Gastrin-releasing peptide (GRP) receptor scintigraphy could allow prediction of response to GRP receptor-targeted treatment options, early non-invasive diagnosis and in vivo prognostic stratification of GRP receptor-positive tumours. This study reports on the imaging characteristics and efficacy for tumour detection of technetium-99m RP527, a 99mTc chelated targeting peptide derived from bombesin, which binds GRP receptors with high affinity. Ten patients (four men and six women, mean age 56.4 years) either suffering from metastasised prostate (n, number of patients = 4) or breast carcinoma (n=1) or presenting with a clinical diagnosis highly suggestive for breast carcinoma (n=5) were included in the study. In the latter five patients, 99mTc-RP527 scintigraphy was performed prior to diagnostic, e.g. biopsy, and staging examinations. Final diagnosis in these patients was breast carcinoma in all five. In all patients, whole-body planar scans and tomographic images were acquired 1 h and 5-6 h post injection of 555 MBq 99mTc-RP527 and tumour to normal tissue (T/N) ratios determined. 99mTc-RP527 showed specific uptake in four of six breast and one of four prostate carcinomas. T/N ratios derived from planar and tomographic images increased significantly (P<0.01) from 1.65 (SD 1.53) and 3.35 (SD 3.04) to 2.58 (SD 1.26) and 7.23 (SD 8.46), respectively. T/N ratios derived from tomographic images were consistently higher (P<0.01). The data presented suggest that 99mTc-RP527 results in specific tumour localisation and exhibits good imaging characteristics with a good T/N ratio that may be further enhanced by single-photon emission tomography.

Neutral Re(V) and Tc(V) oxo complexes of the peptide dimethylglycyl-L-seryl-L-cysteinylglycinamide (RP294) were prepared and characterized by HPLC, spectroscopic techniques, and X-ray crystallographic analysis. The peptide was prepared as a single peptide chain using solid phase methods and characterized by HPLC and various spectroscopic techniques. The water-soluble Re(V) oxo complex of dimethylglycyl-L-seryl-L-cysteinylglycinamide [ReO(RP294)] was prepared from the reaction of the peptide with either [ReO(2)(en)(2)]Cl or ReOCl(3)(PPh(3))(2) in the presence of base. The complex exists as two isomers, the serine CH(2)OH group being in the syn oranti conformation with respect to the Re-oxo bond. The ratio of the isomers at room temperature is 1:1.1. The isomers were separated by reverse-phase HPLC, but the isolation of each isomer was complicated by their rapid interconversion in aqueous solution at room temperature. The molecular structure of the syn isomer of the Re complex was determined by X-ray crystallography. Crystals of syn-[ReO(RP294)] (C(12)H(20)N(6)O(5)ReS) are orthorhombic, of space group P2(1)2(1)2(1), with a = 6.954(1) Å, b = 8.0472(1) Å, c = 32.9183(4) Å, and Z = 4. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.0327 (R(w) = 0.0838) for 10 447 reflections with I > 2sigma(I). The Re metal was coordinated in a distorted square pyramidal geometry with the oxo moiety in the apical position. The peptide coordinated to ReO(3+) via the N(amine) atom of dimethylglycine, the S(thiolate) atom of cysteine, and the two N(amide) atoms of serine and cysteine (an N(2)N'S donor atom set). The Re atom lies approximately 0.74 Å above the distorted plane formed by the N(2)N'S donor atom set. Variable-pH (1)H NMR spectral data showed the Re complex was stable from pH 5 to 8.5. The reaction of (99)TcO(4)(-) with SnCl(2), sodium gluconate, and RP294 produced the (99)Tc(V) oxo RP294 complex, [(99)TcO(RP294)]. Like the [ReO(RP294)] complex, [(99)TcO(RP294)] also exists in the syn and anti conformations in a ratio of approximately 1:1. The (99m)Tc complex of RP294 was prepared at the tracer level from the reaction of Na[(99m)TcO(4)] with excess SnCl(2), sodium gluconate, and RP294. The (99m)Tc and Re RP294 complexes behaved similarly under identical HPLC conditions.

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. Can. J. Chem. 58, 1125Chem. 58, (1980. Ruthenium(I1) phthalocyanine complexes of the type RuPcL, (PC = the phthalocyaninato dianion. L = various pyridines, imidazole, dimethylformamide, dimethylsulfoxide, and acetonitrile) may be prepared generally in solution by photolysis of RuPc(C0)L' complexes in the presence of excess L (L' may be the same as L or may be a different ligand), and in some cases a s solids by extraction of crude RuPc with L. The solid RuPc(C0)L monocarbonyls can be formed from reaction of the RuPcL, complexes with carbon monoxide, as well as via an extraction procedure using L with crude RuPc(C0) formed from Ru,(CO),, and phthalocyanine.Chemical or electrochemical oxidation of the RuPcL' or monocarbonyl complexes generates a cationic ruthenium(I1) phthalocyanine radical species and not ruthenium(III), as evidenced by esr and visible spectroscopy. DAVID DOLPHIN, BRIAN R. JAMES, ALAN J. MURRAY et JOHN R. THORNBACK. Can. J. Chem. 58, 1125Chem. 58, (1980. Les complexes phthalocyanine de ruthenium(I1) du type RuPcLz (PC = dianions phthalocyaninato, L = differentes pyridines, imidazole, dimethylformamide, dimethylsulfoxyde et acetonitrile) peuvent generalement i t r e prepares en solution par photolyse des complexes de RuPc(CO)L1 en presence d'un exces de L (L' peut i t r e identique a L ou peut Ctre un ligand different) et dans certains cas ils peuvent i t r e prepares sous forme solide par extraction du RuPc brut avec L . Le solide monocarbonyle RuPc(C0)L peut i t r e forme par la reaction des complexes RuPcL, avec le monoxyde de carbone aussi bien que par le procede d'extraction utilisant L avec le RuPc(C0) brut forme partir de Ru,(CO),, et la phthalocyanine.L'oxydation chimique ou electrochimique de RuPcL, ou des complexes monocarbonyles genere un radical cationique de phthalocyanine de ruthCnium(I1) et non de ruthenium(II1) tel que mis en evidence par la rpe et la spectroscopie visible.[Traduit par le journal]

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