CO2_2016 - page 59

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Chimica Oggi - Chemistry Today
- vol. 34(2) March/April 2016
OSOR AND SUBSTANCE SAMENESS
Another principle of REACH is ‘One Substance, One
Registration’ or OSOR; a premise of which is to prevent
duplicate vertebrate animal testing. All registrants for
the same substance and registration type should be part
of the same registration to facilitate the joint submission
of data and data sharing. Unnecessary duplication of
vertebrate animal testing is forbidden under REACH and
vertebrate testing must be justified against alternative
methods (e.g. in vitro) before being undertaken in the
first place (9). Another outcome of OSOR is that costs
are shared to help reduce the burden on industry.
Determining substance sameness is the enabling factor for
OSOR, which, in turn, depends on substance ID. Rules that
govern the assignment of European INventory of Existing
commercial Chemical Substances (EINECS) numbers are
applied when determining sameness, hence the utility
of EINECs numbers during the registration process. Some
general rules have been established for the assessment of
substance sameness, examples are:
--
there is no differentiation between technical, pure or
analytical grades of a substance;
--
well defined substances should contain the same
main ingredients, the only impurities tolerated are
those derived from the production process or added
for stability;
--
there is no distinction between hydrates of a
substance or hydrate ions formed by association of a
substance with water ;
--
substances differing by branched and linear alkyl
chains or by the salts (including individual salts)
of acids or bases are different substances for the
purposes of registration;
--
alkyl chains, in the absence of further description, will
be interpreted as linear and saturated; and
--
chiral centres are assumed racemic unless stated
otherwise (10).
It should be noted that the impurity profile in the SIP
dictates the tolerated levels for a substance to be within
- in order for a joint registration to be possible. Impurity
variations can also affect the classification of a substance
accordingly. These rules, and others, are used by ECHA
during the inquiry process and registrants in pre-SIEF
activities.
WAIVING DATA REQUIREMENTS
In some cases, some analytical tests and therefore data
are not technically possible or do not appear to be
scientifically necessary (11). It must be noted that if a test
is waived, it needs to be justified in the registration dossier
with sound scientific reasoning, or else the dossier may
fail evaluation. An example of which is a 13C NMR was
not included within a HCl registration dossier - reasoning
that a signal would not be expected due to the absence
of organics. The dossier was rejected on the grounds
that ECHA deemed that proof of absence of any organic
substances was desirable and therefore was scientifically
necessary. Extra testing may also need to be undertaken
for complete and unambiguous substance identification,
like X-ray crystallography for a TiO2 compound due
to its various polymorphs (12). Waiving tonnage band
longer possible. The pre-registration deadline is 31 May
2017, one year before the 1-100 tpy registration deadline,
31 May 2018.
Meeting REACH registration obligations for importers of
mixtures can be particularly challenging; determining the
composition of the mixtures and aggregating substances
quantities across multiple mixtures requires robust
communication with suppliers, who will likely be reluctant
to divulge potentially sensitive commercial information –
especially to the extent of impurity profiling, from which
the manufacturing process may be evident. Correct
substance identification is critical for substance sameness
verification. Analytical chemistry is employed from the
beginning of the registration process as prospective
registrants (pre-SIEF route) or ECHA (inquiry route) decide
upon substance sameness by analysis of data (5).
SUBSTANCE IDENTIFICATION
Each legal entity must have their own analytical data for
Substance IDentification (SID) and not purchase the data
from others that have already performed the necessary
tests because the data is specific to the substance a
particular legal entity is manufacturing or importing. It
is, however, acceptable to outsource the testing for SID
provided the tests are performed on the substance that a
legal entity is intending to register (6).
Substance ID can be relatively straightforward for simple
organic molecules of high purity, such as analytical
grade ethanol. On the other hand, Naturally Complex
Substances (NCS) such as essential oils may fall into the
Unknown or Variable Composition, Complex reaction
products, or Biological material (UVCB) category. These
substances can be particularly challenging to define,
many of the compounds may be neither known nor easy
to decipher and natural variations in the compositions
can vary within the same substance as defined in a
registration. Clearly, analytical data for such substances
is seldom simple and identifiers that can help to quickly
highlight likely differences in composition are useful. For
essential oils and similarly botanically derived substances
the botanical source and process are used to identify the
substance, if these components are different to another
essential oil, it is very likely the substances will not be
treated the same under REACH and as a result will be
registered in separate registrations – although there are
exceptions (7).
UVCBs often have many complex compounds within
them, with few, if any, compounds present in greater than
10% (concentrations are w/w for solids and liquids, v/v
for gases); an example of which is petrochemicals. The
composition of crude oil naturally varies between sources;
this gives rise to a spread of chain lengths within classes
of compounds, often resulting in no compounds present
above 10%. In this case the variations in chain length are
grouped together i.e. carbon chain ranges for linear,
branched and cyclic alkanes (8). Alongside UVCB, there is
another category: well-defined substances. This category
is further split into mono constituent (one substance >/=
80% by weight) and multi constituent (more than one
substance >/= 10% and < 80%). In both well-defined cases,
substances present in < 10% are generally considered
impurities.
1...,49,50,51,52,53,54,55,56,57,58 60,61,62,63,64,65,66,67,68
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