Del Turco, A.

Pietra , R.

Archive of European Integration

KW« PREPARATION OF COLLOIDAL CHROMIC »lì Æ m ÍMí Él Ml L. m Ispra Establishment (Italy) Nuclear Chemistry Service Reprinted from il of Applied Ra Vol. 14 - 1963 International Journal diation and Isotopes ψWiiHrfHrtLlPi·''•»»rt·""**'ΒηκΗ'*ΐ·* •Jr*MW ¡iWteínaü'kiíüiíVi »5'*^* This document was prepared under the sponsorship of the Commission of the European Atomic Energy Community (EURATOM). m Neither the EURATOM Commission, its contractors nor any person acting on their behalf : 1° — Make any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this document, or tha t the use of any information, apparatus , method, or process disclosed in this document may not infringe privately owned rights; or 2° — Assume any liability with respect to the use of, or for damages resulting from the use of any information, apparatus , method or process disclosed in this document. The authors ' names are listed in alphabetical order. m íi^lil^ill^lii mm di l l i Q Qifl ' war' This reprint is intended for restricted distribution only. It reproduces, by kind permission of the publisher, an article from "INTERNA­TIONAL JOURNAL OF APPLIED RADIATION AND ISOTO­PES", Vol. 14 ­ 1963, 279­283. For further copies please apply to Pergamon Press Ltd., Journals Department, Headington Hill Hall ­1ÍÜ mm* r-nr wim <f«i«i Oxford [England). Dieser Sonderdruck ist für eine beschränkte Verteilung bestimmt. Die Wiedergabe des vorliegenden in „INTERNATIONAL JOURNAL OF APPLIED RADIATION AND ISOTOPES", Vol. 14 ­ 1963, 279­283. erschienenen Aufsatzes erfolgt mit freundlicher Genehmigung des Herausgebers. Bestellungen weiterer Exemplare sind an Pergamon Press Ltd., Journals Department, Headington Hill Hall — Oxford {England), zu richten. ! . ♦ » ! Ce tiré­à­part est exclusivement destiné à une diffusion restreinte. Il reprend, avec l'aimable autorisation de l'éditeur, un article publié dans le «INTERNATIONAL JOURNAL OF APPLIED RADIATION AND ISOTOPES», Vol. 14 ­ 1963, 279­283. Tout autre exemplaire de cet article, doit être demandé à Pergamon Press Ltd. , Journals Department, Headington Hill Hall — Oxford (England). Questo estratto è destinato esclusivamente ad una diffusione limitata. Esso è stato riprodotto, per gentile concessione dell'Editore, da « INTER­NATIONAL JOURNAL OF APPLIED RADIATION AND ISOTOPES», Vol. 14 ­ 1963, 279­283. Ulteriori copie dell'articolo debbono essere richieste a Pergamon Press Ltd. Journals Department, Headington Hill Hall — Oxford (England). Deze overdruk is slechts voor beperkte verspreiding bestemd. Het artikel is met welwillende toestemming van de uitgever overgenomen uit,,INTER m NATIONAL JOURNAL^OF APPLIED RADIATION AND ISOTOPES", Vol. 14 ­ 1963, 279­283. Meer exemplaren kunnen besteld worden bij Pergamon Press Ltd., Journals Department, Hea­dington Hill Hall — Oxford (England). i!k^A»î$ Etilem E U R 4 1 9 . e R E P R I N T PREPARATION OF COLLOIDAL CHROMIC PHOSPHATE (P32) FOR MEDICAL USE by A.M. DEL TURCO and R. PIETRA. European Atomic Energy Community - EURATOM Joint Nuclear Research Centre Ispra Establishment (Italy) Nuclear Chemistry Service Reprinted from "International Journal of Applied Radiation and Isotopes", Vol. 14-1963 - pp. 279-283. A method for preparation of radioactive colloidal chromic phosphate (1 mC P32/ mg CrP3204) for medical use has been studied. The radioactive colloidal chromic phosphate does not hydrolyse and sediment. The particle size of 50 per cent of colloid is about 200 Â and the other par-ticles are condensed into aggregates. E U R 4 1 9 . e R E P R I N T PREPARATION OF COLLOIDAL CHROMIC PHOSPHATE (P32) FOR MEDICAL USE by A.M. DEL TURCO and R. PIETRA. European Atomic Energy Community - EURATOM Joint Nuclear Research Centre Ispra Establishment (Italy) Nuclear Chemistry Service Reprinted from "international Journal of Applied Radiation and Isotopes", Vol. 14-1963 - pp. 279-283. A method for preparation of radioactive colloidal chromic phosphate (1 mC P32/ mg CrP3204) for medical use has been studied. The radioactive colloidal chromic phosphate does not hydrolyse and sediment. The particle size of 50 per cent of colloid is about 200 A and the other par-ticles are condensed into aggregates. International Journal of Applied Radiation and Isotopes, 1963, Vol. 14, pp. 279­283. Pergamon Press Ltd. Printed in Northern Ireland Preparation of Colloidal Chromic Phosphate 'P32) for Medical Use A. M. DEL T U R C O and R. P I E T R A Laboratorio di Chimica Nucleare, Euratom, C.CR.