Synthesis and Properties of Cleavable Quaternary Ammonium Compounds.

Quaternary ammonium compounds are widely used as antiseptic and disinfectant. It is been a concern that their widespread use will lead to an increase of environmental problems, therefore the development of biodegradable surfactants is necessary. The present research is aimed at the design of novel amphiphilic molecules with similar properties to those already known but more biodegradable. Based on benzalkonium chloride (BAC), novel carbonate cleavable surfactants (CBAC) were synthesized. The breakable carbonate sites make CBAC compounds more degradable and potentially more biodegradable than their non-cleavable BAC analogues. Natural products such as fatty alcohols (C8-C16) and N,N-dimethyl-2-aminoethanol were used as reagents for the synthesis of CBAC8-16. These amphiphilic compounds were characterized in terms of surface properties and antimicrobial activity against Gram-positive and Gram-negative bacteria, yeasts and moulds. The novel surfactants showed similar surface activities in aqueous solutions when compared to BAC. Also, the surface activity/structure relationship revealed that carbonate cleavable surfactants with n-decyl group (CBAC10) showed the same behaviour as non-cleavable BAC. Furthermore, compounds containing n-octyl (CBAC8), n-decyl (CBAC10) and n-dodecyl (CBAC12) group showed strong antimicrobial activities.

Novel flurbiprofen derivatives with improved brain delivery: synthesis, in vitro and in vivo evaluations.

Tarenflurbil (R-flurbiprofen) was acknowledged as a promising candidate in Alzheimer's disease (AD) therapy. However, the Phase III study of tarenflurbil was extremely restricted by its poor delivery efficiency to the brain. To tackle this problem, the novel carriers for tarenflurbil, racemic flurbiprofen (FLU) derivatives (FLU-D1 and FLU-D2) modified by N,N-dimethylethanolamine-related structures were synthesized and characterized. These derivatives showed good safety level in vitro and they possessed much higher cellular uptake efficiency in brain endothelial cells than FLU did. More importantly, the uptake experiments suggested that they were internalized via active transport mechanisms. Biodistribution studies in rats also illustrated a remarkably enhanced accumulation of these derivatives in the brain. FLU-D2, the ester linkage form of these derivatives, achieved a higher brain-targeting efficiency. Its Cmax and AUC0-t were enhanced by 12.09-fold and 4.61-fold, respectively compared with those of FLU. Additionally, it could be hydrolyzed by esterase in the brain to release the parent FLU, which might facilitate its therapeutic effect. These in vitro and in vivo results highlighted the improvement of the brain-targeted delivery of FLU by making use of N,N-dimethylethanolamine ligand, with which an active transport mechanism was involved.

Collision-induced dissociation of aminophospholipids (PE, MMPE, DMPE, PS): an apparently known fragmentation process revisited.

A new type of low-mass substituted 4-oxazolin product ions of [M + H](+) precursor ions of aminophospholipids (glycerophosphatidylethanolamine, glycerophosphatidyl-N-methylethanolamine, glycerophosphatidyl-N,N-dimethylethanolamine, glycerophosphatidylserine) resulting from high-energy collision-induced dissociation (matrix-assisted laser desorption/ionization time-of-flight/reflectron time-of-flight mass spectrometry) and low-energy collision-induced dissociation (e.g., electrospray ionization quadrupole reflectron time-of-flight mass spectrometry) with accurate mass determination is described; these were previously misidentified as CHO-containing radical cationic product ions. The mechanism for the formation of these ions is proposed to be via rapid loss of water followed by cyclization to an 11-membered-ring transition state for the sn-1 fatty acid substituent and to a ten-membered-ring transition state for the sn-2 fatty acid substituent, and via final loss of monoacylglycerol phosphate, leading to substituted 4-oxazolin product ions. The minimum structural requirement for this interesting skeletal rearrangement fragmentation is an amino group linked to at least one hydrogen atom (i.e., ethanolamine, N-methylethanolamine, serine). Therefore, N,N-dimethylethanolamine derivates do not exhibit this type of fragmentation. The analytical value of these product ions is given by the fact that by post source decay and particularly high-energy collision-induced dissociation achieved via matrix-assisted laser desorption/ionization time-of-flight/reflectron time-of-flight mass spectrometry, the sn-2-related substituted 4-oxazolin product ion is always significantly more abundant than the sn-1-related one, which is quite helpful for detailed structural analysis of complex lipids. All other important product ions found are described in detail (following our previously published glycerophospholipid product ion nomenclature; Pittenauer and Allmaier, Int. J. Mass. Spectrom. 301:90-1012, 2011).

