Document ID: EPA-HQ-OPPT-2003-0010-0009
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2003-03-11T05:00Z

APPENDIX
C
PK/
MECH
PROCEDURES
AND
ROUTE
TO
ROUTE
EXTRAPOLATION
REPORTING
FOR
ETHYLENE
BICHLORIDE
This
Appendix
contains
detailed
procedures
for
the
kinetic
studies
and
route­
to­
route
extrapolation
to
be
conducted
for
ethylene
dichioride,
and
is
organized
into
the
following
sections:

C.
1
Pharmacokinetic
Studies
for
F344
Rats
C.
2
Subchronic
Toxicity
C.
3
Subchronic
Neurotoxicity
C.
4
Reproductive
Toxicity
C.
5
PBPK
Model
Description
and
Coding
C.
6
General
Outline
for
Route­
to­
Route
Extrapolation
Reports
1
OPPT­
2003­
0010­
0009
RECEIVED
OPPT
NCIC
2003
MAR11
5:
03PM
CA.
Pharmacokinetic
Studies
for
F344
Rats
A
total
of
4
pharmacokinetic
studies
will
be
conducted
to
support
PBPK
modeling
activities
for
ethylene
dichloride,
as
described
below.
It
is
anticipated
that
the
pharmacokinetic
studies
will
start
one
year
after
the
ECA
is
signed
(
during
the
1St
quarter
of
2003),
with
an
interim
report
generated
six
months
later
(
3
rd
quarter
of
2003),
with
the
final
report
submitted
three
months
later
(
during
the
4th
quarter
of2003)
(
see
Appendix
A
for
complete
schedule).

Study
1:
Demonstration
ofPeriodicity
Following
Repeated
Inhalation
Exoosures
Parameter
Proposed
Species
Rat
Strain
F344
Age
Young
adult
Number
ofanimals
132
animals
(
3
controls
at
beginning
(
t
=

0)
and
3
at
end
ofexposure
(
t
=
6
hr)
on
days
1,
3,
and
5;
3
exposed
animals
at
the
beginning
ofexposure
(
t
=
0)
on
days
3
and
5,
3
exposed
animals/
time
point
at
t
=
0.25,
0.5,
6.25
and
16
hr
during
and
after
exposure
on
days
1,
3,
and
5,
and
6
exposed
animals/
time
point
at
t
=
1,
3,
6,
and
8
hr
during
and
after
exposure
on
days
1,
3,
5)
Dose(
s)
To
be
determined
Route
Inhalation
Exposure
Frequency
6
hrs/
day,
5
consecutive
days
Observations
Liver
and
lung
GSH
in
controls
(
n
=
3)
at
beginning
and
end
ofexposure
(
0
and
6
hrs)
on
days
1
,3
and
5.
Lung
and
liver
GSH
in
exposed
animals
(
n
=
3)
at
beginning
ofexposure
on
days
3
and
5.
Venous
blood
concentrations
ofEDC
(
n
=
3)
at
0.25,
0.5,
6.25,
and
16
hrs
after
exposure
starts
on
days
1,
3,
and
5.
Venous
blood
concentrations
ofEDC
(
n
=
6)
and
lung
and
liver
GSH
concentrations
(
n
=
3)
at
1,
3,
6,
and
8
hours
after
exposure
starts
on
days
1,
3,
and
5.

Kinetic
studies
will
be
conducted
for
demonstrating
periodicity
in
the
rat.
Air
concentrations
should
be
measured
hourly.
Blood
samples
will
be
drawn
on
days
1,
3,
and
5.
Blood
samples
(
from
3
or
6
animals)
and
liver
and
lung
of
3
animals
(
for
glutathione
determination)
will
be
collected
immediately
following
sacrifice.
Lung,
liver,
kidney,
brain,
adrenal
gland,
and
thyroid
will
be
frozen
pending
further
analysis
following
the
completion
of
the
toxicity
testing.
A
2
positive
control
will
be
required
to
demonstrate
the
recovery
of
ethylene
dichloride
in
tissues
following
freezing.