­Ispra, Italy (Received 26 October 1962) A method for preparation of radioactive colloidal chromic phosphate ( lmCP 3 2 /mg CrP3204) for medical use has been studied. The radioactive colloidal chromic phosphate does not hydrolyse and sediment. The particle size of 50 per cent of colloid is about 200 A and the other particles are condensed into aggregates. PREPARATION DU PHOSPHATE (P32) CHROMIQUE COLLOIDAL POUR EMPLOI MEDICAL Une méthode pour la préparation du phosphate chromique colloïdal radioactif (1 mC P32/mg CrP3204) pour usage médical a été étudiée. Ce radiophosphate chromique colloïdal ne s'hydrolyse et ne sedimente pas. La grosseur de 50 pour cent des particles du colloïde est de l'ordre de 200 A et les autres particules sont condensées en agglomérés. nPHrOTOBJIEHME KOJIJIOHflHOrO ΦΟΟΦΑΤΑ (Ρ32) XPOMA flJIfl VnOTPEBJIEHHH Β M Ε Τ M IJ, Il H E MaynancH ΜΘΤΟΑ ΠΡΗΓΟΤΟΒ,ΙΙΘΗΗΗ paattoaKTiiuiioro κο.Ί.-ioiijiioro (}>oc(|)aTa xpo.\ia (hiKiopn P32/MI'P CrP0324) a-na ynoTpeÖJieiiiin IÌ Mehuunne. PajiHOaKTHBHbiH KO.uioiiaiiuiì (|)OC(¡)aT xpoMa ne nosuepraeTcn rimpoJiray n He ocan^aeTCH. Be.ini'iHua 'lacran 50% KO.i.ionjra panna npiiõ.TH3irre.­n.no 200 Å (ΑκτοτρβΜ), a spyriie wacTiiuH HOiiaeiicii])yioTCH n arpera™. DIE HERSTELLUNG VON KOLLOIDALEM CHROMPHOSPHAT (P32i FÜR MEDIZINISCHE ZWECKE Eine Methode zur Herstellung von radioaktivem kolloidalem Ghromphosphat (1 mC P32/mg CrP32Oj) ist für den medizinischen Gebrauch studiert worden. Das so erhaltene radioaktive, kolloidale Chromphosphat hydrolisiert und sedimentiert nicht. Die Teilchengrösse von 5 prozent des Kolloids ist ungefähr 200 Â und die anderen Teilchen sind zu Aggregaten zusammengeballt. I N T R O D U C T I O N system. This substance was also used inter­INTEREST is increasing in the use of colloids of stitially in mice in therapy of mammary adeno­radioactive materials in the therapy of neo­ carcinomata (1945) and then in treatment of plasms. patients afflicted with a wide variety of malig­H A H N and co­workers'1 ' have used Au198 nant tumours13 ' with apparent good results. in colloidal form in interstitial, intraperitoneal Radioactive phosphorus P32 seems to have and intravenous routes of administration. some advantages over radioactive gold Au198. As early as 1944 JONES and co­workers'2 ' Radioactive phosphorus P32, in fact, is demonstrated the use of P32 in a chemically essentially a pure beta­emitter (Emax — 1­7 inert colloidal form, chromic phosphate, for the MeV) ; hence handling is simpler and safer irradiation of tissues of the reticuloendothelial than with radioactive gold (Au198 decays with 279 280 Α. Μ. Del Turco and R. Pieira two beta spectra on the excited levels of 1­088 and 0­412 MeV ofHg 1 9 8 ) ' 4 ' . Furthermore the half­life of P32 is 14­3 days while Au198 decays with a half­life of 2­69 days. Because of the longer half­life of P32, storage is possible and considerably smaller doses than in the case of Au198, in terms of millicuries, are equivalent in total ionizing radiation ultimately delivered. These reasons indicate that colloidal chromic radiophosphate may displace Au198 colloids in radiotherapy. Published methods of preparation of colloidal chromic radiophosphate can be divided in two main groups : precipitation methods and re­duction methods. The precipitation methods'0 '1 '1 arc based on the original technique of JONES and co­workers'2 ' . This method consists in a precipitation reaction of insoluble chromic phosphate from a solution of alkaline phosphate and a soluble chromic salt (generally nitrate). The precipitate is then filtered, ignited, crushed, suspended and centri­fugea. The results are not too satisfactory. The yield is rather low (about 25 per cent) and the operations require several days of work and elaborate equipment. The ¡'eduction methods'7­81 arc based on a reduction­oxidation reaction involving chromic acid, phosphoric acid and a reducing agent in absence, or presence of a protective colloid. The subsequent purification of the colloidal chromic phosphate obtained as above requires (ANGIIILERI) flocculation, washing and sus­pension in isotonic solution or (CHEVALLIER and co­workers) elaborate technique based on the use of a lactose column. The method described in this work is a reduction method according to the technique of ANGIIILERI. The reaction used involves chromic acid, sodium sulphite as reducing agent, phosphoric acid in presence of gelatin as protective colloid, 2 H 2 C r O , 4­ 3 N a 2 S 0 3 + 2 H 3 P 0 4 ­> 2 C r P 0 4 4­ 3Na2SO., ­'­ 5 H , 0 . The purification of the colloidal chromic radiophosphate is carried out by dialysis. The yield is 80 per cent; the equipment and handling are very simple. The colloidal chromic radiophosphate pre­pared by the method described in this paper is a green, clear suspension