The Potential of a Site-Specific Delivery of Thiamine Hydrochloride as a Novel Insect Repellent Exerting Long-Term Protection on Human Skin: In-vitro,Ex-vivo Study and Clinical Assessment

Thiamine hydrochloride (TH) was thought to exert a good insect repellent activity. The purpose of this work was to develop a formulation that releases TH in sustained regimen on human skin. Long lasting protection against mosquito bites was achieved. Pullulan acetate (PA) was used to prepare TH nanospheres. Optimal system was incorporated in Pluronic® hydrogel. Formulae were tested for in-vitro release and ex-vivo permeation. Complete protection time (CPT) was done adopting Kaplan-Meier survival function for the synthetic repellent (DEET), TH solution and nanospheres in hydrogel. Release profile of TH solution, nanospheres and nanosphere-loaded hydrogel (DG) demonstrated an added effect of DG, where t _1/2 was 11.2 ± 1.4 h. SEM for DG showed homogenous dispersion of nanospheres inside the matrix of the gel. Ex-vivo permeation showed only 0.761 ± 0.04% of TH in hydrogel permeated the skin after 12 h, while 44.98 ± 3.2% permeated when TH solution was applied. Clinical study revealed a significant difference in CPT between TH solution with either DEET or (DG) (p<0.05), and no significant difference between DEET and DG with CPT 400 ± 31 and 360 ± 18 min, respectively (P > 0.05). The high efficacy of TH-loaded hydrogel rendered it a successful alternative for DEET, offering long protection against mosquito bites.     

Vectorization of Harungana madagascariensis Lam. ex Poir. (Hypericaceae) ethanolic leaf extract by using PLG‐nanoparticles: antibacterial activity assessment

This study was undertaken to compare the in vitro and ex vivo antibacterial activity of an ethanolic Harungana madagascariensis leaf extract (HLE) incorporated into poly (D,L ‐lactide‐co–glycolide) nanoparticles (HLE‐PLG‐NP). Two concentrations of HLE (500 and 1,000 µg/mL) for the in vitro study and one concentration (500 µg/mL) for the ex vivo study were compared using two gram‐positive bacterial strains (Micrococcus luteus and Staphylococcus epidermidis), and one gram‐negative bacterial strain (Moraxella sp.). The ex vivo antibacterial activity was evaluated on S. epidermidis CIP 55109 (SE) using an artificial contamination method. SE was inoculated for 12 h onto human skin fragment surfaces treated for 5 min either with HLE loaded, unloaded PLG‐NP, or HLE solution. In vitro, the two preparations inhibited completely the growth of all bacterial strains at 1,000 µg/mL. However, the HLE‐PLG‐NP had a significant antibacterial activity against SE (18.4±1.8–0.4±0.2 CFU/mL, P<0.05), and a marked antibacterial effect against M. luteus (ML) and Moraxella sp. (Msp) compared to HLE solution at 500 µg/mL. Ex vivo, HLE‐PLG‐NP at 500 µg/mL reduced viable bacteria (6.3–4.8 log₁₀), compared to the HLE solution (6.3–5.5 log₁₀) after 4 h artificial contamination (P<0.05). A thin layer chromatography study of both HLE solution and HLE‐PLG‐NP showed that among the seven components found on the chromatogram of the HLE solution, only two were present on the nanoparticles, one including a flavonoid heteroside fraction responsible for the antibacterial properties. The incorporation of the HLE into a colloidal carrier improved antibacterial performance. Drug Dev. Res. 65:26–33, 2005. © 2005 Wiley‐Liss, Inc.     

