3.1.3. Polyolefines
EUROPEAN PHARMACOPOEIA 5.0
Verify the absence of tin in the sulphuric acid used.
Heavy metals (2.4.8). To 10 ml of solution S1 add 0.5 ml
of phenolphthalein solution R and then strong sodium
hydroxide solution R until a pale pink colour is obtained.
Dilute to 25 ml with water R. 12 ml of the solution complies
with limit test A for heavy metals (50 ppm). Prepare the
standard using lead standard solution (2 ppm Pb) R.
ASSAY
To 0.500 g add 30 ml of tetrahydrofuran R and heat with
stirring on a water-bath under a hood for 10 min. The
material dissolves completely. Add 60 ml of methanol R
dropwise with stirring. A granular precipitate of poly(vinyl
chloride) is formed. Allow to stand for a few minutes.
Continue addition of methanol R until no further
precipitation is observed. Transfer to a sintered-glass filter
(40), using three small quantities of methanol R to aid
transfer and to wash the precipitate. Dry the filter and the
precipitate to constant mass at 60 °C and weigh.
In addition, carry out the following tests on sterilised sets.
Solution S3. Make a closed circulation system from three
sets and a 300 ml borosilicate-glass vessel. Fit to the vessel
a thermostat device that maintains the temperature of
the liquid in the vessel at 37 ± 1 °C. Circulate 250 ml of
water for injections R through the system in the direction
used for transfusion for 2 h at a rate of 1 litre per hour (for
example using a peristaltic pump applied to as short a piece
of suitable silicone tubing as possible). Collect the whole of
the solution and allow to cool.
Appearance of solution. Solution S3 is clear (2.2.1) and
colourless (2.2.2, Method II).
Acidity or alkalinity. To 25 ml of solution S3 add 0.15 ml of
BRP indicator solution R. Not more than 0.5 ml of 0.01 M
sodium hydroxide is required to change the colour of the
indicator to blue. To 25 ml of solution S3 add 0.2 ml of
methyl orange solution R. Not more than 0.5 ml of 0.01 M
hydrochloric acid is required to initiate the colour change
of the indicator from yellow to orange.
Absorbance (2.2.25). Examined from 230 nm to 250 nm,
solution S3 shows no absorbance greater than 0.30.
Examined from 251 nm to 360 nm, solution S3 shows no
absorbance greater than 0.15.
Reducing substances. Carry out the test within 4 h of
preparation of solution S3. To 20.0 ml of solution S3 add 1 ml
of dilute sulphuric acid R and 20.0 ml of 0.002 M potassium
permanganate. Boil for 3 min and cool immediately. Add
1 g of potassium iodide R and titrate with 0.01 M sodium
thiosulphate using 0.25 ml of starch solution R as indicator.
Carry out a blank test using 20 ml of water for injections R.
The difference between the titration volumes is not greater
than 2.0 ml.
Water extractable substances. Evaporate 50.0 ml of solution
S3 to dryness on a water-bath and dry to constant mass in
an oven at 100 °C to 105 °C. Carry out a blank test using
50.0 ml of water for injections R. The residue obtained with
solution S3 is not greater than 1.5 mg, taking account of
the blank test.
274
01/2005:30103
3.1.3. POLYOLEFINES
DEFINITION
Polyolefines are obtained by polymerisation of ethylene or
propylene or by copolymerisation of these substances with
not more than 25 per cent of higher homologues (C4 to C10)
or of carboxylic acids or of esters. Certain materials may be
mixtures of polyolefines.
PRODUCTION
A certain number of additives are added to the polymer in
order to optimise their chemical, physical and mechanical
properties in order to adapt them for the intended use. All
of these additives are chosen from the appended list which
specifies for each product the maximum allowable content.
They may contain at most 3 antioxidants, one or several
lubricants or antiblocking agents as well as titanium dioxide
as an opacifying agent when the material must provide
protection from light.
