A Compound for Imaging Cell Death

The invention pertains to a compound for imaging cell death in vitro and in vivo, as well as to a method for detecting the progression or regression of a tumor in a patient. Furthermore, the invention relates to a pharmaceutical composition, comprising such a compound, a precursor suitable for obtaining it, a method for obtaining it and to a kit for imaging cell death.

Throughout this application, various publications and handbooks are cited. The disclosure of these publications and handbooks are hereby incorporated by reference in its entirety into this application to describe more fully the state of the art to which this invention pertains.

Introduction

Therapy control of tumors is one of the main areas of interest during the follow up of cancer patients. This information is currently acquired by a series of conventional investigations including morphological changes, symptomatic responses and clinical chemistry. Radiological techniques like X-ray, computed tomography (CT), ultrasonography (US) and magnetic resonance (MR) are imaging techniques which cover the size and morphology of tumor masses and to some degree alterations of tumor perfusion.

At the same time, nuclear medicine has a series of radiopharmaceuticals at its disposal which are successfully used for the assessment of therapy response. Among those agents, [ F]FDG represents the main protagonist which is acting as a surrogate marker used to show the influence of e.g. cytostatic drugs on the glucose transport and hexokinase activity in tumors. A de- crease in tracer accumulation is expected to indicate treatment response and a better survival. However, interpretation of the signal might be complicated by inflammatory reactions, for example early after radiation therapy. Furthermore, tumor response is shown via a negative signal, i.e. a decrease in tracer uptake. This may be problematic in cases of a moderate accumulation of the tracer prior to therapy. In this respect, tracers providing a positive signal are more desirable. A few years ago, ^99m Tc labeled annexin V was presented as a new agent capable to image cell death in vivo. Apoptosis was visualized in several model systems including myocardial infarction, Fas antibody treated liver and tumors after cytostatic drug application (1, 2). The use of ^99m Tc labeled annexin V as an in vivo imaging indicator for apoptosis based on results ob- tained with the annexin V - fluorescent dye conjugate was used to show apoptotic cells under the microscope (3).

Annexin V has first been isolated from human placenta (4) demonstrating an anticoagulant effect by inhibiting among other factors prothrombinase activity. This effect was attributed to the displacement of coagulation factors from the phospholipid membrane (5). Annexins are ubiquitous homologous proteins that bind to phospholipids in the presence of calcium. Annexin V, formerly also named as placental anticoagulant protein (PAP) or vascular anticoagulant protein (VAC-α) (5), binds together with Ca ²⁺ on externalized phosphatidyl- serine (PS) present on the cell membranes early after the onset of apoptosis. Under normal conditions, phosphatidylserine resides to about 100 % on the interior leaflet of the bi-layered cell membrane where it functions as an anchor for e.g. annexin I, which is involved in transmembrane signaling and internalization processes (6). Due to the activation of effector cas- pases 3, 6 and 7, which are induced either after intrinsic or extrinsic stimuli, proteolytic inac- tivation of proteins occurs which maintain under normal conditions the asymmetric distribution of lipids within the cell membrane. Several types of translocase enzymes belong to these proteins, including an ubiquitous Mg ²⁺ -ATP dependent aminophospholipid flippase that selectively catalyzes the inward transport of phosphatidylserine and phosphatidylethanolamine, an ATP dependent floppase that moves phospholipids outward with little headgroup specificity, and a Ca ²⁺ dependent scramblase that destroys the bilayer asymmetry (7). ATP depletion due to the energy demanding apoptotic process may also hamper the maintenance of the asymmetric lipid distribution.

The high affinity of annexin V for cells which expose phosphatidylserine, exhibiting a K _< i of <10 ^"10 mol/1 (8) is the basis of detecting apoptosis in vivo. The structural background for this strong annexin V - phosphatidylserine interaction is slowly elucidated.

It is known from X-ray structure analyses that this kind of binding functions through the co- complexation of Ca ²⁺ with the carboxyl-phospholipid headgroup in collaboration with so called AB, AB' and DE Ca ²⁺ -binding sites. These binding sites are located in each of the four tandemly repeated segments of annexin V. Figure 1 illustrates the interaction in one of these segments (domain III) with glycerophos- phoserine (truncated phosphatidylserine) on Ca ²⁺ -annexin V binding sites (9). Primary AB and secondary AB' Ca ²⁺ sites are located within the loop between the A and B helices of each domain. They are also called type II and type III Ca ²⁺ binding sites, respectively. It should be noted that the three complexation sites AB, AB' and DE imply differently coordinated calcium cations with different stabilities, namely AB > AB' > DE. The second complex entity phosphatidylserine coordinates Ca ²⁺ in the AB' site with the carboxyl function of serine and with the negatively charged phosphate oxygen in the AB site. In addition, the α- amino group of serine interacts in this domain with Threonine (Thr) 187. The interaction of annexin V with phosphatidylserine through jointly used Ca ²⁺ is, however, not alone responsible for the strong binding affinity. Multivalent binding must be taken into account, since Ca ²⁺ is forming peptide complexes with a stability constant of log K ₁ in the range of only 4-5. In combination with phosphatidylserine, this value may increase to some degree because of the bidenticity of phosphatidylserine for Ca ²⁺ . However, in order to meet the above mentioned small dissociation constant, two or more domains must be involved in the annexin V / Ca ²⁺ / phosphatidylserine headgroup interactions. These considerations assume that Ca ²⁺ is present in a sufficient concentration. The Ca ²⁺ dependency was validated by titration in presence of annexin V binding at low membrane occupancy showing strong coop- erativity of this interaction with respect to Ca ²⁺ (10). Up to 12 Ca ²⁺ ions can theoretically be complexed by three binding sites (AB, AB' and DE) in each of the domains. As many as 10 Ca ²⁺ ions have been located in rat annexin V crystal structures all binding at the membrane- facing surface of the protein (9).

Besides the annexin V/phosphatidylserine system, other approaches have been tested for the imaging of cell death resulting from apoptosis but also necrosis. Alternative targets in the apoptotic pathway potentially useful for the in vivo detection of apoptosis are activated cas- pases (11-13). The two systems tested in this context are based on the binding of irreversible inhibitors or substrates to activated executioner caspases. The hitherto obtained results have been summarized recently (14, 15).

As already mentioned before, annexin V is typically labeled with a fluorescent dye for in vitro assays (3). Although it is utilized extensively in molecular biology, the labeled protein is expensive and moderately unstable. Thus, it is not convenient for high throughput screening assays in drug discovery. Additionally, approximately 2.5 mmol/1 of extracellular Ca ²⁺ is needed for complete binding. This can lead to false positive results because most animal cells have a Ca ²⁺ dependent scram- blase that can move phosphatidylserine to the cell surface (16). Furthermore, complete an- nexin binding requires incubation times of up to one hour, which is problematic for kinetic as- says (17, 18). hi short, dye labeled annexin V is a useful apoptosis sensor, but it has a number of limitations and there is a need for replacement reagents that are cheap, robust, low-molecular weight, rapidly-binding, membrane-impermeable, and Ca ²⁺ -independent. Accordingly, the problem underlying the present invention was to provide a molecule that would show improved charac- teristics as a phosphatidylserine-binding agent and, in particular, to provide a molecule that would show improved characteristics as an apoptosis sensor over annexin V.

In more general term, the aim of the invention is to provide improve molecule enabling the in vivo or in vitro detection of cell death. The improved molecule is a marker specifically binding to dying or dead cells resulting from apoptosis or necrosis. One of the recent developments introduced zinc bis-(2,2-dipicolylamine) (Zn ²⁺ bis-DPA) coordination complex shown in Figure 2 has been designed to mimic the apoptosis sensing function of annexin V (19, 20). According to Figure 1, one phosphatidylserine head group is coordinated to two bridging Ca ²⁺ ions that are in turn coordinated to one of the four canonical binding sites at the protein surface (9).

Description of the invention

Contrary to the expectation that one of the Zn-coordinating heteroatoms has to be water in order to provide a replacable binding site for phosphatidylserine, the inventors used a compound with at least one cyclic polyamine unit for the complexation of a bi- or trivalent metal ion, in particular cyclen (12[ane]N ₄ ) or cyclam (14[ane]N ₄ ) instead of DPA. Preferably, the cyclen is a cyclic ethylene bridged tetramine, and the cyclam is a mixed ethylene- propylene bridged tetramine, both of which have four nitrogen atoms for Zn ²⁺ complexation. The stability constant for this class of compounds is about 10 ¹⁵ (mol/1) ^"1 (for cyclam), as compared to 10 ⁵ (mol/1) ^"1 for DPA.

Accordingly, in a first aspect of the invention, the underlying problem is solved by a compound or complex that comprises or contains at least one cyclic polyamine unit (C). This cyclic polyamine unit (C) allows for the binding or complexation of a multivalent, in particular of a bi- and/or a trivalent metal ion as a central ion of the complex.

Excluded from the scope of the invention, in one aspect of the invention, is AMD3100 (1,1'- [ 1 ,4-Phenylenebis(methylen)]bis [ 1 ,4,8, 11 -tetraazacyclotetradecan]-octohydrobromid-dihy- drate) as such and its derivatives (i.e. substituted AMD3100), which is a compound with cyclic polyamine units. AMD 3100 was designed to treat HIV infections by inhibiting the viral entry through the CD4 / CXCR4 receptor assembly. The use of AMD3100 for binding phosphatidylserine and for apoptosis imaging, however, lies within the scope of the invention. 1 , 1 '-[ 1 ,3-Phenylenebis-(methylene)]-bis-tris(p-toluenesulphonyl)- 1 ,4,7,10- tetraazacyclododecane is excluded from the invention because it concerns active ingredient active against HIV, compound disclosed below.

