ISO 19609-4:2022

INTERNATIONAL ISO
STANDARD 19609-4
First edition
2022-12
Traditional Chinese medicine —
Quality and safety of raw materials
and finished products made with raw
materials —
Part 4:
Testing for preservatives and
unwanted compounds
Médecine traditionnelle chinoise — Qualité et sécurité des matières
premières et des produits finis fabriqués à partir de matières
premières —
Partie 4: Essais des conservateurs et composés indésirables
Reference number
ISO 19609-4:2022(E)
© ISO 2022

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ISO 19609-4:2022(E)
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© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 19609-4:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Testing for the absence of unwanted compounds and radiation . 2
4.1 General . 2
4.2 Overview . 2
4.3 Determination of preservatives . 2
4.3.1 General . 2
4.3.2 Determination of preservatives . 2
4.3.3 Declaration . 3
4.3.4 Analysis of sulfur and sulfur derivatives . 3
4.3.5 Analysis of ethylene oxide . 5
4.4 Determination of irradiated material . 6
4.4.1 General . 6
4.4.2 Analysis of irradiated traditional Chinese medicine using photostimulated
luminescence . 6
4.5 Determination of toxic compounds . 7
4.5.1 General . 7
4.5.2 Natural toxins . 7
4.5.3 Toxins resulting from degradation reactions .13
Annex A (informative) Materia medica .14
Annex B (informative) Examples of typical chromatograms of Ephedra herba, Strychni
semen, Sophorae tonkinensis radix et rhizoma and their toxic compounds .15
Bibliography .22
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ISO 19609-4:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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expressions related to conformity assessment, as well as information about ISO's adherence to
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 249, Traditional Chinese medicine.
A list of all parts in the ISO 19609 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 19609-4:2022(E)
Introduction
The ISO 19609 series consists of four different parts with different content as shown in Figure 1.
Figure 1 — Overview of the ISO 19609 series
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INTERNATIONAL STANDARD ISO 19609-4:2022(E)
Traditional Chinese medicine — Quality and safety of
raw materials and finished products made with raw
materials —
Part 4:
Testing for preservatives and unwanted compounds
1 Scope
This document specifies the testing of preservatives and unwanted compounds within a quality control
framework for starting materials and finished products used in and as traditional Chinese medicine.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 22256, Traditional Chinese medicine — Detection of irradiated natural products by photostimulated
luminescence
ISO 22590, Traditional Chinese medicine — Determination of sulfur dioxide in natural products by titration
ISO 23190, Traditional Chinese medicine — Determination of aristolochic acids in natural products by high-
performance liquid chromatography (HPLC)
ISO 23956, Traditional Chinese medicine — Determination of benzopyrene in processed natural products
ISO 23962, Traditional Chinese medicine — Processed Aconitum carmichaelii lateral root
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
unwanted compound
Constituent of a product which is unsuitable or unsafe for the intended use of that product.
Note 1 to entry: Such compounds can be those added for preservation or which result from a degradation process.
Toxic natural compounds can also be considered unwanted compounds.
3.2
preservative
component intended to prevent the growth of microorganisms in or on a product
[SOURCE: ISO 18369-1:2017, 3.1.11.7]
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ISO 19609-4:2022(E)
3.3
excipient
material that is present in a therapeutic product administered to a patient, other than the active
substance(s)
[SOURCE: ISO/TS 20399-1:2018, 3.7, modified — Definition revised, example and note to entry
removed.]
4 Testing for the absence of unwanted compounds and radiation
4.1 General
For the risk assessment of traditional Chinese medicine products, the presence and/or the amount of
unwanted compounds shall be estimated.
4.2 Overview
These unwanted compounds and radiation can be categorized in three main groups:
a) preservatives;
b) radiation;
c) toxic compounds:
— natural toxins;
— toxins resulting from degradation reactions;
d) other additives.