A report of the automated radiosynthesis of the tau positron emission tomography radiopharmaceutical, [18F]‐THK‐5351

The radiotracer, [¹⁸F]‐THK‐5351, is a highly selective and high‐binding affinity PET imaging agent for aggregates of hyper‐phosphorylated tau protein. Our report is a simplified 1‐pot, 2‐step radiosynthesis of [¹⁸F]‐THK‐5351. This report is broadly applicable for routine clinical production and multi‐center trials on account of favorable half‐life of flourine‐18 and the use of a commercially available radiosynthesis module, the GE TRACERlab™ FX_FN. First, the O‐THP protected tosyl precursor underwent nucleophilic fluorinating reaction with potassium cryptand fluoride ([¹⁸F] fluoride (K[¹⁸F]/K₂₂₂)) in Dimethyl sulfoxide at 110°C for 10 minutes followed by O‐THP removal by using diluted hydrochloric acid (HCl) at same temperature. [¹⁸F]‐THK‐5351 was purified via semi‐preparative high‐performance liquid chromatography and formulated by using 10% EtOH, United States Pharmacopeia (USP) in 0.9% sodium chloride for injection, USP and an uncorrected radiochemical yield of 21 ± 3.5%, with a specific activity of 153.11 ± 25.9 GBq/μmol (4138 ± 700 mCi/μmol) at the end of synthesis (63 minutes; n  = 3).     

Synthesis of (R)‐ and (S)‐[O‐methyl‐11C]N‐[2‐[3‐(2‐cyano‐phenoxy)‐2‐hydroxy‐propylamino]‐ethyl]‐N′‐(4‐methoxy‐phenyl)‐urea as candidate high affinity β1‐adrenoceptor PET radioligands

Molecular imaging and quantification of myocardial β₁‐adrenoceptor (AR) rather than total β‐AR density is of great clinical interest since cardiac biopsy studies suggest that myocardial β₁‐AR density is reduced in patients with chronic heart failure whereas cardiac β₂‐AR density may vary. Positron emission tomography (PET), with appropriate radioligands, offers the possibility to assess β‐AR density non‐invasively in humans. However, no PET radioligand for the selective imaging of cardiac β₁‐ARs is clinically available. Here some derivatives of the well characterized β₁‐AR selective antagonist, ICI 89,406, namely the enantiomers of N‐[2‐[3‐(2‐cyano‐phenoxy)‐2‐hydroxy‐propylamino]‐ethyl]‐N′‐(4‐hydroxy‐phenyl)‐urea ( 5a and 5b ) were synthesized and evaluated in vitro. The (R)‐isomer 5a was more β₁‐selective but has lower affinity than its (S)‐enantiomer 5b (β₁‐AR selectivity: 6100 vs 1240; β₁‐affinity: K₁ = 0.288 nM vs K₁ = 0.067 nM). Etherification of the analogous desmethyl precursors, 5e and 5f , respectively, with [¹¹C]iodomethane gave ¹¹C‐labelled versions of 5a and 5b , namely 5g and 5h , in 44 ± 5% radiochemical yield (decay‐corrected) and 97.4 ± 1.3% radiochemical purity with specific radioactivities of 26.4 ± 9.4 GBq/µmol within 41.2 ± 3.4 min from the end of bombardment (n = 14). 5g and 5h are now being evaluated as candidate radioligands for myocardial β₁‐ARs. Copyright © 2005 John Wiley & Sons, Ltd.     

