
for solutions or liquid preparations
(solid in liquid)

% w/v

for solutions of liquids in liquids

% v/v

for mixtures of solids

% w/w

for solutions of gases in liquids

% w/v

Milligrams percent
(mg%) :

Expresses the number of.
milligrams of a substance in
100 ml. of solution
It is used frequently to
denote the concentration of a
drug or natural substance in a
biological fluid, as in the
blood.

Parts per million
(ppm):

For very dilute
solutions e.g.in
designating test limits
The limit of arsenic in
zinc oxide is 6 parts per
million (6 ppm) or
0.0006%.

N.B
 1% solution is prepared by dissolving 1 g of a
solid or 1 ml of a liquid in sufficient of the
solvent to make final volume of the
solution is 100 ml.

Ratio strength
 It is anthor way of expressing concentration

For example
5% means

5 parts per 100

5 : 100

1:20

It is a ratio the first figure of which is 1

When a ratio strength 1 :1000 is used to designate
conc. , it is interpreted as :
1) For solids in
liquid:

1 gram of solute or constituent in 1000
milliliters of solution or liquid preparation,
or
1 grain of solute or constituent in a volume
of solution or liquid preparation
represented by that of 1000 grains of water.

2)For liquid in
liquids:

1 milliliter of constituent in 1000 milliliters
of solution or liquid preparation, or
1 minim of active ingredient in 1000 minims
of solution or liquid preparation.

3)For solids in
solids

1 gram of constituent in 1000 grams of
mixture or
1 grain of active ingredient in 1000 grains
of mixture.

Examples
(1) Express 0.02% as a ratio strength
0.02 → 100
1 → x
⇨x= 1 x 100/0.02 = 5000
∴ Ratio strength = 1 : 5000
(2) Express 1 : 4000 as a percentage strength
1 → 4000
x → 100 ⇨
x = 100 x 1/4000 = 0.025%
∴ % strength = 0.025 %

Percentage of error
% error = ( error / quantity desired) x 100
N.B. error and the quantity desired are expressed in the
same denomination.

Example:
When the maximum potential error is ±4 milligrams in
total of 100 mg what is the percentage of error?
Anwer: (4/100) x 100% = 4 %

 When certain % of error is not to be exceeded

and the maximum potential error of a balance
is known the smallest quantity that can be
weighed is calculated from this equation :

Smallest quantity =(max. potential error/permissible %
error) x100

Smallest quantity =(max. potential error/permissible %
error) x100
% error =

error

x 100

Quantity measured

Quantity measured=

error
% error

If the quantity increases
% error decreases

x 100

If quantity decreases
%error increases

Example: What is the smallest quantity that can be
weighed with a potential error of not more than 5% on a
balance sensitive to 6 milligrams?
Answer: (100 x 6) / 5 =120 mg

Prelab6

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