3
Study
2:
Demonstration
of
Periodicity
Following
Repeated
Oral
Exposures
to
Ethylene
Dichloride
by
Corn
Oil
Gavage
Parameter
Proposed
Species
Rat
Strain
F344
Age
Young
adult
Number
of
animals
132
animals
(
3
controls
at
dosing
(
t
=
0)
and
3
after
dosing
(
t
=
2­
6
hr)
on
days
1,
3,
and
5;
3
exposed
animals
prior
to
dosing
(
t
=
0)
on
days
3
and
5;
3
exposed
animals
at
t=
0.25,
4,
16,
and
24
hrs
after
dosing
on
days
1,
3,
and
5;
and
6
exposed
animals/
time
point
0.5,
1,
2,
and
8
hrs
after
dosing
on
days
1,
3,
5)
Dose(
s)
150
mg/
kg
Route
Corn
oil
gavage
Exposure
Frequency
ix/
day,
5
consecutive
days
Observations
Liver
and
lung
GSH
in
controls
(
n
=
3)
prior
to
dosing
(
at
0
hrs)
and
at
8
hrs
after
dosing.
Liver
and
lung
GSH
in
previously
dosed
animals
(
n
=
3)
prior
to
dosing
ofremaining
animals
(
t
=
0)
on
days
3
and
5.
Venous
blood
concentrations
of
EDC
(
n=
3)
at
0.25,
4,
16,
and
24
hrs
after
dosing
on
days
1,
3,
and
5.
Venous
blood
concentrations
of
EDC
(
n
=
6)
and
lung
and
liverGSH
concentrations
(
n
=
3)
at
0.5,
1,
2,
and
8
hours
after
exposure
starts
on
days
1,
3,
and
5.

The
test
dose
was
selected
based
on
the
doses
administered
to
rats
in
the
high
dose
group
for
the
90­
day
study
conducted
by
Daniel
et
al.
(
1994).
Blood
samples
will
be
drawn
on
days
1,
3,
and
5.
Blood
samples
(
from
3
or
6
animals)
and
liver
and
lung
of
3
animals
(
for
glutathione
determination)
will
be
collected
immediately
following
sacrifice.
Lung,
liver,
kidney,
brain,
adrenal
gland,
and
thyroid
will
be
frozen
pending
further
analysis
following
the
completion
of
the
toxicity
testing.
A
positive
control
will
be
required
to
demonstrate
the
recovery
of
ethylene
dichioride
in
tissues
following
freezing.

4
Study
3:
Demonstration
of
Periodicity
Following
Repeated
Oral
Exposures
to
Ethylene
Dichloride
by
Aqueous
Gavage
Parameter
Proposed
Species
Rat
Strain
F344
Age
Young
adult
Number
ofanimals
132
animals
(
3
controls
at
dosing
(
t
=
0)
and
3
after
dosing
(
t
=
2­
6
hr)
on
days
1,
3,
and
5;
3
exposed
animals
prior
to
dosing
(
t
=
0)
on
days
3
and
5;
3
exposed
animals
at
t=
0.25,
4,
16,
and
24
hrs
after
dosing
on
days
1,
3,
and
5;
and
6
exposed
animals/
time
point
0.5,
1,
2,
and
8
hrs
after
dosing
on
days
1,
3,
5)
Doses
150
mg/
kg­
day
Route
Aqueous
gavage
Exposure
Frequency
ix/
day,
5
consecutive
days
Observations
Liver
and
lung
GSH
in
controls
(
n
=
3)
prior
to
dosing
(
at
0
hrs)
and
at
8
hrs
after
dosing.
Liver
and
lung
GSH
in
previously
dosed
animals
(
n
=
3)
prior
to
dosing
of
remaining
animals
(
t
=
0)
on
days
3
and
5.
Venous
blood
concentrations
of
EDC
(
n=
3)
at
0.25,
4,
16,
and
24
hrs
after
dosing
on
days
1,
3,
and5.
Venous
blood
concentrations
of
EDC
(
n
=
6)
and
lung
and
liver
GSH
concentrations
(
n
=
3)
at
0.5,
1,
2,
and
8
hours
after
exposure
starts
on
days
1,
3,
and
5
The
test
dose
was
selected
based
on
the
doses
administered
to
rats
in
the
high
dose
group
for
the
90­
day
study
conducted
by
Daniel
et
al.
(
1994).
Blood
samples
will
be
drawn
on
days
1,
3,
and
5.
Blood
samples
(
from
3
or
6
animals)
and
liver
and
lung
of
3
animals
(
for
glutathione
determination)
will
be
collected
immediately
following
sacrifice.
Lung,
liver,
kidney,
brain,
adrenal
gland,
and
thyroid
will
be
frozen
pending
further
analysis
following
the
completion
of
the
toxicity
testing.
A
positive
control
will
be
required
to
demonstrate
the
recovery
ofethylene
dichloride
in
tissues
following
freezing.