Inhibition of nitrergic relaxations by the M3‐selective antagonist 4‐DAMP

The inhibitory effect of the selective M₃ musarinic acetylcholine receptor antagonist, 4‐diphenylacetoxy‐N‐methylpiperidine methobromide (4‐DAMP, 0.1–10 μM) on nicotine (100 μM)‐induced nitrergic relaxation was investigated in comparison to d‐tubocurarine (0.1–10 μM) and hexamethonium (0.1–10 μM) by using phenylephrine (1 μM)‐precontracted rat anococcygeus muscles in vitro. Nicotine produced a 60.1± 2.4% (n = 40) inhibition of phenylephrine precontractions. But this relaxant response was at a significantly lower magnitude of 20.2± 4.6% (n = 18, P < 0.01 vs. control) in the presence of the nitric oxide synthase (NOS) blocker N^G‐nitro‐L ‐arginine methyl ester (L ‐NAME, 30 μM), and it was 26.5± 5.5% (n = 8, P < 0.01 vs. control) in the presence of the soluble guanylate cyclase inhibitor methylene blue (30 μM). However, aminoguanidine (100 μM), a relatively selective blocker of the inducible nitric oxide synthase (iNOS), had no significant effect. Similarly, other iNOS inhibitors such as dexamethasone (5 mg/kg) or L ‐canavanine (100 mg/kg) did not modify contractile nor relaxant responses when they were given in vivo, concomitantly with Escherichia coli endotoxin (1 mg/kg, ip) 4 h before the isolation of the tissues. 4‐DAMP, hexamethonium, and d‐tubocurarine inhibited nicotine‐induced relaxation in a concentration‐dependent manner with the following order of potency: 4‐DAMP > hexamethonium > d‐tubocurarine with IC₅₀ values being 0.47± 0.04 μM, 0.75± 0.06 μM, and 1.02± 0.05 μM, respectively. Therefore, it was concluded that the selective M₃ muscarinic acetylcholine receptor antagonist 4‐DAMP also possesses potent antagonistic action on nicotinic receptors of peripheral nitrergic neurons that innervate the rat anococcygeus muscle. Drug Dev. Res. 46:148–154, 1999. © 1999 Wiley‐Liss, Inc.     

Radiosynthesis and in vivo study of [18F]1‐(2‐fluoroethyl)‐4‐[(4‐cyanophenoxy)methyl]piperidine: a promising new sigma‐1 receptor ligand

The novel sigma‐1 receptor PET radiotracer [¹⁸F]1‐(2‐fluoroethyl)‐4‐[(4‐cyanophenoxy)methyl]piperidine ([¹⁸F]WLS1.002, [¹⁸F]‐2) was synthesized (n=6) by heating the corresponding N‐ethylmesylate precursor in an anhydrous acetonitrile solution containing [¹⁸F]fluoride, Kryptofix K₂₂₂ and potassium carbonate for 15 min. Purification was accomplished by reverse‐phase HPLC methods, providing [¹⁸F]‐2 in 59±8% radiochemical yield (EOB), with specific activity of 2.89±0.80 Ci/µmol (EOS) and radiochemical purity of 98.3±2.1%. Rat biodistribution studies revealed relatively high uptake in many organs known to contain sigma‐1 receptors, including the lungs, kidney, heart, spleen, and brain. Good clearance from normal tissues was observed over time. Blocking studies (60 min) demonstrated high (>80%) specific binding of [¹⁸F]‐2 in the brain, with reduction also noted in other organs known to express these sites. Copyright © 2005 John Wiley & Sons, Ltd.     

羟基喜树碱脂质体的制备及质量评价研究

目的:制备羟基喜树碱(HCPT)脂质体,并对其质量进行评价.方法:采用薄膜分散-高压乳匀法制备羟基喜树碱脂质体;用激光粒度分析仪测定其Zeta电位、粒径大小;考察其在0.9%NaCl溶液、水、5%葡萄糖溶液中8 h的稳定性;用凝胶柱层析法考察包封率;采用薄膜透析法考察体外释药性质.结果:羟基喜树碱脂质体Zeta电位为(-33.1±1.3) mV,平均粒径(182.5±5.6) nm,8 h内在水、5%葡萄糖溶液中稳定性良好;包封率(91.2±1.2)%;体外释药曲线符合Higuchi方程Q=1.291 6t1/2 0.309 8,r=0.980 3.结论:本试验制备的羟基喜树碱脂质体稳定性好,大小均匀, 包封率高,并具有延缓药物释放的性质.     

