Page 8 - phytochemistry II -pharmD general

Solubility:

As a general rule:
❑ The free alkaloid bases are
➢ soluble in organic solvents.
➢ sparingly soluble in H2O

❑ Alkaloid salts are
➢ soluble in H2O
➢ sparingly soluble in organic solvents.

❑ Alcohol, dissolve both (bases & salts).

Exceptions:

a) H2O-soluble alk. bases

• Caffeine, and still
• Colchicine Soluble in organic solvents
• Ephedrine
• Pilocarpine

• Quaternary alk and Insoluble in organic solvents
• Alk. N-oxides because they are ionic comp.

b) Alk. bases very sparingly soluble in org. solvent
e.g. Morphine insoluble in CHCL3 & Ether moderately Soluble in alc. (1:300)

c) Alkaloidal salts sol in organic solvents

Lobeline HCl Soluble in CHCl3

d) Alk. salts sparingly soluble in H2O
Quinine sulphate (1:810)

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