— butylhydroxytoluene (plastic additive 07) (not more than
0.125 per cent),
— pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4hydroxyphenyl)propionate] (plastic additive 09) (not more
than 0.3 per cent),
— 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,
6(1H,3H,5H)-trione, (plastic additive 13) (not more than
0.3 per cent),
— octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate
(plastic additive 11) (not more than 0.3 per cent),
— ethylene bis[3,3-bis[3-(1,1-dimethylethyl)-4hydroxyphenyl]butanoate] (plastic additive 08) (not more
than 0.3 per cent),
— dioctadecyl disulphide (plastic additive 15) (not more
than 0.3 per cent),
— 4,4′,4″-(2,4,6-trimethylbenzene-1,3,5-triyltrismethylene)trio[2,6-bis(1,1-dimethylethyl)phenol] (plastic
additive 10) (not more than 0.3 per cent),
— 2,2′-bis(octadecyloxy)-5,5′-spirobi[1,3,2dioxaphosphinane] (plastic additive 14) (not more
than 0.3 per cent),
— didodecyl 3,3′-thiodipropionate (plastic additive 16) (not
more than 0.3 per cent),
— dioctadecyl 3,3′-thiodipropionate (plastic additive 17) (not
more than 0.3 per cent),
— tris[2,4-bis(1,1-dimethylethyl)phenyl] phosphite (plastic
additive 12) (not more than 0.3 per cent),
— plastic additive 18 (not more than 0.1 per cent),
— copolymer of dimethyl succinate and (4-hydroxy-2,2,6,6tetramethylpiperidin-1-yl)ethanol (plastic additive 22) (not
more than 0.3 per cent).
The total of antioxidant additives listed above does not
exceed 0.3 per cent.
— hydrotalcite (not more than 0.5 per cent),
— alkanamides (not more than 0.5 per cent),
— alkenamides (not more than 0.5 per cent),
— sodium silico-aluminate (not more than 0.5 per cent),
— silica (not more than 0.5 per cent),
— sodium benzoate (not more than 0.5 per cent),
— fatty acid esters or salts (not more than 0.5 per cent),
— trisodium phosphate (not more than 0.5 per cent),
— liquid paraffin (not more than 0.5 per cent),
— zinc oxide (not more than 0.5 per cent),
See the information section on general monographs (cover pages)
EUROPEAN PHARMACOPOEIA 5.0
3.1.3. Polyolefines
TESTS
If necessary, cut samples of the material to be examined
into pieces of maximum dimension on a side of not greater
than 1 cm.
Solution S1. Use solution S1 within 4 h of preparation.
Place 25 g in a borosilicate-glass flask with a ground-glass
neck. Add 500 ml of water for injections R and boil under a
reflux condenser for 5 h. Allow to cool and decant. Reserve
a portion of the solution for the test for appearance of
solution S1 and filter the rest through a sintered-glass
filter (16).
Solution S2. Place 2.0 g in a conical borosilicate-glass flask
with a ground-glass neck. Add 80 ml of toluene R and boil
under a reflux condenser with constant stirring for 90 min.
Allow to cool to 60 °C and add with continued stirring 120 ml
of methanol R. Filter the solution through a sintered-glass
filter (16). Rinse the flask and the filter with 25 ml of a
mixture of 40 ml of toluene R and 60 ml of methanol R, add
the rinsings to the filtrate and dilute to 250 ml with the same
mixture of solvents. Prepare a blank solution.
Solution S3. Place 100 g in a conical borosilicate-glass flask
with a ground-glass neck. Add 250 ml of 0.1 M hydrochloric
acid and boil under a reflux condenser with constant stirring
for 1 h. Allow to cool and decant the solution.
Appearance of solution S1. Solution S1 is clear (2.2.1) and
colourless (2.2.2, Method II).
Acidity or alkalinity. To 100 ml of solution S1, add 0.15 ml
of BRP indicator solution R. Not more than 1.5 ml of 0.01 M
sodium hydroxide is required to change the colour of the
indicator to blue. To 100 ml of solution S1 add 0.2 ml of
methyl orange solution R. Not more than 1 ml of 0.01 M
hydrochloric acid is required to initiate the colour change
of the indicator from yellow to orange.
Absorbance (2.2.25). At wavelengths from 220 nm to
340 nm, the absorbance of solution S1 is not greater
than 0.2.