177Lu‐labeled monomeric,dimeric and multimeric RGD peptides for the therapy of tumors expressing α(ν)β(3) integrins

The conjugation of peptides to gold nanoparticles (AuNPs) produces biocompatible and stable multimeric systems with target‐specific molecular recognition. Peptides based on the cyclic Arg‐Gly‐Asp (RGD) sequence have been reported as high‐affinity agents for the α(ν)β(3) integrin. The aim of this research was to prepare a multimeric system of ¹⁷⁷Lu‐labeled gold nanoparticles conjugated to c(RGDfK)C (cyclo(Arg‐Gly‐Asp‐Phe‐Lys)Cys) and to compare the radiation‐absorbed dose with that of ¹⁷⁷Lu‐labeled monomeric and dimeric RGD peptides to α(ν)β(3) integrin‐positive U87MG tumors in mice. DOTA‐GGC (1,4,7,10‐tetraazacyclododecane‐N‐N′,N″,N?‐tetraacetic acid‐Gly‐Gly‐Cys) and c(RGDfK)C peptides were synthesized and conjugated to AuNPs by a spontaneous reaction of the thiol groups. Transmission electron microscopy, ultraviolet–visible, X‐ray photoelectron spectroscopy, Raman and far‐infrared spectroscopy techniques demonstrated that AuNPs were functionalized with the peptides. For the ¹⁷⁷Lu‐AuNP‐c(RGDfK)C to be obtained, the ¹⁷⁷Lu‐DOTA‐GGC radiopeptide was first prepared and added to a solution of AuNPs followed by c(RGDfK)C (25 µl, 5 µ m ) at 18 °C for 15 min. ¹⁷⁷Lu‐DOTA‐GGC, ¹⁷⁷Lu‐DOTA‐cRGDfK and ¹⁷⁷Lu‐DOTA‐E‐c(RGDfK)₂ were prepared by adding ¹⁷⁷LuCl₃ (370 MBq) to 5 µl (1 mg/ml) of the DOTA derivative diluted with 50 µl of 1 m acetate buffer pH 5. The mixture was incubated at 90 °C in a block heater for 30 min. Radiochemical purity was determined by ultrafiltration and HPLC analyses. Biokinetic studies were accomplished in athymic mice with U87MG‐induced tumors. The radiochemical purity for all ¹⁷⁷Lu‐RGD derivatives was 96 ± 2%. ¹⁷⁷Lu‐absorbed doses per injected activity delivered to U87MG tumors were 0.357 ± 0.052 Gy/MBq (multimer), 0.252 ± 0.027 Gy/MBq (dimer) and 0.102 ± 0.018 Gy/MBq (monomer). ¹⁷⁷Lu‐labeled dimeric and multimeric RGD peptides demonstrated properties suitable for targeted radionuclide therapy of tumors expressing α(ν)β(3) integrins. Copyright © 2012 John Wiley & Sons, Ltd.     