and has the following characteristics: C r P 0 4 gelatin pH 3 mg/ml 5­5 mg/ml 6-7 E X P E R I M E N T A L Malcriáis The following solutions are needed: (1) Chromic acid solution: 10 mg/ml; (2) Phosphoric acid solution: 10 mg/ml— (in this solution H 3 P 3 2 0 4 carrier­free is added according to the required specific activity) ; (3) Sodium sulphite solution: 200 mg/ml; (4) Celatili solution: 20 per cent. All these solutions are freshly (this is a very important point) prepared and sterilized at 1 1 2 'C for half an hour. Preparation In order to obtain colloidal chromic radio­phosphate, the operations are carried out as follows. To 6 ml of chromic acid 4 ml of phosphoric acid (containing P32) arc added. When the mixture reaches the boiling point, 0­5 ml of gelatin, 6­5 ml of pyrogen­free water and 1 ml of sodium sulphite are added. The mixture is kept at the boiling point for 5 min. All these operations arc carried out while agitating by air bubbling through a capillary tube. The preparation requires 15 min. The reaction yield, tested by chromatographic analy­sis according to the EBEL technique'9 ' , results 90 per cent. The colloidal chromic phosphate has Rf = 0 and phosphoric ions Rf = 0­7 ­­­ 0­8, with Whatman No. 1 paper using ascending mono­dimensional method and as clucnt : isopropyl alcohol (75 ml), water (25 ml), trichloroacetic acid (5 g), ammonia 22 Bé (0­3 ml), checked pH 1­5­2. Purification anil sterilization The colloidal chromic phosphate containing about 10 per cent of free orthophosphoric ions is then dialyscd overnight using cellulose membrane (C. ERBA, Milan). Preparation of colloidal chromic phosphate (P32) for medical use 281 Hot p la te Hot ba th React ion vessel Reagent inlet Connexion f rem C to vacuum Capi l lary tor' air i n t r oduc t i on and l iqu id t r a n s f e r Condenser "hree way unlubr icated stopcock A i r f i l te r Reservo i r Del ivery tube f r o m reservo i r Dialyser Dispensing p ipe t te Dispensing bo t t l e P lungers FIG. 1. Equipment used for the preparation of colloidal CrP3 204 . In this way the content of phosphoric ions is reduced to 1 per cent or less. The colloid is then sterilized at 112°C for half an hour. In this way the content of phosphoric ions increases to 3-4 per cent. The equipment used for this method of pre-paration and purification (Fig. 1) is placed in a glove box shielded by 12-mm Plexiglas walls. D I S C U S S I O N The following characteristics were checked on the colloidal chromic radiophosphate pre-pared as above: (a) Content in phosphoric ions, (b) Chemical stability, (c) Colloidal stability. All these tests were made on samples contain-ing P32 at tracer level. (a) Content in phosphoric ions The content in phosphoric ions was tested by chromatographic analysis'9 ' and was found equal to 1-4 per cent. The chromatographic analysis shows also the absence of condensed phosphate. (b) Chemical stability The colloidal chromic radiophosphate shows satisfactory chemical stability. Hydrolysis was checked by chromatographic analysis'9 ' . The colloid kept at room temperature and at 40°C does not hydrolyse even after one month. On the contrary the pH and the dilution have influence on the hydrolysis. The obtained data are reported in Tables 1 and 2. Tables 1(a) and 1 (b) show that the hydrolysis is rather low for the p H of the human parts into which colloidal chromic radiophosphate can be injected'11". 282 Α. Μ. Del Turco and R. Pietra Table 1. Influence of the pH (a) Colloidal chromic radiophosphate kept at room temperature . Initial content of phosphoric ions = 1%. p H 4 5 6 7 8 9 % of orthophosphoric ions After 1 day 6-5 3-5 2-2 2 2 3 After 2 weeks 9-5 6 3-2 3 4 4 After 4 weeks 11-5 6-5 3-5 3 4 4 (b) Colloidal chromic radiophosphate kept at 40°C. Initial content of phosphoric ions = 1%. P H 4 5 6 7 8 9 % of orthophosphoric ions After 1 day 14-5 9 6 6 6 6 After 2 weeks 52 40 6 6 6 6 After 4 weeks 52 40 6 6 6 6 Table 2. Influence of the dilution (a) Colloidal chromic radiophosphate diluted with NaCl 0-9% and kept at room temperature. Initial content of phosphoric ions = 1%. Dilution 1:1 1:5 1:10 % of orthophosphoric ions After 1 day 1 1-4 1-6 After 2 weeks 1-5 2-3 3 After 4 weeks 1-4 3 4-5 (b) Colloidal chromic radiophosphate diluted with NaCl 0-9% and kept at 40°C. Initial content of phosphoric ions = 1%. Dilution 1:1 1:5 1:10 % of orthophosphoric ions After 1 day 1-4 2-7 4 After 2 weeks 2-8 3-2 4-2 After 4 weeks 2-5 3-3 4-2 (c) Colloidal stability Stability was checked for samples: 1—Kept at room temperature one month from preparation, 2—Kept at high and low temperature several hours, 3—Diluted with phvsiological