Reducing substances. To 20 ml of solution S1 add 1 ml of
dilute sulphuric acid R and 20 ml of 0.002 M potassium
permanganate. Boil under a reflux condenser for 3 min
and cool immediately. Add 1 g of potassium iodide R and
titrate immediately with 0.01 M sodium thiosulphate, using
0.25 ml of starch solution R as indicator. Carry out a blank
titration. The difference between the titration volumes is
not more than 3.0 ml.
Substances soluble in hexane. Place 10 g in a 250 ml
conical borosilicate-glass flask with a ground-glass neck. Add
100 ml of hexane R and boil under a reflux condenser for
4 h, stirring constantly. Cool in iced water and filter rapidly
(the filtration time must be less than 5 min ; if necessary the
filtration may be accelerated by applying pressure to the
solution) through a sintered-glass filter (16) maintaining
the solution at about 0 °C. Evaporate 20 ml of the filtrate
in a tared borosilicate-glass dish on a water-bath. Dry the
residue in an oven at 100-105 °C for 1 h. The mass of the
residue obtained must be within 10 per cent of that of the
residue obtained with the type sample and does not exceed
5 per cent.
Extractable aluminium. Not more than 1 ppm of extractable
Al, determined by atomic emission spectrometry in an argon
plasma (2.2.22, Method I).
Test solution. Use solution S3.
Reference solutions. Prepare the reference solutions using
aluminium standard solution (200 ppm Al) R, diluted with
0.1 M hydrochloric acid.
Carry out the determination using the emission of aluminium
at 396.15 nm, the spectral background being taken as
396.25 nm.
Verify the absence of aluminium in the hydrochloric acid
used.
Extractable titanium. Not more than 1 ppm of extractable
Ti, determined by atomic emission spectrometry in an argon
plasma (2.2.22, Method I).
Test solution. Use solution S3.
Reference solutions. Prepare the reference solutions using
titanium standard solution (100 ppm Ti) R, diluted with
0.1 M hydrochloric acid.
Carry out the determination using the emission of titanium
at 336.12 nm, the spectral background being taken as
336.16 nm.
Verify the absence of titanium in the hydrochloric acid used.
Extractable zinc. Not more than 1 ppm of extractable Zn,
determined by atomic absorption spectrometry (2.2.23,
Method I).
Test solution. Use solution S3.
General Notices (1) apply to all monographs and other texts
275
— talc (not more than 0.5 per cent),
— magnesium oxide (not more than 0.2 per cent),
— calcium stearate or zinc stearate or a mixture of both (not
more than 0.5 per cent),
— titanium dioxide (not more than 4 per cent).
The supplier of the material must be able to demonstrate
that the qualitative and quantitative composition of the type
sample is satisfactory for each production batch.
CHARACTERS
Powder, beads, granules or, after transformation, sheets
of varying thickness or containers. They are practically
insoluble in water, soluble in hot aromatic hydrocarbons,
practically insoluble in ethanol, in hexane and in methanol.
They soften at temperatures between 65 °C and 165 °C.
They burn with a blue flame.
IDENTIFICATION
If necessary, cut samples of the material to be examined
into pieces of maximum dimension on a side of not greater
than 1 cm.
A. To 0.25 g add 10 ml of toluene R and boil under a
reflux condenser for about 15 min. Place a few drops
of the solution obtained on a sodium chloride slide and
evaporate the solvent in an oven at 80 °C. Examine by
infrared absorption spectrophotometry (2.2.24). The
spectrum of the material to be examined shows maxima
in particular at some of the following wave-numbers :
2920 cm− 1, 2850 cm− 1, 1475 cm− 1, 1465 cm− 1, 1380 cm− 1,
1170 cm− 1, 735 cm− 1, 720 cm− 1 ; the spectrum obtained
is identical to the spectrum obtained with the material
selected for the type sample. If the material to be
examined is in the form of sheets, the identification may
be determined directly on a cut piece of suitable size.
B. It complies with the supplementary tests corresponding
to the additives present.
C. In a platinum crucible, mix about 20 mg with 1 g of
potassium hydrogen sulphate R and heat until completely
melted. Allow to cool and add 20 ml of dilute sulphuric
acid R. Heat gently. Filter the resulting solution. To
the filtrate add 1 ml of phosphoric acid R and 1 ml of
strong hydrogen peroxide solution R. If the substance is
opacified with titanium dioxide, an orange-yellow colour
develops.
