Powdered Acacia
Gummi Arabicum Pulveratum
Powdered Acacia is the powder
of Acacia.
Description:
Powdered Acacia occurs as a white to light yellowish
white powder. It is odorless, tasteless, but produces a mucilaginous sensation
on the tongue.
Under a microscope, Powdered Acacia,
immersed in olive oil or liquid paraffin, reveals colorless, angular fragments
or nearly globular grains. Usually starch grains or vegetable tissues are not
observed or very trace, if any.
Powdered Acacia (1.0 g)
dissolves almost completely in 2.0 mL of water, and the solution is acid.
It is practically insoluble in
ethanol (95).
Identification:
To 1 g of Powdered Acacia add 25 mL of water and 1
mL of sulfuric acid, and heat under a reflux condenser in a boiling water bath
for 60 minutes. After cooling, add gently 2.0 g of anhydrous sodium carbonate.
To 1 mL of this solution add 9 mL of methanol, mix well, centrifuge, and use
the supernatant liquid as the sample solution. Separately, dissolve 10 mg of D-galactose
in 1 mL water, add methanol to make 10 mL, and use this solution as the standard
solution (1). Proceed with L-arabinose and with L-rhamnose monohydrate in the
same manner as for the preparation of the standard solution (1), and use so
obtained solutions as the standard solution (2) and the standard solution (3),
respectively. Perform the test with these solutions as directed under Thin layer
Chromatography. Spot 10 mL each of
the sample solution and standard solutions (1), (2) and (3) on a plate of
silica gel for thin-layer chromatography. Develop the plate with a mixture of
acetone and water (9:1) to a distance of about 10 cm, and air-dry the plate.
Spray evenly 1-naphthol-sulfuric acid TS on the plate, and heat at 105oC for 5
minutes: the three spots from the sample solution are the same with the spots
of D-galactose, L-arabinose and L-rhamnose from the standard solution in the
color tone and the Rf value, respectively.
Purity:
(1) Insoluble residue.To 5.0 g of Powdered Acacia add 100 mL of
water and 10 mL of dilute hydrochloric acid, and dissolve by gentle boiling for
15 minutes with swirling. Filter the warm mixture through a tared glass filter (G3),
wash the residue thoroughly with hot water, and dry at 105oC for 5 hours: the
mass of the residue does not exceed 10.0 mg.
(2) Tannin-bearing gums.To 10 mL of a solution of Powdered Acacia
(1 in 50) add 3 drops of iron (III) chloride TS: no dark green color is
produced.
(3) Glucose.Dissolve 10 mg of glucose in 1 mL of water, add
methanol to make 10 mL, and use this solution as the standard solution. Proceed
with the sample solution obtained in the Identification and the standard
solution obtained here as directed in the Identification: any spot at the Rf
value corresponding to glucose from the standard solution does not appear from
the sample solution.
Loss on drying:
Not more than 15.0z (6 hours).
Total ash:
Not more than 4.0z.
Acid-insoluble ash:
Not more than 0.5z.
Containers and storage:
Containers.Tight containers.
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