solution (NaCl 0-9%), 4—Buffered from p H 4 to pH 9. No flocculation was found in any sample. COLLOIDAL CHROMIC P H O S P H A T E WITH HIGH SPECIFIC ACTIVITY Samples of colloidal chromic phosphate with high specific activity (3 mC/ml) were prepared as above. Stability tests made on these samples show that also the colloidal chromic radiophosphate with high specific activity does not hydrolyse and sediment even after one month. PARTICLE SIZE D E T E R M I N A T I O N Great difficulties were found in the particle size determination by electronic microscope. Colloidal chromic phosphate has, in fact, a remarkable tendency to condense into aggre­gates and its low mean atomic number makes a rather difficult task to obtain good micrographs. Figure 2 shows the presence of aggregates and small diameter particles. By fractionated centri-fuging the fraction containing aggregates was found equal to about 50 per cent. The remain­ing fraction has a diameter smaller than 200 A. Acknowledgments—The authors wish to thank Prof. G. BERTOLINI, Dr. M. BRESESTI, Mr. R. LANZ of this laboratory and Dr. G. POLVANI of C.N.E.N. for their help and assistance. REFERENCES 1. HAHN P. F. Proceedings of the First International Conference on the Peaceful Uses of Atomic Energy, Geneva, A/Conf. 8/P/202. United Nations, New York (1955). FIG. 2. Photograph at the electronic microscope of the colloidal chromic phosphate ( χ 72,000). Preparation of colloidal chromic phosphate (P32) for medical use 283 2. JONES H . B., W R O B E L G. J . and LYONS W. R. J. clin. Invest. 28, 783 (1944). 3. CHEVALLIER A. and BURG C. Proceedings of the First International Conference on the Peaceful Uses of Atomic Energy, Geneva, A/Conf. 8/P/367. United Nations, New York (1955). 4. STROMINGER D., HOLLANDER J . M. and SEABORG G. T . Rev. mod. Phys. 30, 2 (1958). 5. M O R T O N M. E. Nucleonics 10, 92 (1952). 6. NESS A. T., SMITH R. E. and EVANS R. L. J. Amer. ehem. Soc. 74, 4685 (1952). 7. ANGIIILERI L. J . Proceedings of the Second Inter-national Conference on the Peaceful Uses of Atomic Energy, Geneva, A/Conf. 15/P/1575. United Nations, New York (1958). 8. CHEVALLIER A. and BURG C. Proceedings of the Second International Conference on the Peaceful Uses of Atomic Energy, Geneva, A/Conf. 15/P/1220. Uni ted Nations, New York (1958). 9. E B E L J . P. Mikrochimica Acta H 6 , 679 (1954). 10. Handbook of Biological Data. SPECTOR (Ed.), pp . 68-69 (1956). 11. DUBINI M. and FANTECHI R. CNI 32 (1960). Preparation of colloidal chromic phosphate (P32) for medical use 283 2. JONES H . B., W R O B E L G. J . and LYONS W. R. J. clin. Invest. 28, 783 (1944). 3. CHEVALLIER A. and BURG C. Proceedings of the First International Conference on the Peaceful Uses of Atomic Energy, Geneva, A/Conf. 8/P/367. United Nations, New York (1955). 4. STROMINGER D., HOLLANDER J . M. and SEABORG G. T . Rev. mod. Phys. 30, 2 (1958). 5. M O R T O N M. E. Nucleonics 10, 92 (1952). 6. NESS A. T., SMITH R. E. and EVANS R. L. J. Amer. ehem. Soc. 74, 4685 (1952). 7. ANGIIILERI L. J . Proceedings of the Second Inter-national Conference on the Peaceful Uses of Atomic Energy, Geneva, A/Conf. 15/P/1575. United Nations, New York (1958). 8. CHEVALLIER A. and BURG C. Proceedings of the Second International Conference on the Peaceful Uses of Atomic Energy, Geneva, A/Conf. 15/P/1220. Uni ted Nations, New York (1958). 9. E B E L J . P. Mikrochimica Acta H 6 , 679 (1954). 10. Handbook of Biological Data. SPECTOR (Ed.), pp . 68-69 (1956). 11. DUBINI M. and FANTECHI R. CNI 32 (1960). ■1 '-'MlUUWeft iiimtxm KÍ.WÜÍ." 'JMÎÛ:iU- iiíir.KiaÊiiii CDNA00419ENC 

PREPARATION OF COLLOIDAL CHROMIC PHOSPHATE (p32) FOR MEDICAL USE. EUR 419.e

KW« 
PREPARATION OF COLLOIDAL CHROMIC 
»lì 
Æ 
m 
ÍMí 
Él 
Ml L. 
m 
Ispra Establishment (Italy) 
Nuclear Chemistry Service 
Reprinted from 
il of Applied Ra 
Vol. 14 - 1963 
International Journal diation and Isotopes 
ψWiiHrfHrtLlPi·''•»»rt·""**'ΒηκΗ'*ΐ·* •Jr*MW ¡iWteínaü'kiíüiíVi »5'*^* This document was prepared under the sponsorship of the Commission of the European 
Atomic Energy Community (EURATOM). 
m 
Neither the EURATOM Commission, its contractors nor any person acting on their behalf : 
1° — Make any warranty or representation, express or implied, with respect to the accuracy, 
completeness, or usefulness of the information contained in this document, or tha t the use 
of any information, apparatus , method, or process disclosed in this document may not 
infringe privately owned rights; or 
2° — Assume any liability with respect to the use of, or for damages resulting from the use of 
any information, apparatus , method or process disclosed in this document. 