3.1.3. Polyolefines
EUROPEAN PHARMACOPOEIA 5.0
Reference solutions. Prepare the reference solutions using
zinc standard solution (10 ppm Zn) R, diluted with 0.1 M
hydrochloric acid.
Measure the absorbance at 213.9 nm using a zinc
hollow-cathode lamp as a source of radiation and an
air-acetylene flame.
Verify the absence of zinc in the hydrochloric acid used.
Extractable heavy metals (2.4.8). Evaporate 50 ml of
solution S3 to about 5 ml on a water-bath and dilute to
20.0 ml with water R. 12 ml of the solution complies with
limit test A for heavy metals (2.5 ppm). Prepare the standard
using 2.5 ml of lead standard solution (10 ppm Pb) R.
Sulphated ash (2.4.14). Not more than 1.0 per cent,
determined on 5.0 g. This limit does not apply to material
that has been opacified with titanium dioxide.
SUPPLEMENTARY TESTS
These tests are to be carried out, in whole or in part, only
if required by the stated composition or the use of the
material.
Phenolic antioxidants. Examine by liquid chromatography
(2.2.29).
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 (5 µm),
— as mobile phase one of the 4 following mixtures :
Mobile phase 1 at a flow rate of 2 ml/min : 30 volumes of
water R, 70 volumes of acetonitrile R,
Mobile phase 2 at a flow rate of 1.5 ml/min : 10 volumes
of water R, 30 volumes of tetrahydrofuran R, 60 volumes
of acetonitrile R,
Mobile phase 3 at a flow rate of 1.5 ml/min : 5 volumes
of water R, 45 volumes of 2-propanol R, 50 volumes of
methanol R,
Mobile phase 4 at a flow rate of 1.5 ml/min : 20 volumes
of tetrahydrofuran R, 80 volumes of acetonitrile R,
— as detector a spectrophotometer set at 280 nm for mobile
phases 1 to 3, and set at 270 nm for mobile phase 4.
The chromatographic system must ensure the following :
— a resolution of not less than 8.0 between the peaks
corresponding to plastic additive 07 and plastic
additive 08, with mobile phase 1,
— a resolution of not less than 2.0 between the peaks
corresponding to plastic additive 09 and plastic
additive 10, with mobile phase 2,
— a resolution of not less than 2.0 between the peaks
corresponding to plastic additive 11 and plastic
additive 12, with mobile phase 3,
— a resolution of not less than 6.0 between the 2 principal
peaks (approximate retention times of 3.5 and 5.8) in the
chromatogram obtained with plastic additive 18, with
mobile phase 4.
Test solution S21. Evaporate 50 ml of solution S2 to
dryness in vacuo at 45 °C. Dissolve the residue in 5.0 ml
of a mixture of equal volumes of acetonitrile R and
tetrahydrofuran R. Prepare a blank solution from the blank
solution corresponding to solution S2.
Test solution S22. Evaporate 50 ml of solution S2 to dryness
in vacuo at 45 °C. Dissolve the residue with 5.0 ml of
methylene chloride R. Prepare a blank solution from the
blank solution corresponding to solution S2.
Test solution S23. Evaporate 50 ml of solution S2 to dryness
in vacuo at 45 °C. Dissolve the residue in 5.0 ml of a mixture
of equal volumes of acetonitrile R and a 10 g/l solution of
276
tert-butylhydroperoxide R in tetrahydrofuran R. Close the
flask and allow to stand for 1 h. Prepare a blank solution
using the blank of solution S2.
Of the following reference solutions, prepare only those that
are necessary for the analysis of the phenolic antioxidants
stated in the composition of the substance to be examined.
Reference solution (a). Dissolve 25.0 mg of
butylhydroxytoluene CRS (plastic additive 07) and
60.0 mg of plastic additive 08 CRS in 10.0 ml of a mixture
of equal volumes of acetonitrile R and tetrahydrofuran R.
Dilute 2.0 ml to 50.0 ml with a mixture of equal volumes of
acetonitrile R and tetrahydrofuran R.