4.3 Determination of preservatives
4.3.1 General
Preservatives are pharmaceutical excipients added to therapeutic products to extend their shelf life
and prevent contamination with microorganisms such as bacteria and fungi. Their possible adverse
effects include allergic reactions and irritation.
4.3.2 Determination of preservatives
4.3.2.1 General
The determination and quantification should be done by specific and valid analytical procedures.
Preservatives in traditional Chinese medicine products are listed on the product ingredient list.
4.3.2.2 Sulfur and sulfur derivatives
Sulfur and sulfur derivatives include elemental sulfur and sulfites such as potassium sulfide and sodium
sulfite, as well as sulfur dioxide and other sulfur-containing additives.
NOTE Sulfur dioxide or sulfite formed in aqueous solution has a preserving effect by irretrievably inhibiting
metabolism and damage to the cell membranes from microorganisms as well as destroying the secondary and
tertiary structure of microbial enzymes.
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ISO 19609-4:2022(E)
4.3.2.3 Ethylene oxide
Ethylene oxide gas kills bacteria, viruses and fungi, so it can be used for fumigation of heat-sensitive
substances. Sterilization with ethylene oxide is a widespread process in the industrial manufacture of
medical products, especially disposable products such as dressings, sutures or syringes and catheters.
NOTE The use of ethylene oxidein pharmaceuticals has been banned in the territory of the European
pharmacopoeia since 1981 because it can produce toxic 2-chloroethanol.
4.3.3 Declaration
Preservatives shall be declared in all traditional Chinese medicine products and starting materials on
the product label or in related documents such as a Certificate of Analysis (CoA).
4.3.4 Analysis of sulfur and sulfur derivatives
4.3.4.1 General
Based on the chemical inhomogeneity of the variety of preservatives, a few specific valid analytical
methods shall be implemented.
NOTE Sulfur dioxide is a toxic gas and reacts immediately with water to sulfurous acid.
4.3.4.2 Elemental sulfur
NOTE Elemental sulfur is used as a protecting compound on herbal surfaces.
4.3.4.2.1 Sample preparation
In the case of declaration on the product documents or suspicion based on yellow powder on the
surfaces, an analytical measurement shall be used.
An appropriate amount of test sample of minimum 50 g shall be used and washed with cold water.
The resulting suspension shall be separated from the test material and then filtered over an appropriate
typical laboratory folded filter.
The resulting residue shall be dried.
4.3.4.2.2 Reagents
Reagents are not needed.
4.3.4.2.3 Apparatus
Test tube or melting pot: bunsen burner or other appropriate heating source with a minimum
temperature of about 150 °C.
4.3.4.2.4 Analytical instrumentation
None.
4.3.4.2.5 Analytical procedure
The dried test residue shall be heated with air contact until melting under appropriate conditions.
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ISO 19609-4:2022(E)
4.3.4.2.6 Measurement and reporting
If the test sample contains elemental sulfur or other sulfur derivatives in the reaction with air, the
colourless gas SO with a characteristic sticky odour appears.
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Other appropriate methods can be used.
4.3.4.3 Quantification of sulfur derivatives as sulfur dioxide
ISO 22590 shall be applied for the quantification of sulfur derivatives as sulfur dioxide.
Other appropriate valid methods can be used alongside ISO 22590.
4.3.4.4 Qualitative quick test for sulfur dioxide
4.3.4.4.1 General
For easy screening it is also possible to use a quick test with a lead acetate paper.
4.3.4.4.2 Sample preparation
The herbal test material shall be milled to < 1 mm diameter.
4.3.4.4.3 Reagents
Water for analysis (p.a.).
Zinc for analysis (p.a.).
Hydrochloric acid for analysis (p.a.).
Lead acetate solution for analysis (p.a.).
4.3.4.4.4 Apparatus
Test tube.
4.3.4.4.5 Analytical instrumentation
None.
4.3.4.4.6 Analytical procedure
Place about 0,5 g of zinc granules with 2 ml of 5 mol/l hydrochloric acid and add about 0,1 g of the test
material (dried residue) in a test tube.