5
Study
4:
Determination
of
Partition
Coefficients
The
rat
brain:
air,
kidney:
air,
testes:
air,
and
ovary:
air
partition
coefficients
will
be
determined
using
the
vial
equilibration
technique
described
by
Gargas
et
a!.
(
1989,
Toxicol.
Appi.
Pharmacol.
98,
87­
99).

A
total
of
5
rats
will
be
used,
if
partition
coefficients
are
determined
individually.
A
higher
number
of
animals
may
be
required
if
composite
samples
are
used.
It
is
preferred
that
partition
coefficients
be
determined
for
individual
animals,
however
if
tissue
volumes
are
insufficient
to
measure
individually
a
composite
sample
may
be
used.

6
C.
2
Subchronic
Toxicity
Route­
To­
Route
Extrapolation
The
NOAEL/
LOAEL
values
obtained
from
the
existing
subchronic
study
ofDaniel
et
al.
(
1994)
will
be
extrapolated
from
the
oral
route
to
the
inhalation
route
using
a
PBPK
model
(
Appendix
C.
5).
The
internal
dose
(
parent
chemical,
amount
metabolized)
and
metric
(
peak
concentration,
average
concentration,
AUC)
used
to
perform
this
extrapolation
will
be
determined
based
on
a
consideration
of
the
effects
observed
and
a
plausible
mechanism
of
action.

7
C.
3
Subchronic
Neurotoxicity
Route­
To­
Route
Extrapolation
The
NOAEL/
LOAEL
values
obtained
from
the
subchronic
neurotoxicity
testing
will
be
extrapolated
from
the
oral
route
to
the
inhalation
route
using
a
PBPK
model
(
Appendix
C.
5).
The
internal
dose
(
parent
chemical,
amount
metabolized
in
brain)
and
metric
(
peak
concentration,
average
concentration,
AUC)
used
to
perform
this
extrapolation
will
be
determined
based
on
a
consideration
ofany
neurological
effects
observed
and
a
plausible
mechanism
of
action.

8
C.
4
Reproductive
Toxicity
Route­
To­
Route
Extrapolation
The
NOAEL/
LOAEL
values
obtained
from
the
reproductive
toxicity
testing
will
be
extrapolated
from
the
oral
route
to
the
inhalation
route
using
a
PBPK
model
(
Appendix
C.
6).
The
results
of
Alumot
et
al.
(
1976),
Rao
et
al.
(
1980)
and
Lane
et
al.
(
1982)
will
also
be
compared
to
the
current
reproductive
toxicity
testing.
The
internal
dose
(
parent
chemical,
amount
metabolized)
and
metric
(
peak
concentration,
average
concentration,
AUC)
used
to
perform
this
extrapolation
will
be
determined
based
on
a
consideration
of
any
reproductive
effects
observed
and
a
plausible
mechanism
of
action.

9
C.
5
PBPK
Model
Description
and
Coding
The
preliminary
PBPK
model
(
to
be
refined
as
part
ofthis
ECA)
is
a
modification
ofD'Souza
et
al.
(
1987,
1988)
to
include
periodic
consumption
of
drinking
water.
Rat
physiology
is
represented
by
five
tissue
groups
(
lung,
liver,
richly
perfused
tissues,
slowly
perfused
tissues,
and
adipose
tissues).
Because
conjugation
of
EDC
with
glutathione
in
the
lung
and
liver
is
an
important
pathway
of
elimination,
the
model
includes
normal
synthesis
and
breakdown
of
glutathione
in
the
lung
and
liver
and
a
time­
delayed
compensatory
increase
in
glutathione
synthesis
when
glutathione
concentrations
are
less
than
steady­
state
values.

The
model
code
is
provided
below.