Reference solution (b). Dissolve 60.0 mg of plastic
additive 09 CRS and 60.0 mg of plastic additive 10 CRS in
10.0 ml of a mixture of equal volumes of acetonitrile R and
tetrahydrofuran R. Dilute 2.0 ml to 50.0 ml with a mixture
of equal volumes of acetonitrile R and tetrahydrofuran R.
Reference solution (c). Dissolve 60.0 mg of plastic
additive 11 CRS and 60.0 mg of plastic additive 12 CRS in
10.0 ml of methylene chloride R. Dilute 2.0 ml to 50.0 ml
with methylene chloride R.
Reference solution (d). Dissolve 25.0 mg of plastic
additive 07 CRS in 10.0 ml of a mixture of equal volumes
of acetonitrile R and tetrahydrofuran R. Dilute 2.0 ml to
50.0 ml with a mixture of equal volumes of acetonitrile R
and tetrahydrofuran R.
Reference solution (e). Dissolve 60.0 mg of plastic
additive 08 CRS in 10.0 ml of a mixture of equal volumes
of acetonitrile R and tetrahydrofuran R. Dilute 2.0 ml to
50.0 ml with a mixture of equal volumes of acetonitrile R
and tetrahydrofuran R.
Reference solution (f). Dissolve 60.0 mg of plastic
additive 13 CRS in 10.0 ml of a mixture of equal volumes
of acetonitrile R and tetrahydrofuran R. Dilute 2.0 ml to
50.0 ml with a mixture of equal volumes of acetonitrile R
and tetrahydrofuran R.
Reference solution (g). Dissolve 60.0 mg of plastic
additive 09 CRS in 10.0 ml of a mixture of equal volumes
of acetonitrile R and tetrahydrofuran R. Dilute 2.0 ml to
50.0 ml with a mixture of equal volumes of acetonitrile R
and tetrahydrofuran R.
Reference solution (h). Dissolve 60.0 mg of plastic
additive 10 CRS in 10.0 ml of a mixture of equal volumes
of acetonitrile R and tetrahydrofuran R. Dilute 2.0 ml to
50.0 ml with a mixture of equal volumes of acetonitrile R
and tetrahydrofuran R.
Reference solution (i). Dissolve 60.0 mg of plastic
additive 11 CRS in 10.0 ml of methylene chloride R. Dilute
2.0 ml to 50.0 ml with methylene chloride R.
Reference solution (j). Dissolve 60.0 mg of plastic
additive 12 CRS in 10.0 ml of methylene chloride R. Dilute
2.0 ml to 50.0 ml with methylene chloride R.
Reference solution (k). Dissolve 20.0 mg of plastic
additive 18 CRS in 10.0 ml of a mixture of equal
volumes of acetonitrile R and a 10 g/l solution of
tert-butylhydroperoxide R in tetrahydrofuran R. Allow to
stand in a closed container for 1 h. Dilute 2.0 ml of the
solution to 50.0 ml with a mixture of equal volumes of
acetonitrile R and tetrahydrofuran R.
If the substance to be examined contains plastic additive 07
and/or plastic additive 08, use mobile phase 1 and inject
20 µl of test solution S21, 20 µl of the corresponding blank
solution, 20 µl of reference solution (a), and either 20 µl each
of reference solutions (d) or (e) or 20 µl each of reference
solutions (d) and (e).
See the information section on general monographs (cover pages)
EUROPEAN PHARMACOPOEIA 5.0
3.1.3. Polyolefines
If the substance to be examined contains one or more of the
following antioxidants :
— plastic additive 09,
— plastic additive 10,
— plastic additive 11,
— plastic additive 12,
— plastic additive 13,
use mobile phase 2 and inject 20 µl of test solution S21,
20 µl of the corresponding blank solution, 20 µl of reference
solution (b) and 20 µl of each of the reference solutions
of the antioxidants on the list above that are stated in the
composition.
If the substance to be examined contains plastic additive 11
and/or plastic additive 12, use mobile phase 3 and inject
20 µl of test solution S22, 20 µl of the corresponding blank
solution, 20 µl of reference solution (c), and either 20 µl of
reference solution (i) or (j) or 20 µl of reference solutions
(i) and (j).
