Synthesis and biological evaluation of [99m]Tc[CO][3]-OH-PP-CS[2] for brain receptor imaging

5-HT[1A] receptor is related with a variety of neuropsychiatric disorders. In this study a phenolic analogue derived from DWAY [Desmethyl WAY-100635 [N-[2-[1-[4-[2-methoxyphenyl]piperazinyl]-ethyl]]-N-[2-pyridinyl] cyclohexanecarboxamide]] is used to design the desired structure of 5-HT1A receptor imaging agents after labeling with [[99m]Tc [CO] [3][H[2]O] [3]] [+] core via dithiocarbamate moiety. 2-[piperazin-1-yl] phenol Dithiocarbamate was synthesized by the reaction of 2-[piperazin-1-yl] phenol with an equivalent amount of carbon disulfide in KOH solution then radiolabeled with [[99m]Tc[CO][3][H2O][3][+] core. Radioligand chemical analysis involved high-performance liquid chromatography methods. Radioconjugate stability and lipophilicity were determined. Biodistribution of labeled compound was studied in rats. The final complex was characterized by HPLC and its radiochemical purity was more than 90%. In vitro stability studies have shown the complex was stable at least 6-hrs after labeling at room temperature. The n-octanol/water partition coefficient experiment demonstrated Log P = 0.74 for [99m]Tc[CO][3]-OH-PP-CS[2]. Biodistribution results showed that radio tracer had moderate brain uptake [0.32 +/- 0.03%ID/g at 30 min post injection]. This complex may lead to a further development of a radiotracer with specific binding to 5-HT[1A] receptor

Freeze-dried cold kit for Preparation of [99M]Tc-ciprofloxacin as an infection imaging agent

Radiolabeled antibiotics are being used for the specific diagnosis of infection by exploiting their specific binding properties to the bacterial components, thereby making it possible to differentiate infection from sterile lesions. The aim of this work was to prepare and evaluate a freeze-dried kit of ciprofloxacin designed for the labeling with [99m]Tc. Factors like amount of reducing agent and optimum pH were investigated to make the ciprofloxacin kit. The kit was reconstituted with [99m]Tc at room temperature and the radiochemical purity was evaluated by ITLC method. Stability and protein binding in human serum followed by in vitro binding to bacteria were assessed. Biodistribution of labeled kit in staphylococcus aureus infected rats muscles were studied using ex vivo counting and scintigraphy. Labeling yield of >90% was obtained corresponding to a specific activity of 178 GBq/mmol. The stability of radiolabeled kit in human serum was 84.2% after 1 hour post incubation. In-vitro studies showed 75% of radioactivity was bound to bacteria. After injection into mice clearance from the circulation occurred mainly by biliary-renal clearance and site of infection was rapidly detected within 30 min. Target to non-target muscle ratio was 3.23 +/- 0.05% at 30 min post injection. [99m]Tc-ciprofloxacin showed favorable radiochemical and biological characteristics which permitted detection of the infection with optimal visualization

Synthesis and evaluation of a new radiolabeled bombesin analogue for diagnosis of GRP receptor expressing tumors

Bombesin [BN], a 14-amino acid neuropeptide, shows high affinity for the human GRP [gastrin releasing peptide] receptors, which are overexpressed by a variety of cancers, including prostate, breast, pancreas, gastrointestinal, and small cell lung cancer. Aim was to prepare [6-hydrazinopyridine-3-carboxylic acid [HYNIC[0], D-Tyr[6], D-Trp[8]] - BN [6-14] NH[2] that could be easily labeled with[99m]Tc and evaluation of its potential as an imaging agent. Synthesis of the peptide amide was carried out onto Rink Amide MB HA [4-Methylbenzhydrylamine] resin. A bifunctional chelating agent [BFCA] was attached to the N terminal peptide in solid-phase. [99m]Tc labeling was performed by addition of sodium pertechnetate to solution that include [HYNIC[0], D-Tyr[6], D-Trp[8]] Bombesin [6-14] NH[2], tricine, ethylenediamine-N,N'-diaeetic acid [EDDA] and SnCl[2]. Radiochemical evaluation was carried out by reverse phase high-performance liquid chromatography [HPLC] and instant thin layer chromatography [ITLC]. In- vitro internalization was tested using human prostate cancer cells [PC-3] with blocked and non-blocked receptors. Biodistribution was determined in rats. [99m]Tc/tricine/EDDA-HYNIC[0], D-Tyr[6], D-Trp[8]] bombesin [6-14] NH[2] was obtained with radiochemical purities >98%. Results of in-vitro studies demonstrated a high stability in serum and suitable internalization. Biodistribution data showed a rapid blood clearance, with renal excretion and specific binding towards GRP receptor-positive tissues such as pancreas. In this study, labeling of this novel conjugate with [99m] Tc easily was performed using coligand. The prepared [99m]Tc-HYNIC-BN conjugate has promising characteristics for the diagnosis of malignant tumors

