Radiochemical and biological evaluation of novel Sm-153/Ho-166-amino acid-chitosan complexes

Radiochemical and biological e alua ion o no el 153 Sm/ 166 Ho-amino acid–chi osan complexes F. Ma ques, a L. Gano, a M. K. S. Ba is a, b,c C. A. R. Gomes, c P. Gomes, b and I. San os a 153 Sm/ 166 Ho-chi osan complexes ha e been conside ed p omising agen s o in e nal adia ion he apy. By di ec adminis a ion, complexes solu ion con e s in o a gel, a physiological pH, allowing i s e en ion o a long ime. He ein, we epo on he syn hesis o 153 Sm/ 166 Ho complexes wi h he no el amino acid–chi osan polyme s, N-(c-p opanoyl- alin)–chi osan (CHICO- al) and N-(c-p opanoyl-aspa ic acid)–chi osan (CHICO-asp). The main goal o his s udy was o ob ain da a on he adiochemical and biological beha iou o hese complexes and in o ma ion ega ding hei he apeu ic po en ial when compa ed o 153 Sm/ 166 Ho-chi osan. Radiolabelling yield o 153 Sm/ 166 Ho-amino acid–chi osan complexes was dependen on polyme concen a ion bu less dependen on pH. Radiochemical s abili y was shown o be highe o amino acid–chi osans han o chi osan, wi h 153 Sm/ 166 Ho-CHICO- al being s able up o 3 h, while 153 Sm/ 166 Ho-CHICO-asp is s able up o 24 h. In he p esence o asco bic acid adiochemical s abili y o 153 Sm/ 166 Ho-CHICO- al and 153 Sm/ 166 Ho-CHICO was imp o ed, dec easing o 153 Sm/ 166 Ho-CHICO-asp. In i o beha iou o 153 Sm complexes was s udied in mice. The adioac i e amino acid–chi osans can be di ec ly injec ed in o blood s eam wi hou signi ican e en ion on injec ion si e, being apped by li e . Biodis ibu ion s udies sugges ha he adioac i e amino acid–chi osans, due o i s wa e solubili y and s abili y may be conside ed po en ial candida es o be u he explo ed o li e a ge ed nuclea he apy. Keywo ds: adiolan hanides; chi osan de i a i es; amino acid; polyme s; in e nal adia ion he apy In oduc ion In e nal adia ion he apy (IRT) wi h unsealed b-emi ing adio- nuclides has eme ged o he ea men o cance as an al e na i e o ex e nal adio he apy. b-emi e s ha e ad an ages o he ea men o umou s owing o hei physical cha ac e - is ics, in pa icula hei sho so issue pene a ion ange, deli e ing high adia ion dose o umou wi hou ad e se adia ion e ec s on he su ounding no mal issues. 1 Among he b-emi e s, 166 Ho ( 1/2 26.8 h, b max 1.85 MeV (51%), g0.081 MeV (7.5%) and 153 Sm ( 1/2 46.8 h, b max 0.81 MeV (21%), g0.103 MeV (38%) appea o be good candida es o IRT. 2 Chi osan, a polyme o 2-deoxy-2-amino-D-glucose ob ained by N-deace yla ion o chi in has unique p ope ies o a b oad a ie y o applica ions. 3–5 I s chemical s uc u e is cha ac e ized by he deg ee o ace yla ion (DA), which also de e mines i s abili y o chela e me al ions. 3 Chemical modi ica ions o enhance chela ing p ope ies, selec i i y and me al ion capaci y o chi osan ha e been p oposed and a ious chi osan de i a- i es ha e been designed o imp o e hese ea u es. 6 Keeping his in mind, N-(2-ca boxye hyl)–chi osans ha e been p epa ed and hei me al complexa ion p ope ies and po en ial applica- ions ha e been s udied. 