Synthesis of a new class of Betti bases by the Mannich-type reaction: efficient, facile, solvent-free and one-pot protocol.

A variety of organocatalysts has been screened for the synthesis of arylaminonaphthols. It has been shown that (N,N-dimethylethanolamine) is a highly efficient organocatalyst for the direct synthesis of a novel class of arylaminonaphthols via three-component condensation of 2-naphthol, aldehydes, and arylamines under solvent-free conditions. Mild, one-pot, and green reaction conditions, relatively short reaction times and good yields make this protocol highly significant. 25 new compounds have been synthesized by this method.

Sensitive determination of four tetracycline antibiotics in pig plasma by field-amplified sample stacking open-tubular capillary electrochromatography with dimethylethanolamine aminated polychloromethyl styrene nano-latex coated capillary column.

This paper described the preparation and application of a new dimethylethanolamine aminated polychloromethyl styrene nano-latex (DMEAPL) coated capillary column (ccc-DMEAPL) in the determination of four tetracycline antibiotics (TCA) including tetracycline (TC), oxytetracycline (OTC), doxycycline (DC) and chlorotetracycline (CTC) in pig plasma. The ccc-DMEAPL column was characterized with steady EOF values of ca. 1.5-5.2×10(-5)cm(2)/Vs at pH 1.8-6.3. The optimized conditions for field-amplified sample stacking open-tubular capillary electrochromatography (FASS-OT-CEC) were as following: background electrolyte, 10mmol/L Na2HPO4+15mmol/L citric acid (pH 3.2); ccc-DMEAPL, 50µm i.d.×50cm (effective length 41.5cm), separation voltage, 18kV; column temperature, 25°C; UV detection wavelength, 270nm; water-plug injection: 30mbar×10s; sample electrokinetic injection, 10kV×20s. The four TCA were extracted with the solution of 10mmol/L Na2HPO4+15mmol/L citric acid+4g/L EDTA-2Na (pH 3.2). The FASS-OT-CEC method was validated in terms of linearity, sensitivity, selectivity, precision and accuracy. The LODs ranged from 3 to 7ng/mL, the recoveries for the four TCA were all more than 80%. The developed method was successfully applied for the determination of TCs in the actual pig plasma samples.

A fully-automated one-pot synthesis of [18F]fluoromethylcholine with reduced dimethylaminoethanol contamination via [18F]fluoromethyl tosylate.

INTRODUCTION: A novel one-pot method for preparing [(18)F]fluoromethylcholine ([(18)F]FCH) via in situ generation of [(18)F]fluoromethyl tosylate ([(18)F]FCH2OTs), and subsequent [(18)F]fluoromethylation of dimethylaminoethanol (DMAE), has been developed. METHODS: [(18)F]FCH was prepared using a GE TRACERlab FXFN, although the method should be readily adaptable to any other fluorine-(18) synthesis module. Initially ditosylmethane was fluorinated to generate [(18)F]FCH2OTs. DMAE was then added and the reaction was heated at 120 °C for 10 min to generate [(18)F]FCH. After this time, reaction solvent was evaporated, and the crude reaction mixture was purified by solid-phase extraction using C(18)-Plus and CM-Light Sep-Pak cartridges to provide [(18)F]FCH formulated in USP saline. The formulated product was passed through a 0.22 µm filter into a sterile dose vial, and submitted for quality control testing. Total synthesis time was 1.25 h from end-of-bombardment. RESULTS: Typical non-decay-corrected yields of [(18)F]FCH prepared using this method were 91 mCi (7% non-decay corrected based upon ~1.3 Ci [(18)F]fluoride), and doses passed all other quality control (QC) tests. CONCLUSION: A one-pot liquid-phase synthesis of [(18)F]FCH has been developed. Doses contain extremely low levels of residual DMAE (31.6 µg/10 mL dose or ~3 ppm) and passed all other requisite QC testing, confirming their suitability for use in clinical imaging studies.