The first aspect is in a first embodiment directed to a compound or complex characterized in that the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of bi- or trivalent metal ion or complexing bi- or trivalent metal ion, and pharmaceutical salt, diastereomere and enantiomere thereof.

Optionally, the compound or complex of the invention comprises further at least one Tag (T) or linker (L)-Tag (T), and/or at least one Bridge unit (B) or a bond,

Preferably, the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of bi- or trivalent metal ion or complexing bi- or trivalent metal ion, at least one Tag (T) or linker (L)-Tag (T), and at least one Bridge unit (B) or a bond.

Preferably, the bi- or trivalent metal ion is a non-radioactive bi- or trivalent metal ion.

Preferably, the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of bi- or trivalent metal ion or complexing bi- or trivalent metal ion, and at least one Tag (T) or linker (L)-Tag (T).

When the multivalent metal ion is a bivalent metal ion, this bivalent metal ion is chosen from the group consisting of Zn ²⁺ , Ca ²⁺ , Cu ²⁺ , Be ²⁺ , Mg ²⁺ , Sr ²⁺ , Ba ²⁺ , Cd ²⁺ , Cr ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ ,

Ni ²⁺ , Pb ²⁺ , and Hg ²⁺ .

Preferably, the bivalent metal ion is selected from the group of Zn ²⁺ , Ca ²⁺ and Cu ²⁺ . More preferably, the bivalent metal ion is Zn ²⁺ .

When the multivalent metal ion is a trivalent metal ion, this trivalent metal ion is chosen from the group consisting of Al ³⁺ , Ga ³⁺ , In ³⁺ , Cr ³⁺ , Mn ³⁺ , Fe ³⁺ , Co ³⁺ , Ni ³⁺ .

Preferably, the trivalent metal ion is selected from the group of Ga ³⁺ , Mn ³⁺ , Fe ³⁺ , Ni ³⁺ . More preferably, the trivalent metal ion is Ga ³⁺ . In embodiments in which the compound or complex of the invention comprises more than one cyclic polyamine unit (C), different metal ions can be complexed by the compound or complex.

In order to facilitate easy detection of the compound or complex, e.g. after administration to a patient or when used in an in vitro detection method for dying cells, the compound or complex further comprises at least one detectable tag (T) (such as a label or signalling group) for detecting the compound or complex, e.g. in the patient. This detectable tag (T) is preferably covalently bond to the compound or complex.

Such a tag (T) can be chosen from the group consisting of fluorescent dyes, enzymes (in particular for the use in an ELISA assay), proteins, magnetic particles, nano particles, liposomes, X-radiation absorbing elements for CT (e.g. iodines, lanthanoids, etc.), elements altering the relaxation times of tissues for MRT (e.g. gadolinium, superparamagnetic Iron Oxide (SPIO)), and radioactive labels.

In particular, the fluorescent dye is selected from the group of a Fluorescein isothiocyanate (FITC), a rhodamine and derivatives, a BODIPY fluorophore (4,4-difluoro-4-bora-3a,4a- diaza-s-indacene, Molecular Probes, Invitrogen), an Alexa Fluor dye (Molecular Probes, Invi- trogen), cyanine and merocyanine, Atto (Sigma), Naphtalene derivatives (Dansyl and Prodan derivatives), Pyridyloxazole, Nitrobenzoxadiazole and Benzoxadiazole derivatives, Coumarin derivatives, Pyrene derivatives, Oregon green, eosin, texas red, Cascade blue, Nile red, Cy-3, Cy-5, and derivatives thereof, and any other fluorescent compound which is listed in the Handbook of Fluorescent Probes R.P. Hangland, ISBN 0-9652240-1-5; 1996, pp 8-39. Preferably, the fluorescent dye is Fluorescein isothiocyanate (FITC).

The protein is selected from the group of peroxidase, luziferase, biotin, avidin, an antibody and/or a part of an antibody (e.g. Fc-fragments, diabodies, scFv, F(ab')2 fragment, Fab ....), a toxine, recombinant proteins like scFv's, diabodies, minibodies and suitable proteins known from the skilled person.

The CT label can be chosen from the group consisting of iodines or lanthanoids-containing complexes suitable for computed tomography (CT). The MRT label can be chosen from the group consisting of gadolinium or superparamagnetic Iron Oxide (SPIO)-containing com- plexes suitable for magnetic resonance computed tomography (MRT) imaging. Suitable CT or MRT elements are well known in the art. The CT/MRT label is a iodine or lanthanoid or gadolinium-contained complex and/or is a moiety or atom that is covalently bound to the compound or complex.

The radioactive label can be chosen from the group consisting of known radioisotopes or their derivatives or radioisotope-contained complexes suitable for positron emission tomography (PET) or single-photon emission computed tomography (SPECT) imaging. Suitable PET radioisotopes (29) are well known in the art (Handbook of Nuclear Chemistry, Vol. 4 (Vol. Ed. F. Rδsch;Ed. Vertes, A., Nagy, S., Klencsar, Z.,) Kluver Academic Publishers, 2003; pp 119- 202). Suitable radioisotope-contained complexes for SPECT imaging (30) are well known in the art ((Handbook of Nuclear Chemistry, Vol. 4 (Vol. Ed. F. Rδsch;Ed. Vertes, A., Nagy, S., Klencsar, Z.,) Kluver Academic Publishers, 2003; pp 279-310). The radioactive label is a radioisotope-contained complex and/or is a moiety or atom that is covalently bond to the com- pound or complex. The radioisotope is selected from the groups of ^99m Tc, ¹⁸ F, ¹¹ C, ¹²³ I, ¹²⁴ I, ¹²⁵ 1, ¹³¹ I, ⁶⁴ Cu ²⁺ , ⁶⁷ Cu ²⁺ , ⁸⁹ Zr, ⁶⁸ Ga ³⁺ , ⁶⁷ Ga ³⁺ , ¹¹¹ In ³⁺ , ¹⁴ C, ³ H, ³² P, ⁸⁹ Zr and ³³ P. In particular, for positron emission tomography (PET), ¹⁸ F, ⁶⁸ Ga, ⁶⁴ Cu or ¹²⁴ I are preferred as positron emitting radioisotopes, more preferably ¹⁸ F or ⁶⁸ Ga. For single-photon emission computed tomography (SPECT), ¹²³ I, ¹²⁵ I, ¹¹¹ In, and ^99m Tc are preferred, more preferably ¹²³ I or " ^m Tc.

Preferably, the Tag (T) is selected from

escent dyes

The linker (L) is Ci-C ₆ alkyl, 0-Ci-C ₆ alkyl, Ci-C ₆ alkoxy, Ci-C ₆ alkylene, (CH ₂ CH ₂ O) _n CH ₂ CH ₂ , substituted or non-substituted aryl, substituted or non-substituted O- aryl, substituted or non-substituted heteroaryl, (CH ₂ ) _n Ph, (CH ₂ CH ₂ CH ₂ O) _n CH ₂ CH ₂ , CO(CH ₂ ) _n , [O(CH ₂ ) _n -O(CH ₂ ) _n ] _m , or -O(CH ₂ ) _n , [O(CH ₂ ) _n -O(CH ₂ ) _n ] _m wherein Ph = phenyl and n or m = 1, 2, 3, 4, 5, 6.

Preferably, n or m indepedently from each other is 1 to 4 and more preferably 1 to 3. Preferably, the linker (L) is C]-C ₆ alkyl, 0-Ci-C ₆ alkyl, or Ci-C ₆ alkoxy. Preferably, the linker (L) is a PEG chain of formula well known in the art. Preferably, the linker (L) is (CH ₂ CH ₂ CH ₂ O) _n CH ₂ CH ₂ , CO(CH ₂ ) _n , [O(CH ₂ ) _n -O(CH ₂ ) _n ] _m , or -O(CH ₂ ) _n ,

[O(CH ₂ ) _n -O(CH ₂ ) _n ] _m. More preferably, the linker is O(CH ₂ ) _n , [O(CH ₂ ) _n -O(CH ₂ ) _n ] _m wherein n is 2 and m is 1.

Besides detectable tags (T), the compound or complex can also be covalently or non- covalently bond to therapeutic compounds, such as drugs, like anti-apoptotic substances which can be administered to a patient, for example after a stroke.

hi a preferred embodiment of the invention, the cyclic polyamine unit (C) is a substituted or non-substituted moiety having from 9 to 20 ring members and from 3 to 6 amine nitrogens in the ring spaced by 2 or more carbon atoms from each other. Preferably, the cyclic polyamine unit (C) is cyclen (an ethylene bridged tetramine) of formula Ia, cyclam (a mixed ethylene-propylene bridged tetramine) of formula Ib and cyclen-cyclam mix (a mixed ethylene-propylene bridged tetramine) of formula Ic

Formula Ia Formula Ib Formula Ic wherein Rl, R2, R3 and R4 are independently from each other selected from bond, Hydrogen, Ci-C ₆ alkyl, Ci-C ₆ alkoxy or Alkyl-COO-, Aryl-COO- .

Preferably, Rl, R2, R3 and R4 are independently from each other selected from Hydrogen, C i -C ₄ alkyl, C i -C ₄ alkoxy. More preferably, the cyclen is a cyclen of formula Ia wherein Rl to R4 is hydrogen.

Formula Ia (H)

More preferably, the cyclam is a cyclam of formula Ib wherein Rl to R4 is hydrogen.

Formula Ib (H)

More preferably, the cyclen-cyclam mix is a cyclen-cyclam mix of formula Ic wherein Rl to R4 is hydrogen.