7–9 Owing o i s capaci y o complex b-emi e me al ions h ough i s amino g oups, chi osan appea s o be a p omising he apeu ic al e na i e o local ea men o umou s. 10 The main ea u es o hese complexes a e hei solubili y unde acidic condi ions and he easy con e sion o gel a he local o adminis a ion (physiological pH), wi h he co esponding e en ion o he adionuclide. Based on his p inciple, 153 Sm/ 166 Ho-chi osan complexes ha e been p epa ed wi h ela i ely high adiochemical pu i y (490%) and hei biological beha iou has been conside ed p omising o local he apy o p os a e and skin cance , 11–13 b ain glioma, 14 enal cys s 15 and heuma oid a h i is. 16–17 Following hese esul s, 166 Ho-chi osan (DW-166HC) has been app o ed in Ko ea as a adiopha maceu- ical o he ea men o small hepa ocellula ca cinoma (HCC). 18,19 Howe e , DW-166HC is sensi i e o deg ada ion induced by adia ion and i s use immedia ely a e syn hesis is highly equi ed. We ha e been wo king on he chemical modi ica ion o chi osan amino g oups in o de o imp o e bo h he polyme wa e solubili y o e a b oade pH ange and i s chela ing 79 Resea ch A icle Recei ed 24 Janua y 2008, Re ised 28 Oc obe 2008, Accep ed 1 No embe 2008 Published online 16 Decembe 2008 in Wiley In e science (www.in e science.wiley.com) DOI: 10.1002/jlc .1571 J. Label Compd. Radiopha m 2009, 52 79–83 Copy igh 2008 John Wiley & Sons, L d. a Ins i u o Tecnolo ´gico e Nuclea , Es ada Nacional 10, 2686-953 Saca e ´m, Po ugal b CIQUP, Depa amen o de Quı ´ mica, Faculdade de Cie ˆncias, Uni e sidade do Po o, Rua do Campo Aleg e 687, P-4169-007 Po o, Po ugal c LAQUIPAI, Depa amen o de Quı ´ mica, Faculdade de Cie ˆncias, Uni e sidade do Po o, Rua do Campo Aleg e 687, P-4169-007 Po o, Po ugal *Co espondence o: F. Ma ques, Ins i u o Tecnolo ´gico e Nuclea , Es ada Nacional 10, 2686-953 Saca e ´m, Po ugal. E-mail: [email p o ec ed] p ope ies, o po en ial biomedical applica ions. 7–9 Recen ly, we ha e p epa ed wo no el amino acid–chi osan polyme s, N-(g-p opanoyl- alin)–chi osan and N-(g-p opanoyl-aspa ic acid)–chi osan, om low molecula weigh chi osan and N a -(3-b omop opanoyl)– aline o N a -(3-b omop opanoyl)–aspa ic acid, espec i ely. 20 S uc u es o chi osan (CHICO, 1), N-(g-p opanoyl- alin)–chi osan (CHICO- al, 2a)andN-(g-p opanoyl- aspa ic acid)–chi osan (CHICO-asp, 2b) a e p esen ed in Figu e 1. In iew o he in e es ing p ope ies o ou no el amino acid–chi osan de i a i es, 21 we decided o explo e he coo dina ion capabili y o hese modi ied chi osan owa ds 153 Sm/ 166 Ho, wo he apeu ically ele an adionuclides. He ein, we desc ibe he syn hesis o 153 Sm/ 166 Ho-N-(g-p opanoyl- alin)–chi osan and 153 Sm/ 166 Ho-N-(g-p opanoyl-aspa ic acid)– chi osan as well as ou da a on hei adiochemical and biological beha iou as compa ed wi h he espec i e chi osan analogous. Resul s and discussion Syn hesis and s abili y o he adiolabelled complexes I adia ion o 152 Sm/Ho-ni a es yielded 140 MBq/mg ( 153 Sm) and 190 MBq/mg ( 166 Ho) wi h high adionuclidic pu i y as con i med by he ypical g- ay spec um. 22 The complexa ion eac ion condi ions we e op imized in o de o ob ain 153 Sm/ 166 Ho-complexes wi h high adiochemical pu i y. The labelling yield o 153 Sm/ 166 Ho-CHICO–amino acid complexes was no highly dependen on he pH, bu depends on he polyme concen a ion. Complexes we e ob ained wi h yields highe han 98% a pH 3–7 wi h 1% (w/ ) polyme solu ion, while he complexa ion yield d as ically dec eases a lowe concen a ion (Table 1). In con as , he labelling yield o 153 Sm/ 166 Ho-CHICO complexes was highly dependen on bo h pa ame e s, eaching only 98% a pHC3 and using a 1% CHICO solu ion. 11,16 The s abili y o he CHICO–amino acid complexes was ollowed by ITLC, using he ch oma og aphic sys ems indica ed in he expe imen al sec ion. Bo h complexes ha e in i o adiochemical beha iou di e en han ha o hei CHICO analogous. While he la e complex emains in he o igin, in acco dance wi h i s colloidal na u e, he CHICO-asp and CHICO- al complexes mig a e wi h R alues o app oxima ely 0.4 and 0.6, espec i ely (Table 2). None heless, in bo h cases he p esence o ee adiolan hanide was ne e de ec ed. A e o ma ion, 153 Sm/ 166 Ho-CHICO-asp/CHICO- al com- plexes showed ela i ely high adiochemical pu i y wi hin a su icien ime pe iod o e en ual clinical applica ions ( 153 Sm/ 166 Ho-CHICO- al is s able up o 3 h and 153 Sm/ 166 Ho- CHICO-asp is s able up o 24 h), while 153 Sm/ 166 Ho-CHICO appea ed o be mo e sensi i e and deg ading wi h s o ing. 23 As an example, we show in Figu e 2 how as 153 Sm-CHICO deg ades leading o new adiochemical species wi h ime. As shown in Figu e 2, 153 Sm-CHICO leads o a new species wi h R E0.22, 30 min a e o ma ion, and wi h ime new species a e o med p og essi ely wi h highe R alues. The amino acid de i a i es a e s able o a longe pe iod o ime and he decomposi ion co esponds o he o ma ion o a new adio- chemical species along wi h he o iginal ones. The di e en beha iou ound o ou complexes may be due o he p esence o one o wo ca boxyla e g oups in he chi osan backbone, which may con ibu e o s uc u al s abiliza ion o he adio- ac i e complexes. Conside ing ha asco bic acid (AA), an an ioxidan adical sca enge , is o en used as a ood addi i e o as a s abilize in adiopha maceu ical composi ions, 24,25 we ha e decided o e alua e he e ec o his compound on he adiochemical s abili y o 153 Sm/ 166 Ho-chi osan de i a i es and a he same ime on 153 Sm/ 166 Ho-chi osan. As can be seen in Figu e 2, 80 Table 1. Labelling yield s polyme concen a ion a he pH ange 3–7 Polyme Conc. (% w/ ) Labelling yield (%) CHICO- al 0.5 0 1100 CHICO-asp 0.5 0 1100 Table 2. Radiochemical beha iou o 153 Sm/ 166 Ho-amino acid–CHICO complexes R 153 Sm/ 166 Ho-CHICO 153 Sm/ 166 Ho-CHICO- al 153 Sm/ 166 Ho-CHICO-asp 153 Sm/ 166 Ho(NO 3 ) 3 00.6 0.4 0.9–1.0 Figu e 1. Molecula s uc u es o chi osan (1), N-(g-p opanoyl- alin)–chi osan (2a) and N-(g-p opanoyl-aspa ic acid)–chi osan (2b). F. Ma ques e al. www.jlc .o g Copy igh 2008 John Wiley & Sons, L d. J. Label Compd. Radiopha m 2009, 52 79–83 he adical sca enge has sligh ly imp o ed he s abili y o 153 Sm-CHICO, in ag eemen wi h he esul s p e iously de- sc ibed by Zoldne s e al. 24 The s abili y o his compound seems o be ela i ely dependen on he na u e o he solu ion componen s. In ace ic acid solu ions, o example, Zoldne s e al. desc ibed ha chi osan deg ades wi h he o ma ion o mo e wa e -soluble agmen s along he ime, as a esul o oxida i e and hyd oly ic spli ing o he polyme chains. Mo eo e , i has also been e e ed ha 166 Ho-chi osan is adia ion sensi i e, heading o dec easing in he complex iscosi y. 23 The inc ease s abili y o 153 Sm-CHICO in he p esence o AA may be due o he e ec o AA as a sca enge o possible adicala species and/ o o he addi