(Ph Eur monograph 1070)
1135 68168-23-0 (monohydrate)
Betadex (betacyclodextrin) contains not less than 98.0 per
cent and not more than the equivalent of 101.0 per cent of cyclo-a-(1®4)-D-heptaglucopyranoside, calculated with reference
to the dried substance.
A white or almost white, amorphous or crystalline powder,
sparingly soluble in water, freely soluble in propylene glycol, practically insoluble in
ethanol and in methylene chloride.
complies with the test for specific optical rotation (see Tests).
the chromatograms obtained in the assay. The retention time and size of the principal peak
in the chromatogram obtained with test solution (b) are approximately the same as those of
the principal peak in the chromatogram obtained with reference solution (c).
0.2 g in 2 ml of iodine solution R4 by warming on a water-bath, and allow to stand
at room temperature. A yellowish-brown precipitate is formed.
Dissolve 1.000 g in carbon dioxide-free water R with heating, allow to cool and dilute to
100.0 ml with the same solvent.
Appearance of solution
Solution S is clear (2.2.1).
To 10 ml of solution S add 0.1 ml of a saturated solution of potassium
chloride R. The pH of the solution is 5.0 to 8.0.
Specific optical rotation (2.2.7)
+160 to +164, determined on solution S and calculated with
reference to the dried substance.
To 1 ml of solution S add 1 ml of cupri-tartaric solution
R4. Heat on a water-bath for 10 min, cool to room temperature. Add 10 ml of ammonium
molybdate reagent R1 and allow to stand for 15 min.
Prepare a reference solution at the same time and in the same
manner as the test solution, using 1 ml of a 0.02 g/l solution of glucose R.
Measure the absorbance of the test solution and the reference
solution (2.2.25) at the maximum at 740 nm using water
R as the compensation liquid. The absorbance of the test solution is not
greater than that of the reference solution (0.2 per cent).
Examine solution S between 230 nm and 750 nm (2.2.25). Between
230 nm and 350 nm, the absorbance is not greater than 0.10. Between 350 nm and 750 nm, the
absorbance is not greater than 0.05.
Examine by liquid chromatography (2.2.29), as described under
Assay. Inject separately test solution (a) and reference solution (b). In the chromatogram
obtained with test solution (a): the areas of any peaks corresponding to gammacyclodextrin
and alphacyclodextrin are not greater than half of the area of the corresponding peaks in
the chromatogram obtained with reference solution (b) (0.25 per cent); the sum of the
areas of all the peaks, apart from the principal peak and any peaks corresponding to
alphacyclodextrin and gammacyclodextrin, is not greater than half of the area of the peak
corresponding to betadex in the chromatogram obtained with reference solution (b) (0.5 per
Not more than 10 ppm of trichloroethylene and not more than 10
ppm of toluene. Examine by head-space gas chromatography (2.2.28), using the standard
additions method and ethylene chloride R as the internal standard.
In each of four identical 20 ml flasks, dissolve 500 mg of the
substance to be examined in water R and add 0.10 g of calcium chloride R and 30 ml of a-amylase
solution R. Add 1 ml of reference solutions (a), (b), (c) and (d), adding a different
solution to each flask. Dilute to 10 ml with water
Prepare reference solution (a) containing 10 ml of ethylene
chloride R per litre. From reference solution (a), prepare reference solutions (b),
(c) and (d) containing per litre: 5 ml, 10 ml and 15 ml each of trichloroethylene R
and of toluene R.
The chromatographic procedure may be carried out using:
a fused-silica column 25m long and 0.32 mm in internal
diameter coated with a layer about 1 mm thick of macrogol 20 000 R,
helium for chromatography R as the
a flame-ionisation detector,
maintaining the temperature of the column at 50C, that of
the injection port at 140C and that of the detector at 280C. Place the samples in a
thermostated chamber at 45C for 2 h. Inject 200 ml of the head-space of each flask and
repeat each test at least three times. The retention time of toluene is about 10 min. The
test is not valid unless: the resolutions between the peaks corresponding to
trichloroethylene and toluene and between the peaks corresponding to toluene and ethylene
chloride are greater than 1.1 and the relative standard deviations of the ratios of the
areas of the peaks corresponding to trichloroethylene and toluene to that of the peak
corresponding to ethylene chloride are less than 5 per cent.
Calculate the content of trichloroethylene and of toluene
taking their relative densities to be 1.46 and 0.87, respectively.
Heavy metals (2.4.8)
1.0 g complies with limit test C for heavy metals (10 ppm).
Prepare the standard using 1 ml of lead standard solution (10 ppm Pb) R.
Loss on drying (2.2.32)
Not more than 16.0 per cent, determined on 1.000 g by drying
in an oven at 120C for 2 h.
Sulphated ash (2.4.14)
Not more than 0.1 per cent, determined on 1.0 g.
Examine by liquid chromatography (2.2.29).
Test solution (a)
Dissolve 0.25 g of the substance to be examined in water R with heating, cool and dilute to 25.0 ml
with the same solvent.
Test solution (b)
Dilute 5.0 ml of test solution (a) to 50.0 ml with water R.
Reference solution (a)
Dissolve 25.0 mg of alfadex CRS, 25.0 mg of gammacyclodextrin
CRS and 50.0 mg of betadex CRS in water R and dilute to 50.0 ml with the same solvent.
Reference solution (b)
Dilute 5.0 ml of reference solution (a) to 50.0 ml with water R.
Reference solution (c)
Dissolve 25.0 mg of betadex CRS in water R and dilute to 25.0 ml with the same solvent.
The chromatographic procedure may be carried out using:
a stainless steel column 0.25 m long and 4.6 mm in internal
diameter packed with octadecylsilyl silica gel for chromatography R (10 mm),
as mobile phase at a flow rate of 1.5 ml/min a mixture of 10
volumes of methanol R and 90 volumes
of water R,
as detector a differential refractometer,
a 50 ml loop injector.
Equilibrate the column with the mobile phase at a flow rate of
1.5 ml/min for about 3 h. Inject each solution. Record the chromatograms for 1.5 times the
retention time of betadex. Adjust the sensitivity of the detector so that the height of
the peak corresponding to gammacyclodextrin, in the chromatogram obtained with reference
solution (a), is 55 per cent to 75 per cent of the full scale of the recorder. The
retention time of betadex is about 10 min, the relative retention time of
gammacyclodextrin is about 0.3 and that of alfadex is about 0.45. The test is not valid
unless the resolution between the peaks corresponding to gammacyclodextrin and alfadex is
not less than 1.5, and the relative standard deviation of the area of the peak
corresponding to betadex is less than 2.0 per cent. If necessary, adjust the concentration
of methanol in the mobile phase to achieve the required resolution. Calculate the
percentage content of [C6H10O5]7 from the area
of the principal peak in each of the chromatograms obtained with test solution (b) and
reference solution (c) and the declared content of betadex CRS.
Store in an airtight container .
= 6: alfadex,
= 8: gammacyclodextrin.
Action and use