wound healing (absorption of malodours). By this
definition, and also with regard to the fact that carbon,
as a small molecule, can penetrate the systemic
system, all carbon-based dressings should be
classified as class III MD.
3.4.3 Metalloproteinase Regulating
Dressings
Another special case is the MMP-regulating
dressings. These dressings contain molecules with
physiological activity since they are able to induce the
inhibition of MMP activity. However, as explained
previously, according to rule 8 of Annex VIII of the
new European regulation 2017/745, “All invasive
surgical-type devices intended for long term use are
class IIb, except: if they have a biological effect or
are fully or substantially absorbed, in which case they
are class III. […]”. This definition clearly states that
these MMP-regulator dressings should be classified
as class III. However, only the Promogran® dressing
is classified in class III. The UrgoStart® is classified
as a class IIb MD.
3.4.4 Non-combined Dressings Classified in
Class IIb or III
On the contrary of combined dressings being
classified in class IIa and IIb, it also exists some
dressings that might be considered as being at low
risk and non-combined, according to their
composition and their main action, and which still
found classified in higher risk-classes (IIb and III).
This is the case for example of the Ialuset dressing®,
whose main function is to maintain a moist
environment, and which is mainly composed of
hyaluronic acid for its strong hygroscopic power,
which is classified in class IIb. The explanation for
this high-risk classification certainly comes from the
hyaluronic acid which, depending on its size (the
smaller, the more it will be considered at risk because
of the risk of entering the systemic circulation), can
be considered as a MD or a drug.
Another example of a careful classification is the
UrgoTul® dressing which is composed of a
moisturizing matrix (CMC, Vaseline, Paraffin) and
apart from the fact that it is used over long periods
(more than 30 days), its composition does not
represent any particular danger for the patient.
Indeed, the Algoplaque® dressing, also composed of
CMC is classified as class I MD. Moreover, the
association paraffin/vaselin/glycerol is considered as
being one of the most moisturizing mixtures and is
often used in cosmetic moisturizing cream (Mylan®,
Biogaran®, Dextopia®…). The classification of
UrgoTul® as a high-risk class (IIb) is then difficult to
understand in view of these elements, especially
considering its counterparts, UrgoStart®, which is a
combined MD also classified in class IIb.
Another example is the Duoderm® dressing,
which is a hydrocolloid dressing composed of a
matrix of pectin, gelatin, sodium CMC and a
polyurethane foam. The main function is to maintain
a moist environment. Despite a description that seems
without particular risk, this dressing is classified as
class III. It is therefore difficult to explain why this
dressing is considered to be riskier than UrgoStart®,
for example, or of equivalent risk to all silver
dressings.
These are few examples illustrating the lack of
uniformity for MD classification before the
implementation of the new European regulation.
4 CONCRETE EXAMPLE OF AN
INDUSTRIAL DRESSING,
INTENDED FOR SKIN
HEALING, CLASSIFIED AS A
COMBINED MD
4.1 Medical Device under Study
The MD used as an example to illustrate this research
is intended for skin healing of chronic wounds. This
MD consists of the association of a moisturizing
dressing with a peptide solution. The peptide included
in the solution was developed, in partnership with the
CNRS, on the basis of the activity of matrikines,
molecules derived from natural degradation of
elastin. This innovative bifunctional peptide (BFP)
has the ability to activate the synthesis of the
extracellular matrix (ECM) on one hand and to
inhibit, by a competitive mechanism, the molecule
responsible for inflammation (MMP) on the other
hand (Attia-Vigneau J, 2014) (Figure 1).
The promising performances of the peptide led the
industrials, responsible of its development, to
consider a medical application. Indeed, considering
the effects of the peptide on cellular regeneration,
proved by in vitro studies (Attia-Vigneau J, 2014),
this peptide was integrated to a phosphate buffer
solution to be applied on chronic wounds, such as
Venous Leg Ulcers (VLU), in association with a
secondary dressing to promote healing mechanisms.
Apart from pathological cases, like diabetes or
chronic wounds (ulcers), the healing process is 6
weeks. In case of chronic wounds, this healing
ClinMed 2022 - Special Session on Dealing with the Change in European Regulations for Medical Devices