Download - Orthogonal imaging jan 2012
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S y s t e m s f o r L i f e S c i e n c e R e s e a r c h
Act P x
Orthogonal four dimensional imaging:
Rapid development of products
using flow through laminar device
Jim Lenke
Act P x
Can changing your perspective Can changing your perspective... improve getting more into the water?
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Measurement
Reaction
Relocate the detector onto the reaction zone – see more!
Measurement Reaction
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•System Operation
•Recent data
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System operation
Programmable
Digital temp control
Software controlled
Programmable pump
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Camera
Pulsed Xenon lamp
Single
wavelength
filter
UV flash lamp
Recording movies in the UV/ VIS
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SDI 300 simplified
J. Østergaard et. Al. Pharm. Res. (2010) 27:2614
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Laminar flow
A B Front view
Laminar flow creates a steady state where the donor concentration
(boundary layer) can be controlled with flow rate. Thereby enabling
probing of the solid-liquid interface in real-time.
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System operation
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Buffer flow ml/min
Solvate particles Move molecules
Mass F
lux
dete
ctio
n z
one
Sample Cup
Surface area
0.0314 cm2
Absorbance *Flow/Surface area =
Intrinsic dissolution rate (IDR) (mg/ml)*(ml/ min)/(cm2)= mg/min/ cm2
Measure
Absorbance
3 easy steps to measure IDR
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Flow (ml/min) IDR (mg/min/cm2)
Buffer capacity
Compression force
Surface energy
pH pKa
Factors influencing laminar-IDR
IDR (mg/min/cm2)
Buffer capacity
Surface energy
pH
pKa
Flow rate
Compression
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Flow through IDR: Viewing dissolution at the surface
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Obvious increase in release in Organic environment
Nicotine release from patch
100%
Phosphate
50%
Phosphate/
50% ACN
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Nicotine release improvement
0
20
40
60
80
100
120
140
160
180
200
0.00 5.00 10.00 15.00 20.00
AU
C (
mm
*A
U)
Time (min)
AUC vs. time
100% PBS
50% CAN/PBS
Linear (100% PBS)
Linear (50% CAN/PBS)
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Diffusion rate
0
200
400
600
800
1000
1200
1400
0 5 10 15 20 25 30
AU
C (m
M *
mm
)
Time (min)
Diffusion vs. pH : Furosemide
pH 1.2
pH 4.5
pH 6.8
0
200
400
600
800
1000
1200
0 5 10 15 20 25 30
AU
C (
mM
*m
m)
Time (min)
Diffusion vs. pH: Ketoprofen
pH 1.2
pH 4.5
pH 6.8
-0.02
0
0.02
0.04
0.06
0.08
0.1
0.12
0 0.2 0.4 0.6 0.8 1
Co
nce
ntr
atio
n (
mM
)
Vertical distance (mm)
Ketoprofen: Concentration profile vs. pH @ 0.2 ml/min
pH 6.8
pH 4.5
pH 1.2
How fast will a constant surface area achieve equilibrium in a static, small volume vessel?
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Crystalline
Amorphous co-precipitate
Diffusion height tracks IDR values
Visualizing IDR
3 decreasing flow rates (0.8, 0.4, 0.2 ml/min )
followed by no flow step.
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IDR vs. Flow rate
y = 0.0186x - 0.0003 R² = 0.9995
y = -0.018x2 + 0.0152x + 0.023 R² = 1
y = -0.009x2 + 0.0101x + 0.0338 R² = 1
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0 0.1 0.2 0.3 0.4 0.5 0.6
IDR
(mg/
min
/cm
^2
)
flow rate (ml/min)
IDR vs. Flow
Flat profile suggests swelling which
‘controls’ dissolution
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Cumulative mass loss per time. Time IDR SD CV
0 0.0304 0.0028 9.2%
1 0.0316 0.0021 6.6%
2 0.0327 0.0021 6.4%
3 0.0315 0.0020 6.3%
4 0.0319 0.0022 6.9%
5 0.0322 0.0022 6.8%
6 0.0321 0.0021 6.5%
7 0.0328 0.0022 6.7%
8 0.0328 0.0020 6.1%
9 0.0329 0.0020 6.1%
10 0.0327 0.0021 6.4%
11 0.0327 0.0021 6.4%
12 0.0330 0.0019 5.8%
13 0.0326 0.0021 6.4%
14 0.0324 0.0022 6.8%
15 0.0321 0.0020 6.2%
16 0.0312 0.0019 6.1%
avg 0.0322 0.0021 6.6%
std 0.0007 0.0002 0.0074
rsd 2.19% 9.48% 11.28%
32.2 ±0.7 µg/min/cm2
y = 0.00101x R² = 0.99984
y = 0.00099x R² = 0.99957
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0 2 4 6 8 10 12 14 16 18
Mas
s (
mg)
Time ( min)
Mass loss per time
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Sample prep influence on IDR
AAPS 2011 Poster: Advances in Novel Dissolution Imaging to Measure IDR rates of Polymorphic API’s.