1,8‐Cineole induces relaxation in rat and guinea‐pig airway smooth muscle

Objectives 1,8‐Cineole is a monoterpene with anti‐inflammatory, vascular and intestinal smooth muscle relaxant activity. We have evaluated the potential bronchodilatatory activity of this compound. Methods 1,8‐Cineole was tested against carbachol, histamine, K⁺ 80 mM and ovalbumin‐induced bronchial contractions in Wistar rat or guinea‐pig tissues. Some of the guinea‐pigs had been previously sensitized with an intramuscular injection of 5% (w/v) ovalbumin/saline solution. Control animals received 0.3 ml saline. In separate experimental groups the response to 1,8‐cineole (1–30 mg/kg), phenoterol (0.05–5 mg/kg) or vehicle (0.3% Tween in saline) was studied. Key findings 1,8‐Cineole decreased, in vivo, rat bronchial resistance with similar efficacy as phenoterol (66.7 ± 3.2% vs 72.1 ± 5.3%). On the other hand, the maximal relaxant response to 1,8‐cineole in carbachol‐precontracted rat tracheas was 85.5 ± 5.7% (IC50 = 408.9 (328–5196) μg/ml) compared with 80.2 ± 4.8% (IC50 = 5.1 (4.3–6.1) μg/ml) with phenoterol. The addition of 1,8‐cineole to guinea‐pig tracheal rings tonically contracted with K⁺ 80 mM induced a concentration‐related relaxation. The maximal relaxation elicited by 1,8‐cineole was 113.6 ± 11.7% (IC50 127.0 (115.9–139.2) μg/ml) compared with 129.7 ± 14.6% (IC50 0.13 (0.12–0.14) μg/ml) achieved after phenoterol administration. In addition, the incubation of tracheal rings with 1,8‐cineole (100, 300 or 1000 μg/ml), 15 min before inducing phasic contractions with K⁺ 80 mM, decreased the maximal amplitude of the contraction by 31.6 ± 4.6, 75.7 ± 2.7 and 92.2 ± 1.5%, respectively. In another set of experiments, neither the maximal response nor the IC50 for the 1,8‐cineole‐induced relaxation were different between normal and ovalbumin‐sensitized tissues. Moreover, the relaxation of bronchial rings contracted after exposure to 1 μg/ml ovalbumin occurred at a faster rate in rings pre‐incubated with 1,8‐cineole when compared with rings pre‐incubated with vehicle only (Tween 0.3%). Therefore, in the first minute after the antigen challenge, the tracheal tissue relaxed after the peak contraction by 6.5, 21.4 (P < 0.05 vs control) and 66.9% (P < 0.05 vs control) in the presence of 100, 300 or 1000 μg/ml 1,8‐cineole, respectively. Conclusions 1,8‐Cineole relaxed rat and guinea‐pig (nonsensitized and ovalbumin‐sensitized) airway smooth muscle by a nonspecific mechanism.     

A fully automated synthesis of [18F]‐FEAU and [18F]‐FMAU using a novel dual reactor radiosynthesis module

2′‐Deoxy‐2′‐[¹⁸F]fluoro‐5‐substituted‐1‐β‐D ‐arabinofuranosyluracils, including 2′‐deoxy‐2′‐[¹⁸F]fluoro‐5‐methyl‐1‐β‐D ‐arabinofuranosyluracil [¹⁸F]FMAU and [¹⁸F]FEAU are established radiolabeled probes to monitor cellular proliferation and herpes simplex virus type 1 thymidine kinase (HSV1‐tk) reporter gene expression with positron emission tomography. For clinical applications, a fully automated CGMP‐compliant radiosynthesis is necessary for production of these probes. However, due to multiple steps in the synthesis, no such automated synthetic protocols have been developed. We report here a fully automated synthesis of [¹⁸F]‐FEAU and [¹⁸F]‐FMAU on a prototype dual reactor module TRACERlab FX FN. The synthesis was performed by using a computer‐programmed standard operating procedure, and the product was purified on a semipreparative high‐performance liquid chromatography (HPLC) integrated with the synthesis module using 12% EtOH in 50 mM Na₂HPO₄. Finally, the percentage of alcohol was adjusted to 7% by adding Na₂HPO₄ and filtered through a Millipore filter to make dose for human. The radiochemical yield on the fluorination was 40±10% (n=10), and the overall yields were 4±1% (d. c.), from the end of the bombardment; [¹⁸F]FEAU (n=7) and [¹⁸F]FMAU (n=3). The radiochemical purity was >99%, specific activity was 1200–1300 mCi/µmol. The synthesis time was 2.5 h. This automated synthesis should be suitable for production of [¹⁸F]FIAU, [¹⁸F]FFAU, [¹⁸F]FCAU, [¹⁸F]FBAU and other 5‐substitued thymidine analogues. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of [3′‐14C] coenzyme Q10

Radio‐labelled coenzyme Q₁₀, labelled at the 3′‐position with ¹⁴C, was synthesized starting from natural solanesol and ethyl [3‐¹⁴C] acetoacetate. The radiochemical yield was 8.0% from ethyl [3‐¹⁴C] acetoacetate. The specific radioactivity of the product was 44.8 μCi, 1.66 MBq/mg. The specific radioactivity and radiochemical purity are sufficiently high to enable us to use this labelled form of coenzyme Q₁₀ in metabolic studies. Copyright © 2002 John Wiley & Sons, Ltd.     