PROGRAM:
GLUTATHIONE
DEPLETIONMODEL
FOR
EDC
(
EDC­
GSH.
CSL)
`
Initial
parameter
values
for
the
rat
(
D'Souza
et
al.
1987,
1988)'
`
Retyped,
documentation
modified
by
LMS
7/
19/
01'

INITIAL
`
SPECIAL
FLOW
RATES'
CONSTANT
QPC=
1
5
$`
alveolar
ventilatioh
rate
L/
hr/
kgt'
0.74'
CONSTANT
QCC=
1
5
$`
Cardiac
output
L/
hr/
kg/'
0.74'

`
FRACTIONAL
BLOOD
FLOW
TO
TISSUES'
CONSTANT
QLC
=
0.07
$`
Fractional
blood
flow
to
liver'
CONSTANT
QFC
=
0.05
S'Fractional
blood
flow
to
fat'
CONSTANT
QRC
=
0.64
$`
Fractional
blood
flow
to
rapid'
CONSTANT
QSC
=
0.24
$`
Fractional
blood
flow
to
slow'

`
BODY
WEIGHT'
CONSTANT
BW
=
0.22
$`
Body
weight
(
kg)'

`
FRACTIONAL
TISSUE
VOLUMES'
CONSTANT
VPC
=
0.004
$`
Fraction
lung
tissue'
CONSTANT
VLC
=
0.04
$`
Fraction
liver
tissue'
CONSTANT
VFC
=
0.07
$`
Fraction
fat
tissue'
CONSTANT
VRC
=
0.316
$`
Fraction
rapid
tissue'
CONSTANT
VSC
=
0.48
$`
Fraction
slow
tissue'

`
PARTITION
COEFFICIENTS'
CONSTANT
PP
=
1.1
$`
Lung/
blood
partition
coefficient'
CONSTANT
PL
=
1.1
$`
Liver/
blood
partition
coefficient'
CONSTANT
PF
=
12.2
$`
Fat/
blood
partition
coefficient'
CONSTANT
PS
=
0.8
$`
Slowly
perfused
tissue/
blood
partition
coefficient'
CONSTANT
PR
=
1.1
$`
Richly
perfused
tissue/
blood
partition
coefficient'
CONSTANT
PB
=
27.6
$`
Blood/
air
partition
coefficient'

10
CONSTANT
MW
=
98.96
S'Molecular
weight
(
g/
mol)'

`
KINETIC
CONSTANTS'
CONSTANT
VMAX1C
=
3.15
$`
Maximum
velocity
ofmetabolism
(
mg/
hr­
kg"
0.7)'
CONSTANT
VMAXpC
=
3.15
$`
Maximum
velocity
ofmetabolism
(
mg/
hr­
kg"
0.7)'
CONSTANT
KM
=
0.25
S'Michaelis­
Menten
constant
(
mg/
L)'

CONSTANT
KGSC=
0.0012
$`
conj
rate
const
w
parent(
1/(
uM­
hr­
kg1"­
0.7))'
CONSTANT
KGSMC
=
0.15
$`
conj
rate
const
w
metab
(
1/(
uM­
hr­
kg'~'­
0.7))'
CONSTANT
KFEEC=
4500
S'conj
rate
const
w
non
gsh
(
1/(
hr­
kg"­
0.7))'
CONSTANT
KOalC
=
3.8
$`
GSH
synthase
synthesis
liv(
umol/
hr/
hr/
kg/'­
0.7)'
CONSTANT
KOapC
=
0.22
$`
GSH
synthase
synthesis
lu(
umol/
hr/
hr/
kgt'­
0.7)'
CONSTANT
K1C=
0.1
16
$`
GSH
breakdown
(
1/
hr/
kg'~­
0.7)'
CONSTANT
K1
aC=
0.095
$`
GSH
synthase
breakdown(
1
/
hr/
kg'~­
0.
7)'
CONSTANT
KS
=
1000
$`
Maximum
GSH
induction
(
uM)'
CONSTANT
TD
=
1.5
$`
Time
delay
(
hr)'
CONSTANT
GSO1
=
7000
$`
Initial
GSH
concentration
(
uM)'
CONSTANT
GSOp
=
1200
$`
Initial
GSH
concentration
(
uM)'
CONSTANT
PLRATIO=
0.
14
$`
MFO
ratio
lung/
liver'
CONSTANT
KOOl
=
11.254
$`
liver
(
umol/
hr)'
CONSTANT
KOOp
=
11.254
$`
liver
(
umollhr)'

`
DOSING
INFO'
CONSTANT
CONC
=
10
$`
Inhaled
concentration
(
ppm)'