ional coo dina ion capabili y o AA. 23,24 Rega ding he 153 Sm/ 166 Ho-CHICO–amino acid complexes, he addi ion o AA (2% AA solu ion) has signi ican ly a ec ed i s adiochemical beha iou . Fo compound 153 Sm/ 166 Ho-CHICO- al i s s abili y enhanced signi ican ly up o 24 h. In con as , he addi ion o AA o 153 Sm/ 166 Ho-CHICO-asp esul ed in a high deg ee o deg ada ion o he ini ial complexes, wi h o ma ion o se e al species. Based on he he mo-s abili y and s uc u al s udies p e iously pe o med o CHICO and o CHICO-amino acid polyme s, by di e en ial scanning calo ime y and scanning elec on mic oscopy, he CHICO-asp has a loose mac omolecula s uc u e han i s CHICO- al coun e pa and a highes he mo-sensi i i y and wa e -holding capaci y, which implies ha i s sup amolecula s uc u e is weake han ha o i s coun e pa (Figu e 3). 20,21 Thus, while CHICO- al has a compac and con inuous ilm-like s uc u e, CHICO-asp has a highly po ous mo phology, p obably due o elec os a ic epulsions be ween i s highe numbe o ca boxyla e g oups. The po ous mo phology o CHICO-asp may allow AA, a well- known chela ing agen , 26,27 o e icien ly pene a e in o he polyme ic ma ix and compe e o me al complexa ion wi h he polyme chela ing g oups. In CHICO- al he s uc u e is mo e compac and s able so ano he oxygen dono co-ligand may lead o a mixed-ligand complex, which will be ancho ed on he dono g oups o he amino acids as well as on he AA, leading o he s abiliza ion o he adiome al by a syne gic e ec . 24,26 Biodis ibu ion o he 153 Sm-labelled complexes in mice P elimina y biodis ibu ion s udies we e only pe o med o 153 Sm-complexes. Fo compa ison, 153 Sm-CHICO was also s udied in he same animal model. As expec ed, he 153 Sm-CHICO was almos comple ely e ained a he si e o adminis a ion and no adioac i i y exc e ion was ound up o 24 h. On he con a y, he CHICO-amino acid complexes could be injec ed di ec ly in o he blood s eam by he ail ein. Fo bo h complexes a high li e up ake was ound, despi e i. . injec ion and he exc e ion was e y slow o negligible. Howe e , he wo complexes ha e shown sligh ly di e en biodis ibu ion pa e ns (Figu e 4). While 153 Sm-CHICO- al was associa ed o high hepa ic adioac i i y e en ion ha enhanced o e ime, he 153 Sm-CHICO-asp was slowly clea ed om he li e in o he in es ine, which is a disad an age i one wan s o ea li e cance . Addi ionally, he up ake by he li e should be speed up in o de o educe he adia ion dose o he blood cells. The signi ican e en ion o ac i i y in he li e ound o 153 Sm-CHICO- al can p obably be due o he in i o o ma ion o adiochemical species o colloidal/polyme ic na u e. Expe imen al Chemicals: En iched sama ium oxide (Sm 2 O 3 , 98.4% as 152 Sm) was pu chased om Camp o Scien i ic and na u al Ho 2 O 3 (99.9%) om S em. Chi osan (abb e ia ed CHICO) (MW150 000; DA = 0.10) was supplied by Sigma-Ald ich. 81 Figu e 2. Radioac i e dis ibu ion on he ITLC-SA s ips o 153 Sm-CHICO complex ob ained in he absence and p esence o asco bic acid o e ime. Figu e 3. SEM mic og aphs (100 magni ica ion) o CHICO (A), CHICO- al (B) and CHICO-asp (C). F. Ma ques e al. J. Label Compd. Radiopha m 2009, 52 79–83 Copy igh 2008 John Wiley & Sons, L d. www.jlc .o g Ins an hin laye ch oma og aphy (ITLC) s ips we e supplied by Polyg am, Mache