Apricot Kernel
Armeniacae Semen
Apricot Kernel is the seed of Prunus armeniaca Linnáe, Prunus armeniaca Linnáe var. ansu Maximowicz or Prunus sibirica Linnáe (Rosaceae).
It contains not less than 2.0z of amygdalin, calculated on the basis of dried material.
Description:
Flattened, somewhat asymmetric ovoid seed, 1.1-1.8 cm in length, 0.8-1.3 cm in width, 0.4 -0.7 cm in thickness; sharp at one end and rounded at the other end where chalaza situated; seed coat brown and its surface being powdery with rubbing easily detachable stone cells of epidermis; numerous vascular bundles running from chalaza throughout the seed coat, appearing as thin vertical furrows; seed coat and thin semitransparent white albumen easily separate from cotyledon when soaked in boiling water; cotyledon, white in color. Almost odorless; taste, bitter and oily.
Under a microscope <5.01>, surface of epidermis reveals stone cells on veins protruded by vascular bundles, forming angular circle to ellipse and approximately uniform in shape, with uniformly thickened walls, and 60 . 90 μm in diameter; in lateral view, stone cell appearing obtusely triangular and its wall extremely thickened at the apex.
Identification:
To 1.0 g of ground Apricot Kernel add 10 mL of methanol, immediately heat under a reflux condenser on a water bath for 10 minutes, cool, filter, and use the filtrate as the sample solution. Separately, dissolve 2 mg of amygdalin for thin-layer chromatography in 1 mL of methanol, and use this solution as the standard solution. Perform the test with these solutions as directed under Thin-layer Chromatography. Spot 20 μL each of the sample solution and standard solution on a plate of silica gel for thin-layer chromatography. Develop the plate with a mixture of ethyl acetate, methanol and water (20:5:4) to a distance of about 10 cm, and air-dry the plate. Examine under ultraviolet light (main wavelength: 365 nm): a spot with a bluish white fluorescence appears at around Rf value 0.7. Spray evenly thymol-sulfuric acid-methanol TS for spraying upon the plate, and heat at 105oC for 5 minutes: one of the spot among the several spots from the sample solution has the same color tone and Rf value with the red-brown spot from the standard solution.
Purity:
(1) Rancidity.Grind Apricot Kernel with hot water: no unpleasant odor of rancid oil is perceptible.
(2) Foreign matter. Apricot Kernel does not contain fragments of endocarp and other foreign matter.
Loss on drying:
Not more than 7.0z (6 hours).
Assay:
Weigh accurately 0.5 g of ground Apricot Kernel, add 40 mL of diluted methanol (9 in 10), heat immediately under a reflux condenser on a water bath for 30 minutes, and cool. Filter the mixture, add diluted methanol (9 in 10) to make exactly 50 mL. Pipet 5 mL of this solution, add water to make exactly 10 mL, filter, and use the filtrate as the sample solution. Separately, weigh accurately about 10 mg of amygdalin for assay, previously dried in a desiccator (silica gel) for not less than 24 hours, dissolve in diluted methanol (1 in 2) to make exactly 50 mL, and use this solution as the standard solution. Perform the test with exactly 10 mL each of the sample solution and standard solution as directed under Liquid Chromatography according to the following conditions, and determine the peak areas, AT and AS, of amygdalin.
Amount (mg) of amygdalin ＝ MS × AT/AS× 2
MS: Amount (mg) of amygdalin for assay
Operating conditions.
Detector: An ultraviolet absorption photometer (wave-length: 210 nm).
Column: A stainless steel column 4.6 mm in inside diameter and 15 cm in length, packed with octadecylsilianized silica gel for liquid chromatography (5 mm in particle diameter).
Column temperature: A constant temperature of about 45oC.
Mobile phase: A mixture of 0.05 mol/L sodium dihydrogen phosphate TS and methanol (5:1).
Flow rate: 0.8 mL per minute (the retention time of amygdalin is about 12 minutes).
System suitability.
System performance: When the procedure is run with 10 μL of the standard solution under the above operating conditions, the number of theoretical plates and the symmetry factor of the peak of amygdalin are not less than 5000 and not more than 1.5, respectively.
System repeatability: When the test is repeated 6 times with 10 μL of the standard solution under the above operating conditions, the relative standard deviation of the peak area of amygdalin is not more than 1.5z.
Containers and storage:
Containers.Well-closed containers.
