» Sennosides is a partially purified natural complex of anthraquinone glucosides, isolated from senna leaflets and/or senna pods, Senna alexandrina Mill (Cassia acutifolia or C. angustifolia), as calcium salts. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of sennosides. The labeled amount is not less than 60.0 percent (w/w), calculated on the dried basis.
Packaging and storage Preserve in well-closed containers. Store protected from light and moisture, at controlled room temperature.
Identification Place equal volumes of ethyl acetate, n-propyl alcohol, and water in a separator, shake, and discard the upper layer. Add a sufficient quantity of Sennosides to obtain a solution having a concentration of 1 mg per mL. Prepare similarly a Standard solution of USP Sennosides RS. Apply 20-µL portions of each solution, as 1-cm streaks, on a line about 2.5 cm from the bottom edge of a thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Develop the chromatogram in a solvent system consisting of a mixture of ethyl acetate, n-propyl alcohol, and water (4:4:3) until the solvent front has moved about 15 cm. Remove the plate from the developing chamber, air-dry, and examine under long-wavelength UV light. Expose the plate to ammonium hydroxide vapor until color develops (about 5 minutes). Cover the plate with a piece of glass, and heat at 120 for 5 minutes: the 2 most prominent spots from the test solution corresponds in color and mobility to those from the Standard solution.
pH 791: between 6.3 and 7.3, in a solution (1 in 10).
Loss on drying 731 Dry it in vacuum at 100 to constant weight: it loses not more than 5.0% of its weight.
Residue on ignition 281: between 5.0% and 8.0%, ignited at 800 ± 25, the use of sulfuric acid being omitted.
Heavy metals, Method II 231: 0.006%.
pH 7.0 phosphate buffer Dissolve 4.54 g of monobasic potassium phosphate in water to make 500 mL of solution. Dissolve 4.73 g of anhydrous dibasic sodium phosphate in water to make 500 mL of solution. Mix 38.9 mL of the monobasic potassium phosphate solution with 61.1 mL of the dibasic sodium phosphate solution. Adjust dropwise, if necessary, with the dibasic sodium phosphate solution to a pH of 7.0.
Borate solution Dissolve 75.80 g of sodium borate in water, dilute with water to 2000 mL, and mix.
Sodium dithionite solution Prepare a 1.5 in 100 solution of sodium dithionite in water.
Standard preparation Dissolve about 25 mg of USP Sennosides RS, accurately weighed, in pH 7.0 phosphate buffer in a 25-mL volumetric flask with the aid of an ultrasonic bath, dilute with pH 7.0 phosphate buffer to volume, and mix.
Assay preparation Dissolve about 25 mg of Sennosides, accurately weighed, in pH 7.0 phosphate buffer in a 25-mL volumetric flask, with the aid of an ultrasonic bath, dilute with pH 7.0 phosphate buffer to volume, and mix.
Procedure Pipet 1-mL portions of the Standard preparation and the Assay preparation into separate 100-mL volumetric flasks, dilute with Borate solution to volume, and mix. Transfer 5.0-mL portions of each of the resulting solutions to separate low-actinic glass, 50-mL volumetric flasks, and add 15 mL of Borate solution and 15.0 mL of Sodium dithionite solution. Pass nitrogen through the solutions, seal the flasks with nitrogen-filled balloons, and heat in a water bath for 30 minutes. Cool the flasks for 15 minutes in a water bath thermostatically controlled at 20. Dilute the solutions with Borate solution to volume, and mix. Determine without delay the fluorescence intensities of the resulting solutions in a fluorometer at an excitation wavelength of 392 nm and an emission wavelength of 505 nm, the time elapsed between the addition of the Sodium dithionite solution and the measurement being the same for the two solutions. Calculate the quantity, in mg, of sennosides in the Sennosides taken by the formula:
25C(IU / IS)in which C is the concentration, in mg per mL, of USP Sennosides RS, corrected for loss on drying, in the Standard preparation, and IU and IS are the fluorescence values observed for the solutions from the Assay preparation and the Standard preparation, respectively.
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USP32NF27 Page 3551Pharmacopeial Forum: Volume No. 32(1) Page 141