Water Content Determination

Question 1

Methods used in Water content determination

Answer 1

Method I - Karl Fischer/Titrimetric
Method II - Azeotropic-Toluene Distillation/Modified Xyelene Method
Method III - Gravimetric Method

Question 2

Advantages of Karl Fischer Method

Answer 2

Most rapid
Requires only a small sample
Specific for water
Widely applicable in determination of the water content of drug products

Question 3

Karl Fischer Components ⭐

Answer 3

Pyridine
Iodine
Methanol (Anhydrous)
Sulfur dioxide

PIMS

Question 4

Reduced by SO2 in the presence of water to form Hydroiodic

Answer 4

Iodine

Question 5

Reacts with water to form sulfur trioxide

Answer 5

Sulfur dioxide

Question 6

Forms a complex with SO3 and neutralizes hydroiodic acid and prevents reversal of reaction

Answer 6

Pyridine

Question 7

Reacts with the pyridine-sulfur trioxide complex

Answer 7

Anhydrous methanol

Question 8

Primary Std used in Karl Fischer titration

Answer 8

Na tartrate dihydrate

Question 9

End point of Karl Fischer Titration Method

Answer 9

Canary Yellow to Amber Color

Question 10

Types of Karl Fischer Method

Answer 10

IA: Direct Titration
IB: Residual Titration
IC: Colometric Titration

Question 10

Use of Toluene Moisture Apparatus

Answer 10

Azeotropic / Mod. Xylene

Question 11

Azeotropic - Toluene Distillation is used for what substance

Answer 11

For vegetable drugs (2% moisture or 2-4 mL of water)

Question 12

Sample size used in Azeotropic method

Answer 12

50-100g

Question 13

Solvent used in Azeotropic/Modified Xylene

Answer 13

Toluene (USP Official)
Xylene

Question 14

Method used for articles of Botanical Origin

Answer 14

Gravimetric

Question 15

Sample size and temperature used in Gravimetric Method

Answer 15

10g, Dry at 105C for 5 hours

Question 16

Used when the loss sustained on heating may not be entirely water

Answer 16

Loss on Drying

Question 17

Determination of amount of VOLATILE SUBSTANCES driven off under conditions specified

Answer 17

Loss on Drying

Question 18

Sample size used on Loss on Drying

Answer 18

1-2g

Question 19

Temperature and duration applied on Loss on Drying

Answer 19

110-120C +/-2C
As specified in indiv monograph

Question 20

Specifications for capsules in Loss on Drying

Answer 20

Cap - Mixed contents of >4 capsules
Tab - Use powder from >4 tablets

Question 21

The moisture content of a drug may be

Answer 21

Water of hydration
Water in the absorbed form

Question 22

TF: The amount of extractive a drug yields to a solvent is a measure of the amount of a certain constituents or group of related constituents the drug contains.

Answer 22

True

Question 23

TF: Solvents used for Extractives should only dissolve the target substances during the extraction

Answer 23

True

Question 24

The amount of a drug soluble in a given solvent is an index of its ______

Answer 24

Purity

Question 25

Apparatus used for extractives

Answer 25

Soxhlet extraction

Question 26

Solvent for drugs containing volatile oils or active consituents with volatile matter

Answer 26

Ether ⭐

Question 27

Solvent used for resinous matter, benzoic acid, cinnamic acid, vanillin, exters, styrene, benzaldehyde

Answer 27

Alcohol ⭐

Question 28

Solvent used for glycosides, barbaloin, and isobarbaloin extracts

Answer 28

Water ⭐

Question 29

Solvent used for Fats and fatty oils

Answer 29

Hexane ⭐

Question 30

Method I used for Extractives

Answer 30

Hot Extraction Method

Alcohol & Water Soluble

Question 31

Method II used for Extractives

Answer 31

Cold Extraction Method

Alcohol & Water Soluble

Question 32

The residue consists of CELLULOSE that remains undissolved after successive treatment with boiling ACID/ALKALI

Answer 32

Crude Fiber

Question 33

Crude Fiber Content is important in the examination of:

Answer 33

Spices - used a sadulterant consisting of waste or refuse materials derived from the drugs, spices, or food products.

Question 34

The soluble constituents of crude drug in a certain solvent

Answer 34

Extractives