W. Hulse, J. Gray, R. Forbes, Biopharmaceutical Formulation Group,
University of Bradford, UK
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Sub-surface changes in IDR
As buffer seeps into powder, sub-surface
changes take place, such as pH or
morphology from interacting with buffer.
Typical poorly soluble compounds remove
microns/minute so as new surface becomes
available it’s different.
Wetability and morphology changes are
important factors in API development.
Void pockets = little stagnant reservoirs
Sample
Density Wall
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Release from Sediment
Visible - no molecular
absorbance
UV – ONLY molecular
absorbance
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GI simulation: Mimic continuous pH changes
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0
20
40
60
80
100
120
0 5 10 15 20 25 30 35
% b
uff
er
Time (min)
3 pH gradient profile
A
B
C
A= pH 1.5 B= pH 4.5 C= pH 6.8
A B
C
Variable pH IDR (mimic GI)
effluent
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Rapid evaluation of multiple pH pH 1.2
pH 4.5
pH 6.8
Ketoprofen 0.2 ml/min
sample
2.5
mm
0.0000
0.0040
0.0080
0.0120
0.0160
0.0200
0.0000
0.0500
0.1000
0.1500
0.2000
0.2500
0.3000
0.3500
0 11 22 33
Cu
mu
lati
ve m
ass
(mg)
Cu
mu
lati
ve m
ass
(mg)
Time (min)
Cumulative mass vs. pH @ 0.2 ml/min
Atenolo (pKa 8.9)
Ketoprofen(pKa 4.3)
Furosemide
pH 1.2
pH 4.5
pH 6.8
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IDR vs. pH Ketoprofen
Furosemide
Single experiment, better understanding
•(1) sample
•(1) contious flow rate
•(3) pH buffers
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Conclusion:
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Orthogonal flow through imaging
• Fast and small
o 2-7 mg/run with only 10 ml buffer in less than 20 min
• Able to measure more than just IDR
o IDR vs. flow, IDR vs. pH, diffusion rate, diffusion boundary layer
• GI modeling potential
o Understand how pH affects IDR
Get more into the water by changing your view!
Act P x
Publications 1. Insights into the Early Dissolution Events of Amlodipine Using UV Imaging
and Raman Spectroscopy, J. Boetker et. al. Mol. Pharm. (2011)
dx.doi.org/10.1021/mp200205z
2. Pharmaceutical Dissolution and UV Imaging, S.Wren, J. Lenke, American
Laboratory (2011)
3. Monitoring Lidocaine Single-Crystal Dissolution by Ultraviolet Imaging, J.
Østergaard et. al. J. Pharm. Sci. (2011) DOI 10.1002/jps.22532
4. Realtime UV-imaging of Nicotine Release from Transdermal Patch, J.
Østergaard, Pharm. Res (2010) 27:2614–2623 DOI 10.1007/s11095-010-
0257-9
www.paraytec.com
S y s t e m s f o r L i f e S c i e n c e R e s e a r c h
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Thanks to:
•Prof. R. Forbes, University of Bradford
•Prof. J. Østergaard, University Copenhagen
•Prof. N. Fotaki, University of Bath
•Dr. S. Wren, AstraZeneca (UK)
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Additional Material
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IDR vs. Flow rate
y = 0.0186x - 0.0003 R² = 0.9995
y = -0.018x2 + 0.0152x + 0.023 R² = 1
y = -0.009x2 + 0.0101x + 0.0338 R² = 1
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0 0.1 0.2 0.3 0.4 0.5 0.6
IDR
(mg/
min
/cm
^2
)
flow rate (ml/min)
IDR vs. Flow
IDR at multiple flows provides a better fingerprint of performance-
particularly at physiological linear velocities
3 formulations @
• 3 flow rates
•Identical buffer
•Identical compression
Flat profile suggests swelling which
‘controls’ dissolution
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Particle dissolving rate from IDR
Know that average density = 12 mg/ 2.4 mm
or 5 µg / µm
From average density, can calculate time
needed to dissolve particle.