The authors ' names are listed in alphabetical order. m íi^lil^ill^lii 
mm 
di l l i Q Qifl 
' war' 
This reprint is intended for restricted distribution only. It reproduces, 
by kind permission of the publisher, an article from "INTERNA­
TIONAL JOURNAL OF APPLIED RADIATION AND ISOTO­
PES", Vol. 14 ­ 1963, 279­283. For further copies please apply to 
Pergamon Press Ltd., Journals Department, Headington Hill Hall ­
1ÍÜ 
mm* r-nr wim <f«i«i 
Oxford [England). 
Dieser Sonderdruck ist für eine beschränkte Verteilung bestimmt. Die 
Wiedergabe des vorliegenden in „INTERNATIONAL JOURNAL 
OF APPLIED RADIATION AND ISOTOPES", Vol. 14 ­ 1963, 
279­283. erschienenen Aufsatzes erfolgt mit freundlicher Genehmigung 
des Herausgebers. Bestellungen weiterer Exemplare sind an Pergamon 
Press Ltd., Journals Department, Headington Hill Hall — Oxford 
{England), zu richten. 
! . ♦ » ! 
Ce tiré­à­part est exclusivement destiné à une diffusion restreinte. Il 
reprend, avec l'aimable autorisation de l'éditeur, un article publié dans 
le «INTERNATIONAL JOURNAL OF APPLIED RADIATION 
AND ISOTOPES», Vol. 14 ­ 1963, 279­283. Tout autre exemplaire 
de cet article, doit être demandé à Pergamon Press Ltd. , Journals 
Department, Headington Hill Hall — Oxford (England). 
Questo estratto è destinato esclusivamente ad una diffusione limitata. 
Esso è stato riprodotto, per gentile concessione dell'Editore, da « INTER­
NATIONAL JOURNAL OF APPLIED RADIATION AND 
ISOTOPES», Vol. 14 ­ 1963, 279­283. Ulteriori copie dell'articolo 
debbono essere richieste a Pergamon Press Ltd. Journals Department, 
Headington Hill Hall — Oxford (England). 
Deze overdruk is slechts voor beperkte verspreiding bestemd. Het artikel 
is met welwillende toestemming van de uitgever overgenomen uit,,INTER 
m 
NATIONAL JOURNAL^OF APPLIED RADIATION AND 
ISOTOPES", Vol. 14 ­ 1963, 279­283. Meer exemplaren kunnen 
besteld worden bij Pergamon Press Ltd., Journals Department, Hea­
dington Hill Hall — Oxford (England). i!k^A»î$ Etilem 
E U R 4 1 9 . e 
R E P R I N T 
PREPARATION OF COLLOIDAL CHROMIC PHOSPHATE (P32) FOR 
MEDICAL USE by A.M. DEL TURCO and R. PIETRA. 
European Atomic Energy Community - EURATOM 
Joint Nuclear Research Centre 
Ispra Establishment (Italy) 
Nuclear Chemistry Service 
Reprinted from "International Journal of Applied Radiation and Isotopes", 
Vol. 14-1963 - pp. 279-283. 
A method for preparation of radioactive colloidal chromic phosphate (1 mC P32/ 
mg CrP3204) for medical use has been studied. 
The radioactive colloidal chromic phosphate does not hydrolyse and sediment. 
The particle size of 50 per cent of colloid is about 200 Â and the other par-
ticles are condensed into aggregates. 
E U R 4 1 9 . e 
R E P R I N T 
PREPARATION OF COLLOIDAL CHROMIC PHOSPHATE (P32) FOR 
MEDICAL USE by A.M. DEL TURCO and R. PIETRA. 
European Atomic Energy Community - EURATOM 
Joint Nuclear Research Centre 
Ispra Establishment (Italy) 
Nuclear Chemistry Service 
Reprinted from "international Journal of Applied Radiation and Isotopes", 
Vol. 14-1963 - pp. 279-283. 
A method for preparation of radioactive colloidal chromic phosphate (1 mC P32/ 
mg CrP3204) for medical use has been studied. 
The radioactive colloidal chromic phosphate does not hydrolyse and sediment. 
The particle size of 50 per cent of colloid is about 200 A and the other par-
ticles are condensed into aggregates. 

International Journal of Applied Radiation and Isotopes, 1963, Vol. 14, pp. 279­283. Pergamon Press Ltd. Printed in Northern Ireland 
Preparation of Colloidal Chromic Phosphate 
'P32) for Medical Use 
A. M. DEL T U R C O and R. P I E T R A 
Laboratorio di Chimica Nucleare, Euratom, C.CR.­Ispra, Italy 
(Received 26 October 1962) 
A method for preparation of radioactive colloidal chromic phosphate ( lmCP 3 2 /mg 
CrP3204) for medical use has been studied. 
The radioactive colloidal chromic phosphate does not hydrolyse and sediment. 
The particle size of 50 per cent of colloid is about 200 A and the other particles are condensed 
into aggregates. 
PREPARATION DU PHOSPHATE (P32) CHROMIQUE COLLOIDAL POUR 
EMPLOI MEDICAL 
Une méthode pour la préparation du phosphate chromique colloïdal radioactif (1 mC 
P32/mg CrP3204) pour usage médical a été étudiée. 
Ce radiophosphate chromique colloïdal ne s'hydrolyse et ne sedimente pas. 