Formula Ic (H)

Preferably, the compound or complex comprises 1 to 10 cyclic polyamine units (C). More preferably, the compound or complex comprises 1 to 6 cyclic polyamine units (C). Even more preferably, the compound or complex comprises 1 to 4 cyclic polyamine units (C). Even more preferably, the compound or complex comprises 1 to 2 cyclic polyamine units (C). Even more preferably, the compound or complex comprises 2 cyclic polyamine units (C).

When the invention compound or complex comprises more than 2 cyclic polyamine units (C), then cyclic polyamine units (C) is selected independently from each other from cyclen (an ethylene bridged tetramine) of formula Ia, cyclam (a mixed ethylene-propylene bridged tetramine) of formula Ib or cyclen-cyclam mix (a mixed ethylene-propylene bridged tetramine) of formula Ic. As described above, a multivalent (in particular a bi- or trivalent) metal ion is complexed by a cyclen, a cyclam or a cyclen-cyclam mix wherein the rings are linked through the ring's N atoms or ring's C atoms.

In a preferred embodiment, the compound or complex contains or comprises at least two cyclic polyamine units that are connected via a bridging unit (B). hi another preferred embodiment, the compound or complex containing or comprising a single cyclic polyamine unit (C) is optionally connected to a bridging unit (B)

As a bridging unit, several structures were surprisingly found and are part of the present invention. Below, preferred bridging units are shown: hi one preferred embodiment of the compound or complex of the invention, the bridging unit (B) is a unit according to formula II wherein the phenyl core structure is substituted or non- substituted at the position not occupied by Xl, X2 or X3. Formula II

wherein Xl, X2 and X3 are independently from each other a H, C ₁ -C ₆ alkyl, Ci-C ₆ alkoxy, C ₁ -C ₆ alkylene, C(O), [O(CH ₂ ) _n ] _m , (CH ₂ CH ₂ O) _1n , CH ₂ OPhCH ₂ , (CH ₂ CH ₂ CH ₂ O) _n ,, (CONHPhCH ₂ ), (CONH(CH ₂ CH ₂ O) ₂ CH ₂ CH ₂ ), [O(CH ₂ ) _n ] _m -NH ₂ , or C(O)NH-[(CH ₂ ) _n -O] _m , Ph = phenyl, n = 2 to 6 and m = 1 to 6.

Optionally, Xl, X2 or X3 independently from each other is covalently bond to a cyclic polyamine unit (C), a Tag (T) or linker (L)-Tag (T) with the proviso that Xl, X2 or X3 is not H. Preferably, n = 2 to 3 and m = 1 to 3. Preferably, Xl, X2 and X3 are independently from each other a C ₁ -C ₆ alkyl, C(O), or

(CONH(CH ₂ CH ₂ O) ₂ CH ₂ CH ₂ ). More preferably, Xl, X2 and X3 are independently from each other a methyl or C(O).

Preferably, the bridging unit (B) is a unit according to formula II selected from

wherein X is Xl, X2 or X3.

The bridging unit (B) of formula II is optionally covalently bond to the Tag (T) or linker (L)- Tag (T), see formula Hal

Formula Hal

wherein X is Xl, X2 or X3 as defined above,

R = Tag (T) or linker (L)-Tag (T) as described above.

Preferably, the bridging unit (B) of formula II is optionally covalently bond to the Tag (T) or linker (L)-Tag (T), see formula IIa2

Formula IIa2 wherein, wherein X is Xl and/or X2 are defined as above R = Tag (T) or linker (L)-Tag (T) as described above.

Preferably, the detectable tag (T) is or comprises a fluorescent dye, a radioisotope, an enzyme, a protein, or a labeled substituent as described above. Preferably, the X moieties of the bridging unit of formula II. Hal or IIa2 are identical when there is more than 2 X moieties.

Preferably, the X moieties of the bridging unit of formula II Hal or IIa2 differ from each other.

hi a second preferred embodiment of the compound or complex of the invention, the bridging unit (B) is a unit according to a substituted or non-substituted formula III which is a substituted benzene-based scaffold.

Formula III

wherein Xl and X2 are independently from each other H, Ci-C ₆ alkyl, C ₁ -C ₆ alkoxy, C ₁ -C ₆ alkylene, C(O), [O(CH ₂ ) _n ] _m , (CH ₂ CH ₂ O) _n ,, CH ₂ OPhCH ₂ , (CH ₂ CH ₂ CH ₂ O) _m , (CONHPhCH ₂ ), (CONH(CH ₂ CH ₂ O) ₂ CH ₂ CH ₂ ), [O(CH ₂ ) _n ] _m -NH ₂ , or C(O)NH- [(CH ₂ ) _n -O] _m , Ph = phenyl, n = 2 to 6 and m = 1 to 6

Y = (CH ₂ ) _n (with n=l, 2, or 3), (CH ₂ CH ₂ O) _n , (with m=0, 1, 2, or 3), O(CH ₂ ) _P O (with p=2, 3, or 4), or O (independently of each other).

Preferably, Xl, and X2 are independently from each other a C ₁ -C ₆ alkyl, C(O), or (CONH(CH ₂ CH ₂ O) ₂ CH ₂ CH ₂ ). More preferably, Xl, and X2 are independently from each other a methyl or C(O) and Y is methyl or C(O).

Optionally, Xl or X2 independently from each other is covalently bond to a cyclic polyamine unit (C), a Tag (T) or linker (L)-Tag (T) with the proviso that Xl or X2 is not H. The bridging unit (B) of formula III is optionally covalently bond to the Tag (T) or linker (L)- Tag (T) , see formula IIIal

Formula IIIal wherein X is Xl and/or X2 are defined as above,

R = H, Tag (T) or linker (L)-Tag (T) as described above.

Preferably, the compound of formula Dial is a compound of formula IIIal wherein R is H, Tag (T) or linker (L)-Tag (T) as described above with the proviso that only one R is comprising a Tag (T).

Preferably, the bridging unit (B) of formula III is optionally covalently bond to the Tag (T) or linker (L)-Tag (T) , see formula IIIa2

Formula IIIa2 wherein X is Xl and/or X2 are defined as above R = Tag (T) or linker (L)-Tag (T) as described above.

Preferably, the detectable tag (T) is or comprises a fluorescent dye, a radioisotope, an enzyme, a protein, or a labeled substituent as described above. Preferred embodiments disclosed above are enclosed herein. In formula III, IIIal or IIIa2, the X of the bridging unit (B) is covalently bond to a cyclic polyamine unit (C) through the ring's N atoms or ring's C atoms of the cyclic polyamine unit (C) ring.

Preferably, the X moieties of the bridging unit of formula III, IIIal or IIIa2 are identical when there are more than 2 X moieties. Preferably, the X moieties of the bridging unit of formula III, IIIal or IIIa2 differ from each other.

In a third preferred embodiment of the compound or complex of the invention, the bridging unit (B) is a unit according to a substituted or non-substituted formula IV which is an adaman- tane-based scaffold.

Formula IV

wherein Xl, X2 and X3 are defined as above.

Xl, X2 or X3 independently from each other is covalently bond to a cyclic polyamine unit (C), a Tag (T) or linker (L)-Tag (T) with the proviso that Xl , X2 or X3 is not H.

The bridging unit (B) of formual IV is optionally covalently bond to the Tag (T) or linker (L)- Tag (T), see formula FVa

formula FVa wherein X is Xl , X2 and/or X3 and R are defined as above.

Other molecular constructs like dendrimeric structures containing the above described sub- stituents and tags are possible.

The group X as described above is covalently bond to a cyclic polyamine unit, such as cyclen or cyclam either to a C or N atoms of the cyclic polyamine unit, preferably, to one of its N atoms. In a fourth preferred embodiment of the compound or complex of the invention, the bridging unit (B) is a unit according to a substituted or non-substituted formula V and Va which are peptide-based scaffolds. Formula V is based on a peptidic scaffold with α-amino acids, whereas formula Va is based on a peptidic scaffold with β-amino acids.

Formula V is a linear peptide consisting of α-amino acids.

Formula Va is a linear peptide consisting of β-amino acids.

The bridging unit (B) of formual V and Va are optionally covalently bond to the Tag (T) or linker (L)-Tag (T), see formula V and Va

Formula V

Formula Va

wherein m = 1, 2, 3, 4, 5, or 6, and

R' = X wherein X is Xl, X2 and X3 are independently from each other H, C ₁ -C ₆ alkyl, Ci-C ₆ alkoxy, C ₁ -C ₆ alkylene, C(O), [O(CH ₂ ) _n ] _m , (CH ₂ CH ₂ O) _n ,, CH ₂ OPhCH ₂ ,

(CH ₂ CH ₂ CH ₂ O) _n ,, (CONHPhCH ₂ ), (CONH(CH ₂ CH ₂ O) ₂ CH ₂ CH ₂ ), [O(CH ₂ ) _n ] _m -NH ₂ , or C(O)NH- [(CH ₂ ) _n -O] _m , Ph = phenyl, n = 2 to 6 and m = 1 to 6, Xl, X2 or X3 independently from each other is covalently bond to a cyclic polyamine unit (C), a Tag (T) or linker (L)-Tag (T) with the proviso that Xl, X2 or X3 is not H and R = Tag (T) or linker (L)-Tag (T) as described above.

Preferably, Xl, X2 and/or X3 independently from each other is an alkyl or aryl bridge connected with a cyclic polyamine unit (C) of formula Ia, formula Ib, or formula Ic. The cyclic polyamine unit (C), such as cyclen or cyclam, is bond either via a C or N, preferably, via one of its N atoms in a compound or complex of formula V or Va.

