This product is a cyclic oligosaccharide composed of seven glucose units linked by α-1,4-glycosidic bonds, produced by the action of cyclodextrin glucosyltransferase on starch. Calculated on the dried basis, it contains (C6H10O5)7 not less than 98.0% and not more than 102.0%.     【Description】  This product appears as white crystals or a crystalline powder; odorless, with a slightly sweet taste.   

This product is slightly soluble in water.     Specific optical rotation: Dissolve a precisely weighed quantity in water to prepare a solution containing about 10mg per ml, and determine as directed (General Chapter 0621); the specific optical rotation is between +159° and +164°. 

            【Identification】 (1) Dissolve about 0.2g of the product in 2ml of iodine test solution by heating in a water bath, then cool; a yellowish-brown precipitate is produced.     (2) In the chromatogram obtained in the Assay, the retention time of the principal peak in the test solution corresponds to that of the principal peak in the reference solution.     (3) The infrared absorption spectrum of the product corresponds to that of the reference substance (General Chapter 0402).     

              【Tests】  Absorbance of impurities  Dissolve about 1g, accurately weighed, in 100ml of water, and determine by ultraviolet-visible spectrophotometry (General Chapter 0401); the absorbance in the wavelength range of 230-350nm should not exceed 0.10, and in the range of 350-750nm should not exceed 0.05.   

                Acidity or alkalinity  Dissolve 0.20g in 20ml of water, add 0.2ml of saturated potassium chloride solution, and determine as directed (General Chapter 0631); the pH should be between 5.0 and 8.0.     Clarity and color of solution  Dissolve 0.50g in 50ml of water, and examine as directed (General Chapters 0901 and 0902); the solution should be clear and colorless. If opalescence is observed, it should not be more intense than that of Reference Suspension No. 2 (General Chapter 0902, Method I).     Chloride  Dissolve 0.39g and prepare as directed (General Chapter 0801); when compared with a control solution prepared from 7.0ml of standard sodium chloride solution, the result should not be more intense (0.018%).     Reducing sugars  Dissolve 1.0g, accurately weighed, in 25ml of water, add 40ml of alkaline cupric tartrate test solution, boil gently for 3 minutes, and allow to stand overnight at room temperature. Filter through a No. 4 sintered-glass funnel, wash the precipitate with warm water until the washings are neutral, discard the filtrate and washings. Dissolve the precipitate in 20ml of hot iron test solution, filter, wash the filter with 100ml of water, combine the filtrate and washings, heat to 60°C, and titrate while hot with titrant (0.02mol/L). Calculated on the dried basis, not more than 3.2ml of titrant (0.02mol/L) is consumed per 1g (1.0%).     

               Cyclohexane  Accurately weigh about 0.2g of the product into a headspace vial, add 10.0ml of internal standard solution (prepare by dissolving a suitable amount of dichloroethane in 20% dimethyl sulfoxide solution to obtain a solution containing about 0.04μg per ml), as the test solution. Separately, accurately weigh cyclohexane and prepare a solution with the internal standard solution containing about 0.078mg of cyclohexane per ml, pipette 10.0ml into a headspace vial as the reference solution. Perform the test for residual solvents (General Chapter 0861) using a capillary column with 100% dimethylpolysiloxane as the stationary phase; column temperature 90°C; inlet temperature 200°C; detector temperature 250°C; headspace vial equilibrium temperature 70°C, equilibrium time 20 minutes. Inject the headspace of the reference solution; the resolution between peaks should meet the requirements. Inject the headspace of the test solution and the reference solution separately, record the chromatograms, and calculate by the internal standard method using peak areas; the result should comply with the specification. Loss on drying  Dry the product at 105°C to constant weight; the loss in weight should not exceed 14.0% (General Chapter 0831). Residue on ignition  Ignite 1.0g as directed (General Chapter 0841); the residue should not exceed 0.1%. Heavy metals  Using the residue from the residue on ignition test, determine as directed (General Chapter 0821, Method II); the content of heavy metals should not exceed 10 parts per million.     

Perform microbial limit tests as directed (General Chapters 1105 and 1106); the total aerobic microbial count should not exceed 1000 cfu per gram, the total combined yeasts and molds count should not exceed 100 cfu per gram, and Escherichia coli should be absent. 

【Assay】  Determine by high-performance liquid chromatography (General Chapter 0512).     Chromatographic system and suitability  Use a column packed with octadecylsilane-bonded silica gel; a mixture of water and methanol (85:15) as the mobile phase; and a differential refractive index detector. The number of theoretical plates for the betacyclodextrin peak is not less than 1500.     Procedure  Accurately weigh about 50mg of the product, place in a 10ml volumetric flask, dissolve in and dilute with water to volume, and mix well as the test solution. Precisely inject 10μl into the liquid chromatograph, and record the chromatogram. Separately, accurately weigh about 50mg of betacyclodextrin reference standard, and prepare and inject in the same manner. Calculate by the external standard method using peak areas.

【Category】  Pharmaceutical excipient, used as a complexing agent and stabilizer, etc.     

【Storage】  Preserve in a well-closed container, stored in a dry place.