0Participant3Participant4Participant5Participant6Participant7Participant9ParticipantParticipant11Participant1314
20000 40000 180000 160000 140000 120000 100000 80000 60000
C20:0
C22:0
C18:0
A
B
Participant
12
Time
(minutes)
0
0. 5
1
1. 5
2.0
2. 5
3
3.5
0
0. 5
1
1. 5
2.0
2. 5
3
3.5
0
0. 5
1
1. 5
2.0
2. 5
3
3.5
0
0. 5
1
1. 5
2.0
2. 5
3
3.5
0
0. 5
1
1. 5
2.0
2. 5
3
3.5
0
0. 5
1
1. 5
2.0
2. 5
3
3.5
d31
C26:0
d31
C24:0
d31
C22:0
d31
C20:0
d31
C18:0
d31
C16:0 Retention
time:
3.02
Peak
area:
1182525
Retention
time:
2.37
Peak
area:
192783
Retention
time:
2.13
Peak
area:
26747 Retention
time:
2.64
Peak
area:
1307483
Retention
time:
1.79
Peak
area:
2707320
Retention
time:
1.93
Peak
area:
5697
Figure
2.
(A)
Detection
of
d31-PA
(C16:0)
into
elongated
FFAs
in
solvent
extract
samples
following
syndet
bar
application
at
Day
28.
Baseline
levels
were
calculated
as
the
average
fatty
acid
signal
intensity
across
participants
at
study
initiation.
Elongated
FFAs
were
detected
in
9
out
of
11
participants
versus
average
baseline
levels
(B)
Representative
MRM
chromatogram
of
tape
strip
extracts
obtained
from
a
participant
12
of
a
subset
of
three
participants
at
Day
28.
Elongation
up
to
C26:0
was
detected
in
the
subset
following
4
weeks’
application
of
the
syndet
bar
formulation.
Elongated
deuterated
FFAs
are
labeled
with
retention
time
and
peak
area.
cps,
counts
per
second
d31-PA
FFA,
free
fatty
acid
MRM,
multiple-reaction
monitoring.
194 JOURNAL OF COSMETIC SCIENCE
Baseline
Fatty acid signal intensity (cps)
10
Participant
Participant
Fatty acid signal intensity (%of total)

195 IN VIVO ELONGATION OF TOPICALLY APPLIED FATTY ACIDS
formulations was incorporated into ceramides, as measured by the release of sphingosine
via hydrolysis of ceramides The concept of d31-PA integration into ceramides via the de novo
pathway for ceramide and sphingosine synthesis was introduced by the authors at the AAD
conference.25
0
C18:0 C20:0
Deutered fatty acids detected in skin
Deutered fatty acids detected in skin
d31PA concentration
C22:0 C24:0
10
20
30
40
50
60
70
80
90
100
A
B
10
20
30
40
50
60
70
80
90
100
2% 0.75% 0.25% 0.05%
C18:0 C20:0 C22:0 C24:0
0
Figure 3. Percentage of participants demonstrating conversion of different levels of d31-PA (C16:0) into
elongated FFAs following application of a body wash formulation twice daily for four weeks on the arm (A)
and leg (B). Detectable levels of elongated FFAs (C20:0 to C24:0) were found in tape strip samples for all body
wash d31-PA concentrations.
d31-PA FFA, free fatty acid.
Participants
demonstrating
conversion
of
the
d31PA
concentration
applied
(%)
Participants
demonstrating
conversion
of
the
d31PAconcentration
applied
(%)