`
Periodic
drinking
water
exposure
section'
`
assume
t=
0
is
7
am
for
reference'
iNTEGER
I
$
I=
1
$`
Counter
for
drinking
arrays'
CONSTANT
DRCONC=
0.0
$`
Conc
of
EDC
in
water
(
mg/
L)'
CONSTANT
KA
=
5
$`
rate
const
absorp
EDC
from
stomach'
ARRAY
DRTIME(
6)
$`
store
drinking
times
in
array'
ARRAY
DRPCT(
6)
$`
store
drinking
percentages'
CONSTANT
DRTIIME=
1.0,5.0,9.0,13.0,17.0,21.0
CONSTANT
DRPCT=
0.233,0.1,0.1,0.1,0.233,0.234
`
Assume
70
kg
man
drinks
2
liters/
day,
calc
rodent
allometrically'
DRVOL
=
0.102*
BW**
0.7
$`
calc
vol
water
drunk
from
BW'
DRDOSE
=
DRVOL*
DRCONC
$`
total
dose
from
water
each
day
(
mg)'
ODOSE
=
0.0
$`
to
calculate
input
to
stom
(
mg)'
NEWDAY
=
0.0
$`
to
reset
arrays
each
24
hrs'

`
TIMING
PARAMETERS'
CONSTANT
TSTART
=
48.
$`
Start
of
exposure
(
hrs)'
CONSTANT
TPER=
24
CONSTANT
TSTOP=
120
CONSTANT
POINTS=
1200
$`
Number
ofpoints
in
plot'
CINT
=
TSTOP/
POINTS
$`
Communication
interval'

11
TCHNG=
6
`
SCALED
PARAMETERS'
QC
=
QCC*
BW**
0.74
QP
=
QPC*
BW**
0.74
QL=
QLC*
QC
QF
=
QFC*
QC
QS=
QSC*
QC
QR=
QRC*
QC
VP
=
VPC*
BW
VL
=
VLC*
BW
VF=
VFC*
BW
VS
=
0.82*
BWVF
VR
=
0.09*
BW~
VL
`
Liver
metabolism'
VMAX1=
VMAX1C*
BW**
0.7
KOal
KOalC*
BW**
0.7
Kgs
=
KgsC*
bw**(~
0.3)
Kgsm
=
KgsmC*
bw**(~
0.3)
Kfee
KfeeC*
BW**(~
0.3)
Ki
=
K1C*
BW**(~
0.3)
Kia
=
K1aC*
BW**(~
0.3)
AGSO1=
GSO1*
VL
`
Lung
metabolism'
VMAXp=
PLRATIO*
VMAXpC*
BW**
0.7
KOap
=
KOapC*
BW**
0.7
AGSOp=
GSOp*
VP
P1=
0
P1
R=
0
P2=
0
P2R=
0
P3=
100
P3R=
100
END
$`
End
ofinitial'

DYNAMIC
ALGORITHM
IALG=
2
$`
Gear
method
for
stiff
systems'

DERIVATIVE
`
CI=
Concentration
in
inhaled
air
(
mg/
i)'
CI=
MW/
24450*
CONC*
pulse(
tstart,
tper,
tchng)

`
Algebraic
solution
for
CAl
after
gas
exchange'
CA1=
(
QC*
CV
+
QP*
CJ)/(
QC
+
QP/
PB)

12
CX
=
CAl/
PB
`
Mass
balance
for
the
lung
tissue
compartment'
RAP
=
QC*(
CAl~
CA)­
RAMp
AP
=
INTEG(
RAP,
0.0)
CP
=
AP/
VP
AUCP=
1NTEG(
CP,
0.0)
CA=
CP/
PP
AUCB=
INTEG(
CA,
0.0)

`
UPTAKE
BY
ORAL
ROUTE'
RSTOM
=
~
KA*
STOM
$`
dSTOM/
dT'
STOM
1NTEG(
RSTOM,
0.0)
+
ODOSE
$`
amount
in
stomach
(
mg)'