Furthermore, it is possible to provide functionalized particles like ultrasmall superparamagnetic iron oxide particles (USPIOs) to which the cyclen or cyclam or mixures thereof of the compound or complex of the invention are bond to predefined surfaces. Methods of binding such functionalized particles to the compound or complex have been described elsewhere (27).

By using the Zn ²⁺ complexed and FITC-labeled bis-cyclen derivative shown in figure 3 in binding experiments with control and apoptotic Jurkat cells, the inventors surprisingly obtained results comparable to thoses obtained with fluorescent annexin V. The FACS measurements were reproducible opposing the experiments performed with Zn ²⁺ complexed and FITC-labeled bis-DPA complexes.

The positive results acquired with the in vitro apo-test system (15) show that this class of small metal-organic compound or complex is usefull for cell death imaging such as apoptosis or necrosis imaging. Table 1 lists preferred compounds or complexes of the invention.

In a further embodiment, the invention is directed to a compound or complex for binding or detecting a phosphatidylserine characterized in that the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of bi- or trivalent metal ion. Preferably, compound or complex for binding or detecting a phosphatidylserine comprises at least one cyclic polyamine unit (C) for the complexation of non-radioactive bi- or trivalent metal ion or complexing non-radioactive bi- or trivalent metal ion. Preferred disclosed em- bodiment and preferred alternatives disclosed above are included herein.

In a second aspect, the invention is related to a compound or complex VI characterized in that the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of bi- or trivalent metal ion or complexing bi- or trivalent metal ion and at least one moiety for covalently binding a Tag (T) or linker (L)-Tag (T).

Optionally, the compound or complex VI of the invention comprises further at least one Bridge unit (B) or a bond,

Preferably, the bi- or trivalent metal ion is a non-radioactive bi- or trivalent metal ion.

Preferably, the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of bi- or trivalent metal ion or complexing bi- or trivalent metal ion, at least one moiety for covalently binding Tag (T) or linker (L)-Tag (T), and at least one Bridge unit (B) or a bond. The moiety for covalently binding Tag (T) or linker (L)-Tag (T) are known moieties in the art.

The said moiety will enable the covalently binding of a Tag (T) or a linker (L)-Tag (T) to the cyclic polyamine unit (C) or the Bridge unit (B).

Moiety for covalently binding Tag (T) or linker (L)-Tag (T) wherein the Tag (T) is a fluorescent dye, like for example, a Fluorescein isothiocyanate (FITC), a rhodamine, a BODIPY fluorophore (4,4-difluoro-4-bora-3a,4a-diaza-5'-indacene, Molecular Probes), an Alexa Fluor dye (Molecular Probes), Cy-3, Cy-5, and derivatives thereof, or any other fluorescent compound which is for example listed in the Handbook of Fluorescent Probes R.P. Hangland, ISBN 0-9652240-1-5; 1996, pp 8-39)

Moiety for covalently binding Tag (T) or linker (L)-Tag (T) wherein the Tag (T) is a protein, is well known in the art. Handbooks provide method and reagents suitable for binding a Tag when the Tag is a protein.

Moiety for covalently binding Tag (T) or linker (L)-Tag (T) wherein the Tag (T) is a radioactive label, is selected from the group of suitable PET radioisotopes are well known in the art (Handbook of Nuclear Chemistry, Vol. 4 (Vol. Ed. F. Rδsch;Ed. Vertes, A., Nagy, S., Klenc- sar, Z.) Kluver Academic Publishers, 2003; pp 119-202). Suitable radioisotope containing complexes for SPECT imaging are well known in the art (ibid.; pp 279-310). The embodiments disclosed above apply here. In a third aspect, the invention is related to a compound or complex as described herein used for binding and detecting dying cells, both in vitro and in vivo. In particular, such use makes apoptosis or necrosis imaging in vivo possible, by using positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), and/or optical imaging, preferably positron emission tomography (PET). In one embodiment, the compound or complex characterized in that the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of non-radioactive bi- or trivalent metal ion or complexing non-radioactive bi- or trivalent metal ion.

In one embodiment, the compound or complex characterized in that the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of non-radioactive bi- or trivalent metal ion or complexing non-radioactive bi- or trivalent metal ion for the manufacture of pharmaceutical composition or the use as a imaging agent for detecting dying cells.

Cell death occurs through either necrosis or apoptosis. Necrosis (31) is due to unexpected and accidental cell damage, and is an unregulated process in which the cells do not usually send the same chemical signals to the immune system that cells undergoing apoptosis do. This prevents nearby phagocytes from locating and engulfing the dead cells, leading to a build up of dead tissue and cell debris at or near the site of the cell death. A number of toxic chemical and physical events can cause necrosis like toxins, radiation, heat, trauma, lack of oxygen. Apoptosis (31) is a regulated process of self-destruction of a cell, triggered by non-reparable cell damage, such as DNA-damage, mutations in essential proteins or developmental processes. Programmed cell death involves a series of biochemical events leading to cell death and leading to processes of disposal of cellular debris whose results do not damage the organism.

In a further embodiment, the invention relates to the use of invention cyclic polyamine compound or complex as described herein or composition thereof for in vivo or in vitro detection of cell death resulting from apoptosis or necrosis. More preferably, the use is for in vitro de- tection. In vitro detection can be conducted by FACS, microspectrometry, microscopy or ELISA. More preferably, the use is for in vivo detection. In vivo detection can be conducted by PET, SPECT, CT or MRT. Preferably, the invention relates to the use of invention cyclic polyamine compounds or complexes as described herein or composition thereof for in vivo or in vitro detection apoptosis or necrosis.

Advantageously, such a method allows for the assessment of a patient suffering from a tumor, from an infection, and/or from an inflammation, from injury, from stroke, from heart attack, to an anti-tumor therapy, to anti-infection therapy and/or to anti-inflammatory therapy, respectively as the measurement of cell death which is directly correlated to disease progression or regression and also allows monitoring of therapy efficacy. In particular, the compound or complex of the invention is advantageous as the decrease in its uptake is readily detectable. Preferably the use is for the manufacture of pharmaceutical composition or use as a imaging agent for detecting necrosis.

Preferably the use is for the manufacture of pharmaceutical composition or use as a imaging agent for detecting apoptosis. Accordingly, a method for in vivo or in vitro detection of cell death that occurs during apoptosis or necrosis, and thereby the progression or regression of a tumor, of an infection, and/or of an inflammation in a tissue of a patient is also provided. Such a method comprises or contains the following steps: a) administering a compound or complex as described herein to a patient, and b) measuring the amount and/or the concentration of the compound or complex in the tissue.

Accordingly, a method for detecting phosphatidylserine and thereby the progression or regression of a tumor, of an infection, and/or of an inflammation, stroke, heart attack, injury in a tissue of a patient is also provided. Such a method comprises or contains the following steps: a) administering a compound or complex as described herein to a patient, and b) measuring the amount and/or the concentration of the compound or complex in the tissue.

The patient can be any mammal and is preferably a human being. The measurement of the amount and/or the concentration of the compound or complex in the tissue of interest, i.e. the diseased tissue, can be performed using PET, SPECT, MRI, CT and/or optical imaging.

A compound or complex used in this detection method preferably comprises at least two cyclic polyamine units that are connected via a bridging unit for connecting at least two cyclic polyamine units with each other. The bridging unit is preferably selected from the group consisting of the compound or complex of formulas II to V as shown above. The invention concerns the use of AMD3100 (l,l'-[l,4-Phenylenebis(methylen)]bis [1,4,8,11- tetraazacyclotetradecan]-octohydrobromid-dihy-drate) for binding and detecting dying or dead cells or for binding and detecting phosphatidylserine.

Preferably, the above use is for binding and detecting dying and dead cells wherein dying or dead cells resulting from apoptosis or necrosis.

The embodiments disclosed above apply here.

The compounds of the invention may be used for the detection and diagnosis of a wide variety of medical conditions, characterized by dying cells.

Examples of clinical conditions characterized by dying cells are as follows: Diseases which are characterized by occurrence of excessive apoptosis, such as degenerative disorders, neurodegenerative disorders (e.g., Parkinson's disease, Alzheimer's disease, Huntington chorea), AIDS, Motor Neuron Diseases such as amyotrophic lateral sclerosis (ALS), Prion Diseases (e.g. Creutzfeldt-Jacob disease), myelodysplastic syndromes, ischemic or toxic insults, graft cell loss during transplant rejection; tumors, and especially highly malignant / aggressive tumors, are also often characterized by increased apoptosis in addition to excessive tissue proliferation.

Vascular disorders, such as myocardial infarction, cerebral stroke, deep vein thrombosis, disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura (TTP), sickle cell diseases, thalassemia, antiphospholipid antibody syndrome, systemic lupus erythematosus.

Inflammatory disorders, and / or diseases associated with immune-mediated etiology or pathogenesis; auto-immune disorders such as antiphospholipid antibody syndrome, systemic lupus erythematosus, connective tissue disorders, such as rheumatoid arthritis, scleroderma; thyroiditis; dermatological disorders such as pemphigus or erythema nodosum; autoimmune hematological disorders; autoimmune neurological disorders such as myasthenia gravis, multiple sclerosis, inflammatory bowel disorders, such as ulcerative colitis and vasculitis.

Atherosclerotic plaques, and especially plaques that are unstable, vulnerable and prone to rupture, are also characterized by dying cells, such as apoptotic macrophages, apoptotic smooth muscle cells or apoptotic endothelial cells.