The hydrogen sulfide with typical odour is formed from the nascent hydrogen and the sulfur compound.
A commercial lead acetate paper is placed on the top of the test tube.
4.3.4.4.7 Measurement and reporting
If the paper turns dark (brown to black) this is a positive result in a reaction to lead sulfide (PbS)which
only appears if sulfur dioxide is present in the test sample.
4.3.4.5 Other test methods
For the identification of sulfur dioxide, other appropriate analytical methods such as gas chromatography
or typical commercial quick test kits can be used.
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ISO 19609-4:2022(E)
4.3.5 Analysis of ethylene oxide
4.3.5.1 General
The measurement of etylene oxide shall be done by the proposed analytical method with headspace gas
chromatography (GC) as described in Table 1.
4.3.5.2 Sample preparation
Weigh 1,0 g of the test material into a 10-ml headspace vial, dilute or suspend in 3,0 ml of water, then
close the vial and mix to obtain a homogeneous solution or suspension. Allow to stand at 70 °C for
45 minutes. This resulting mixture shall be used as the test sample.
Reference solution 1: weigh 1,0 g of the test material into a 10-ml headspace vial and dilute or suspend
in 2,5 ml of water. Add 0,5 ml of a reference solution of ethylene oxide (2l µg/ml), then close the vial
and mix to obtain a homogeneous solution or suspension. Allow to stand at 70 °C for 45 minutes. This
resulting mixture shall be used as reference solution 1.
NOTE Reference solutions can be produced or purchased from qualified sources.
Reference solution 2: Add 0,5 ml of a reference solution of ethylene oxide (2 µg/ml), 0,1 ml of a freshly
prepared (10 mg/l) solution of acetaldehyde and 0,1 ml of water into a 10 ml headspace vial, close the
vial and mix to obtain a homogeneous solution or suspension. Allow to stand at 70 °C for 45 minutes.
This resulting mixture shall be used as reference solution 2.
4.3.5.3 Reagents
Ethylene oxide for analysis (p.a.).
Acetaldehyde for analysis (p.a.).
Water for analysis (p.a.).
Helium for GC, or nitrogen for GC.
Hydrogen and oxygen for GC with flame ionization detector (FID).
4.3.5.4 Apparatus
Analytical balance.
Laboratory oven.
4.3.5.5 Analytical instrumentation
Table 1 — Conditions for gas chromatographic headspace GC analysis
Apparatus Gas chromatographic headspace apparatus (headspace GC) with flame ionization
detector (FID)
Column Type: Capillary glass or quartz column
X Pre-column 4 × 4 mm
X Column 30 m × 0,32 mm
Inner surface coated with 0,1 µm layer of
poly(dimethyl) siloxan
Detection X Flame ionization detector
Flowrate Helium or nitrogen as carrier gas with a linear velocity of about 20 cm/s
Splitratio 1:20
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ISO 19609-4:2022(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Apparatus Gas chromatographic headspace apparatus (headspace GC) with flame ionization
detector (FID)
Temperature Equilibrate 70 °C for 45 minutes
Transfer-line temperature 75 °C
Injection port temperature 150 °C
Detector temperature 250 °C
Time headspace Pressurization time 1 min, injection time 12 s
Record interval 38 min
Injection A suitable volume, e.g. 1 ml of gaseous phases
Temperature gradient programme:
50 °C for 5 min
Raise temperature with a rate of 5 °C/min to 180 °C
Raise temperature with a rate of 30 °C/min to 230 °C
230 °C for 5 min
4.3.5.6 System suitability
The resolution of the peaks of acetaldehyde and ethylene oxide shall be at least 2,0.
The relative standard deviation of ethylene oxide of three values shall be not greater than 15 %.
4.3.5.7 Assessment
All tests shall be carried out three times.
The analytical data from the test sample shall be compared and calculated with the data produced with
the reference solutions (see 4.3.4.3.2) made from authentic reference materials.
The content of ethylene oxide shall be calculated in
...