Gastrodin Gastrodia Extract

[Description] This product is a white or almost white crystalline powder; odorless, with a bitter taste; slightly hygroscopic.

It is readily soluble in water and methanol, soluble in ethanol, and insoluble in chloroform.

Melting point The melting point of this product (Pharmacopoeia Part II Appendix page 15) is 153–156°C.

Specific optical rotation Dissolve the product in water to prepare a solution containing 20 mg per ml, accurately weighed, and determine as directed (Pharmacopoeia Part II Appendix page 17). Calculated on the dried basis, the specific optical rotation is –68° to –72°.

[Tests] Clarity and color of solution Dissolve 0.5 g of the product in 10 ml of water; the solution should be clear and colorless. If turbid, it should not be more pronounced than that of a reference solution [prepared by dissolving 1.0 g of hydrazine in water to 100 ml, allowing to stand for 4–6 hours, taking 25 ml, adding 25 ml of aqueous solution (1→10), allowing to stand for 24 hours, taking 15 ml and diluting with water to 1000 ml, mixing well, taking 10 ml and diluting with 90 ml of water, mixing well]. If colored, it should not be deeper than that of the same volume of yellow standard color solution No. 1 (Pharmacopoeia Part II Appendix page 57, Method 1).

Related substances Dissolve the product in ethanol to prepare a solution containing 5 mg per ml. Apply 5 μl of the solution to a silica gel G thin-layer plate. Develop with chloroform-methanol (7:3) as the developing solvent. After development, air-dry, spray with phosphomolybdic acid ethanol solution (1→10), and heat at 105°C for about 5 minutes. Apart from the deep blue principal spot, no other spots should appear.

Loss on drying When dried to constant weight at 105°C, the loss in weight should not exceed 4.0% (Pharmacopoeia Part II Appendix page 55).

Sulfated ash Not more than 0.2% (Pharmacopoeia Part II Appendix page 56).

[Assay] Dissolve the product in water to prepare a solution containing about 15 μg per ml, accurately weighed. Determine the absorbance at 220 nm by spectrophotometry (Pharmacopoeia Part II Appendix page 24). Calculate the content based on the absorption coefficient (E1%1cm) of C13H18O7 as 337.