Elastic Liposomal Formulation for Sustained Delivery of Colchicine: In Vitro Characterization and In Vivo Evaluation of Anti-gout Activity

Colchicine, an alkaloid found in extracts of the plants Colchicum autumnale and Gloriosa superb, is effective in the treatment of acute gout and dermatological conditions like leuko-cytoclastic vasculitis, psoriasis, and Sweet’s syndrome. Oral administration of colchicine is associated with gastrointestinal side effects and its accumulation in the body leads to bone marrow suppression. In the present study, an attempt has been made for development and in vitro and in vivo evaluation of elastic liposomal formulation for topical delivery of colchicine. The in vitro skin permeation study across rat skin found transdermal flux for different elastic liposomal formulations to range between 32.8?±?1.2 and 44.4?±?1.9 μg h^?1 cm^?2, which was approximately seven to 11 times higher than obtained using drug solution (4.3?±?0.6 μg h^?1 cm^?2). The results of skin deposition study showed that elastic liposomal formulation provide 12.5-fold higher skin deposition as compared to drug solution of colchicine. Confocal laser scanning microscopy also revealed better accumulation and deeper penetration (up to 200 μm) of elastic liposomes than drug solution (up to 12 μm). The biological evaluation of various vesicular formulations and drug solution was carried out using monosodium urate-induced air pouch model. The results of anti-gout activity in rats showed better and sustained biological effects in 24 h measured in terms of exudate volume (63.1?±?5.7% and 9.6?±?0.5% reduction with elastic liposomes and drug solution, respectively), reduction in leukocyte count (74.2?±?6.0% and 4.1?±?0.3% reduction with elastic liposomes and drug solution, respectively), decrease in inflammatory cells accumulation, and collagen deposition with elastic liposomal formulation than drug solution. Hence, the present study reveals that elastic liposomal formulation of colchicine possesses greater potential to enhance skin accumulation, prolong drug release, and improve the site-specificity of colchicine.     

Synthesis and in vivo evaluation in mice of [123I]‐(4‐fluorophenyl)[1‐(3‐iodophenethyl)piperidin‐4‐yl]methanone as a potential SPECT‐tracer for the serotonin 5‐HT2A receptor

This work reports the synthesis, radiolabelling and in vivo evaluation in NMRI mice of [¹²³I]‐(4‐fluorophenyl)[1‐(3‐iodophenethyl)piperidin‐4‐yl]methanone ([¹²³I]‐3‐I‐CO) as a potential SPECT tracer for the 5‐HT_2A receptor. The tributylstannylprecursor was synthesized with a 15% overall yield. Radiolabelling was performed using an electrophilic iododestannylation with yields of 85%. Radiochemical purity was always >95%. Log P was determined to be 3.10±0.10. The tracer showed good uptake in mouse brain (6.3±1.3% ID/g tissue at 10 min p.i., 2±0.36% ID/g tissue at 1 h p.i.). These results warrant further research in larger animals to determine suitability of [¹²³I]‐3‐I‐CO as a 5‐HT_2A tracer. Copyright © 2007 John Wiley & Sons, Ltd.     