ey-Nagel. N-(g-p opanoyl- alin)–chi osan (abb e ia ed CHICO- al) and N-(g-p opanoyl-aspa ic acid)–chi- osan (abb e ia ed CHICO-asp) we e syn hesized and pu i ied acco ding o me hods p e iously epo ed. 21 All ma e ials we e eagen g ade unless o he wise speci ied. Syn hesis o he pep ide chi osan polyme s: The syn hesis o he wo no el CHICO-based polyme s was epo ed in de ail elsewhe e. 21 B ie ly, N a -(3-b omop opanoyl)- aline and N a -(3- b omop opanoyl)-aspa ic acid we e p epa ed by eac ing he ele an L-amino acid e -bu yl es e s wi h 3-b omop opanoic acid in he p esence o dicyclohexylca bodiimide (DCCI) as coupling eagen . A e being isola ed by column ch oma o- g aphy on silica, he e -bu yl es e s we e success ully iden i ied by 1 H and 13 C NMR. These es e s we e hen clea ed by acidolysis wi h nea TFA, wi h quan i a i e o ma ion o he co esponding ee ca boxylic acids N a -(3-b omop opanoyl)- aline and N a -(3- b omop opanoyl)-aspa ic acid, whose s uc u es we e also con i med by NMR. The ca boxylic acids ob ained as abo e desc ibed we e co alen ly a ached o chi osan as ollows: chi osan was dissol ed in wa e con aining 4 M equi alen s o N a -(3-b omop opanoyl)- aline o N a -(3-b omop opanoyl)-aspa - ic acid. The eac ions we e allowed o p oceed a 601C unde magne ic s i ing and wi h daily addi ions o NaHCO 3 o keep pH wi hin he 6–8 ange. The pep ide–chi osans we e pu i ied by dialysis agains deionized wa e o 5–7 days, and hen eeze-d ied. P oduc ion o 153 Sm and 166 Ho: 153 Sm and 166 Ho we e p oduced by 152 Sm(n,g) 153 Sm and 165 Ho(n,g) 166 Ho eac ion, espec i ely, in he ITN Nuclea Resea ch Po uguese Reac o (1 MW). I adia ion was pe o med using ni a e a ge s (Sm/Ho, 10 mg) p epa ed om he co esponden iso opically en iched 152 Sm 2 O 3 o na u al Ho 2 O 3 unde a he mal neu on lux o 1.5 10 13 n/cm 2 s and epi he mal neu on lux o 3.1 10 11 n/cm 2 s o 1–2 h. Following i adia ion, he a ge s we e econs i u ed in H 2 O o yield 1% (w/ ) 153 Sm/ 166 Ho-ni a e solu ion o complex p epa a ion. The adionuclide pu i y was assessed by gspec ome y wi h a Ge(Li)-de ec o (Canbe a) and ac i i ies we e measu ed by a adioiso ope calib a o (Aloka, Cu ieme e IGC-3, Tokyo, Japan). Radiolabelling p ocedu e: The p epa a ion o 153 Sm/ 166 Ho- complexes wi h a high labelling yield (498%) was op imized. Typically, 40 mLo 1% 153 Sm(NO 3 ) 3 solu ion o 20 mLo 1% 166 Ho(NO 3 ) 3 solu ion was added o 700 mL o CHICO o CHICO- based polyme solu ion in 1% ( / ) ace ic acid, ollowed by ho ough s i ing o 20 min a oom empe a u e. The adiolabelling pH o he esul ing solu ions was 3.0 o 153 Sm/ 166 Ho-CHICO complex and 7.0 (by adding an app op ia e olume o 1 N NaOH solu ion) o 153 Sm/ 166 Ho-pep ide-chi osan based complexes. The labelling e iciency was accomplished by ITLC, using ITLC-SA s ips de eloped wi h MeOH:H 2 O:ace ic acid (50:50:0.5) as he mobile phase. In his sys em, he adiochemical species mig a e wi h he R p esen ed in Table 2. Radioac i e dis ibu ion on he ITLC-SA s ips was de ec ed by using a Be hold LB 505 de ec o coupled o a adioch oma og am scanne . The s abili y o he 153 Sm/ 166 Ho-CHICO o 153 Sm/ 166 Ho- CHICO-based complexes was assessed by measu ing he adio- chemical pu i y by ITLC o e ime, up o 24 h. The e ec o he adical sca enge AA (2% AA solu