La grosseur de 50 pour cent des particles du colloïde est de l'ordre de 200 A et les autres 
particules sont condensées en agglomérés. 
nPHrOTOBJIEHME KOJIJIOHflHOrO ΦΟΟΦΑΤΑ (Ρ32) XPOMA 
flJIfl VnOTPEBJIEHHH Β M Ε Τ M IJ, Il H E 
MaynancH ΜΘΤΟΑ ΠΡΗΓΟΤΟΒ,ΙΙΘΗΗΗ paattoaKTiiuiioro κο.Ί.-ioiijiioro (}>oc(|)aTa xpo.\ia (hiKiopn 
P32/MI'P CrP0324) a-na ynoTpeÖJieiiiin IÌ Mehuunne. 
PajiHOaKTHBHbiH KO.uioiiaiiuiì (|)OC(¡)aT xpoMa ne nosuepraeTcn rimpoJiray n He ocan^aeTCH. 
Be.ini'iHua 'lacran 50% KO.i.ionjra panna npiiõ.TH3irre.­n.no 200 Å (ΑκτοτρβΜ), a spyriie 
wacTiiuH HOiiaeiicii])yioTCH n arpera™. 
DIE HERSTELLUNG VON KOLLOIDALEM CHROMPHOSPHAT (P32i 
FÜR MEDIZINISCHE ZWECKE 
Eine Methode zur Herstellung von radioaktivem kolloidalem Ghromphosphat (1 mC 
P32/mg CrP32Oj) ist für den medizinischen Gebrauch studiert worden. 
Das so erhaltene radioaktive, kolloidale Chromphosphat hydrolisiert und sedimentiert nicht. 
Die Teilchengrösse von 5 prozent des Kolloids ist ungefähr 200 Â und die anderen Teilchen 
sind zu Aggregaten zusammengeballt. 
I N T R O D U C T I O N system. This substance was also used inter­
INTEREST is increasing in the use of colloids of stitially in mice in therapy of mammary adeno­
radioactive materials in the therapy of neo­ carcinomata (1945) and then in treatment of 
plasms. patients afflicted with a wide variety of malig­
H A H N and co­workers'1 ' have used Au198 nant tumours13 ' with apparent good results. 
in colloidal form in interstitial, intraperitoneal Radioactive phosphorus P32 seems to have 
and intravenous routes of administration. some advantages over radioactive gold Au198. 
As early as 1944 JONES and co­workers'2 ' Radioactive phosphorus P32, in fact, is 
demonstrated the use of P32 in a chemically essentially a pure beta­emitter (Emax — 1­7 
inert colloidal form, chromic phosphate, for the MeV) ; hence handling is simpler and safer 
irradiation of tissues of the reticuloendothelial than with radioactive gold (Au198 decays with 
279 
280 Α. Μ. Del Turco and R. Pieira 
two beta spectra on the excited levels of 1­088 
and 0­412 MeV ofHg 1 9 8 ) ' 4 ' . 
Furthermore the half­life of P32 is 14­3 days 
while Au198 decays with a half­life of 2­69 
days. Because of the longer half­life of P32, 
storage is possible and considerably smaller 
doses than in the case of Au198, in terms of 
millicuries, are equivalent in total ionizing 
radiation ultimately delivered. 
These reasons indicate that colloidal chromic 
radiophosphate may displace Au198 colloids in 
radiotherapy. 
Published methods of preparation of colloidal 
chromic radiophosphate can be divided in two 
main groups : precipitation methods and re­
duction methods. 
The precipitation methods'0 '1 '1 arc based on 
the original technique of JONES and co­workers'2 ' . 
This method consists in a precipitation reaction 
of insoluble chromic phosphate from a solution 
of alkaline phosphate and a soluble chromic 
salt (generally nitrate). The precipitate is then 
filtered, ignited, crushed, suspended and centri­
fugea. The results are not too satisfactory. 
The yield is rather low (about 25 per cent) and 
the operations require several days of work and 
elaborate equipment. 
The ¡'eduction methods'7­81 arc based on a 
reduction­oxidation reaction involving chromic 
acid, phosphoric acid and a reducing agent in 
absence, or presence of a protective colloid. 
The subsequent purification of the colloidal 
chromic phosphate obtained as above requires 
(ANGIIILERI) flocculation, washing and sus­
pension in isotonic solution or (CHEVALLIER 
and co­workers) elaborate technique based on 
the use of a lactose column. 
The method described in this work is a 
reduction method according to the technique 
of ANGIIILERI. The reaction used involves 
chromic acid, sodium sulphite as reducing agent, 
phosphoric acid in presence of gelatin as 
protective colloid, 
2 H 2 C r O , 4­ 3 N a 2 S 0 3 + 2 H 3 P 0 4 ­> 
2 C r P 0 4 4­ 3Na2SO., ­'­ 5 H , 0 . 
The purification of the colloidal chromic 
radiophosphate is carried out by dialysis. 
The yield is 80 per cent; the equipment and 
handling are very simple. 
The colloidal chromic radiophosphate pre­
pared by the method described in this paper is 
a green, clear suspension and has the following 
characteristics: 
C r P 0 4 
gelatin 
pH 
3 mg/ml 
5­5 mg/ml 
6-7 
E X P E R I M E N T A L 
Malcriáis 
The following solutions are needed: 
(1) Chromic acid solution: 10 mg/ml; 
(2) Phosphoric acid solution: 10 mg/ml— 
(in this solution H 3 P 3 2 0 4 carrier­free is added 
according to the required specific activity) ; 
(3) Sodium sulphite solution: 200 mg/ml; 
(4) Celatili solution: 20 per cent. 