Time = ( Thickness X Density) / DR
={(163 µm) x (5 µg / µm)} / (µg /min)
Ex: (815µg)/ 14 µg /min = 58 min
Convert surface area (3.14 x 10 ^6 um2)
into sphere: A particle that is: Diameter = 1000 µm ( 1.0 mm) Volume = 5.1 x 10^8 µm 3
Thickness equivalent to particle volume = Vol/ Area= 163 µm
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In-situ surface pH Measurements
UV pH Dye
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Buffer Capacity: Ketoprofen
50 mM NaH2PO4 pH 6.5
530 nm; Methyl red in buffer;
10 mM NaH2PO4 pH 6.5
Water
Observing in-situ surface pH at
different buffering capacities
provides insight into biorelevant
media performance if surface pH
is altered in standard aqueous media.
**pKa = 4.2
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Atenolol: Surface pH
UV( 254 nm) pH 4.5 50 mM NaH2PO4
Flow = 0.6,
Phenolphtalein (530 nm) pH 4.5 50 mM NaH2PO4
Flow = 0.6
•Rapidly soluble Atenolol ( pKa 9.2) dissolves fast enough to drastically change pH and
amount of ionized API. Dark red in top picture near detector saturation, but important
measurement is thickness of diffusion boundary layer ( Red > Blue).
**pKa= 9.2
Act P x Sensor stand
Quick couple
fittings Imaging
area
Cut away view
Single wavelength UV light passes through
flow cell across sample
Flow cell sits over the camera
Flow cell orientation
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Surface availability
Towards center
Z axis
Surface concentration
Boundary layer
Convective loss
At lower flow rates more material
reaches center stream, farther
away from wall.
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Effluent concentration or ‘dynamic Solubility’
y = 10x + 3E-15
y = 20x + 5E-15
0
10
20
30
40
50
60
70
0 0.5 1 1.5 2 2.5 3 3.5
IDR
( m
g/m
in/c
m^
2)
Flow rate (ml/min)
Solubility and flow rate
API 1
API 2
solubility API 1
solubility API 2
Linear (API 1)
Linear (API 2)
Running a single sample experiment* at different flow rates offers a plot of IDR vs.
flow rate.
(IDR) / (flow rate) = solubility
(mg/min) / (ml/min) = mg/ml
API 2
API 1
Solubility API 1
In Vitro Dynamic Solubility Test: Influence of Various Parameters Sylvie Thelohan and Alain de Meringo
Environ Health Perspect 1 02(Suppl 5):91-96 (1994)
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dynamic Solubility
0.030
0.035
0.040
0.045
0.050
0.055
0.060
0.065
0.070
0.075
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Solu
bil
ity
(mg/
ml)
IDR
(m
g/m
in/c
m^
2)
Flow rate (ml/min)
IDR and dynamic Solubility vs. flow rate
IDR
Solubility
Fa
st
Fe
d
Can effluent concentration from flow through device be successfully used to predict available concentration?
Act P x
dynamic Solubility
Comparison of effluent concentration and calculated dynamic solubility
Strong correlation.
y = 0.0799x-0.473 R² = 0.9994
y = 0.0533x-1.063 R² = 0.9964
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.065
0.085
0.105
0.125
0.145
0.165
0.185
0.205
0.225
0.245
0.265
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Cal
cula
ted
dS
(mg/
ml)
Effl
ue
nt
Co
nce
ntr
atio
n (m
g/m
l)
Flow rate (ml/min)
comparison of effluent and dS
effluent
dS
Power (effluent)
Power (dS)
Implies decrease with increasing flow rate, however………..
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2 ml/min
0.5 ml/min
0.2 ml/min
0.1 ml/min
0.05 ml/min
a)
b)
c)
d)
e)
Radial distribution in GI
Stagnant layer –aqueous boundary layer
Injections from HPLC into flow cell shows rate, amount and time at Lumen wall vs. flow rate. Shown with Caffeine at different flow rates.
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Radial distribution in GI
Stagnant layer –aqueous boundary layer
Injections from HPLC into flow cell shows rate, amount and time at wall vs. flow rate. Shown at 0.5 & 0.05 ml/min flow rates.
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GI Fluid dynamics
Can these technique be used in a predictive manner to
close the gap between in-vitro and in-vivo correlation?