The methods of the present invention may be used to detect and/or diagnose one or more of the aforementioned clinical conditions in a human patient or animal subject. Additionally, the detection may also be carried out in a person already known to have the respective disease, for the purpose of evaluating the disease severity or in order to monitor In a fourth aspect, the invention is related to a method for synthesizing the invention compound or complex as described herein.

In one embodiment the invention is related to a method for synthesizing compound or complex comprising at least one cyclic polyamine unit (C) for the complexation of non- radioactive bi- or trivalent metal ion or complexing non-radioactive bi- or trivalent metal ion. In a further embodiment the invention is related to a method comprising the step of reacting a compound or complex of formula VI comprising at least one cyclic polyamine unit (C) for the complexation of non-radioactive bi- or trivalent metal ion or complexing non-radioactive bi- or trivalent metal ion and at least one moiety for covalently binding a Tag (T) or linker (L)-Tag (T) for obtaining a compound or complex comprising at least one cyclic polyamine unit (C) for the complexation of non-radioactive bi- or trivalent metal ion or complexing non-radioactive bi- or trivalent metal ion, and at least one Tag (T) or linker (L)-Tag (T).

According to this method, at least two cyclic polyamine units are connected via a bridging unit for connecting at least two cyclic polyamine units with each other. Preferably, the bridging unit is selected from the group consisting of the compound or complex of formulas II to V. The embodiments disclosed above apply here.

hi a fifth aspect, the invention is related to a pharmaceutical composition comprising a compound or complex as described herein, and possibly further a suitable carrier and/or additive wherein the compound or complex comprises at least one cyclic polyamine unit (C) for the complexation of non-radioactive bi- or trivalent metal ion or complexing non-radioactive bi- or trivalent metal ion. The embodiments disclosed above apply here. Pharmaceutical compositions for therapeutics, as well as diagnostic compositions of the invention may be administered by any of the known routes, inter alia, oral, intravenous, intraperitoneal, intramuscular, subcutaneous, sublingual, intraocular, intranasal or topical administration, or intracerebral administration. The carrier should be selected in accordance with the desired mode of administration, and include any known components, e.g. solvents; emulgators, excipients, talc; flavors; colors, etc. The pharmaceutical composition may comprise, if desired, other pharmaceutically-active compounds which are used to treat the disease, eliminate side effects or augment the activity of the active component.

In a sixth aspect, the invention is related to a kit comprising one of the invention compound or complex. Preferably the kit is useful for binding and detecting phosphatidylserine, particularly in vitro. Such a kit comprises a compound or complex as described herein and appropriate buffers for dissolving and/or diluting the compound or complex, an agent such as an antibody for detecting the compound or complex and/or ELISA plates for performing an ELISA assay.

In a seventh aspect, the invention is related to a method of selectively targeting a medicinally- useful compound to dying cells within a population of cells, the method comprising: contact- ing the cell population with a compound represented by the structure set forth in any invention compounds as disclosed and claimed in the present application, thereby selectively targeting the medicinally-useful compound to the dying cells within the cell population.

Preferably the compound or complex of the invention are selected from the group below and complexed with bi- or trivalent metal ion thereof

Invention compounds:

bis-Zn(II)-Cyc A bis-Zn(II)-Cyc B tetra-Zn(II)-Cyc

Figures

Figure 1 :

Illustration of the interaction in one of domain El of annexin V with glycerophosphoserine (truncated PS) on Ca ²⁺ -annexin V binding sites (9). Primary AB and secondary AB' Ca ²⁺ sites are located within the loop between the A and B helices of each domain. They are also called type II and type III Ca ²⁺ binding sites, respectively. The structural alignment of glycerophosphoserine (light) in AB and AB' Ca2 ⁺ -binding sites in third domain of annexin V (shaded) is shown (28).

Figure 2:

The depiction of a FITC labeled Zn ²⁺ Ws-DPA complex according to the state of the art.

Figure 3: The depiction of a prefered compound or complex of the invention, namely a FITC labeled Zn ²⁺ bis-cyclen complex.

Figure 4:

Flow cytometry FACS for Annexin V and Propidiumiodide, FL-I, FL-III and FL-I/FL-III- plot.

Figure 5:

Flow cytometry FACS for Annexin V and Propidiumiodide, FL-I, FL-III and FL-I/FL-III- plot.

Figure 6:

Biodistribution data of compound 19 for the 3.5 h time point of induction of hepatic apop- tosis.

Figure 7 :

PET acquisition of the 18F-Zn complex 19 in transversal section. Radiated tumor (left) and control (right) a) 1 d before the radiation therapy, b) 6 d after radiation, c) 10 d after radiation.

Figure 8: Non induced control cells, incubated with compound 1. FL-I is fluorescence of compound 1, FL-III is fluorescence of PI. Apoptotic cells are found in Ql, necrotic cells in Q2 and Q4, vital cells in Q3. First left graphic is green.

Figure 9:

Apoptosis induced Jurkat cells, incubated with compound 1. A: FL-I is fluorescence of compound 1 (green), B: FL-III is fluorescence of PI, (Red). C: Forward and sideward scatter show homogeneous population in region RNl. D: Overlapping fluorescence spectrum was compensated. Apoptotic cells in Ql, necrotic cells in Q2 and Q4, vital cells in Q3.

Figure 10:

Apoptosis induced Jurkat cells, incubated with compound AB (FL-III) and Annexin-V (FL-I).

Figure 11: Apoptosis induced Jurkat cells, incubated with compound 1 (left, green) and compound we (right, green).

Figure 12:

Apoptosis induced Jurkat cells, incubated with compound 1 complexed with Zn ²⁺ (left dia- gram, green) or compound 1 without Zn ²⁺ (right diagram, green).

Figure 13:

Apoptosis induced Jurkat cells, incubated with compound 1 and PI. The overlay of the green fluorescence from compound 1 (2 ^nd from left) with the red fluorescence from PI (2 ^nd from right) gives the yellow fluorescence seen in the right picture. The left picture shows the transmission picture.

Figure 14:

Apoptosis induced Jurkat cells, incubated with compound AB (red) and Annexin-V (green). The overlay of the red fluorescence from compound AB and the green fluorescence from Annexin-V shows labeling of compound AB of both apoptotic and necrotic cells. The left picture shows the transmission picture. Definitions:

A cyclic polyamine unit (C) for the complexation of non-radioactive bi- or trivalent metal ion means a cyclic polyamine unit that is able to complex one or more non-radioactive bi- or trivalent metal ion as suitable. Preferably the cyclic polyamine unit is able to complex one non- radioactive bi- or trivalent metal ion.

A cyclic polyamine unit (C) complexing non-radioactive bi- or trivalent metal ion means a cyclic polyamine unit that is complexing or comprising one or more non-radioactive bi- or trivalent metal ion as suitable. Preferably the cyclic polyamine unit is complexing or comprising one non-radioactive bi- or trivalent metal ion.

The term "alkyl" as used herein refers to C ₁ to C ₆ straight or branched alkyl groups, e. g., methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, n-pentyl, or neopentyl. Alkyl groups can be perfluorated or substituted by one to five substituents selected from the group consisting of halogen, hydroxyl, Ci-C ₄ alkoxy, or C ₆ -Ci ₂ aryl (which can be substituted by one to three halogen atoms). More preferably, alkyl is a C ₁ to C ₄ or C ₁ to C ₃ alkyl.

The term "alkenyl" as used herein refers to a straight or branched chain monovalent or divalent radical, containing at least one double bond and having from two to ten carbon atoms, e.g., ethenyl, prop-2-en-l-yl, but-1-enyl, pent-1-enyl, penta-l,4-dienyl, and the like.

The term "alkynyl" as used herein refers to a substituted or unsubstituted straight or branched chain monovalent or divalent radical, containing at least one triple bond and having from two to ten carbon atoms, e.g., ethynyl, prop-1-ynyl, but-1-ynyl, pent-1-ynyl, pent-3-ynyl, and the like.

Alkenyl and alkynyl groups can be substituted by one or more substituents selected from the group consisting of halogen, hydroxyl, alkoxy, -CO ₂ H, -CO ₂ Alkyl, -NH ₂ , -NO ₂ , -N ₃ , -CN, C ₁ - C ₂₀ acyl, or Ci-C ₆ acyloxy.

The term "aryl" as used herein refers to an aromatic carbocyclic or heterocyclic moiety containing five to 10 ring atoms, e.g., phenyl, naphthyl, furyl, thienyl, pyridyl, pyrazolyl, pyrimidinyl, oxazolyl, pyridazinyl, pyrazinyl, chinolyl, or thiazolyl. Aryl groups can be substituted by one or more substituents selected from the group consisting of halogen, hydroxyl, alkoxy, -CO ₂ H, -CO ₂ Alkyl, -NH ₂ , Alkyl-NH ₂ , Ci-C ₂₀ alkyl-thiolanyl, -NO ₂ , -N ₃ , -CN, Ci-C ₂₀ alkyl, Ci-C ₂₀ acyl, or Ci-C ₂₀ acyloxy. The heteroatoms can be oxidized, if this does not cause a loss of aromatic character, e. g., a pyridine moiety can be oxidized to give a pyridine N- oxide.

Whenever the term "substituted" is used, it is meant to indicate that one or more hydrogens on the atom indicated in the expression using "substituted" is replaced with a selection from the indicated group, provided that the indicated atom's normal valency is not exceeded, and that the substitution results in a chemically stable compound, i. e. a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and formula- tion into a pharmaceutical composition. The substituent groups may be selected from halogen atoms, hydroxyl groups, nitro, (Ci-C ₆ )carbonyl, cyano, nitrile, trifluoromethyl, (C]- C ₆ )sulfonyl, (Ci-C ₆ ) alkyl, (Ci-C ₆ )alkoxy and (Ci-C ₆ )sulfanyl.