ion) on he s abili y o he complexes was also s udied. In i o s udies: Biodis ibu ion s udies we e ca ied ou using no mal CD-1 mice om Cha les Ri e , Spain, acco ding o p e iously epo ed p ocedu es. 22 Animals we e in a enously injec ed, ia he ail ein, o in ape i oneally injec ed wi h 100 ml (3.7 MBq) o he adiolan hanide complexes. A e 1 and 24 h animals we e killed by ce ical disloca ion, he main o gans we e dissec ed and he adioac i i y coun ed in a gcoun e (Be hold LB 2111, Ge many). Biodis ibu ion esul s we e exp essed as pe cen o injec ed dose pe o al o gan (% I.D./o gan). Concluding ema ks Conce ning he bes s a egy o deal wi h inope able HCC, he e is a gene al lack o consensus. Classical app oaches include ans-a e ial chemo-emboliza ion (TACE) o IRT h ough admin- is a ion o adionuclide–lipiodol complexes ha ha e he ad an age o being highly e ained by hepa ic umou s. 28–35 Howe e , TACE is no sui able o ad anced disease o pa ien s wi h an obs uc ed ( h ombo ic) po al ein, whe eas adiola- belled lipiodol (e.g. 131 I-lipiodol) is associa ed wi h pain on injec ion and occasional induc ion o se e e pneumopa- hies. 30,31 Radioimuno he apy can be a way o ci cum en he abo e p oblems. Bu ea men s wi h he monoclonal 131 I-Hepama-1, hough associa ed wi h low oxici y, usually equi es hepa ic a e y liga ion, whe eas polyclonal 131 I abbi an i e i in IgG has been ela ed o h omobocy openia. 31 Al e na i ely, adiolabelled glass o esin mic osphe es ha e been explo ed as po en ially sa e IRT agen s, bu hei clinical e icacy has no been p o ed so a . Success ul ea men o li e umou s in an animal model was achie ed wi h 166 Ho-labelled poly-(L-lac ic acid) mic osphe es, which opens new possibili ies owa ds he use o mic osphe es buil om biocompa ible ma e ials. 31 In his con ex , adiolabelled chi osan-based poly- me s appea as a mos a ac i e and cos -e ec i e choice, as chi osan is cheap, biodeg adable, bioadhesi e and biocompa- ible, and has low oxici y and low immunogenici y. Indeed, he app o ed 166 Ho-chi osan complex (DW-166HC), was ound o be a highly e ec i e and sa e new adiopha maceu ical agen o IRT agains li e cance . 19 The CHICO-amino acid polyme s, desc ibed he ein, we e ound o be sui able ligands o he p epa a ion o s able 153 Sm/ 166 Ho-complexes wi h high labelling yields (498%) and high adiochemical pu i y o e he ime. As compa ed wi h unmodi ied chi osan, he amino 82 Figu e 4. Whole body exc e ion and biodis ibu ion in he mos ele an o gans o 153 Sm-CHICO complexes a 1 and 24 h a e adminis a ion in mice. F. Ma ques e al. www.jlc .o g Copy igh 2008 John Wiley & Sons, L d. J. Label Compd. Radiopha m 2009, 52 79–83 acid de i a i es p esen se e al ad an ages o e en ual clinical applica ions: wa e solubili y o e a wide pH ange and quan i a i e o ma ion o non-colloidal adiolan hanide complexes. Despi e hei highe luidi y, he adiolabelled CHICO-amino acid complexes ha e highe s abili y han hei CHICO coun e pa s and may be po en ially in e es ing o be explo ed o he ea men o HCC and li e me as asis, when ea ing he whole li e makes i mo e sui able as compa ed wi h esec ion o li e ansplan a ion. 36 In addi ion, in a clus e ed me as asis o p ima y umou , he c oss- i e e ec o b  ene gy pa icles migh also be bene icial. 