Synthesis, labeling and quality control of a new neuropeptide Y analogue for diagnosis of breast tumors

Over expression of selected peptide receptors in human tumors has been shown to represent clinically relevant targets for cancer diagnosis and therapy. The aim of this work was to investigate Neuropeptide Y [NPY] as a new radiopharmaceutical for diagnosis of breast cancer. A neuropeptide Y analogues with Y[1] receptor preference and agonistic properties was synthesized by solid phase method. After conjugation with diethylenetriaminepentaacetic acid [DTPA] labeling with [111]In was performed. For labeled peptide, yield of labeling, stability in human serum, receptor binding in cell surface with internalization in SK-N-MC cells, and biodistribution in normal rat were determined. Peptide was synthesized and labeled with more than 95% purity. Radiolabeled peptide was stable in human serum and specifically binds and internalized in the cells with Y1 receptor [4h = 22%]. A rapid clearance from blood pool and urinary with hepatobiliary excretion were observed. Our results showed that this peptide can be considered as a candidate for diagnosis of breast tumors

Radioiodine D amino acids labeling of rituximab, a new method for enhancing the radiopharmaceutical targeting and biostability

Radioimmunotherapy [RIT] is a very promising new therapy for the treatment of recurrent B-Cell non-Hodgkin's lymphoma [NHL]. Iodine-131 is the most frequently used nuclide in clinical RIT, but its usefulness has been limited by dehalogenation of monoclonal antibodies labeled via conventional methods. To circumvent this problem, we have synthesized a tri-peptide consisting of non-metabolizable D amino acids attached to N-Hydroxysuccinimide [NHS]. Tri-peptide was synthesized by standard Fmoc solid phase synthesis on tritylchloride resin. Labeling of tri-peptide was performed using the chloramine-T method and the conventional extraction. Radioiodination of tri-peptide was followed by conjugation to anti-CD20 antibody. In vitro stability of labeled antibody in serum and phosphate buffered saline [PBS] was measured for 48hr by [thin layer chromatography] TLC. Raji cell line was used to test cell binding of the labeled anti-CD20. The chemical purity of synthesized peptide as assessed by analytical [high performance liquid chromatography] HPLC was 95%. Labeling of tri-peptide resulted in a radiochemical yield of 50-71% with radiochemical purity of > 95%. At Rituximab concentration of 10mg/ml, coupling efficiencies of 65-80% was obtained with radiochemical purity of 95% and Specific activity [SA] of 185MBq/mg [5mCi/mg]. This study showed that labeling monoclonal antibodies with radioiodine by non-metabolizable D amino acids will improve bio-stability of the product

Cytotoxic terpenoids from Satureja macrantha C. A. Mey

From the aerial parts of Satureja macrantha C. A. Mey, one monoterpene [1], two triterpenoids [2,3] and one sesquiterpene [4] were isolated. Their structures were determined to be thymol [1], oleanolic acid [2], ursolic acid [3] and caryophyllene oxide [4], by using 1H and 13C-NMR, FTIR and EIMS spectra. Brine shrimp cytotoxicity effects of the crude extracts and isolated compounds were examined. Among them compounds 1 [612 microM], 2 [17 microM] and 3 [29 microM] were effective against Artemia salina larva

Two new valepotriates from the roots of valeriana sisymbriifolia

A dicholoromethane extract of the roots of Valeriana sisymbriifolia Vahl. afforded a new valepotriate. I- alpha -aceisovaltrate and a new valepotriatehydrine, acetoxydesiovaleroxy-1- alpha -acetoxy-isovaleroxy isovaltratehydrine together with a known compound, valtrate. Structural assignments of the compounds were based on spectroscopic methods [UV, IR, MS, 1H-NMR and 13C-NMR]