Page 476 - Applied Pharmacognosy
P. 476
• Example: Rhubarb
• The % of total ash varies from 8 to 40 % in different samples
of genuine Rhubarb .
• Therefore, a total ash figure is of no value for purposes of
evaluation because it varies within wide limit .
• In case of drugs containing large and variable amounts of Ca
oxalates ; the total ash is treated with dil. HCl and the % of
acid insoluble ash is determined.
• The acid insoluble ash consists mainly of silica.
• A high acid insoluble ash in drugs such as Digitalis,
Hyoscyamus, Liquorice, …..etc.