36,37 P elimina y biological esul s ha e shown ha 153 Sm-CHICO-amino acid complexes p esen high li e up ake specially CHICO- al. This a ge ing o he li e may also be exploi ed o li e -speci ic a ge ing and wi h he app op ia e adionuclide, o imaging. 38 Whe he he biodis ibu ion p o ile o his adioac i e amino acid–chi osan could be imp o ed in o de o inc ease he blood clea ance and hen minimize he adia ion dose o non- a ge o gans he chance o adminis e i ia i. . injec ion may be a signi ican ad an age ela i ely o he compounds ad oca ed o he same pu pose, which equi e local adminis a ion. The imp o ed adiochemical and biological cha ac e is ics o 153 Sm/ 166 Ho-CHICO–amino acid complexes highligh he in e es o u he explo e he chemical modi ica ion o chi osan in o de o in oduce unc ional g oups o modula e i s pha macokine ics, coo dina ion capabili y owa ds di e en adionuclides and speci ici y o design speci ic adio ace s. 39 Acknowledgemen The au ho s wish o hank he ITN Po uguese Resea ch Reac o o he p oduc ion o 153 Sm and 166 Ho. P. Gomes and C. A. R. Gomes hank FCT o unding o esea ch uni s CIQUP and LAQUIPAI, espec i ely. M. K. S. Ba is a hanks FCT o he doc o al g an ( e . SFRH/BD/13144/2003). Re e ences [1] W. A. Volke , T. J. Ho man, Chem. Re . 1999,9, 2269–2292. [2] F. Ro ¨sch, E. Fo sell-A onsson, Radiolan hanides in nuclea medi- cine, in Me al Ions in Biological Sys ems,Vol. 42 (Eds.: A. Siegel, H. Siegel), Ma cel Dekke , Inc., New Yo k, 2004, pp. 77–108. [3] M. Rhazi, J. Desb ie ` e, A. Tolaima e, M. Rinaudo, P. Vo e o, A. Alagui, M. El Me ay, Eu . Polym. J. 2002,38, 1523–1530. [4] X. Wang, Y. Du, L. Fan, H. Liu, Y. Hu, Polym. Bull. 2005,55, 105–113. DOI: 10.1007/s00289-005-0414-1. [5] F. Wang, Y. Zhang, X. Fan, M. Wang, Nano echnology 2006,17, 1527–1532. [6] A. J. Va ma, S. V. Deshpande, J. F. Kennedy, Ca bohyd . Polym. 2004,55, 77–93. DOI: 10.1016/j.ca bpol.2003.08.005. [7] Y. A. Sko ik, C. A. R. Gomes, M. T. Vasconcelos, Y. G. Ya luk, Ca bohyd . Res. 2003,338, 271–276. DOI: 10.1016/S0008- 6215(02)00432-9. [8] Y. A. Sko ik, C. A. R. Gomes, N. V. Podbe ezskaya, G. V. Romanenko, L. P. Pin o, Y. G. Ya luk, Biomac omolecules 2005,6, 189–195. DOI: 10.1021/bm049597 . [9] G. Kogan, Y. A. Sko ik, I.  Zi  nano a, L. K iz ˇko a `,Z.  Du ac ˇko a ´, C. A. R. Gomes, Y.G. Ya luk, J. K ajc ˇo ic ˇ,Toxicol. Appl. Pha macol. 2004,201, 303–310. DOI: 10.1016/j. aap.2004.05.009. [10] K. B. Pa k, J. R. Kim, US Pa en 5762903, 1998. [11] S. K. Seong, J. M. Ryu, D. H. Shin, E. J. Bae, A. Shigema su, Y. Ha o i, J. Nishigaki, C. Kwak, S. E. Lee, K. B. Pa k, Eu . J. Nucl. Med. Mol. Imaging 2005,32, 910–917. DOI: 10.1007/s00259-005-1792-1. [12] C. Kwak, S. K. Hong, S. K. Seong, J. M. Ryu, M. S. Pa k, S. E. Lee, Eu . J. Nucl. Med. Mol. Imaging 2005,32, 1400–1405. DOI: 10.1007/ s00259-005-1892-y. [13] J. D. Lee, K. K. Pa k, M.-G. Lee, E.-H. Kim, K. J. Rhim, J. T. Lee, H. S. Yoo, Y. M. Kim, K. B. Pa k, J. R. Kim, J. Nucl. Med. 1997,38, 697–702. [14] R. Huh, Y. S. Pa k, J. D. Lee, Y. S. Chung, Y. G. Pa k, S. S. Chung, J. W. Chang, Yonsei Med. J. 2005,46, 51–60. [15] J. H. Kim, J. T. Lee, E. K. Kim, J. Y. Won, M. J. Kim, J. D. Lee, S. J. Hong, Ko ean J. Radiol. 