Synthesis of indolo[4,3-bc]phenanthridine-6,11(2H,12H)-diones using the schiff base–homophthalic anhydride cyclization reaction

A novel indolophenanthridine ring system has been synthesized via the Schiff base–homophthalic anhydride cyclization followed by thionyl chloride–mediated dehydrogenation and intramolecular Friedel–Crafts acylation. This adds to the array of heterocyclic systems that are available through the cycloaddition reaction of imines with cyclic dicarboxylic acid anhydrides. The cytotoxicities of the indolophenanthridines were investigated in human cancer cell cultures, and the results documented significant antitumor activity in a variety of human cancer cell lines. This provides a new heterocyclic scaffold for anticancer drug design.     

Simultaneous extraction of acidic and basic drugs via on-chip electromembrane extraction

In the present work, a on-chip electromembrane extraction (CEME) was designed and employed for simultaneous extraction of mefenamic acid (MEF) and diclofenac (DIC), as acidic model analytes, and betaxolol (BET), as a basic model analyte, followed by HPLC-UV. The CEME consists of two polymethyl methacrylate (PMMA) parts which each part consists of two separated microfluidic channels. A polypropylene sheet membrane impregnated with an organic solvent was sandwiched between the parts. One of the parts was used as the flow path for the sample solution and the other one as holder for the acceptor phases. The separated microfluidic channels of the sample solution part were connected to each other using a small piece of a capillary tube and the sample solution was pumped through them by means of a micro-syringe pump. However, the acceptor phases of the acidic and basic analytes were separately kept stagnant in the two microfluidic channels during the extraction process. A d.c. potential was applied for migration of the analytes from sample solution through the organic membrane into the acceptor phases. All effective variables on the extraction efficiency of the analytes were optimized. Under the optimized conditions, preconcentration factors higher than 15 were achieved and the calibration curves were linear in the range of 10–500 μg L⁻¹ (r² > 0.9982). RSD% values (n = 4) and LODs were less than 7.1% and 5.0 μg L⁻¹. The results demonstrated that CEME could efficiently be used for the simultaneous analysis of acidic and basic analytes in biological samples.     

Target and suspect screening of psychoactive substances in sewage-based samples by UHPLC-QTOF

The quantification of illicit drug and pharmaceutical residues in sewage has been shown to be a valuable tool that complements existing approaches in monitoring the patterns and trends of drug use. The present work delineates the development of a novel analytical tool and dynamic workflow for the analysis of a wide range of substances in sewage-based samples. The validated method can simultaneously quantify 51 target psychoactive substances and pharmaceuticals in sewage-based samples using an off-line automated solid phase extraction (SPE-DEX) method, using Oasis HLB disks, followed by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF) in MS^e. Quantification and matrix effect corrections were overcome with the use of 25 isotopic labeled internal standards (ILIS). Recoveries were generally greater than 60% and the limits of quantification were in the low nanogram-per-liter range (0.4–187 ng L⁻¹). The emergence of new psychoactive substances (NPS) on the drug scene poses a specific analytical challenge since their market is highly dynamic with new compounds continuously entering the market. Suspect screening using high-resolution mass spectrometry (HRMS) simultaneously allowed the unequivocal identification of NPS based on a mass accuracy criteria of 5 ppm (of the molecular ion and at least two fragments) and retention time (2.5% tolerance) using the UNIFI screening platform. Applying MS^e data against a suspect screening database of over 1000 drugs and metabolites, this method becomes a broad and reliable tool to detect and confirm NPS occurrence. This was demonstrated through the HRMS analysis of three different sewage-based sample types; influent wastewater, passive sampler extracts and pooled urine samples resulting in the concurrent quantification of known psychoactive substances and the identification of NPS and pharmaceuticals.     

Study on electrical current variations in electromembrane extraction process: Relation between extraction recovery and magnitude of electrical current

This contribution presents an experimental approach to improve analytical performance of electromembrane extraction (EME) procedure, which is based on the scrutiny of current pattern under different extraction conditions such as using different organic solvents as supported liquid membrane, electrical potentials, pH values of donor and acceptor phases, variable extraction times, temperatures, stirring rates, different hollow fiber lengths and the addition of salts or organic solvents to the sample matrix. In this study, four basic drugs with different polarities were extracted under different conditions with the corresponding electrical current patterns compared against extraction recoveries. The extraction process was demonstrated in terms of EME-HPLC analyses of selected basic drugs. Comparing the obtained extraction recoveries with the electrical current patterns, most cases exhibited minimum recovery and repeatability at the highest investigated magnitude of electrical current. . It was further found that identical current patterns are associated with repeated extraction efficiencies. In other words, the pattern should be repeated for a successful extraction. The results showed completely different electrical currents under different extraction conditions, so that all variable parameters have contributions into the electrical current pattern. Finally, the current patterns of extractions from wastewater, plasma and urine samples were demonstrated. The results indicated an increase in the electrical current when extracting from complex matrices; this was seen to decrease the extraction efficiency.     