If the substance to be examined contains plastic additive 18,
use mobile phase 4 and inject 20 µl of test solution S23,
20 µl of the corresponding blank solution, and 20 µl of
reference solution (k).
In all cases, record the chromatogram for 30 min ; the
chromatograms corresponding to test solutions S21, S22
and S23 only show peaks due to antioxidants stated in
the composition and minor peaks that also appear in the
chromatograms corresponding to the blank solutions. The
areas of the peaks corresponding to test solutions S21, S22
and S23 are less than the corresponding areas of the peaks
in the chromatograms obtained with reference solutions (d)
to (k).
Non-phenolic antioxidants. Examine by thin-layer
chromatography (2.2.27), using a TLC silica gel GF254
plate R.
Test solution S24. Evaporate 100 ml of solution S2 to
dryness in vacuo at 45 °C. Dissolve the residue in 2 ml of
acidified methylene chloride R.
Reference solution (l). Dissolve 60 mg of plastic
additive 14 CRS in 10 ml of methylene chloride R. Dilute
2 ml of the solution to 10 ml with acidified methylene
chloride R.
Reference solution (m). Dissolve 60 mg of plastic
additive 15 CRS in 10 ml of methylene chloride R. Dilute
2 ml of the solution to 10 ml with acidified methylene
chloride R.
Reference solution (n). Dissolve 60 mg of plastic
additive 16 CRS in 10 ml of methylene chloride R. Dilute
2 ml of the solution to 10 ml with acidified methylene
chloride R.
Reference solution (o). Dissolve 60 mg of plastic
additive 17 CRS in 10 ml of methylene chloride R. Dilute
2 ml of the solution to 10 ml with acidified methylene
chloride R.
Reference solution (p). Dissolve 60 mg of plastic
additive 16 CRS and 60 mg of plastic additive 17 CRS in
10 ml of methylene chloride R. Dilute 2 ml of the solution to
10 ml with acidified methylene chloride R.
Apply separately to the plate 20 µl of test solution S24, 20 µl
of reference solution (p) and 20 µl of each of the reference
solutions corresponding to all the phenolic and non-phenolic
antioxidants mentioned in the type composition of the
material to be examined.
Develop over a path of 18 cm using hexane R. Allow the
plate to dry. Develop a second time over a path of 17 cm
using methylene chloride R. Allow the plate to dry and
examine in ultraviolet light at 254 nm. Spray with alcoholic
iodine solution R and examine in ultraviolet light at 254 nm
after 10-15 min. Any spots in the chromatogram obtained
with test solution S24 are not more intense than the spots in
the corresponding positions in the chromatograms obtained
with the reference solutions. The test is not valid unless the
chromatogram obtained with reference solution (p) shows
2 clearly separated spots.
Plastic additive 22. Examine by liquid chromatography
(2.2.29).
Test solution. Evaporate 25 ml of solution S2 to dryness in
vacuo at 45 °C. Dissolve the residue in 10 ml of toluene R
and 10 ml of a 10 g/l solution of tetrabutylammonium
hydroxide R in a mixture of 35 volumes of toluene R and
65 volumes of ethanol R. Boil under a reflux condenser for
3 h. Allow to cool and filter if necessary.
Reference solution. Dissolve 30 mg of plastic
additive 22 CRS in 50 ml of toluene R. Add 1 ml of this
solution to 25 ml of blank solution S2 and evaporate
to dryness in vacuo at 45 °C. Dissolve the residue
in 10 ml of toluene R and 10 ml of a 10 g/l solution
of tetrabutylammonium hydroxide R in a mixture of
35 volumes of toluene R and 65 volumes of ethanol R. Boil
under a reflux condenser for 3 h. Allow to cool and filter
if necessary.
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 aminopropylsilyl silica gel
for chromatography R (5 µm),
— as mobile phase at a flow rate of 2 ml/min a mixture of
11 volumes of ethanol R and 89 volumes of hexane R,
— as detector a spectrophotometer set at 227 nm.
Inject 20 µl of each solution. Record the chromatograms
for 10 min. When the chromatograms are recorded in the
prescribed conditions the resolution between the peaks
corresponding respectively to the “diol” and diluent of the
reference solution is at least 7.
