Radiosynthesis and biological evaluation of 166Ho labeled methoxylated porphyrins as possible therapeutic agents

¹⁶⁶Ho labeled 5,10,15,20-tetrakis(3,4-dimethoxyphenyl) porphyrin, and 5,10,15,20-tetrakis(3,4,5-trimethoxyphenyl) porphyrin ([¹⁶⁶Ho]–TDMPP and [¹⁶⁶Ho]–TTMPP respectively) were prepared with acceptable radiochemical purity and specific activities. Stability and partition coefficient of the complexes were determined in the final formulations and biodistribution studies in mouse demonstrated high accumulation of [¹⁶⁶Ho]–TDMPP in the lung and liver and less excretion through the kidney. while [¹⁶⁶Ho]–TTMPP was mostly excreted into intestines and kidneys while lungs were a minor accumulation site. In contrast to other reported radiolanthanide labeled porphyrins these two complexes showed less liver accumulation. Further investigation of their potential therapeutic properties is of interest.     

Preclinical evaluation of 188 Re-HYNIC-PSMA as a novel therapeutic agent

Journal of Radioanalytical and Nuclear Chemistry - In this study, optimized preparation, quality control, cell assessments and biostribution of 188Re-HYNIC-PSMA in normal rats and tumor bearing...     

Synthesis of nano-pore samarium (III)-imprinted polymer for preconcentrative separation of samarium ions from other lanthanide ions via solid phase extraction

A batch process was developed to separate samarium ions from some lanthanide ions by a novel solid phase which was prepared via the ion-imprinting technique. The samarium (III) ion-imprinted polymer (IIP) particles were synthesized by preparing the ternary complex of samarium ions with 5,7-dichloroquinoline-8-ol (DCQ) and 4-vinylpyridine (VP). Then, thermally copolymerization with styrene (functional monomer, STY) and divinylbenzene (cross-linking monomer, DVB) followed in the presence of 2-methoxy ethanol (porogen) and 2,2′-azobisisobutyronitrile (initiator, AIBN). The imprinted ion was removed by stirring the above particles with 50% (v/v) HCl to obtain the leached IIP particles. Moreover, control polymer (CP) particles were similarly prepared without the samarium ions. The unleached and leached IIP particles were characterized by X-ray diffraction (XRD), infra-red spectroscopy (IR), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). Finally, preconcentration and selectivity studies for samarium and the other lanthanide ions were carried out. The preconcentration of the samarium (III) traces was studied during rebinding with the leached IIP particles as a function of pH, the weight of the polymer material, the preconcentration and the elution times, the eluent volume and the aqueous phase volume. These studies indicated that the samarium (III) amount as low as 1 μg, present in 200 mL, could be preconcentrated into 25 mL of 1.0 M HCl.     

Preparation of <Superscript>166</Superscript>Dy/<Superscript>166</Superscript>Ho-chitosan as an in vivo generator for radiosynovectomy

¹⁶⁶Ho is one of the most effective radionuclides used for radiosynovectomy. One method to deliver this radioisotope to target tissue is via the ¹⁶⁶Dy/¹⁶⁶Ho in vivo generator system. The aim of this work was to prepare ¹⁶⁶Dy/¹⁶⁶Ho-chitosan (¹⁶⁶Dy/¹⁶⁶Ho-CHIT) in vivo generator for radiosynovectomy applications. ¹⁶⁶Dy obtained by the irradiation of natural ¹⁶⁴Dy target. ¹⁶⁶Dy was separated from ¹⁶⁶Ho by extraction chromatographic method (separation yield; 93% and separation factor;1.7). Chitosan labeling was performed in acetic acid with 99.3 ± 0.6% radiochemical purity. Biodistribution studies on intraarticular injected rats demonstrated high retention in the knee joint even 7 days showing no radioactivity leakage from the injection site into other organs as well as any translocation of the daughter nucleus after β^? decay of ¹⁶⁶Dy.     

Production, quality control and pharmacokinetic studies of 177Lu–zoledronate for bone pain palliation therapy

A new dipeptide derivative, ethyl 2-(3-(4-hydroxyphenyl)-2-(2-(4-phenyl-5-((pyridin-4-ylamino)methyl)-4H-1,2,4-triazol-3-ylthio)acetamido)propanamido)-3-(1H-indol-3-yl)propanoate (EHPTIP) was successfully synthesized and radiolabeled with ¹²⁵I by the direct electrophilic substitution method. The non radiolabeled compound (EHPTIP) was tested as an antimicrobial agent and the radiolabeled derivative was tested as a new imaging agent. The study results showed a good antimicrobial activity of EHPTIP and a good in vitro and in vivo stability of ¹²⁵I-EHPTIP. The biodistribution of the radiolabeled compound showed a high brain uptake of 7.60 ± 0.01 injected activity/g tissue organ at 30 min post-injection and retention in brain remained high up to 1 h, whereas the clearance from the normal mice appeared to proceed via the renal system. Such brain uptake is better than that of currently used radiopharmaceuticals for brain imaging (^99mTc-ECD and ^99mTc-HMPAO). As a conclusion, EHPTIP is a newly synthesized dipeptide with a good antimicrobial activity and the radioiodinated EHPTIP which is labeled with ¹²³I could be used as a novel agent for brain SPECT.