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      Centella Tea contains an amount of powdered Centella equivalent to not less than 90.0 per cent and not more than 110.0 per cent of the labelled amounts for the sum of asiaticoside (C₄₈H₇₈O₁₉) and madecassoside (C₄₈H₇₈O₂0), calculated on the dried basis.
Strength available 2 g (powder), supplied in a sachet.
Dose One or two sachets, prepared as an infusion by soaking with 120 to 200 mL of boiling
water for 10 minutes, three times after meals.
Packaging and storage Centella Tea shall be kept in well-closed containers, protected from
light, and stored in a dry place at a temperature not exceeding 30°.
Labelling The label on the container states (1) the amounts for the sum of asiaticoside and
madecassoside; (2) the expiration date.
Identification
     A. The tea contents exhibit diagnos tic structures of the powdered drug described under
Centella.
     B. The tea contents comply with the tests for Identification A, B, C, and D described
under Centella.
     C. The chromatogram of the Assay preparation shows several peaks, two of which
correspond to the asiaticoside and madecassoside peaks of the Standard preparations as
obtained in the Assay.
Loss on drying Of the tea contents, not more than 14.0 per cent w/w after drying at 105º to
constant weight (Appendix 4.15).
Microbial limit Complies with the requirements for Category 2 in the “Limits for Microbial
Contamination” (Appendix 10.5).
Assay Carry out the determination as described in the “Liquid Chromatography” (Appendix 3.5).
     Mobile phase A Use acetonitrile.
     Mobile phase B Use water.
     Standard preparation A Dissolve a suitable quantity of asiaticoside, accurately weighed,
in sufficient methanol to obtain a stock solution having a known concentration of about 250 μg
of asiaticoside per mL. Dilute the solution quantitatively and stepwise with the same solvent
to obtain six solutions having known concentrations ranging from 10 to 60 μg per mL.
     Standard preparation B Dissolve a suitable quantity of madecassoside, accurately
weighed, in sufficient methanol to obtain a stock solution having known concentrations of
about 300 μg of madecassoside per mL. Dilute the solution quantitatively and stepwise with
the same solvent to obtain six solutions having known concentrations ranging from 30 to
180 μg per mL.
     Assay preparation Grind the contents of not less than 20 sachets of Centella Tea to fine
powder. Transfer about 200 mg, accurately weighed, into a 50-mL round-bottomed flask
and add 25 mL of methanol. Heat under a reflux condenser for 1 hour, filter into a 50-mL
volumetric flask, and add the same solvent to volume. Filter through a membrane having
a 0.22-μm porosity.

     Chromatographic system The chromatographic procedure may be carried out using
(a) a stainless steel column (5 cm × 2.1 mm) packed with octadecylsilane chemically bonded to porous silica or ceramic microparticles (1.7 μm), (b) Mobile phase at a flow rate of about
0.6 mL per minute, and (c) an ultraviolet photometer set at 205 nm.
The step gradient of mobile phases is as follows:

     To determine the suitability of the chromatographic system, chromatograph Standard
preparation A and Standard preparation B having known concentrations of 30 μg per mL of
asiaticoside and 90 μg per mL of madecassoside, respectively, and record the peak responses as directed under Procedure and Calculation: the relative standard deviation for replicate injections is not more than 2.0 per cent.
     Procedure Separately inject equal volumes (about 4 μL) of Standard preparation A and
Standard preparation B into the chromatograph, record the chromatograms, and measure
the responses for asiaticoside and madecassoside peaks. Plot the readings and draw the
standard curves of best fit: the curves show the correlation coefficient of not less than 0.999.
Inject about 4 μL of Assay preparation into the chromatograph, record the chromatogram, and
measure the responses for asiaticoside and madecassoside peaks.
     Calculation By reference to the standard curves, calculate the sum of asiaticoside
(C₄₈H₇₈O₁₉) and madecassoside (C₄₈H₇₈O₂₀) contents in the portion of the Tea taken.
Other requirements  Complies with the requirements described under “Herbal Teas”
(Appendix 1.16H).