Halogen means Chloro, Iodo, Fluoro and bromo. Preferably, halogen means iodo or fluoro.

If a chiral center or another form of an isomeric center is present in a compound according to the present invention, all forms of such stereoisomer, including enantiomers and diastereoi- somers, are intended to be covered herein. Compounds containing a chiral center may be used as racemic mixture or as an enantiomerically enriched mixture or the racemic mixture may be separated using well-known techniques and an individual enantiomer maybe used alone, hi cases in which compounds have unsaturated carbon-carbon bonds double bonds, both the (Z)- isomer and (E)-isomers are within the scope of this invention. In cases wherein compounds may exist in tautomeric forms, such as keto-enol tautomers, each tautomeric form is contemplated as being included within this invention whether existing in equilibrium or predomi- nantly in one form.

It's well known for a person skilled in the art, that the compounds of the invention, as applicable, are or may be in the form of zwitterions and/or salt at the physiological pH of 7.4.

Preferably the patient is a mammal; most preferably the patient is a human.

While it is possible for the imaging agent to be administered alone, it is preferable to present it as a pharmaceutical formulation comprising at least one imaging agent compound, together with one or more pharmaceutically acceptable carriers, such as diluents or excipients which may include, for example, fillers, extenders, wetting agents, disintegrants, surface-active agents, or lubricants, depending on the nature and mode of administration and the dosage forms. Each carrier must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not injurious to the patient. The pharmaceutical formulation may optionally include other diagnostic or therapeutic agents. Techniques and formulations may be found, for example, in Remington's Pharmaceutical Sciences. Mack Publishing Co., Easton, PA. (latest edition).

It should be understood that in addition to the ingredients particularly mentioned above, the formulations of this invention may include other agents conventional in the art having regard to the type of formulation in question, for example, those suitable for oral administration may include such further agents as sweeteners, thickeners and flavouring agents.

Unless otherwise specified, when referring to the compounds of Formula the present invention per se as well as to any pharmaceutical composition thereof the present invention includes all of the hydrates, salts, solvates, complexes, and prodrugs of the compounds of the invention. Prodrugs are any covalently bonded compounds, which releases the active parent pharmaceutical according to the present invention.

The term "prodrug" as used throughout this text means the pharmacologically acceptable derivatives such as esters, amides and phosphates, such that the resulting in vivo biotransformation product of the derivative is the active drug as defined in the compounds of Formula (I). The reference by Goodman and Gilman (The Pharmacological Basis of Therapeutics, 8 ed, McGraw-HiM, Int. Ed. 1992,"Biotransformation of Drugs", p 13-15) describing prodrugs generally is hereby incorporated. Prodrugs of a compound of the present invention are prepared by modifying functional groups present in the compound in such a way that the modifications are cleaved, either in routine manipulation or in vivo, to the parent compound. Prod- rugs of the compounds of the present invention include those compounds wherein for instance a hydroxyl group, such as the hydroxyl group on the asymmetric carbon atom, or an amino group is bonded to any group that, when the prodrug is administered to a patient, cleaves to form a free hydroxyl or free amino, respectively.

Cell death occurs through either necrosis or apoptosis.

Necrosis is due to unexpected and accidental cell damage and is an unregulated process in which the cells do not usually send the same chemical signals to the immune system that cells undergoing apoptosis do. This prevents nearby phagocytes from locating and engulfing the dead cells, leading to a build up of dead tissue and cell debris at or near the site of the cell death. A number of toxic chemical and physical events can cause necrosis like toxins, radiation, heat, trauma, lack of oxygen.

Apoptosis is a regulated process of self-destruction of a cell, triggered by non-reparable cell damage, such as DNA-damage, mutations in essential proteins or developmental processes Programmed cell death involves a series of biochemical events leading to cell death and leading to processes of disposal of cellular debris whose results do not damage the organism. The term "dying cell" refers herein to a cell that undergoes a death process. Such cells may be exemplified by cells undergoing an apoptotic process, or neuronal cells undergoing neurodegeneration.

The following disclosure is part of the invention. The invention concerns additionally a compound for binding phosphatidylserine, characterized in that the compound comprises at least one cyclic polyamine unit for the complexation of a bi- or trivalent metal ion.

2. The compound according to claim 1, wherein the bivalent metal ion is chosen from the group consisting OfZn ²⁺ , Ca ²⁺ , Cu ²⁺ , Be ²⁺ , Mg ²⁺ , Sr ²⁺ , Ba ²⁺ , Cd ²⁺ , Cr ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Pb ²⁺ , Hg ²⁺ , and corresponding radiometals of the aforementioned ions.

3. The compound according to claim 1, wherein the trivalent metal ion is chosen from the group consisting of Al ³⁺ , Ga ³⁺ , In ³⁺ , Cr ³⁺ , Mn ³⁺ , Fe ³⁺ , Co ³⁺ , Ni ³⁺ , and corresponding radiometals of the aforementioned ions.

4. The compound according to claims 1 to 3, further comprising a tag for detecting the compound.

5. The compound according to claims 1 to 4, wherein the tag is chosen from the group consisting of fluorescent dyes, enzymes, proteins, and radioactive labels.

6. The compound according to claim 5, wherein

- the fluorescent dye is chosen from the group consisting of fluoresceins, rhodamines, BODIPY, Cy-3, Cy-5, and derivatives thereof.

- the protein is chosen from the group consisting of peroxidases, luziferase, biotin, avidin, and antibodies or parts thereof;

- the radioactive label is chosen from the group consisting of ^99m Tc, ¹⁸ F, ¹¹ C, ¹²⁴ 1, ¹²³ I,

(A _n Cu 2+ , 68 _n Ga _n 3+ , l l l _T In _r ,3+ , IV C, 3τ Hτ, 32 _D P, a _o _nd , 33τ Pj.

7. The compound according to claims 1 to 6, wherein the cyclic polyamine unit is cyclen with a structure of formula Ia or cyclam with a structure of formula Ib.

Formula Ia Formula Ib

8. The compound according to claims 1 to 7, comprising two cyclic polyamine units that are connected via a bridging unit, that is selected from a group consisting of (a) Formula II

with

X = (CH ₂ ) _n , (CH ₂ CH ₂ O) _n , or CH ₂ OPhCH ₂ , or CO, wherein n=l, 2, or 3, and Ph = phenyl, wherein X is each covalently bound to a cyclic polyamine unit; and Z = a halogen, a radiohalogen (such as ¹⁸ F, ¹²³ I), or H; and

R = H, or a tag as described in claim 4-6, preferably a fluorescent dye, 18T F ₇ , 1 1 _/ C,

¹²³ I, or a labeled substituent, wherein the tag is preferably a labeled substituent R ₂ ,

with R ₂ =

or

'5F which optionally comprises a spacer Rj, such that the labeled substituent R ₂ with the spacer R ₁ is

^■ ft* R ¹ 2

1,2,3

(b) a substituted benzene-based scaffold of formula III Formula III

with

Y = (CH ₂ ) _n with n=l, 2, or 3, (CH ₂ CH ₂ O) _1n with m=0, 1, 2, or 3 O(CH ₂ ) _P O

(with p=l, 2, 3, or 4), or O (independently of each other), or mixtures thereof; and

Z = a halogen, a radiohalogen (such as F, T), or H; and

R and X as described for formula II above;

(c) an adamantane-based scaffold of formula IV

with X and R as described above for formula II;

(d) a peptide-based scaffold of formula V (peptidic scaffolds with of-amino acids) or formula Va (peptidic scaffolds with /3-amino acids) Formula V

Formula Va

R

wherein m = 1, 2, 3, 4, 5, or 6, and with R' = an alkyl or aryl bridge connected with a cyclen or a cyclam, independently of each other; and with R as described for formula II.

9. The compound according to claims 1 to 8, as shown in table 1 or table 2, or of formula VI, VII, or VIII.

10. Use of a compound according to claims 1 to 9 for binding phosphatidylserine. 11. Use of a compound according to claims 1 to 9 for apoptosis imaging. 12. Use according to claim 10 or 11, using positron emission tomography (PET), single- photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), or optical imaging.

13. Use according to claims 10 to 12, for assessing the status of a tumor or the response of a patient suffering from a tumor, from an infection, and/or from an inflammation, to an anti-tumor therapy, to anti-infection therapy and/or to anti-inflammatory therapy, respectively.

14. A method for detecting the progression of a tumor, of an infection, and/or of an inflammation in a tissue of a patient, comprising a) administering a compound according to claims 1 to 9 to a patient, and b) measuring the amount or the concentration of the compound in the tissue.

15. A method for synthesizing of a compound according to claims 1 to 9, wherein at least two cyclic polyamine units are covalently bound to each other via a bridging unit.

16. The method according to claim 15, wherein the bridging unit is selected from the for- mulas II, III, IV, V, Va.

17. A pharmaceutical composition, comprising a compound of claims 1 to 9.

18. The pharmaceutical composition according to claim 17, further comprising a suitable carrier and/or additive.

19. A kit for binding phosphatidylserine, comprising a compound of claims 1 to 9, and op- tionally buffers for detecting phosphatidylserine in vitro.

20. Use of a compound according to claims 1 to 9 or pharmaceutical composition according to claim 17 for in- vivo or in- vitro detection of apoptosis.

Table 1. Preferred compounds of the invention: Each compound shown comprises at least two cyclic polyamine units in the form of a cyclen or cyclam, joined by a bridging unit. The bridging unit may also carry a detectable tag R, which may be a labeled substituent R ₂ that can, optionally, comprise a spacer R ₁ . Any given bridging unit given below can be combined with any combination of Ri and R ₂ written in the same portion of the table (separated by bold lines).