Fully automated synthesis and purification of 4‐(2′‐methoxyphenyl)‐1‐[2′‐(N‐2″‐pyridinyl)‐p‐[18F]fluorobenzamido]ethylpiperazine

We have developed an efficient synthesis method for the rapid and high‐yield automated synthesis of 4‐(2′‐methoxyphenyl)‐1‐[2′‐(N‐2″‐pyridinyl)‐p‐[¹⁸F]fluorobenzamido]ethylpiperazine (p‐[¹⁸F]MPPF). No‐carrier‐added [¹⁸F]F^? was trapped on a small QMA cartridge and eluted with 70% MeCN(aq) (0.4 mL) containing Kryptofix 222 (2.3 mg) and K₂CO₃ (0.7 mg). The nucleophilic [¹⁸F]fluorination was performed with 3 mg of the nitro‐precursor in DMSO (0.4 mL) at 190 °C for 20 min, followed by the preparative HPLC purification (column: COSMOSIL Cholester, Nacalai Tesque, Kyoto, Japan; mobile phase: MeCN/25 mm AcONH₄/AcOH = 200/300/0.15; flow rate: 6.0 mL/min) to afford p‐[¹⁸F]MPPF (retention time = 9.5 min). p‐[¹⁸F]MPPF was obtained automatically with a radiochemical yield of 38.6 ± 5.0% (decay corrected, n = 5), a specific activity of 214.3 ± 21.1 GBq/µmol, and a radiochemical purity of >99% within a total synthesis time of about 55 min. Copyright © 2012 John Wiley & Sons, Ltd.     

Design and synthesis of enantiopure 18F‐labelled [18F]trifluoromethyltryptophan from 2‐halotryptophan derivatives via copper(I)‐mediated [18F]trifluoromethylation and evaluation of its in vitro characterization for the serotonergic system imaging

We synthesized [¹⁸F]trifluoromethyl‐l ‐tryptophan ([¹⁸F]CF₃‐l ‐Trp) using Cu(I)‐mediated [¹⁸F]trifluoromethylation to image serotonergic system. Radiochemical yield was 6 ± 1.5% (n = 9), and radiochemical purity was over 99%. The molar activity was 0.44 to 0.76 GBq/μmol. [¹⁸F]CF₃‐l ‐Trp was stable for up to 6 hours in mouse and human sera at 37°C. Protein‐binding was 0.26 ± 0.03% and 0.34 ± 0.02% in human and mouse serum at 60 minutes, respectively. In conclusion, enantiopure [¹⁸F]CF₃‐l ‐Trp was synthesized as a feasible imaging agent for the serotonergic system.     

A toxicokinetic study to elucidate 3‐hydroxybenzo(a)pyrene atypical urinary excretion profile following intravenous injection of benzo(a)pyrene in rats

The toxicokinetics of benzo(a)pyrene (BaP) and 3‐hydroxybenzo(a)pyrene (3‐OHBaP) were assessed in 36 male Sprague–Dawley rats injected intravenously with 40 µmol kg¹ of BaP to explain the reported atypical urinary excretion profile of 3‐OHBaP. Blood, liver, kidney, lung, adipose tissue, skin, urine and feces were collected at t = 2, 4, 8, 16, 24, 33, 48, 72 h post‐dosing. BaP and 3‐OHBaP were measured by high‐performance liquid chromatography/fluorescence. A biexponential elimination of BaP was observed in blood, liver, skin and kidney (t_½ of 4.2–6.1 h and 12.3–14.9 h for initial and terminal phases, respectively), while a monoexponential elimination was found in adipose tissue and lung (t_½ of 31.2 and 31.5 h, respectively). A biexponential elimination of 3‐OHBaP was apparent in blood, liver and skin (t_½ of 7.3–11.7 h and 15.6–17.8 h for initial and terminal phases, respectively), contrary to adipose tissue, lung and kidney. In adipose tissue and lung, a monophasic elimination of 3‐OHBaP was observed (t_½ of 27.0 h and 24.1 h, respectively). In kidney, 3‐OHBaP kinetics showed a distinct pattern with an initial buildup during the first 8 h post‐dosing followed by a gradual elimination (t_½ of 15.6 h). In the 72‐h post‐treatment, 0.21 ± 0.09% (mean ± SD) of dose was excreted as 3‐OHBaP in urine and 12.9 ± 1.0% in feces while total BaP in feces represented 0.40 ± 0.16% of dose. This study allowed the identification of the kidney as a retention compartment governing 3‐OHBaP atypical urinary excretion. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of (±)‐6,6‐[2H6]dimethyl‐11‐nor‐Δ9‐tetrahydrocannabivarin‐9‐carboxylic acid

