Analysis of Crude Drugs

the residue remaining after incineration; represents the inorganic salts naturally occurring in the drug and adhering to it, but may also include inorganic matter added for adulteration purposes

represents the inorganic salts/substances present (residue remaining after incineration)

the part of the total ash which is insoluble in diluted HCl or the ash treated with 3N HCl

The residue after carbonized mass is treated with one ml of sulfuric acid and further incinerated after evaporating the acid under the hood

Temperature Equivalents (Heat Type)

It is the determination of ash content by ignition to dull redness

It is performed to control the amount of inorganic matter that may be contained in substances..

Residue on Ignition Examples and Percentage/Wt

It provides a means of determining the percentage of test material which is volatilized and driven off under specified conditions.

It is the amount of volatile matter lost when heated

Loss on Ignition Examples and Percentage/wt

Ignition shall be continued at 800oC otherwise indicated until two consecutive weighs do not differ by more than 0.5mg/g of the substance taken, the second weighing following an additional 15-minute ignition period.

Drying shall be continued until two consecutive weighings do not differ by more than 0.5mg/g of the substance taken, the second weighing following an additional hour of drying..

Determine the amount of volatilematter of any kind that is driven off under the conditions specified

Many drugs that are official in the USP and NF contain varying amounts of water either as BLANK

To make sure that all products fall within BLANK and to ensure product uniformity, it is necessary to specify the water content limits in BLANK

METHODS IN WATER CONTENT DETERMINATION

KARL FISCHER METHOD (3)

It is a reference method and a chemical analysis based on the oxidation of sulfur dioxide by iodine in a methanolic hydroxide solution. The original titrimetric solution (Karl Fischer Reagent) contains sulfur dioxide and iodine dissolved in pyrimidine and methanol. The analyte is to be titrated with the reagent.

If sample solutions are colorless, the endpoint may be observed as a change in color from BLANK (KFM)

The endpoint is more commonly determined electrometrically with an apparatus employing a simple electrical circuit. At the endpoint, a slight increase of current flow is observed. (KFM)

For test preparations, the analyte/specimen shall contain an estimated amount of ---, unless otherwise specified in the individual monograph

If the specimen is an aerosol with propellant, store it in a freezer for NLT 2 hours, open the container, and test 10.0 ml of the well-mixed specimen. In a titration, determine the endpoint at a temperature of 10°C or higher.

If specimen is a capsule, use a portion of the mixed contents of not fewer than 4 capsules.

If specimen is a tablet, use powder from not fewer than 4 tablets ground to a fine powder

If specimen is hygroscopic, dissolve the specimen in a suitable solvent (mostly methanol). Using a syringe, transfer the solution to a titration vessel. Using a 2nd portion of solvent, rinse the container where the specimen was dissolved and add the washing to the titration vessel and immediately proceed to titration.