In the chromatogram obtained with the test solution, the
area of the peak corresponding to the “diol” component
from plastic additive 22 is less than the corresponding peak
in the chromatogram obtained with the reference solution.
Amides and stearates. Examine by thin-layer
chromatography (2.2.27), using 2 plates of the TLC silica
gel GF254 plate R type.
Test solution. Use test solution S24 described in the test
for non-phenolic antioxidants.
Reference solution (q). Dissolve 20 mg of stearic acid
(plastic additive 19 CRS) in 10 ml of methylene chloride R.
Reference solution (r). Dissolve 40 mg of oleamide (plastic
additive 20 CRS) in 20 ml of methylene chloride R.
Reference solution (s). Dissolve 40 mg of erucamide (plastic
additive 21 CRS) in 20 ml of methylene chloride R.
Apply to the 2 plates 10 µl of test solution S24. Apply 10 µl
of reference solution (q) to the first plate and 10 µl each of
reference solutions (r) and (s) to the second plate.
Develop the first plate over a path of 10 cm using a
mixture of 25 volumes of ethanol R and 75 volumes of
trimethylpentane R. Allow the plate to dry in air. Spray
with a 2 g/l solution of dichlorophenolindophenol, sodium
salt R in ethanol R and heat in an oven at 120 °C for a few
minutes to intensify the spots. Any spot corresponding to
plastic additive 19 in the chromatogram obtained with test
solution S24 is identical in position to (Rf about 0.5) but not
more intense than the spot in the chromatogram obtained
with reference solution (q).
General Notices (1) apply to all monographs and other texts
277
3.1.4. Polyethylene without additives for containers
EUROPEAN PHARMACOPOEIA 5.0
Develop the second plate over a path of 13 cm using
hexane R. Allow the plate to dry in air. Develop a second
time over a path of 10 cm using a mixture of 5 volumes
of methanol R and 95 volumes of methylene chloride R.
Allow the plate to dry. Spray with a 40 g/l solution of
phosphomolybdic acid R in ethanol R. Heat in an oven
at 120 °C until spots appear. Any spots corresponding to
plastic additive 20 or plastic additive 21 in the chromatogram
obtained with test solution S24 are identical in position to
(Rf about 0.2) but not more intense than the corresponding
spots in the chromatograms obtained with reference
solutions (r) and (s).
01/2005:30104
3.1.4. POLYETHYLENE WITHOUT
ADDITIVES FOR CONTAINERS FOR
PARENTERAL PREPARATIONS AND
FOR OPHTHALMIC PREPARATIONS
DEFINITION
Polyethylene without additives is obtained by the
polymerisation of ethylene under high pressure in the
presence of oxygen or free-radical-forming initiators as
catalyst.
CHARACTERS
Beads, granules, powder or, after transformation, translucent
sheets of varying thickness or containers, practically
insoluble in water, soluble in hot aromatic hydrocarbons,
practically insoluble in ethanol, in hexane and in methanol.
It softens at temperatures above 65 °C.
The relative density (2.2.5) of the material is 0.910 to 0.937.
IDENTIFICATION
If necessary, cut the material to be examined into pieces of
maximum dimension on a side of not greater than 1 cm.
A. To 0.25 g add 10 ml of toluene R and boil under a
reflux condenser for about 15 min. Place a few drops of
the solution on a sodium chloride disc and evaporate
the solvent in an oven at 80 °C. Examine by infrared
absorption spectrophotometry (2.2.24). The spectrum of
the substance to be examined shows maxima in particular
at some of the following wave-numbers : 2920 cm− 1,
2850 cm− 1, 1465 cm− 1, 730 cm− 1, 720 cm− 1 ; the spectrum
obtained is identical to that obtained with the material
selected for the type sample. If the material to be
examined is in the form of sheets, the identification may
be performed directly on a cut piece of suitable size.
B. The substance to be examined complies with the test for
additives (see Tests).
TESTS
If necessary, cut the material to be examined into pieces of
maximum dimension on a side of not greater than 1 cm.
