Частные фармакопейные статьи к лабораторно-практическому занятию№1

Potassium Iodide

KI 166.0

Potassium Iodide complies with the requirements of the 3rd edition of the European Pharmacopoeia.

These requirements are reproduced after the heading ‘Definition’ below.

Action and use Antithyroid.

DEFINITION

Potassium iodide contains not less than 99.0 per cent and not more than the equivalent of 100.5 per

cent of KI, calculated with reference to the dried substance.

CHARACTERS

A white powder or colourless crystals, very soluble in water, freely soluble in glycerol, soluble in

alcohol.

IDENTIFICATION

A. Solution S (see Tests) gives the reactions of iodides (2.3.1).

B. Solution S gives the reactions of potassium (2.3.1).

TESTS

Solution S Dissolve 10.0 g in carbon dioxide-free water R prepared from distilled water R and dilute to

100 ml with the same solvent.

Appearance of solution Solution S is clear (2.2.1) and colourless (Method II, 2.2.2).

Alkalinity To 12.5 ml of solution S add 0.1 ml of bromothymol blue solution R 1. Not more than

0.5 ml of 0.01M hydrochloric acid is required to change the colour of the indicator.

Iodates To 10 ml of solution S add 0.25 ml of iodide-free starch solution R and 0.2 ml of dilute

sulphuric acid R and allow to stand protected from light for 2 min. No blue colour develops.

Sulphates (2.4.13). 10 ml of solution S diluted to 15 ml with distilled water R complies with the limit

test for sulphates (150 ppm).

Thiosulphates To 10 ml of solution S add 0.1 ml of starch solution R and 0.1 ml of 0.005M iodine. A

blue colour is produced.

Heavy metals (2.4.8). 12 ml of solution S complies with limit test A for heavy metals (10 ppm).

Prepare the standard using lead standard solution (1 ppm Pb) R.

Iron (2.4.9). 5 ml of solution S diluted to 10 ml with water R complies with the limit test for iron

(20 ppm).

Loss on drying (2.2.32). Not more than 1.0 per cent, determined on 1.00 g of previously powdered

substance by drying in an oven at 100°C to 105°C for 3 h.

ASSAY

Dissolve 1.500 g in water R and dilute to 100.0 ml with the same solvent. To 20.0 ml of the solution

add 40 ml of hydrochloric acid R and titrate with 0.05M potassium iodate until the colour changes from

red to yellow. Add 5 ml of chloroform R and continue the titration, shaking vigorously, until the

chloroform layer is decolourised.

1 ml of 0.05M potassium iodate is equivalent to 16.60 mg of KI.

STORAGE

Store in a well-closed container, protected from light.

Calcium Lactate Pentahydrate

Calcium Lactate

C6H10CaO6,5H2O (approx.) 218.2 (anhydrous)

Calcium Lactate Pentahydrate complies with the requirements of the 3rd edition of the European

Pharmacopoeia . These requirements are reproduced after the heading ‘Definition’ below.

Action and use Used in treatment of calcium deficiency.

Preparations

Calcium and Ergocalciferol Tablets

Calcium Lactate Tablets

DEFINITION

Calcium lactate pentahydrate contains not less than 98.0 per cent and not more than the equivalent

of 102.0 per cent of calcium (RS)-2-hydroxypropionate or of a mixture of calcium (R)-, (S)- and

(RS)-2-hydroxypropionates, calculated with reference to the dried substance. It contains not less than

22.0 per cent and not more than 27.0 per cent of water, determined by the loss on drying.

CHARACTERS

A white or almost white, crystalline or granular powder, slightly efflorescent, soluble in water, freely

soluble in boiling water, very slightly soluble in alcohol.

IDENTIFICATION

A. It complies with the test for loss on drying (see Tests).

B. It gives the reaction of lactates (2.3.1).

C. It gives reaction (b) of calcium (2.3.1).

TESTS

Solution S Dissolve 5.0 g with heating in carbon dioxide-free water R prepared from distilled water R,

allow to cool and dilute to 100 ml with the same solvent.

Appearance of solution Solution S is not more opalescent than reference suspension II (2.2.1) and

not more intensely coloured than reference solution BY6 (Method II, 2.2.2).

Acidity or alkalinity To 10 ml of solution S add 0.1 ml of phenolphthalein solution R and 0.5 ml of

0.01M hydrochloric acid. The solution is colourless. Not more than 2.0 ml of 0.01M sodium hydroxide is

required to change the colour of the indicator to pink.

Volatile fatty acids In a 100 ml ground-glass-stoppered flask stir 0.5 g with 1 ml of phosphoric

acid R. Close the flask. Heat cautiously at 50°C for 10 min. No unpleasant odour resembling that of

the lower fatty acids is recognisable immediately after opening the flask.

Chlorides (2.4.4). 5 ml of solution S diluted to 15 ml with water R complies with the limit test for

chlorides (200 ppm).

Sulphates (2.4.13). 7.5 ml of solution S diluted to 15 ml with distilled water R complies with the

limit test for sulphates (400 ppm).

Barium To 10 ml of solution S add 1 ml of calcium sulphate solution R. Allow to stand for 15 min.

Any opalescence in the solution is not more intense than that in a mixture of 1 ml of distilled water R

and 10 ml of solution S.

Heavy metals (2.4.8). 12 ml of solution S complies with limit test A for heavy metals (20 ppm).

Prepare the standard using lead standard solution (1 ppm Pb) R.

Iron (2.4.9). 4 ml of solution S diluted to 10 ml with water R complies with the limit test for iron

(50 ppm).

Magnesium and alkali salts To 20 ml of solution S add 20 ml of water R, 2 g of ammonium

chloride R and 2 ml of dilute ammonia R1. Heat to boiling and rapidly add 40 ml of hot ammonium

oxalate solution R. Allow to stand for 4 h, dilute to 100.0 ml with water R and filter. To 50.0 ml of the filtrate add 0.5 ml of sulphuric acid R, evaporate to dryness and ignite the residue to constant mass at 600°C. The residue weighs not more than 5 mg (1 per cent).

Loss on drying (2.2.32). 22.0 per cent to 27.0 per cent, determined on 0.500 g by drying in an oven

at 125°C.