Synthesis and anticonvulsant evaluation of dimethylethanolamine analogues of valproic acid and its tetramethylcyclopropyl analogue.

BACKGROUND: Valproic acid (VPA) is a major antiepileptic drug (AED) that is less potent than other AEDs. 2,2,3,3-Tetramethylcyclopropanecarboxylic acid (TMCA) is an inactive cyclopropyl analogue of VPA that serves as a starting material for the synthesis of CNS-active compounds. METHODS: New conjugation products between N,N'-dimethylethanolamine to VPA and TMCA to form N,N-dimethylethanolamine valproate (DEVA) and N,N-dimethylethanolamine 2,2,3,3-tetramethylcyclopropionate were synthesized and their anticonvulsant activity was assessed in the maximal electroshock seizure (MES) and subcutaneous metrazol (scMet) seizure tests and the hippocampal kindling model in mice and/or rats. An amide analogue of DEVA (DEVAMIDE) was also synthesized and evaluated. The pharmacokinetics of DEVA and DEVAMIDE was comparatively evaluated in rats. RESULTS: In rats DEVA acted as a prodrug of VPA and had ED(50) values of 73 mg/kg and 158 mg/kg in the MES and the hippocampal kindling models, respectively. At these two anticonvulsant models DEVA was seven-times more potent than VPA. DEVAMIDE was active in the MES test at doses of 100 mg/kg (mice) and its rat-MES-ED(50)=38.6 mg/kg however, its protective index (PI=TD(50)/ED(50)) was twice lower than DEVA's PI. The TMCA analogues were inactive at the mice MES and scMet models. DEVA underwent rapid metabolic hydrolysis to VPA and consequently, in its pharmacokinetic analysis only VPA plasma levels were monitored. In contrast, DEVAMIDE was stable in whole blood. CONCLUSION: DEVA acts in rats as a prodrug of VPA yet shows a more potent anticonvulsant activity than VPA. DEVAMIDE acted as the drug on its own and was more potent than DEVA at the rat-MES test.

Fully automated SPE-based synthesis and purification of 2-[18F]fluoroethyl-choline for human use.