The preferred compounds are shown here complexed with Zn ²⁺ . It is possible, however, that the compounds form a complex with any other multivalent (in particular a bi- or trivalent) metal ion as described herein, or with mixtures thereof.

Table 2. Preferred compounds of the invention: Each compound shown comprises at least two cyclic polyamine units in the form of a cyclen or cyclam, joined by a bridging unit. The bridging unit may also carry a residue A. Z is a radiohalogen for detecting the compound. The cyclic polyamine unit joined by the bridging unit given below can be combined with any combination of residue A and Z in the table.

The preferred compounds are shown here complexed with Zn ²⁺ . It is possible, however, that the compounds form a complex with any other multivalent (in particular a bi- or trivalent) metal ion as described herein, or mixtures thereof.

Examples

a) Synthesis of fluorescence-labeled Bis-Cyclen complexes a-1

Zn(NOs) ₂ EtOH/ H ₂ O, 40°C, 30min

All solvents used were bought as water-free p. A.-solvents. Silica gel 60 (0.04 - 0.063 μm, Fluka) was used for the column chromatography purification. The preparative HPLC- purification was performed with an HPLC by Agilent (1100 Series) using the semi-preparative column Chromolith® SemiPrep, RP18e, 100-10 mm (Merck). Synthesis of Compound 4

The bromo compound 2 (22) (130 mg, 254 μmol) and l,4,7-tris(tert-butyloxycarbonyl)cy- clen (3) (23) (295 mg, 624 μmol, 2.5 eq.) were dissolved in 4 ml acetonitril and potassium carbonate (175 mg, 1.27 mmol) was added. The suspension was stirred for 60 h at 40 °C. Subsequently, the potassium carbonate was removed by filtering and the solvent was removed i. vac. Following column chromatography purification using silica gel with EtOAc/petrol ether = 1 : 1 as eluent, a white solid substance was obtained. Yield: 220 mg (90 %)

Synthesis of Compound 5

The biscyclen compound 4 (220 mg, 170 μmol) was dissolved in 1.4 ml 50 % TFA in dichlo- romethane and stirred for 3 h at room temperature. The solvent was removed i. vac. No further purification was performed. Yield: quantitatively

Synthesis of Compound 6

The amine 5 (8.3 mg, 13.9 μmol) was dissolved in 250 μl DMF anhydr. 5-/6-carboxyfluores- ceinpentafluorophenylester (24) (7.5 mg, 13.9 μmol) was also dissolved in DMF anhydr. and added to 5. The reaction mixture was stirred for 16 h at room temperature. The solvent was removed i. vac. The raw product was purified at the semi-preparative HPLC (A = H ₂ O, B = ACN, 0.1 % TFA; 5 min 40 % B). MALDI-MS: m/z = 968.6 (M+H ⁺ ), 990.6 (M+Na ⁺ ) (calc 967.55)

Synthesis of Compound 1 The ligand 6 (1.1 mg, 1.16 μmol) was dissolved in 20 μl EtOH and 23.1 μl of an aqueous 0.1 mol/1 Zn(NO ₃ ) ₂ -solution (2.31 μmol). The solution was heated for 40 minutes to 50 °C. After lyophilizing a yellow solid substance was obtained. Yield: 100%

a-2 Flow cytometry (FACS) a-2.1 Flow Cytometry Methodology

Flow cytometry is a technology for counting and examining cells which pass in a flow of single cells through a laser beam. The laser light scatter provides information about cell features. The forward scatter (FSC) depends basically on the size of the cell, whereas the side scatter (SSC) is used to measure the granularity of the cell. Furthermore, if the cells carry fluorescence dyes, the respective fluorescence signal can be detected.

Flow cytometry is a widely applied technique in cell biology. Especially in the research of cell death mechanisms it is a standard procedure to count and differentiate between apoptotic, necrotic and healthy cells. For the detection of apoptosis the protein Annexin V is applied which is usually attached to a green fluorescence dye. Because Annexin V can also bind to necrotic cells, the red fluorescent nuclear stain propidium iodide is simultaneously applied as a necrosis marker.

The resulting fluorescence diagrams that are obtained from a flow cytometry procedure with Annexin V and propidium iodide are shown below. The detection channel for green fluorescence is termed FL-I (fig 4), the one for red fluorescence FL-III (fig 4). The plot of cell number (counts) versus FL-I intensity is called histogram. The fluorescence signal of the sample is always accompanied by a second signal at low intensities (left in the histogram) which is background fluorescence. By plotting the red fluorescence versus the green fluorescence (FL- I/FL-III-plot) a diagram is obtained in which the cells can be divided into red, green and red+green fluorescent cells. After gating the signals into four quadrant regions (Ql - Q4) (fig 4), the percentages of the differently stained cells is indicated in the diagram.

a-2.2 Flow Cytometry analysis

Both the fluorescein-labeled bis-cyclen compound and the tetra-cyclen compound stained cells which were treated with staurosporine in order to induce apoptosis (fig 5). The green fluorescence signal indicates the number of cells that interact with these cyclen compounds. The FL-I/FL-III-plot shows that the majority of stained cells are not only green but also red fluorescent which means that the cells carry additionally to the cyclen compounds (green) also the necrosis marker propidium iodide (red). FACS measurements were performed with a DAKO Galaxy Flow Cytometry System using the following experimental setup: Jurkat-cells were grown to a density of about l*10 ⁶ cells/ml. Apoptosis was induced by adding 1 μmol/1 staurosporine (Stepczynska A et al, Staurosporine and conventional anticancer drugs induce overlapping, yet distinct pathways of apoptosis and caspase activation, Oncogene (2001) 20, 1193). After incubation for 4 h at 37 °C, the cells were washed with cold PBS-buffer (140 mmol/l NaCl, lO mmol/1 KCl, 6.4 mmol/1 Na ₂ HPO ₄ , 2 mmol/1 KH ₂ PO ₄ ) and resuspended in cold TES-buffer (5 mmol/1 TES, 145 mmol/1 NaCl). 10 ⁶ cells in 100 μl buffer with 1 μl of a 0.5 mmol/1 aqueous solution of complex 1 were incubated for 15 minutes at 37 °C. Subsequently, cells were washed twice with 500 μl TES-buffer and the cells were resuspended in 400 μl TES-buffer. 100 μl of the probe were diluted with 900 μl of buffer and measured immediately. To discriminate against necroses, 10 μl propidiumiodide solution (250 μg/ml) were added directly before the measurement.

Table 2. Examples for apoptosis detection by Annexin V and three different Zn(II)- complexes on staurosporine treated Jurkat cells, using propidium iodide (PI) for necrosis discrimination.

Examples for apoptosis detection with Annexin V and three different Zn(II)-complexes on staurosporine treated Jurkat cells, using propidium iodide (PI) for necrosis discrimination are summarized in Table 2. The results demonstrate the parallelism of apoptosis-detection potency of the three Zn(II)-Cyclene derivatives with Annexin V.

FACS analysis of un-induced Jurkat cells showed very little apoptosis and thus very little binding of the bis-cyclen compounds to vital living cells. Figure 8 shows the results for compound 1, the vital cells are the largest fraction with 82 % in Q3, few apoptotic cells (4 %) in Ql, necrotic cells in Q2 and Q4 (together 14 %). But no labelling was seen of the vital living cells in Q3 with compound 1. The same results were obtained for compound xx. If apoptosis is induced via staurosporin (Figure 9), labeling of the apoptotic cells (Ql = 12 %) and necrotic cells (Q2 = 42 %) with compound 1 can be observed (same results with compound xx).

In a direct comparison with Annexin-V, it was shown that bis-cyclen showed labeling of some apoptotic and most necrotic cells. Figure 10 shows for example compound AB labeling apoptotic cells in Q2 and necrotic cells in Q4, while Annexin-V labels apoptotic cells in Ql and Q2.

It could be observed with induced apoptotic Jurkat cells, that multimerisation of bis-cyclen compounds led to an increase in labelling intensity while the percentage of labelled cells remained unchanged. Figure 11 shows an example for compound 1 (dimer = two cyclen-units) and compound we (tetramer = four cyclen-units) where the median fluorescence intensity for the tetramer is 130, while the median fluorescence intensity for the dimer is 56 while the percentage of labelled cells remained unchanged.

The complexation of bivalent cations, especially with Zn ²⁺ , is important for the binding specificity of the bis-cyclen compounds. This is, e.g. very pronounced for compound 1, which shows as a complex with Zn ²⁺ good binding to induced Jurkat cells, but almost no binding to induced Jurkat cells if no Zn ²⁺ is complexed (see Figure 12). The same effect was observed with compound we although not as pronounced as with compound 1.

In order to verify the FACS data with visual data confocal microscopy was performed. Con- focal microscopy was also performed on Jurkat cells and apoptosis was induced by incubating 10 ⁶ cells/ml in lμM staurosporin for 4 h (Stepczynska A et al, Staurosporine and conventional anticancer drugs induce overlapping, yet distinct pathways of apoptosis and caspase activatio- nOncogene (2001) 20, 1193). The experiments were also carried out in TES-buffer. For compound binding 10 ⁶ cells (either induced with staurosporin or non-induced) were incubated for 15 min at RT in 100 μL cold TES buffer with a final concentration of 5 μM compound, then the cells were fixed onto polylysine coated slides and shortly incubated with propidium iodine (PI).

The incubation of induced cells with compound 1 and PI showed good uptake of compound 1 and PI into to same cells, showing the uptake of compound 1 into necrotic cells (Figure 13).

