Development of a Ready-to-Use PSMA-11 Kit Formulation and Biological Evaluation of Binding Affinity

Introduction: 68Ga-PSMA-11 is considered the gold standard in detection of micro and oligometastases in advanced prostate cancer, being used for therapeutic planning, as well as, potentially, for evaluating response to treatment. The development of ready-to-use lyophilized kit of PSMA-11 adds quality and safety to the routine use of this radiopharmaceutical and represents a pharmacotechnical challenge as it must preserve the integrity and specificity of the ligand. Methods: PSMA-11 kit formulation was proposed, considering radiolabeling parameters and the preservation of the peptide during the lyophilization process, using mannitol as an excipient. Critical temperature characterization studies were carried out using DSC equipment and the freeze-drying process was developed. The direct radiolabeling conditions were evaluated and standardized using 68Ge/68Ga generator eluate from two different manufacturers (ITG and Eckert & Ziegler). The radiochemical purity was evaluated by TLC and HPLC. Biological evaluation was carried out with lyophilized PSMA-11 to demonstrate the integrity of the peptide and preservation of biological activity after the lyophilization process. Results: Based on critical temperature characterization studies, the freeze-drying cycle was designed to reach a freezing temperature of around −40˚C and primary drying at 2˚C. Using 20 mg of mannitol, an intact and elegant lyophilized cake was obtained. PSMA-11 lyophilized kit was directly labeled with 68Ga eluate from 68Ge/68Ga GMP generators (ITG and Eckert & Ziegler) resulting in % RP > 95% at pH 4.0 to 4.5. The results obtained from in vitro and in vivo biological competition studies confirmed the preservation of PSMA-11 affinity for the receptor after lyophilization. Conclusion: A lyophilized formulation (Kit) of PSMA-11 was successfully obtained, which preserved the integrity and biological activity of the peptide and guaranteed radiolabeling efficiency.

The supernova remnant CTB 37B and its associated magnetar CXOU J171405.7-381031:evidence for a magnetar-driven remnant

We discuss the association between the candidate magnetar CXOU J171405.7-381031 and the supernova remnant CTB 37B.The recent detection of the period derivative of the object allowed an estimation of a young characteristic age of only ～ 1000yr.This value is too small to be compatible even with the minimum radius of the remnant being ≥ 10 pc,the value corresponding to the lower limit of the estimated distance of 10.2 ± 3.5 kpc,unless the true distance happens to be even smaller than the lower limit.We argue that a consistent scenario for the remnant＇s origin,in which the latter is powered by the energy injected by a young magnetar,is indeed more accurate to explain the young age,and demonstrates its non-standard（i.e.magnetar-driven） nature.

Ni/Carbon Hybrid Prepared by Hydrothermal Carbonization and Thermal Treatment as Support for PtRu Nanoparticles for Direct Methanol Fuel Cell

Ni/Carbon was prepared in two steps： initially cellulose as carbon source and NiCl2·6H2O as catalyst of the carbonization process were submitted to hydrothermal treatment at 200 ℃ and further to thermal treatment at 900 ℃ under argon atmosphere. The obtained material contains Ni nanoparticles with face-centered cubic （fcc） structure dispersed on amorphous carbon with graphitic domains. PtRu/C electrocatalysts （carbon- supported PtRu nanoparticles） were prepared by an alcohol-reduction process using Ni/Carbon as support. The materials were characterized by thermogravimetric analysis, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and tested as anodes in single direct methanol fuel cell （DMFC）. The performances of PtRu/C electrocatalysts using Ni/Carbon as support were superior to those obtained for PtRu/C using commercial carbon black Vulcan XC72 as support.