INTRODUCTION: 2-[(18)F]Fluoroethyl-choline ([(18)F]FECH) is a promising tracer for the detection of prostate cancer as well as brain tumors with positron emission tomography (PET). [(18)F]FECH is actively transported into mammalian cells, becomes phosphorylated by choline kinase and gets incorporated into the cell membrane after being metabolized to phosphatidylcholine. So far, its synthesis is a two-step procedure involving at least one HPLC purification step. To allow a wider dissemination of this tracer, finding a purification method avoiding HPLC is highly desirable and would result in easier accessibility and more reliable production of [(18)F]FECH. METHODS: [(18)F]FECH was synthesized by reaction of 2-bromo-1-[(18)F]fluoroethane ([(18)F]BFE) with dimethylaminoethanol (DMAE) in DMSO. We applied a novel and very reliable work-up procedure for the synthesis of [(18)F]BFE. Based on a combination of three different solid-phase cartridges, the purification of [(18)F]BFE from its precursor 2-bromoethyl-4-nitrobenzenesulfonate (BENos) could be achieved without using HPLC. Following the subsequent reaction of the purified [(18)F]BFE with DMAE, the final product [(18)F]FECH was obtained as a sterile solution by passing the crude reaction mixture through a combination of two CM plus cartridges and a sterile filter. The fully automated synthesis was performed using as well a Raytest SynChrom module (Raytest, Germany) or a Scintomics HotboxIII module (Scintomics, Germany). RESULTS: The radiotracer [(18)F]FECH can be synthesized in reliable radiochemical yields (RCY) of 37±5% (Synchrom module) and 33±5% (Hotbox III unit) in less than 1 h using these two fully automated commercially available synthesis units without HPLC involvement for purification. Detailed quality control of the final injectable [(18)F]FECH solution proved the high radiochemical purity and the absence of Kryptofix2.2.2, DMAE and DMSO used in the course of synthesis. Sterility and bacterial endotoxin testing following standard procedures verified that the described production method for [(18)F]FECH is suitable for human applications. CONCLUSIONS: The routine production of [(18)F]FECH with sufficient RCYs was established by reliable and fast solid-phase extraction purifications of both the secondary labeling precursor [(18)F]BFE and the final product [(18)F]FECH, avoiding complex and sensitive HPLC equipment. The purity of the product was >95%, rendering the tracer suitable for human application. The newly developed purification procedure for [(18)F]BFE significantly reduces the complexity of the automated synthesis unit, hence reducing the cost for routine production in a clinical setup and allowing easy transfer to different synthesis modules.

Characterization of the DMAE-modified juvenile excretory-secretory protein Juv-p120 of Litomosoides sigmodontis.

Juv-p120 is an excretory-secretory 160 kDa glycoprotein of juvenile female Litomosoides sigmodontis and exhibits features typical for mucins. 50% of its molecular mass is attributed to posttranslational modifications with the unusual substituent dimethylaminoethanol (DMAE). By that Juv-p120 corresponds to the surface proteins of the microfilarial sheath, Shp3 and Shp3a. The secreted protein consists of 697 amino acids, organized in two different domains of repeat elements separated by a stretch of polar residues. The N-terminal domain shows fourteen P/S/T/F-rich repeat elements highly modified with phospho-DMAE substituted O-glycans confering a negative charge to the protein. The C-terminal domain is extremely rich in glutamine (35%) and leucine (25%) in less organized repeats and may play a role in oligomerization of Juv-p120 monomers. A protein family with a similar Q/L-rich region and conserved core promoter region was identified in Brugia malayi by homology screening and in Wuchereria bancrofti and Loa loa by database similarity search. One of the Q/L-rich proteins in each genus has an extended S/T-rich region and due to this feature is supposed to be a putative Juv-p120 ortholog. The corresponding modification of Juv-p120 and the microfilarial sheath surface antigens Shp3/3a explains the appearance of anti-sheath antibodies before the release of microfilariae. The function of Juv-p120 is unknown.

Structural characterization and stability of dimethylaminoethanol and dimethylaminoethanol bitartrate for possible use in cosmetic firming.

2-Dimethylaminoethanol (DMAE) (also known as deanol) has been used as an ingredient in skin care, and in cognitive function- and mood-enhancing products. It is marketed as a free base or salt, and in theory, the two forms should be equally effective and able to substitute for each other in pharmaceutical formulations. Detecting possible alterations in the active principle is a basic part of preformulation studies. Accordingly, this study compared DMAE and DMAE bitartrate to identify potential alterations or differences between the free base and the salt that might compromise the long-term stability of cosmetic preparations at different temperatures, and also compared the behavior of the base substance and derivative alone and in solution. Samples were analyzed with different physicochemical methods such as differential scanning calorimetry, ultraviolet and infrared spectroscopy, and nuclear magnetic resonance spectroscopy.

