1. Miscellaneous Tests
Weight/ml
Total solids
Loss on drying
Ash test
Toxicity tests
Moisture contents

2. Weight per milliliter
 Important for tinctures and extracts and
defined as
The weight per milliliter of a liquid is the
weight expressed in grams of 1 milliliter
of a liquid when weighed in air at the
specific temperature

3.  Almost equal to density of the liquid
 For this,
– Weigh a clean and dry pycnometer
accurately
– Fill it with liquid, remove any access and
weigh
– Determine the weight of liquid by subtraction

4.  Determine wt/ml by dividing the
weight of liquid that filled the
pycnometer by the capacity of
pycnometer
 Expressed in g/ml

5. Total Solids (BP)
 The term total solids is applied to the residue
obtained when the prescribed amount of the
preparation is dried to constant weight under
the conditions specified
 Total solids usually include extractives, both
soluble in alcoholic or hydroalcoholic
preparations as tinctures and extracts

6.  Apparatus a hollow flat bottom, flanged dish
75mm in diameter 25mm deep made up of
nickel or other metal
 Place an accurately measured weight or
quantity of the preparation after thorough
shaking, say 10 ml in a tarred dish
 Evaporate at as low a temperature as
possible until the alcohol is removed, and
heat on a water bath until the residue is
apparently dry

7.  Transfer to oven and dry to a
constant weight at 105oC or dry in
desiccator
 Weigh the dish containing residue
 Difference in two weights is the
amount of total solid per 10ml.
 Determine total solid as g/100ml

8. Determination of Ash
 Acid soluble ash
 Acid insoluble ash
 Water soluble ash
 Sulphated ash

9. Total ash
 Clean dry silica crucible is heated and
weighed to a constant weight. Then 2 g
accurately weighed sample is taken in it and
incinerated by gradually increasing heat to
dull redness (675 ± 25 oC) until free from
carbon. The crucible was then kept in
desiccator and allowed to cool to a constant
weight and weighed. The percentage of total
ash with reference to air dried sample was
calculated

10. Acid insoluble Ash
 The total ash is boiled for 5 min in 25 mL
dilute HCl. The insoluble matter is collected
on ash less filter paper and washed with hot
distilled water. The filter paper is then dried
and ignited in tarred silica crucible until free
from carbon. The crucible is allowed to cool
in desiccator till a constant weight and
weighed. The percentage of acid insoluble
ash with reference to air dried sample is
calculated

11. Sulphated Ash
 Two gram accurately weighed sample is
taken in tarred silica crucible, moistened with
sulphuric acid and ignited gently. Crucible is
then allowed to cool in desiccator and again
moistened with sulphuric acid, reignited and
weighed. The process is repeated till a
constant weight is obtained. The percentage
of sulphated ash with reference to air dried
sample was calculated

12. Toxicity test
 Usually performed on finished dosage form of
toxoids and plastic containers in order to determine
there safety or toxicity.
 DIPHTHERIA TOXOID
 Inject IV/SC 4 healthy guinea pigs (300-400g) with a
of DT that is atleast 5 times the human immunizing
dose (not less than 2ml).
 Comply if no symptom of DT poisoning appear within
30 days.

13.  TETANUS TOXOID
 Perform similar as DT but it is given SC.
 Check the symptoms of tetanus toxin poisoning after
21 days.
 PLASTIC CONTAINERS
 Extract of plastic containers used for parenteral
preparations is prepared.
 Its IV injection to mice determine its gross toxicity
and mortality.

14. Give IC into dorsal shaved skin of rabbit
or
The standardized plastic strips are
implanted
The local reaction is observed for toxicity.

15. Loss on drying
 Test determines the amount of volatile matter of any
kind that is driven of under specified conditions.
 Take 1-2g of substance, reduce particle size if
necessary, in a dried glass stoppered, weighed
bottle.
 Weigh and shake to evenly distribute the substance.
 Place the loaded bottle in drying chamber, remove
stopper and place it also in the chamber.
 Dry the sample at temperature specified in
monograph, close the bottle. Cool in desiccator &
weigh

16.  If the substance melts at a temperature at which loss
on drying is to be performed, it is kept at 5 -10oC for
1-2 h for drying.
 For substance requiring thermogravimetric analysis a
sensitive electrobalance is used.
 For vacuum drying vacuum desiccator or vacuum
drying pistol are used.

17. Moisture Content
 Heating
method/thermogravimetry
 Karl Fischer
– Volumetricmethod
– Coulometric method

18. Moisture contents
 Accurately weighed powder (2 g) of the plant
material is taken in a tarred silica crucible.
 The powder is the dried in an oven at 105 oC
for 30 min, cooled at room temperature in
desiccator until constant weight and weighed
to calculate the moisture contents.
 The results are expressed as a percent of
dry powder.

19. Karl Fisher Method---Standard technique for low
moisture products.
Especially good for reducing sugars, protein-rich
food and foods and pharmaceuticals with high
volatile oils.

20. Karl Fischer
German Petrochemist,
1901 – 1958
Publication: 1935
2 H2O + SO2 + I2 = H2SO4 + 2 HI
Taiwan, September 2002 20

21. s KF Reaction
SO2 + RN + ROH ------> (RNH)SO3R
a sulfite compound
(RNH)SO3R + H2O + I2 + 2RN ------> (RNH)SO4R + 2(RNH)I
a sulfate compound
s Summary
H2O + I2 + SO2 + 3RN + ROH ----->(RNH)SO4R + 2(RNH)I
s The solvent (generally methanol) is involved in the reaction
s A suitable base keeps the pH 5 - 7
Taiwan, September 2002 21

22. 1. + + + H2 O 2 +
N N N N N
I2 SO2 HI SO3
2. + CH3 OH
N N
SO3 H SO4 CH3
Brown Mahogany Color

23. Karl Fisher Reagent: Dissolve Iodine in the mixture of
Pyridine, MeOH and SO2.
Titrate 100 mg of H2O with Carl Fisher Reagent.
Calculate Concentration of K F Reagent =mg H2O /ml of Reagent
% H2O = Concentration x ml Reagent / mg of Sample x 100