【Characters】Colorless crystalline powder; No odor, bitter taste.
This product is dissolved in boiling ethanol, slightly dissolved in methanol or ethanol, very slightly dissolved in chloroform, and almost insoluble in water.
The melting point should be 226-230℃, and it will decompose at the same time when melting.
【Identify】
(1)Take about 10mg of this product, add 2ml of ethanol to dissolve it, and add 2 drops each of 2% ethanol solution of 3, 5-dinitrobenzoic acid and 5% ethanol solution of potassium hydroxide respectively, and shake well to show purple red color.
(2)Take about 10mg of this product, add 2ml ethanol to dissolve it, add 2 ~ 3 drops of potassium hydroxide test solution made by ethanol, gradually show red, and turn yellow after placement.
(3)Take this product, add anhydrous ethanol to make a solution containing 10ug per 1ml, detecting according to uV-visible spectrophotometry, there is maximum absorption in the wavelength of 224nm.
【Inspection】
Other lactones: Take this product, add absolute ethanol to make a solution containing 2mg per 1ml as the test solution. Testing according to thin layer chromatography (general rule 0502), draw 10μl of the above solution, spot it on the silica gel G thin layer plate, and take chloroform-methanol (19:1) as the developing agent, unfold, take out, dry, and spray with equal amount of mixture (pre-use preparation) with 2% ethanol solution of 3,5-Dinitrobenzoic acid and 5% ethanol solution of potassium hydroxide. In the chromatogram of the test product, no other spots shall be displayed except the main spot.
Loss on drying: Take this product and dry it to constant weight at 105°C. The weight loss should not exceed 1.0%.
Residue on ignition: shall not exceed 0.1%.
【Content Detection】According to HPLC.
The content of andrographolide C20H30O5 should be 95.0%--101.0%.
Chromatographic Conditions and System Suitability Test:
Take octadecylsilane bonded silica gel as filler, the methanol-water (52:48) as mobile phase, and detection wavelength as 225nm, the number of theoretical plate should not be less than 5000 calculated based on the peak of andrographolide.
Preparation of Reference Solution:
Take appropriate amount reference substance of andrographolide and dehydrated andrographolide, accurately weigh, and add methanol to make a mixed solution each containing 0.1 mg per 1 ml, then get it.
Preparation of Test Solution:
Take about 25mg of this product, accurately weigh it, and put it in a 50ml measuring flask, then add methanol to dissolve and dilute to the mark and shake well. Accurately measure 5ml, place it in a 25ml measuring flask, then add methanol to dilute to the mark, shake well, and get it.
Dection Method:
Precisely draw 10 μl each of the reference solution and the test solution, and inject them into the HPLC instrument for determination, then get it.
Calculated as a dried product, the content of andrographolide (C20H30O5) should be 95.0% to 101.0%.