Kaito, T; Tomioka, I; Sagara, K; Ito, Y
For the determination of berberine chloride the two phase titration method with sodium tetraphenylboron has been presented. In this experiment, five basic dyes (i.e., Brilliant Cresyl Blue, Neutral Red, Toluidine Blue, Capri Blue and Nile Blue) and three organic solvents (i.e., ethylene dichloride, chloroform and benzene) were examined at the pH range 8 to 12, and good results were obtained when Brilliant Cresyl Blue was used as an indicator and ethylene dichloride as an organic solvent at pH 11. The proposed method could be applied to determine berberine chloride in pharmaceutical preparations. Coexistent components, such as acrinol, papaverine hydrochloride, carbinoxamine maleate and riboflavin did not interfere. Berberine tannate was determined by this method too, but tannic acid must be removed before the determination by ion-exchange chromatography, because it interfere with the titration. On the determination of berberine content in powdered phellodendron bark by this method, the results obtained agreed well with those by spectrophotometry. The analytical procedures are as follows. (1) Berberine chloride: Transfer 10 ml of the test solution containing about 15∼20 mg of berberine chloride into a glass stoppered 100 ml flask, add 10 ml of Sorensen's buffer solution (pH 11), 0.5 ml of Brilliant Cresyl Blue solution and 10 ml of ethylene dichloride. Shake well and titrate with 0.01M sodium tetraphenylboron until the ethylene dichloride layer changes from red through brown to green. Add the last portions of the sodium tetraphenylboron solution dropwise and agitate vigorously after each addition. Each [Formula omited] (2) Berberine tannate: Dissolve 150 mg of berberine tannate in 50% dimethylformamide and dilute to 200 ml. Pipet 50 ml of this solution into the ionexchange column (Amberlite CG 50 NH4-form) prepared previously, pass the solution through the column, and wash with 50 ml of water. Elute the berberine with 30 ml of 0.5 N NaOH and then with 100 ml of 1 N Na2CO3. Collect the eluate into a 200 ml flask and adjust the pH to 11 with dilute hydro-chloric acid. Proceed to the same procedure described in (1), beginning with “0.5 ml of Brilliant Cresyl Blue solution…‥”. (3) Powdered phellodendron bark: Put 3 g of the sample, dried at 60°C previously, in a Soxhlet extractor, wash with 100 ml of ether for one hour and discard the ether extract. Extract with 100 ml of methanol until the extract in the thimble becomes almost colorless and concentrate the combined methanol extract to on-etenth of the original volume by evaporation. To the concentrated solution add 70 ml of water and 2 g of talc and warm up for a few minutes. After the solution was cooled, filter and dilute with water up to 100 ml. Take 20 ml of this solution and proceed to the same procedure as described in (1), beginning with “add 10 ml of Sorensen's buffer solution (pH 11),…‥”. © 1973, The Japan Society for Analytical Chemistry. All rights reserved.