Capillary electrophoresis-electrochemiluminescent detection of N,N-dimethyl ethanolamine and its application in impurity profiling and stability investigation of meclophenoxate.

Numerous drugs are carboxylic acid derivatives containing amino group, and hydrolysis reaction of these agents often generates toxic amines. Thus, the detection of amine impurity is of great importance in drug quality control of these amino group-containing ester and amide. A capillary electrophoresis method coupled with end-column electrochemiluminescent detection based on tris(2,2'-bipyridyl)ruthenium(II) system was proposed for the analysis of N,N-dimethyl ethanolamine (DMEA, the degradation product of meclophenoxate) in the presence of its precursor. Baseline separation of DMEA and meclophenoxate can be easily achieved under the selected conditions. DMEA can be assayed within 3 min over the concentration range of 5.0x10(-8) to 3.0x10(-6) mol L(-1) with a detection limit of 2.0x10(-8) mol L(-1) at the signal-to-noise ratio of 3. The relative standard deviations of the signal intensity and the migration time were less than 5.3 and 2.5% for a standard sample containing 1.0x10(-7) mol L(-1) DMEA (n=5), respectively. The presented method has been successfully applied for the profiling of DMEA resulting from the hydrolysis of meclophenoxate in commercial formulations. A primary stability investigation of meclophenoxate in aqueous solution was also carried out at different temperatures, and the results showed that the degradation of meclophenoxate accelerated at the higher temperature.

In vivo skin effects of a dimethylaminoethanol (DMAE) based formulation.

Dimethylaminoethanol (DMAE) has been used in anti-aging formulations but few scientifically based data address its efficacy. The aim of this study was to evaluate the effects of DMAE-based formulations on hairless mice and human skin. Formulations containing with or without DMAE were applied to the dorsum of hairless mice. Histopathological and histometric evaluations were carried out after seven days. Formulations were also applied to the ventral forearm and the lateral periocular area of human volunteers. Stratum corneum water content and skin mechanical properties were analyzed using Corneometer and Cutometer, before and after a single and repeated application. Histometric evaluations showed that formulations with or without DMAE increased the viable epidermis thickness, but only the DMAE-supplemented formulation led to increased dermal thickness. DMAE also induced increase in collagen fiber thickness, which was observed in the histopathological study. After the single and the 8-week period application on human skin, formulations with and without DMAE enhanced the stratum corneum water content in the forearm skin. Mechanical properties were not significantly modified. So, we can suggest that DMAE action is related to its effects on the dermis as observed in the histopathological and histometric studies and showed hydration effects on skin.

[Synthesis and cytotoxicity of novel phosphorusless analogues of edelfosine].

Modified series of phosphorusless edelfosine analogues bearing the polar heads of aliphatic bases, N,N-dimethylethanolamine and N,N,N(1),N(1)-tetramethylethylenediamine, were synthesized, with the length of the spacer varying from three to four methylene units. The cytotoxic characteristics of the compounds synthesized were studied.

Does Litomosoides sigmodontis synthesize dimethylethanolamine from choline?

Juvenile female Litomosoides sigmodontis secrete a protein (Juv-p120) highly modified with dimethylethanolamine (DMAE). In an attempt to establish the source of this decoration worms were pulsed with [3H]-choline and [3H]-ethanolamine and the radio-isotope labelled products analysed. Both isotope labels were successfully taken up by the worms, as demonstrated by labelling of phospholipids with [3H]-choline, being predominantly incorporated into phosphatidylcholine and [3H]-ethanolamine into phosphatidylethanolamine. Isotope labelling of phosphatidylethanolamine was particularly striking with the worms taking up approximately 30 times as much labelled ethanolamine as choline. It was possible to detect faint labelling of Juv-p120 with [3H]-ethanolamine after prolonged exposure periods but, unlike the situation with the phospholipids, it was much more readily labelled with [3H]-choline. When pulsing with [3H]-ethanolamine it was also possible to detect isotope-labelled phosphatidylcholine, which may ultimately account for the low levels of labelling of Juv-p120. Overall our results raise the previously unconsidered but intriguing possibility that in L. sigmodontis, choline may be the precursor of DMAE.