Electromembrane extraction of polar basic drugs from plasma with pure bis(2-ethylhexyl) phosphite as supported liquid membrane

Electromembrane extraction (EME) of polar basic drugs from human plasma was investigated for the first time using pure bis(2-ethylhexyl) phosphite (DEHPi) as the supported liquid membrane (SLM). The polar basic drugs metaraminol, benzamidine, sotalol, phenylpropanolamine, ephedrine, and trimethoprim were selected as model analytes, and were extracted from 300 μL of human plasma, through 10 μL of DEHPi as SLM, and into 100 μL of 10 mM formic acid as acceptor solution. The extraction potential across the SLM was 100 V, and extractions were performed for 20 min. After EME, the acceptor solutions were analyzed by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). In contrast to other SLMs reported for polar basic drugs in the literature, the SLM of DEHPi was highly stable in contact with plasma, and the system-current across the SLM was easily kept below 50 μA. Thus, electrolysis in the sample and acceptor solution was kept at an acceptable level with no detrimental consequences. For the polar model analytes, representing a log P range from −0.40 to 1.32, recoveries in the range 25–91% were obtained from human plasma. Strong hydrogen bonding and dipole interactions were probably responsible for efficient transfer of the model analytes into the SLM, and this is the first report on efficient EME of highly polar analytes without using any ionic carrier in the SLM.     

Solubility and preferential solvation of some non-steroidal anti-inflammatory drugs in methanol + water mixtures at 298.15 K

The equilibrium solubilities of naproxen (NAP), ketoprofen (KTP), and ibuprofen (IBP) in methanol + water binary mixtures at 298.15 K were determined and the preferential solvation parameters were derived by means of the inverse Kirkwood–Buff integrals (IKBI) method. These drugs are very sensitive to specific solvation effects. The preferential solvation parameters by methanol δx_1,3 are negative in water-rich mixtures but positive in compositions from 0.32 in mole fraction of methanol to pure methanol. It is conjecturable that in the former case the hydrophobic hydration around aromatic rings and/or methyl groups plays a relevant role in the solvation. The higher solvation by methanol in mixtures of similar co-solvent compositions and in methanol-rich mixtures could be explained in terms of the higher basic behaviour of this co-solvent interacting with the hydroxyl group of the drugs. Moreover, drug solubilities were correlated by using the modified nearly ideal binary solvent/Redlich–Kister model obtaining average percentage deviations (APDs) lower than 9.0%.     

小尺寸低聚壳聚糖/丹参酮ⅡA纳米载药体系

正纳米载药系统以其独特的化学性质已广泛应用于小分子药物转运,并已有相关的临床实例报道[1~6].壳聚糖(CS)因其所特有的无生物毒性、易生物降解和良好生物相容性等优点而备受关注[7~16].由于传统方法制备的壳聚糖纳米颗粒粒径高达数百纳米,使其生物利用度低,限制了其更广泛应用.我们在前期工作中发现:一种无残留合成方法可以制备粒径在50~80 nm的小尺寸低聚壳聚     

Tandem air-agitated liquid–liquid microextraction as an efficient method for determination of acidic drugs in complicated matrices

A rapid and simple microextraction method with a high sample clean-up, termed as tandem air-agitated liquid–liquid microextraction (TAALLME), is described. This method is based upon the tandem implementation of the air-agitated liquid–liquid microextraction (AALLME), and this approach improves the applicability of the dispersive liquid–liquid microextraction (DLLME) methods in complicated matrices. With very simple tools, the three non-steroidal anti-inflammatory drugs diclofenac, ibuprofen, and mefenamic acid were efficiently extracted, with an overall extraction time of 7 min. By performing the first AALLME, these acidic analytes, contained in an aqueous sample solution (donor phase, 8.0 mL), were extracted into the organic solvent (1,2-dichloroethane, 37 μL), and their simple back-extraction into the aqueous acceptor solution (pH, 10.01, 51 μL) was obtained in 2 min by a second implementation of AALLME. Response surface methodology (RSM) was used for optimization of the experimental parameters. The pH values 2.94 and 10.01 were obtained for the donor and acceptor phases, respectively, and the volumes 99.5 and 51 μL were obtained for the organic solvent and the acceptor phase, respectively, as the optimal extraction conditions. Under the optimized conditions, tandem AALLME-HPLC-UV provided a good linearity in the range of 0.5–4000 ng mL⁻¹, limits of detection (0.1–0.3 ng mL⁻¹), extraction repeatabilities (relative standard deviations (RSDs) below 7.7%, n = 5), and the enrichment factors (EFs) of 80–104. Finally, the applicability of the proposed method was evaluated by the extraction and determination of the drugs under study in the wastewater and human plasma samples.     

非经典铂类抗肿瘤药物研究

本文综述了非经典铂类抗肿瘤药物的发展概况,介绍了具有口服活性的铂(Ⅳ)配合物,具有空间位阻的铂(Ⅱ)配合物,反式铂(Ⅱ、Ⅳ)配合物,多核铂(Ⅱ)配合物和含有铂-硫键的铂(Ⅱ)配合物,并总结了这几类新型铂配合物的抗肿瘤机理,克服顺铂的耐药性机理及其临床进展。