Starting from divarinol ( 4 ) using previously published procedures, (±)‐6,6‐[²H₆]Dimethyl‐11‐nor‐Δ⁹THCV‐9‐carboxylic acid ( 3 ) was synthesized for use as an internal standard in GC/MS analysis of 11‐nor‐Δ⁹THCV‐9‐carboxylic acid ( 2 ). The detection of 2 distinguishes the use of marijuana from the ingestion of Marinol^®. Copyright © 2002 John Wiley & Sons, Ltd.     

Synthesis and evaluation of [O‐methyl‐11C]4‐[3‐[4‐(2‐methoxyphenyl)‐ piperazin‐1‐yl]propoxy]‐4‐aza‐tricyclo[5.2.1.02,6]dec‐8‐ene‐3,5‐dione as a 5‐HT1A receptor agonist PET ligand

4‐[3‐[4‐(2‐Methoxyphenyl)piperazin‐1‐yl]propoxy]‐4‐aza‐tricyclo[5.2.1.02,6]dec‐8‐ene‐3,5‐dione (4), a potent and selective 5‐HT_1A agonist, was labeled by ¹¹C‐methylation of the corresponding desmethyl analogue 3 with ¹¹C‐methyl triflate. The precursor molecule 3 was synthesized from commercially available endo‐N‐hydroxy‐5‐norbornene‐2,3‐dicarboximide in two steps with an overall yield of 40%. Radiosynthesis of ¹¹C‐4 was achieved in 35 min in 20±5% yield (n=6) at the end of synthesis with a specific activity of 2600±250 Ci/mmol. In vivo positron emission tomography (PET) studies in baboon revealed rapid uptake of the tracer into the brain. However, lack of specific binding indicates that ¹¹C‐4 is not useful as a 5‐HT_1A agonist PET ligand for clinical studies. Copyright © 2008 John Wiley & Sons, Ltd.     

Factors affecting the labeling yield of F‐18‐labeled AS1411

The labeling of AS1411, a guanine (G)‐rich oligonucleotide (ON), conjugated with [¹⁸F]SFB was evaluated at different experimental conditions: ON concentration, base composition (G‐rich [AS1411] vs cytosine‐rich [CRO]), ON purity (desalted vs high‐pressure liquid chromatography (HPLC)‐purified) and buffers (tris‐HCl, sodium borate, and potassium phosphate (PBK)). The labeling yield, defined as % F‐18 incorporated into the ON, of HPLC‐purified AS1411 was significantly improved with increasing concentration – 7±3, 12±2, and 25±5% (n=5) at 56, 93, and 160 nmol/100 µL, respectively. The labeling yields, however, were much higher if guanines of AS1411 were completely replaced by cytosines – 22±1, 41±2, and 59±3% (n=3), respectively, at the same corresponding concentration (p<0.05). The specific activity of ¹⁸F‐AS1411 and ¹⁸F‐CRO was 4.2–12.6 and 4.2–25 mCi/µmol, respectively, after alcohol precipitation. If desalted grade of AS1411 and CRO was used instead for the conjugation, the yields were dropped to only 0–5 and 0–1 (n=5), respectively, regardless of the concentration used. The labeling yields were 5±2, 12±3, and 31±4 (n=3) at 200 nmol/100 µL of AS1411; and 30±2, 45±3, and 68±4 (n=3) at 200 nmol/100 µL of CRO for tris‐buffer, sodium borate, and PBK, respectively, at pH of 8.5 (p<0.05). Copyright © 2007 John Wiley & Sons, Ltd.