`
AS
=
Amount
in
slowly
perfused
tissues
(
mg)'
RAS
=
QS*(
CACVS)
AS
=
1NTEG(
RAS,
0.0)
CVS
=
AS/(
VS*
PS)
CS
=
AS/
VS
`
AR
=
Amount
in
richly
perfused
tissues
(
mg)'
RAR
=
QR*(
CA~
CVR)
AR
=
INTEG(
RAR,
0.0)
CVR
=
AR/(
VR*
PR)
CR
=
AR/
VR
`
AF
=
Amount
in
fat
tissues
(
mg)'
RAF
=
QF*(
CA~
CVF)
AF
=
INTEG(
RAF,
0.0)
CVF
=
AF/(
VF*
PF)
CF
=
AF/
VF
`
CV
=
Mixed
venous
blood
concentration
(
mg/
i)'
CV
=
(
QF*
CVF
+
QL*
CVL
+
QS*
CVS
+
QR*
CVR)/
QC
`
LIVER
METABOLISM'
`
AL
=
Amount
in
liver
tissue
(
mg)'
RAL
=
QL*(
CA~
CVL)~
RAMi
+
~
AL
=
INTEG(
RAL,
0.0)
CVL
=
AL/(
VL*
PL)
CL
=
AL/
VL
AUCL
=
INTEG(
CL,
0.)

`
AM
=
Amount
metabolized
liver
(
mg)'
RAM1=(
VMAX1*
CVL)/(
KM+
CVL)+
RACPG1*
MW/
1000
AM1=
INTEG(
RAM1,0.)
AMPl=
AM1*
1
000/
MW
13
RAMPl=
RAML*
1000/
MW
`
CMlOXIDATIVE
METABOLITE
LIVER
mg/
L)'
RAMMl=(
VMAXl*
CVL)/(
KM+
CVL)~
RACMGl*
MW/
1000~
RACMEEl*
MW/
1000
AMM1=
INTEG(
RAMM1,0.)
CML=
AMM1/
VL
`
GSl
=
GLUTAHIONE
LIVER
(
uM)'
GSHtd1
=
DELAY(
GS1*
1,
GSi,
TD,
10000)
$`
Time
delayed
GSH
levels'
RKO1=
KOal*(
GSO1+
KS)/(
GSHtd1
+
KS)­
K1
A*
KOl
KOl=
INTEG(
RKOL,
KOOl)
RAMGS1=
KOl­
K1*
GS1*
VLRACMG1RACPGI
AMGS1=
INTEG(
RAMGSi,
AGSO1)
GS1=
AMGS1/
VL
`
ACMGi=
AMT
METABOLITE
CONJUGATED
WITH
GSH
LIVER
(
uMOLES)'
RACMG1=
KGSM*
GS1*
CM1*
1000/
MW
ACMG1=
INTEG(
RACMGi,
0.0)

`
ACMEEl=
AMT
METABOLITE
CONJUGATED
WITH
EVERYTHING
ELSE
LIVER'
`
uMOLES'
RACMEE1=
KFEE*
VL*
CM1*
1000/
MW
ACMEEi=
INTEG(
RACMEEI,
0.)

`
ACPGl
=
AMT
PARENT
CONJUGATED
WITH
GSH
LIVER
(
uMOLES)'
RACPGi=
KGS*
GS1*
CVL*
VL*
1000/
MW
ACPG1=
INTEG(
RACPG1,0.)

`
LUNG
METABOLISM'
`
AMp=
Amount
metabolized
lung
(
mg)'
RAMp=(
VMAXp*
CA)/(
KM+
CA)+
RACPGp*
MW/
1
000
AMp=
INTEG(
RAMp,
0.)
AMPp=
AMp*
1000./
MW
RAMPp=
RAMp*
1000./
MW
`
CMp=
OXIDATIVE
METABOLITE
(
mg!
L)'
RAMMp=(
VMAXp*
CA)/(
KM+
CA)~
RACMGp*
MW/
1000~
RACMEEp*
MW/
1000
AMMp=
INTEG(
RAMMp,
0.)
CMpAMMp/
VP
`
GSp=
GLUTAHIONE
LUNG
(
uM)'
GSHtdpDELAY(
GSp*
1
,
GSp,
TD,
1
0000)$'
Time
delayed
GSH
levels'
RK0pK0AP*(
GSOp+
KS)/(
GSHtdp+
KS)~
K1A*
KOp
KOp=
INTEG(
RKOp,
KOOp)
RAMGSp=
KOp­
K1
*
GSp*
Vp..
RACMGpRACpGp
AMGSp=
INTEG(
RAMGSp,
AGSOp)
GSp=
AMGSp/
VP
14
`
ACMGp=
AMT
METABOLITE
CONJUGATED
WITH
GSH
LUNG
(
uMOLES)'
RACMGp=
KGSM*
GSp*
CMp*
VP*
1000/
MW
ACMGp=
INTEG(
RACMGp,
0.)