All these solutions are freshly (this is a very 
important point) prepared and sterilized at 
1 1 2 'C for half an hour. 
Preparation 
In order to obtain colloidal chromic radio­
phosphate, the operations are carried out as 
follows. 
To 6 ml of chromic acid 4 ml of phosphoric 
acid (containing P32) arc added. When the 
mixture reaches the boiling point, 0­5 ml of 
gelatin, 6­5 ml of pyrogen­free water and 1 ml 
of sodium sulphite are added. The mixture is 
kept at the boiling point for 5 min. 
All these operations arc carried out while 
agitating by air bubbling through a capillary 
tube. The preparation requires 15 min. The 
reaction yield, tested by chromatographic analy­
sis according to the EBEL technique'9 ' , results 
90 per cent. 
The colloidal chromic phosphate has Rf = 0 
and phosphoric ions Rf = 0­7 ­­­ 0­8, with 
Whatman No. 1 paper using ascending mono­
dimensional method and as clucnt : isopropyl 
alcohol (75 ml), water (25 ml), trichloroacetic 
acid (5 g), ammonia 22 Bé (0­3 ml), checked pH 
1­5­2. 
Purification anil sterilization 
The colloidal chromic phosphate containing 
about 10 per cent of free orthophosphoric ions 
is then dialyscd overnight using cellulose 
membrane (C. ERBA, Milan). 
Preparation of colloidal chromic phosphate (P32) for medical use 281 
Hot p la te 
Hot ba th 
React ion vessel 
Reagent inlet 
Connexion f rem C to vacuum 
Capi l lary tor' air i n t r oduc t i on 
and l iqu id t r a n s f e r 
Condenser 
"hree way unlubr icated stopcock 
A i r f i l te r 
Reservo i r 
Del ivery tube f r o m reservo i r 
Dialyser 
Dispensing p ipe t te 
Dispensing bo t t l e 
P lungers 
FIG. 1. Equipment used for the preparation of colloidal CrP3 204 . 
In this way the content of phosphoric ions is 
reduced to 1 per cent or less. 
The colloid is then sterilized at 112°C for 
half an hour. In this way the content of 
phosphoric ions increases to 3-4 per cent. 
The equipment used for this method of pre-
paration and purification (Fig. 1) is placed in a 
glove box shielded by 12-mm Plexiglas walls. 
D I S C U S S I O N 
The following characteristics were checked 
on the colloidal chromic radiophosphate pre-
pared as above: 
(a) Content in phosphoric ions, 
(b) Chemical stability, 
(c) Colloidal stability. 
All these tests were made on samples contain-
ing P32 at tracer level. 
(a) Content in phosphoric ions 
The content in phosphoric ions was tested 
by chromatographic analysis'9 ' and was found 
equal to 1-4 per cent. The chromatographic 
analysis shows also the absence of condensed 
phosphate. 
(b) Chemical stability 
The colloidal chromic radiophosphate shows 
satisfactory chemical stability. Hydrolysis was 
checked by chromatographic analysis'9 ' . The 
colloid kept at room temperature and at 40°C 
does not hydrolyse even after one month. 
On the contrary the pH and the dilution have 
influence on the hydrolysis. The obtained data 
are reported in Tables 1 and 2. Tables 1(a) and 
1 (b) show that the hydrolysis is rather low for 
the p H of the human parts into which colloidal 
chromic radiophosphate can be injected'11". 
282 Α. Μ. Del Turco and R. Pietra 
Table 1. Influence of the pH 
(a) Colloidal chromic radiophosphate kept at 
room temperature . Initial content of phosphoric 
ions = 1%. 
p H 
4 
5 
6 
7 
8 
9 
% of orthophosphoric ions 
After 
1 day 
6-5 
3-5 
2-2 
2 
2 
3 
After 2 
weeks 
9-5 
6 
3-2 
3 
4 
4 
After 4 
weeks 
11-5 
6-5 
3-5 
3 
4 
4 
(b) Colloidal chromic radiophosphate kept at 40°C. 
Initial content of phosphoric ions = 1%. 
P H 
4 
5 
6 
7 
8 
9 
% of orthophosphoric ions 
After 
1 day 
14-5 
9 
6 
6 
6 
6 
After 2 
weeks 
52 
40 
6 
6 
6 
6 
After 4 
weeks 
52 
40 
6 
6 
6 
6 
Table 2. Influence of the dilution 
(a) Colloidal chromic radiophosphate diluted with 
NaCl 0-9% and kept at room temperature. 
Initial content of phosphoric ions = 1%. 
Dilution 
1:1 
1:5 
1:10 
% of orthophosphoric ions 
After 
1 day 
1 
1-4 
1-6 
After 2 
weeks 
1-5 
2-3 
3 
After 4 
weeks 
1-4 
3 
4-5 
(b) Colloidal chromic radiophosphate diluted with 
NaCl 0-9% and kept at 40°C. Initial content of 
phosphoric ions = 1%. 