2004,5, 128–133. [16] B. C. Shin, K. B. Pa k, B. S. Jang, S. M. Lim, C. K. Shim, Nucl. Med. Biol. 2001,28, 719–725. [17] S. H. Lee, J. S. Suh, H. S. Kim, J. D. Lee, J. Song, S. K. Lee, Ko ean J. Radiol. 2003,4, 170–178. [18] B. C. Cho, E. H. Kim, H. J. Choi, J. H. Kim, J. K. Roh, H. C. Chung, J. B. Ahn, J. D. Lee, J. T. Lee, N. C. Yoo, J. H. Sohn, Yonsei Med. J. 2005,46, 799–805. [19] J. K. Kim, K.-H. Han, J. T. Lee, Y. H. Paik, S. H. Ahn, J. D. Lee, K. S. Lee, C. Y. Chon, Y. M. Moon, Clin. Cance Res. 2006,12, 543–548. DOI: 10.1158/1078-0432.CCR-05-1730. [20] M. K. S. Ba is a, L. F. Pin o, C. A. R. Gomes, P. Gomes, Ca bohyd . Polym. 2006,64, 299–305. DOI: 10.1016/j.ca bpol.2005.11.040. [21] P. Gomes, C. A. R. Gomes, M. K. S. Ba is a, L. F. Pin o, P. A. P. Sil a, Ca bohyd . Polym. 2008,71, 54–65. DOI: 10.1016/j.ca bpol.2007.05.015. [22] F. Ma ques, L. Gano, M. P. Campello, S. Lace da, I. San os, L. M. P. Lima, J. Cos a, P. An unes, R. Delgado, J. Ino g. Biochem. 2006,100, 270–280. DOI: 10.1016/j.jino gbio.2005.11.011. [23] F. Melicha , M. K opacek, M. Mi zaje o a, J. Labelled Compd. Radiopha m. 2003,46, S303. [24] J. Zoldne s, T. Kisele a, I. Kaiminsh, Ca bohyd . Polym. 2005,60, 215–218. DOI: 10.1016/j.ca bpol.2005.01.013. [25] S. Liu, D. S. Edwa ds, Bioconjuga e Chem. 2001,12, 554–558. [26] B. Teuche , M. Oli a es, H. Co i, In . J. Vi am. Nu i . Res. 2004,74, 403–419. DOI: 10.1024/0300-9831.74.6.403. [27] Y. D. F idman, S. V. Alikee a, N. V. Dolgasho a, M. T. Nanae a, T. S. Sabi o a, L. I. A a skaya, Pha m. Chem. J. 1988,22, 300–303. DOI: 10.1007/BF00768248. [28] H. S. Han, W. K. Cho, U. J. Pa k, D. Hong, K. B. Pa k, J. Radioanal. Nucl. Chem. 2003,257, 47–51. [29] F. Sund am, T. C. M. Chau, P. Onkhuudai, P. Be nal, A. K. Padhy, Eu . J. Nucl. Med. Mol. Imaging 2004,31, 250–257. DOI: 10.1007/s00259- 003-1363-2. [30] B. Lambe , C. an de Wiele, Eu . J. Nucl. Med. Mol. Imaging 2005, 32, 980–989. DOI: 10.1007/s00259-005-1859-z. [31] M. A. D. Ven e, G. G. Hobbelink, A. D. an he Schip, B. A. Zonnenbe g, F. W. Nijsen, An icance Agen s Med. Chem. 2007,7, 441–459. [32] M. M. Saw, P. Ku z, N. Ago as os, T. S. A. Ho , F. X. Sund am, Y. K. Yan, R. Albe o, Ino g. Chim. Ac a 2006,359, 4087–4094. DOI: 10.1016/j.ica.2006.04.023. [33] Y. S. Lee, J. M. Jeong, Y. J. Kim, Y. S. Chang, H. J. Lee, M. Son, J. W. Lee, H. S. Yoon, W. J. Kang, D. S. Lee, J.-K. Chung, M. C. Lee, Y.-G. Suh, Appl. Rad. Iso . 2007,65, 64–69. DOI: 10.1016/ j.ap adiso.2006.07.008. [34] A. K. Padhy, M. Dondi, Semin. Nucl. Med. 2008,38, S5–S12. DOI: 10.1053/j.semnuclmed.2007.10.002. [35] J. M. Jeong, F. F. Knapp, Semin. Nucl. Med. 2008,38, S19–S29. DOI: 10.1053/j.semnuclmed.2007.10.003. [36] B. B ans, O. Linden, F. Giamma ile, J. Tenn all, C. Pun , Eu . J. Cance 2006,42, 994–1003. DOI: 10.1016/j.ejca.2005.12.020. [37] S. A. Enge , T. Ha man, J. Ca lsson, H. Lundq is , Phys. Med. Biol. 2008,53, 1909–1920. DOI: 10.1088/0031-9155/53/7/007. [38] E.-M. Kim, H.-J. Jeong, S.-L. Kim, M.-H. Sohn, J.-W. Nah, H.-S. Bom, I.-K. Pa k, C.-S. Cho, Nucl. Med. Biol. 2006,33, 529–534. DOI: 10.1016/j.nucmedbio.2006.03.005. [39] I.-C. Wei, N. Tsao, Y.-H. Huang, Y.-S. Ho, C.-C. Wu, D.-F. Yu, D. J. Yang, Appl. Radia . Iso . 2008,66, 320–331. DOI: 10.1016/ j.ap adiso.2007.10.002. 83 F. Ma ques e al. J. Label Compd. Radiopha m 2009, 52 79–83 Copy igh 2008 John Wiley & Sons, L d. www.jlc .o g