Solution S1. Place 25 g in a borosilicate-glass flask with a
ground-glass neck. Add 500 ml of water for injections R
and heat under a reflux condenser for 5 h. Allow to cool and
decant. Keep part of the solution for the test for appearance
of solution. Filter the rest through a sintered glass filter (16).
Use solution S1 within 4 h of preparation.
Solution S2. Place 2.0 g in a conical borosilicate-glass flask
with a ground-glass neck. Add 80 ml of toluene R and
boil under a reflux condenser with constant stirring for
1 h 30 min. Allow to cool to 60 °C and add with continued
stirring 120 ml of methanol R. Filter the solution through
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a sintered-glass filter (16). Rinse the flask and the filter
with 25 ml of a mixture of 40 ml of toluene R and 60 ml of
methanol R, add the rinsings to the filtrate and dilute to
250 ml with the same mixture of solvents. Prepare a blank
solution.
Solution S3. Place 100 g in a conical borosilicate-glass flask
with a ground-glass neck. Add 250 ml of 0.1 M hydrochloric
acid and boil under a reflux condenser with constant stirring
for 1 h. Allow to cool and decant the solution.
Appearance of solution. Solution S1 is clear (2.2.1) and
colourless (2.2.2, Method II).
Acidity or alkalinity. To 100 ml of solution S1 add 0.15 ml
of BRP indicator solution R. Not more than 1.5 ml of 0.01 M
sodium hydroxide is required to change the colour of the
indicator to blue. To 100 ml of solution S1 add 0.2 ml of
methyl orange solution R. Not more than 1.0 ml of 0.01 M
hydrochloric acid is required to reach the beginning of the
colour change of the indicator from yellow to orange.
Absorbance (2.2.25). At wavelengths from 220 nm to
340 nm, the absorbance of solution S1 is not greater
than 0.2.
Reducing substances. To 20 ml of solution S1 add 1 ml of
dilute sulphuric acid R and 20 ml of 0.002 M potassium
permanganate. Boil under a reflux condenser for 3 min
and cool immediately. Add l g of potassium iodide R and
titrate immediately with 0.01 M sodium thiosulphate, using
0.25 ml of starch solution R as indicator. Carry out a blank
titration. The difference between the titration volumes is
not more than 0.5 ml.
Substances soluble in hexane. Place 10 g in a 250 ml
conical borosilicate-glass flask with a ground-glass neck.
Add 100 ml of hexane R and boil under a reflux condenser
for 4 h, stirring constantly. Cool in iced water and filter
rapidly through a sintered-glass filter (16) maintaining the
solution at 0 °C (the filtration time must be less than 5 min ;
if necessary the filtration may be accelerated by applying
pressure to the solution). Evaporate 20 ml of the filtrate in a
tared glass dish on a water-bath. Dry the residue in an oven
at 100-105 °C for 1 h. The mass of the residue obtained is
within 10 per cent of the residue obtained with the type
sample and does not exceed 5 per cent.
Additives. Examine by thin-layer chromatography (2.2.27),
using a TLC silica gel G plate R.
Test solution. Evaporate 50 ml of solution S2 to dryness in
vacuo at 45 °C. Dissolve the evaporation residue with 5 ml
of methylene chloride R. Prepare a blank solution from the
blank solution corresponding to solution S2.
Reference solution. Dissolve 20 mg of plastic
additive 15 CRS and 20 mg of plastic additive 08 CRS in
methylene chloride R and dilute to 10 ml with the same
solvent.
Apply to the plate 10 µl of each solution. Develop over a
path of 13 cm using hexane R. Allow the plate to dry in
air. Carry out a second development over a path of 10 cm
using a mixture of 5 volumes of methanol R and 95 volumes
of methylene chloride R. Allow the plate to dry in air,
spray with a 40 g/l solution of phosphomolybdic acid R
in alcohol R and heat at 120 °C until the spots appear in
the chromatogram obtained with the reference solution.
No spot appears in the chromatogram obtained with the
test solution, except for a spot which may be at the solvent
front from the first development and which corresponds
to oligomers. Disregard any spots corresponding to those
obtained in the chromatogram with the blank solution. The
chromatogram obtained with the reference solution shows
two distinct spots.
See the information section on general monographs (cover pages)