Upload
morris-walsh
View
219
Download
0
Embed Size (px)
Citation preview
1
LADEK ZDRÓJ
2003
2
LASER SPECTROSCOPIC STUDY OF PHTHALOCYANINE DERIVATIVES SYNTHESIZED FOR PHOTODYNAMIC
THERAPY
András Grofcsik
Budapest University of Technology and Economics
Department of Physical Chemistry
3
Photodynamic therapy (PDT)
Hematoporphyrin derivative (HpD)
Phthalocyanines (Pc)
Synthesis
Photophysical properties
in solutions
in vesicles
5-Amino-levulinic acid (ALA)
4
Cancer therapies surgery radiotherapy chemotherapy
Photodynamic therapy (PDT): use of visible light in combination with a photosensitiser
5
Number of publications in PDT
0
500
1000
1500
2000
2500
3000
1981-85 1986-90 1991-95 1996-2000
6
Administration of
photosensitizer
Irradiation with visible light
Photosensitizer accumulates in
the tumour.
Tumour is selectively destroyed
Steps of photodynamic therapy
7
Photodynamic effect:Cell destruction by
photosensitiser + visible light + O2
)()()( 110 TPSPSP ISCh
ProductsOesBiomolecul
OSPOTP
*2
1
*2
102
31 )()(
•TYPE II: energy transfer
•TYPE I: electron-transfer: Radicals and radical ions
8
vessel
blood
The wavelength dependence of depth of penetration of light into soft tissue
9
Requirements for the photosensitiser:
• Selective accumulation in malignant tissues• High absorbance between 600 and 800 nm• Chemical homogenity• Long triplet lifetime and sufficient triplet energy
(>94 kJ/mol)• Chemical, biological and photochemical stability• Little or no dark toxicity• Simple and cheap syntesis
10
The first sensitiser used in clinical PDT:Hematoporphyrin derivative (HpD) Photofrin®
It is a mixture of compounds.
11 Hematoporphyrin
12
HPLC analysis of HpD
13
• Selective accumulation in malignant tissues• High absorbance between 600 and 800 nm• Chemical homogenity• Long triplet lifetime and sufficient triplet energy
(>94 kJ/mol)• Chemical, biological and photochemical stability• Little or no dark toxicity• Simple and cheap syntesis
Requirements for the photosensitiser:
14
”Second generation" photosensitisers:
porphyrins
chlorins
bacteriochlorins
phthalocyanines (Pc)
naphthalocyanines
5-Aminolevulinic acid (ALA)
15Phthalocyanine
16
00,20,40,60,8
11,21,41,61,8
500 550 600 650 700 750
(nm)
Ab
sorb
an
ce
b
a
Absorpion spectrum of a porphyrin (a) and a phthalocyanine (b) derivative (Ethanol solutions,
c = 1.5*10-5 mol dm-3)
17
Synthesis
4 M = 2H
M = Zn
ROH, DMF, K2CO3
60 W, 20 min
3
21
60 W, 3 minDBU
Zn(OAc)2
60 W, 15 minK2CO3
ROH, DMF CN
CNRO
CN
CNNO2
OR
RO
OR
N N
N
NN N
N
N
OR
M
18
N
NN
M
NN
Phthalocyanine derivatives
I: M: Zn R: 4-tert-Bu-Ph-
II: M: Zn R: CH3O(CH2)2O(CH2)2-
III: M: Zn R: (2,6-dimethyl-4- N,N-dimethylamino- methylen)-phenyl-
IV: M: H2
R: CH3O(CH2)2O(CH2)2-
19
Structure of III
20
Experimental setup for studying triplet states
21
Triplet lifetime and triplet absorption spectrum
II
IlgA
0
0
tOkAlnAln 20 400 450 500 550 600
0,000
0,002
0,004
0,006
0,008
0,010
0,012
0,014
Ethanol solution of I
(7,7*10--6 mol/dm
3)
Abs
orba
nce
[nm]
0 500 1000 1500 2000 2500
-0,03
-0,02
-0,01
0,00
0,01
0,02 Triplet decay
Abs
orba
nce
t [ns]
22
Reaction of triplet Pc with molecular oxygen:
21
023
1 )()( OSPcOTPc
The rate constant can be determined from the decay curves.
23
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,80
5
10
15
20
25
I 0 [m
V]
Laser energy [mJ]
Ref I II IIIIV
Quantum yield of singlet oxygen formation
refref
phtalphtal m
m
24
Triplet lifetimes (), second order rate constants and quantum yields of singlet oxygen formation
Pc (solvent) I (Et) I (To) II (Et) II (To) III (Et) IV (To)
(ns) 306 287 381 263 231 504
k*10-9
(M-1s-1)1.55 1.67 1.25 1.81 2.09 0.95
0.47 0.58 0.42 0.44 0.59 0.19
25
Photosensitisers in vesicles
Vesicles are simple models of cell membranes.
DPPC (dipalmitoylphosphatidylcholine)
26
27
28
Temperature dependence of the rate constant (III in DPPC vesicles)
RT
EexpAk a
Arrhenius plot: Ea = 60.7 kJ
20
20,4
20,8
21,2
21,6
22
0,00300 0,00305 0,00310 0,00315 0,00320 0,00325 0,00330 0,00335 0,00340 0,00345
1/T [1/K]
ln k
29
Use of 5-amino-levulinic acid (ALA) for PDT
COOH
CH2
CH2
C
O
CH2 NH2
ALA stimulates the cellular synthesis of an endogenous photosensitiser: Protoporphyrin IX
Administration of exogenious ALA causes the build-up of phototoxic levels of Protoporphyrin IX
30
Advantages (over HpD):
•Treatment follows 2-4 hours after administration
•Systemic clearence of photosensitiser within 24 hours
•Treatment can be repeated within two days
•ALA can be administered topically
The method was approved by FDA in the 90s) In Hungary clinical trials started in 2001 (National Medical Center)
31
Basal cell carcinoma - before treatment
32
After PDT with ALA
33
PARTICIPANTS Miklós Kubinyi
István Bitter
Viktor CsokaiJanka Tatai Klára Szegletes
Éva BacskayJános Brátán
Tamás VidóczyPéter BaranyaiLajos Csokonai Vitéz
34
The End