A co-incubation of induced cells with Annexin-V and compound AB was performed to visualise apoptotic cells. Figure 14 shows the green membrane staining of Annexin-V for apop- totic cells. The red labeling from compound AB co-labels the apoptotic cells stained with Annexin-V but also shows labeling of cells, which were not detected by Annexin-V. This clearly shows labeling of apoptotic and necrotic cells with compound AB.

b) Synthesis of radioactively-labeled bis-cyclen complexes b-1 Synthesis of compound 15

15 14

Synthesis of the 2-[ rl8τ F]fluoroethyltosylat 12 was performed according to the literature (25). The ¹⁸ F-Fluorethyltosylate was dissolved in 200 μL anhydrous DMF and 5 mg Of K ₂ CO ₃ was added. The precursor 11 (2 mg) in 10 μL anhydrous DMF was added and the solution was heated for 30 minutes at 120 °C. The reaction mixture was run over an RPl 8 HPLC. Solvent was evaporated. Radiochemical yield: 65%

The ¹⁸ F-fluorethoxy-bis(cyclen) was dissolved in 50 μL ACN and 200 μL TFA was added. After 10 min at RT the solvent was removed. The reaction mixture was run over an RP 18 HPLC. The deprotected ¹⁸ F-fluorethoxy-bis(cyclen) was dissolved in 100 μL PBS-buffer, 10 μL 1.5 mM Zn(NO ₃ ) ₂ -solution was added and the solution was heated for 5 min at 70°C. The mixture was diluted with 400 μL PBS. Radiochemical yield > 50% (d.c) -2 Synthesis of compound 19

16 17

TFA

19 18

¹⁸ F-Fluorethyltosylate was dissolved in 200 μL anhydrous DMF and 5 mg of K ₂ CO ₃ was added. The phenolic precursor 16 (2 mg) in 10 μL anhydrous DMF was added and the solution was heated for 35 minutes at 120 ⁰ C. The reaction mixture was purified by preparative HPLC: Chromolith® SemiPrep RP-18e column (100x10 mm, Merck, Darmstadt, Germany), gradient, 100% Water (0.1%TFA) to 100% acetonitrile (0.1% TFA), flow: 8 mL/min; (t _R =5.7min). Radiochemical yield: 77%

The ¹⁸ F-fluorethoxy-BOC-bis(cyclen) 17 was dissolved in 50 μL MeCN and 200 μL TFA were added. After 10 min at RT the solvent was removed in vacuum. The reaction mixture was purified by preparative HPLC: Chromolith® SemiPrep RP-18e column (100x10 mm, Merck, Darmstadt, Germany), gradient, 100% Water (0.1%TFA) to 100% acetonitrile (0.1% TFA), flow: 8 mL/min; (t _R =1.7 min). The quantitatively deprotected ¹⁸ F-fluorethoxy- bis(cyclen) was dissolved in 100 μL PBS-buffer, 10 μL 1.5 mM Zn(NO ₃ ) ₂ -solution was added and the solution was heated for 5 min at 70°C. The mixture was diluted with 400 μL PBS and used without further purification.

b-3 Biodistribution and PET diagnostic

The biodistribution was performed in male Balb/c mice (6-8 weeks, body weight approx. 20 g). Hepatic apoptosis were induced by intraperitoneal injection of Cycloheximid (50 μg/kg in 500 μL PBS) (J. F. Tait, C. Smith, Z. Levashova, B. Patel, F. G. Blankenberg, J. Vander- heyden, J. Nucl. Med. 2006, 47, 1546). 1.5 h and 3.5 h after induction of hepatic apoptosis the 18F-labeled compound was injected i.v. (1 - 2 MBq in 100 μL PBS). The organ distribution was done after 30 min, Ih, 2h and 3h. The amount of 18F-compound was determined by gamma counter.

Biodistribution data of compound 19 for the 3.5 h time point after induction of hepatic apoptosis is shown in Figure 6. The compound showed accumulation in the apoptotic liver as early as 30 min after injection and the signal was stable for more than 3 h.

The PET images were obtained using a radiation model. Male Copenhagen rats with approx. 180 g body weight were transplanted with the hormone independent adenocarcinoma (Prostata) R3327-AT1 on the left and right upper leg. The left tumor, as it reached a size of 3.5 cm ³ was radiated by linear particle accelerator with a single dosis of 50 Gy, whereas the right tumor served as control.

One day prior to the radiation as well as 6 and 1O d after radiation, the 18F-compound 19 (15 - 25 MBq in ca. 200 μL PBS) was injected i.v. and PET-aquisition with Ih dynamic PET measurements were performed. Figure 7 clearly showed an increase in accumulation of compound 19 on day 6 and day 10 for the irradiated tumor in comparison to the control tumor.

c) Synthesis of radioactively-labeled tetra-cyclen complexes c-1 Indirect labeling, compound 21:

21 22

The radiolabeling was done in according to compound 15 and 19 to give compound 22 with an overall radiochemical yield of 30% corrected for decay regarding [ ¹⁸ F]fluoro ethyl tosylate. c-2 Direct labeling, compound 17:

Synthesis of compound 20

Compound 16, (25 mg, 24 μmol) was dissolved in 10OmL extra dry MeCN and potassium carbonate (10 mg, 72 μmol, 3 eq.) and ethylene glycol ditosylate (100 mg, 235 μmol, 10 eq.) were added. The reaction mixture was refluxed for 16 h. Potassium carbonate was filtered off and the solvent was removed in vacuum. The crude was purified via semipreparative HPLC (100% H2O (0.1% TFA) to 80% MeCN in 0.1 trifluoroacetic acid in 8 min). After removing the solvent in vacuum 19 mg of product 20 were obtained as a colorless solid in 67% yield.

Analytical HPLC: Chromolith® Performance RP-18e column (100x4.6 mm; Merck KGaA, Darmstadt, Germany); solvent gradient: 100% water (0.1 % trifluoroacetic acid) 95%acetonitril in 0.1% trifluoroacetic acid in 5 min., flow: 4mL/min Rt (analyt. HPLC, X= 215, 254 nm): 4.2 min IH-NMR (500 MHz, DMSO-D6, 343 K): δ - 7.80-7.77 (m, 2 H, H-3, 3J2.3 = 8.2 Hz); 7.49- 7.45 (m, 2 H, H-3); 6.84-6.67 (m, 3 H, H-9, H-I l); 4.35-4.31 (m, 2 H, H-7); 4.17-4.13 (m, 2 H, H-6); 3.74 (bs, 4 H, H-12); 3.49 (bs, 8 H, H-Cy4); 3.37-3.27 (m, 16 H, H-Cy3, H-Cy2); 2.60 (bs, 8 H, H-CyI); 2.42 (s, 3 H, H-I); 1.41 (s, 18 H, H-Boc3); 1.36 (s, 36 H, H-Boc3) ppm.

13C-NMR (500 MHz, DMSO-D6, 343 K): δ = 157.48 (C-8); 155.31 (C-Bocl); 154.30 (C-Bocl); 144.42 (C-5); 139.53 (C-2); 137.47 (C-IO); 129.64 (C-3); 127.08 (C-4); 125.50 (C-I l); 114.94 (C-9); 78.05 (C-Boc2); 77.84 (C-Boc2); 68.43 (C-7); 65.20 (C-6); 53.40 (C-12); 48.28 (C-CyI, C-Cy3); 47.03 (C-Cy2); 46.20 (C-Cy4); 27.86 (C-Boc3); 27.64 (C-Boc3); 20.59 (C-I) ppm.

Direct radiosyn thesis of compound 17

Aqueous [18F]Fluoride (1 GBq) was trapped on a QMA cartridge (Waters) and eluted with 5mg K2.2.2 in 0,95ml MeCN + lmg K2CO3 in 50μl water into a Wheaton V-vial. The sol- vent was removed by heating at 12O ⁰ C for 10 min under a stream of nitrogen. Anhydrous

MeCN (1 mL) was added and evaporated as before. A solution of precursor 20 (5 mg) in 500 μL anhydrous DMF was added. After heating at 130°C for 30 min the crude reaction mixture was mixted with 3 mL H2O and purified by preparative HPLC: Chromolith® SemiPrep RP- 18e column (100x10 mm, Merck, Darmstadt, Germany), gradient,100% Water (0.1%TFA) to 100% acetonitrile (0.1% TFA), flow: 8 mL/min; tR=5.7 min. The collected HPLC fraction was diluted with 40ml water and immobilized on a Sep-Pak light Cl 8 cartridge (Waters), which was washed with 5ml water and eluted with 2 ml ethanol to deliver 340 MBq product (50 %, corrected for decay; radiochemical purity >95% TLC, >95% HPLC) in a overall synthesis time of 60 min. The desired F- 18 labeled product was analyzed using analytical HPLC: Chromolith® Performance RP-18e column (100-4.6 mm; Merck KGaA, Darmstadt, Germany); solvent gradient: start 100% water (0.1 % trifluoroacetic acid) - 95%acetonitril in 0.1% trifluoroacetic acid in 5 min., flow: 4mL/min and confirmed by co-injection with the corresponding non-radioactive F- 19 fluoro-standard on the analytical HPLC. Abbreviations

ACN - Acetonitril

CF-PFPE - S-Zό-Carboxyfluoresceinpentafluorphenylester DCM - Dichloromethane DMF - N,N-Dimethylformamide EtOAc - Ethyl acetate EtOH - Ethanol

FACS - Fluorescence-activated cell sorting FITC - Fluorescein TES - [N-[Tris(hydroxymethyl)methyl] -2-aminosulfonic acid] PI - Propidium iodide TFA - Trifluoro acetic acid

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