Dilution 
1:1 
1:5 
1:10 
% of orthophosphoric ions 
After 
1 day 
1-4 
2-7 
4 
After 2 
weeks 
2-8 
3-2 
4-2 
After 4 
weeks 
2-5 
3-3 
4-2 
(c) Colloidal stability 
Stability was checked for samples: 
1—Kept at room temperature one month 
from preparation, 
2—Kept at high and low temperature several 
hours, 
3—Diluted with phvsiological solution (NaCl 
0-9%), 
4—Buffered from p H 4 to pH 9. 
No flocculation was found in any sample. 
COLLOIDAL CHROMIC P H O S P H A T E 
WITH HIGH SPECIFIC ACTIVITY 
Samples of colloidal chromic phosphate with 
high specific activity (3 mC/ml) were prepared 
as above. 
Stability tests made on these samples show 
that also the colloidal chromic radiophosphate 
with high specific activity does not hydrolyse 
and sediment even after one month. 
PARTICLE SIZE D E T E R M I N A T I O N 
Great difficulties were found in the particle 
size determination by electronic microscope. 
Colloidal chromic phosphate has, in fact, a 
remarkable tendency to condense into aggre­
gates and its low mean atomic number makes a 
rather difficult task to obtain good micrographs. 
Figure 2 shows the presence of aggregates and 
small diameter particles. By fractionated centri-
fuging the fraction containing aggregates was 
found equal to about 50 per cent. The remain­
ing fraction has a diameter smaller than 200 A. 
Acknowledgments—The authors wish to thank Prof. G. 
BERTOLINI, Dr. M. BRESESTI, Mr. R. LANZ of this 
laboratory and Dr. G. POLVANI of C.N.E.N. for their 
help and assistance. 
REFERENCES 
1. HAHN P. F. Proceedings of the First International 
Conference on the Peaceful Uses of Atomic Energy, 
Geneva, A/Conf. 8/P/202. United Nations, New 
York (1955). 
FIG. 2. Photograph at the electronic microscope 
of the colloidal chromic phosphate ( χ 72,000). 

Preparation of colloidal chromic phosphate (P32) for medical use 283 
2. JONES H . B., W R O B E L G. J . and LYONS W. R. 
J. clin. Invest. 28, 783 (1944). 
3. CHEVALLIER A. and BURG C. Proceedings of the 
First International Conference on the Peaceful Uses of 
Atomic Energy, Geneva, A/Conf. 8/P/367. United 
Nations, New York (1955). 
4. STROMINGER D., HOLLANDER J . M. and SEABORG 
G. T . Rev. mod. Phys. 30, 2 (1958). 
5. M O R T O N M. E. Nucleonics 10, 92 (1952). 
6. NESS A. T., SMITH R. E. and EVANS R. L. J. 
Amer. ehem. Soc. 74, 4685 (1952). 
7. ANGIIILERI L. J . Proceedings of the Second Inter-
national Conference on the Peaceful Uses of Atomic 
Energy, Geneva, A/Conf. 15/P/1575. United 
Nations, New York (1958). 
8. CHEVALLIER A. and BURG C. Proceedings of the 
Second International Conference on the Peaceful Uses of 
Atomic Energy, Geneva, A/Conf. 15/P/1220. Uni ted 
Nations, New York (1958). 
9. E B E L J . P. Mikrochimica Acta H 6 , 679 (1954). 
10. Handbook of Biological Data. SPECTOR (Ed.), pp . 
68-69 (1956). 
11. DUBINI M. and FANTECHI R. CNI 32 (1960). 
Preparation of colloidal chromic phosphate (P32) for medical use 283 
2. JONES H . B., W R O B E L G. J . and LYONS W. R. 
J. clin. Invest. 28, 783 (1944). 
3. CHEVALLIER A. and BURG C. Proceedings of the 
First International Conference on the Peaceful Uses of 
Atomic Energy, Geneva, A/Conf. 8/P/367. United 
Nations, New York (1955). 
4. STROMINGER D., HOLLANDER J . M. and SEABORG 
G. T . Rev. mod. Phys. 30, 2 (1958). 
5. M O R T O N M. E. Nucleonics 10, 92 (1952). 
6. NESS A. T., SMITH R. E. and EVANS R. L. J. 
Amer. ehem. Soc. 74, 4685 (1952). 
7. ANGIIILERI L. J . Proceedings of the Second Inter-
national Conference on the Peaceful Uses of Atomic 
Energy, Geneva, A/Conf. 15/P/1575. United 
Nations, New York (1958). 
8. CHEVALLIER A. and BURG C. Proceedings of the 
Second International Conference on the Peaceful Uses of 
Atomic Energy, Geneva, A/Conf. 15/P/1220. Uni ted 
Nations, New York (1958). 
9. E B E L J . P. Mikrochimica Acta H 6 , 679 (1954). 
10. Handbook of Biological Data. SPECTOR (Ed.), pp . 
68-69 (1956). 
11. DUBINI M. and FANTECHI R. CNI 32 (1960). 
■1 '-'MlUUWeft i
iimtxm 
KÍ.WÜÍ." 'JMÎÛ:iU- iiíir.KiaÊiiii 
CDNA00419ENC 


PREPARATION OF COLLOIDAL CHROMIC PHOSPHATE (p32) FOR MEDICAL USE. EUR 419.e

Abstract

Similar works

Full text

Available Versions

Archive of European Integration

Archive of European Integration