Functionalization of 6-nitrobenzo[1,3]dioxole with carbonyl compounds via TDAE methodology.

We report herein the synthesis of substituted 2-(6-nitrobenzo[1,3]dioxol-5-yl)-1- aryl ethanols and 2-(6-nitrobenzo[1,3]dioxol-5-yl)-propionic acid ethyl esters from the reaction of 5-chloromethyl-6-nitrobenzo[1,3]dioxole with various aromatic carbonyl and alpha- carbonyl ester derivatives using the tetrakis(dimethylamino)ethylene (TDAE) methodology.

Self-organized, highly luminescent CdSe nanorod-DNA complexes.

DNA molecules are useful building blocks and nanotemplates for controllable fabrication of various bioinorganic nanostructures due to their unique physical-chemical properties and recognition capabilities and the synthetic availability of desired nucleotide sequences and length. We have synthesized novel DNA complexes with positively charged, highly luminescent CdSe nanorods that can be self-organized into filamentary, netlike, or spheroidal nanostructures. DNA-CdSe-nanorod filaments possess strongly linearly polarized photoluminescence due to the unidirectional orientation of nanorods along the filaments.

Improved method for the quality assurance of [C-11]choline.

[C-11]choline is a very promising radiomarker for the diagnosis of various human tumors using Positron Emission Tomography (PET). The existing quality control process for [C-11]choline is complicated and combines two HPLC methods with limited separation and sensitivity which prevent the accurate determination of the specific activity. We have developed a new efficient single HPLC method for the detection of choline chloride and dimethylaminoethanol with high resolution and sensitivity using cation-exchange chromatography.

Pharmacological interventions against aging through the cell plasma membrane: a review of the experimental results obtained in animals and humans.

As was shown in a recent review by this author (Ann. N.Y. Acad. Sci., 928: 187-199, 2001), oxyradicals cannot be considered only as harmful by-products of the oxidative metabolism, but living cells and organisms implicitly require their production. This idea is supported by numerous facts and arguments, the most important of which is that the complete inhibition of the oxyradical production by KCN (or by any block of respiration) kills the living organisms long before the energy reserves would be exhausted. This new theoretical approach not only helps our understanding of the normal functions of the living organisms, such as the basic memory mechanisms in the brain cells, but also helps in identifying the site-specific, radical-induced damaging mechanisms that represent the undesirable side effects of oxygen free radicals. First of all, these effects make the cell plasma membrane vulnerable and cause a series of intracellular functional disorders, as described by the membrane hypothesis of aging (MHA). The logical way for any antiaging intervention therefore should be to increase the available number of loosely bound electrons inside the plasma membrane that are easily accessible for OH(*) free radical scavenging. The present review summarizes the available knowledge regarding the theory of the use of membrane-related antiaging pharmaca, like centrophenoxine (CPH), tested in both animal experiments and human clinical trials. A modified, developed version of CPH coded as BCE-001 is also reported.

Juvenile female Litomosoides sigmodontis produce an excretory/secretory antigen (Juv-p120) highly modified with dimethylaminoethanol.

A 120 kDa antigen produced by juvenile female Litomosoides sigmodontis (Juv-p120) was isolated and purified. The amino acid composition of the molecule was determined. Juv-p120 was shown to be highly modified with N,N-dimethyl-aminoethanol (28.4 mol%). Treatment of Juv-p120 with potassium hydroxide (beta-elimination) or with sodium m-periodate leads to the destruction of epitopes recognized by antibodies immune affinity-purified with isolated Juv-p120. Juvenile L. sigmodontis were shown to release Juv-p120 into the pleural cavity of infected Mastomys coucha before the onset of patency.