Z axis
Z axis
X axis
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Measurement location
3-Dimensional data ( intensity over X-Z) over time= 4 Dimensional data
True sample-liquid interface measurements
vx
z
Detector
Flow (ml/min)
Downstream absorbance
measure
X axis
Z axis Downstream measure zone
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Press operation
Sample cup
Dissolution face
Compression rod
Top plate
Sample plate
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Powder sample compression
Automatically aligned
sample cup
Load sample powder. Compress using reproducible
torque wrench
Quality of sample surface
depends on face
Image of sample cup
surface after compressing
powder
Other experiments can be carried out on surface before
and after dissolution analysis!!
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Linear velocity related to App4 SDI APP 4 APP 4
Sectional area
(cm2)
0.14 11.3 22.6
Flow rate (ml/min)
0.1 0.7 0.1 0
0.2 1.4 0.2 0
0.4 2.9 0.4 0.1
0.8 5.7 0.8 0.2
1.2 8.6 1.2 0.3
2.0 14.3 2.0 0.5
4.0 28.6 4.0 1.0
8.0 57.1 8.0 2.0
16 114 16.0 4.0
32 227 32.0 8.0
Time (min) 60 270 420 Total(mL)
Flow rate
(ml/min)
SDI 0.2 12 54 84 150
App 4 1.2 72 324 504 900
App 4 4.0 240 1080 1680 3000
Linear velocity range
compared to App 4 device.
Covers same physiological
range using less volume.
Additional benefit from
no-flow measurements
12.5 hrs uses only 150 ml
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Highly stable process
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 0.07 0.14 0.21 0.28 0.35 0.42 0.49 0.56 0.63 0.7
Ab
sorb
ance
(A
U)
Z Distance (mm)
Absorbance profile vs. time:
0
2
4
6
8
10
12
14
16
Profile over 17 min at constant flow.
• Time zero (blue line) shows pump start.
210 µm
0.14 0.15 0.16 0.17 0.18 0.19 0.2 0.21
Time IDR SD CV
0 0.0304 0.0028 9.2%
1 0.0316 0.0021 6.6%
2 0.0327 0.0021 6.4%
3 0.0315 0.0020 6.3%
4 0.0319 0.0022 6.9%
5 0.0322 0.0022 6.8%
6 0.0321 0.0021 6.5%
7 0.0328 0.0022 6.7%
8 0.0328 0.0020 6.1%
9 0.0329 0.0020 6.1%
10 0.0327 0.0021 6.4%
11 0.0327 0.0021 6.4%
12 0.0330 0.0019 5.8%
13 0.0326 0.0021 6.4%
14 0.0324 0.0022 6.8%
15 0.0321 0.0020 6.2%
16 0.0312 0.0019 6.1%
avg 0.0322 0.0021 6.6%
std 0.0007 0.0002 0.0074
rsd 2.19% 9.48% 11.28%
32.2 ±0.7 µg/min/cm2
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IDR vs. time: A Change ? Time IDR SD CV
0 0.0304 0.0028 9.2%
1 0.0316 0.0021 6.6%
2 0.0327 0.0021 6.4%
3 0.0315 0.0020 6.3%
4 0.0319 0.0022 6.9%
5 0.0322 0.0022 6.8%
6 0.0321 0.0021 6.5%
7 0.0328 0.0022 6.7%
8 0.0328 0.0020 6.1%
9 0.0329 0.0020 6.1%
10 0.0327 0.0021 6.4%
11 0.0327 0.0021 6.4%
12 0.0330 0.0019 5.8%
13 0.0326 0.0021 6.4%
14 0.0324 0.0022 6.8%
15 0.0321 0.0020 6.2%
16 0.0312 0.0019 6.1%
avg 0.0322 0.0021 6.6%
std 0.0007 0.0002 0.0074
rsd 2.19% 9.48% 11.28%
32.2 ±0.7 µg/min/cm2
1.75
2.00
2.25
2.50
2.75
30.25
30.50
30.75
31.00
31.25
31.50
31.75
32.00
32.25
32.50
32.75
33.00
33.25
0 2 4 6 8 10 12 14 16 18
Stan
dar
d D
evi
atio
n
IDR
(µg/
min
/cm
^2
)
Time (min)
IDR vs. time
µg/min IDR
Std. Dev.
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Minimum flow step
0.000
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0 15 30 45
3 m
in C
um
ula
tive
mas
s (m
g)
Cu
mu
lati
ve m
ass(
mg)
Time (min)
Cumulative mass vs. pH: Ketoprofen
pH 6.8
pH 4.5
pH 1.2
3 min step pH 6.8
3 min pH 4.5
3 min pH 1.2
Equivalent rank order values can be found with as little as 3 min when compared to 15 min step.