`
ACMEEp=
AMT
METABOLITE
CONJUGATED
WITH
EVERYTHING
ELSE
LUNG
(
uMOLES)'
RACMEEp=
KFEE*
VP*
CMp*
1000/
MW
ACMEEp=
INTEG(
RACMEEp,
0.)

`
ACPGp=
AMT
PARENT
CONJUGATED
WITH
GSH
LUNG
(
uMOLES)'
RACPGp=
KGS*
GSp*
CP*
VP*
1000/
MW
ACPGPp=
INTEG(
RACPGp,
0.)

`
PCTGSH­
PERCENT
GSH
COMPARED
TO
CONTROL'
PCTGSHP=
GSp/
GSOp*
100
TERMT(
T.
GE.
TSTOP)

PROCEDURAL
(
P1
,
P
1R=
AMP,
RAMP)

IF(
T.
LT.(
DRTIME(
I)+
NEWDAY))
GO
TO
SKIP2
ODOSE=(
ODOSE+
DRPCT(
I)*
DRDOSE)*
PULSE(
TSTART,
TPER,
TPER)
1=
1+
1
IF(
I.
LT.
7)
GO
TO
SKJP2
1=
1­
6
NEWDAY=
NEWDAY+
24.0
SKJIP2..
CONTINUE
IF
(
AMIN1(
AMP1,
RAMP1,
ACMGI,
RACMG1,
ACMEE1,
RACMEE1).
LT.
1E­
9)
GOTO
OUT
`
Pl=
PERCENT
PARENT
METABOLISM
THROUGH
GSH'
P1
=
ACPG1/
AMP1*
100
P1R=
RACPG1/
RAMP1*
100
`
P2=
PERCENT
METABOLITE
CONJUGATED
WITH
GSH'
P2=
ACMG1/(
ACMG1+
ACMEE1)*
100
P2R=
RACMG1/(
RACMG1+
RACMEE1)*
100
P3=
1
00­
P2
P3R=
1
00­
P2R
OUT..
CONTINUE
END
$`
End
ofprocedural'
END
$`
End
ofderivative'
END
$`
End
ofdynamic'
END
$`
End
ofprogram'

15
16
C.
6
General
Outline
for
Route­
to­
Route
Extrapolation
Reports
A
total
of
three
route­
to­
route
extrapolation
reports
will
be
generated
for
EDC,
one
for
each
of
the
following
endpoints:
subchronic
toxicity,
subchronic
neurotoxicity,
and
reproductive
toxicity.
At
a
minimum,
each
ofthese
reports
will
follow
the
general
outline
presented
below.

1.0
Introduction
Statement
of
objectives
for
a
specific
endpoint
route­
to­
route
extrapolation
relevant
to
the
testing
for
EDC
Application
ofthe
PBPK
Model
for
EDC
relevant
to
specific
endpoint
2.0
Summary
of
Key
Study
(
ies)

For
subchronic
toxicity,
the
design
and
results
ofDaniel
et
al.
(
1994)
will
be
summarized
relevant
to
the
route­
to­
route
extrapolation
and
results
from
Tier
I
Program
Review
Testing.

For
subchronic
neurotoxicity,
the
design
and
results
of
the
Tier
II
testing
will
be
summarized
relevant
to
the
route­
to­
route
extrapolation
and
results
from
Tier
I
Program
Review
Testing.

For
reproductive
toxicity,
the
design
and
results
ofthe
Tier
II
testing
will
be
summarized
and
the
results
of
Alumot
et
al.
(
1976),
Rao
et
al.
(
1980)
and
Lane
et
al.
(
1982)
will
be
summarized
relevant
to
the
route­
to­
route
extrapolation
and
results
from
Tier
I
Program
Review
Testing.

3.0
Selection
of
Critical
Endpoints
and
Dose
Measure(
s)

For
subchronic
toxicity,
subchronic
neurotoxicity
and
reproductive
toxicity,
the
endpoints
and
dose
measures
will
be
determined
from
the
Tier
II
testing.
4.0
Route­
to­
Route
Extrapolation
Results
Quantitative
calculation
of
inhalation
NOAEL/
LOAEL
values
for
corresponding
oral
values.

5.0
Sensitivity
Analysis
Assessment
of
the
contribution
of
variability/
uncertainty
in
each
parameter
to
PK
modeling
results.

6.0
Conclusions
7.0
References
17