Erratum to: UPLC versus HPLC on Drug Analysis: Advantageous,Applications and Their Validation Parameters

Liquid chromatography (LC) is a separation technique used in many different areas to aid the identification and quantification of substances in various matrices. LC techniques with various detection modes have been widely used for the sensitive and selective determination of trace amounts of pharmaceutical active compounds in biological samples and their dosage forms. A completely new system design with advanced technology has been developed, called ultra high performance liquid chromatography, which has evolved from high performance liquid chromatography. The application of LC methods to drug analysis introduces a powerful tool for therapeutic drug monitoring as well as for clinical research. The advantages of short turnaround time, method reliability, method sensitivity, and drug specificity justify the use of LC techniques for various groups of the drug active compounds. This review describes some of the principles of ultra high performance liquid chromatography and high performance liquid chromatography, validation of these methods, system suitability tests for the methods, and application of methods to pharmaceutical analysis in the last 3 years.

     

Homo‐ and Copolymerization of Phenacyl Methacrylate via the Atom Transfer Radical Polymerization Method

The homo‐ and copolymers via atom transfer radical (co)polymerization (ATRP) of phenacyl methacrylate (PAMA) with methyl methacrylate (MMA) and t‐butyl methacrylate (t‐BMA) was performed in bulk at 90°C in the presence of ethyl 2‐bromoacetate, cuprous(I)bromide (CuBr), and 2,2′‐bipyridine. The polymerization of PAMA was carried out at 70, 80, and 100°C. Also, free‐radical polymerization of PAMA was carried out at 60°C. Characterization using FT‐IR and ¹³C‐NMR techniques confirmed the formation of a five‐membered lactone ring through ATRP. The in situ addition of methylmethacrylate to a macroinitiator of poly(phenacyl methacrylate) [Mn=2800, Mw/Mn=1.16] afforded an AB‐type block copolymer [Mn=13600, Mw/Mn=1.46]. When PAMA units increased in the living copolymer system, the Mn values and the polydispersities were decreased (1.1<Mw/Mn<1.79). The monomer reactivity ratios were computed using Kelen‐Tüdös (K‐T), Fineman‐Ross (F‐R) and Tidwell‐Mortimer (T‐M) methods and were found to be r₁= 1.17; r₂= 0.76; r₁=1.16; r₂=0.75 and r₁=1.18; r₂=0.76, respectively (r₁=is monomer reactivity ratio of PAMA). The initial decomposition temperatures of the resulting copolymers were measured by TGA. Blends of poly(PAMA) and poly(MMA) obtained via the ATRP method have been characterized by differential thermal and thermogravimetric analyses.     

Triclinic and monoclinic polymorphs of meso‐(E,E)‐1,1′‐[1,2‐bis(4‐chlorophenyl)ethane‐1,2‐diyl]bis(phenyldiazene): the high‐yield synthesis of an unexpected product,concomitant polymorphism and configurational disorder

Pyrazolidine‐3,5‐diones and their derivatives exhibit a wide range of biological activities. Seeking to explore the effect of combining a hydrocarbyl ring substituent, as present in sulfinpyrazone (used to treat gout), with a chlorinated aryl ring, as present in muzolimine (a diuretic), we explored the reaction between 1‐phenylpyrazolidine‐3,5‐dione and 4‐chlorobenzaldehyde under mildly basic conditions in the expectation of producing the simple condensation product 4‐(4‐chlorobenzylidene)‐1‐phenylpyrazolidine‐3,5‐dione. However, the reaction product proved to be meso‐(E,E)‐1,1′‐[1,2‐bis(4‐chlorophenyl)ethane‐1,2‐diyl]bis(phenyldiazene), C₂₆H₂₀Cl₂N₄, and a tentative mechanism is proposed. Crystallization from ethanol produces two concomitant polymorphs, i.e. a triclinic form, (I), in the space group P, and a monoclinic form, (II), in the space group C2/c. In both polymorphs, the molecules lie across centres of inversion, but in (II), the molecules are subject to whole‐molecule disorder equivalent to configurational disorder with occupancies of 0.6021 (19) and 0.3979 (19). There are no hydrogen bonds in the crystal structure of polymorph (I), but the molecules of polymorph (II) are linked by C—H...π(arene) hydrogen bonds into complex chains, which are further linked into sheets by C—H...N interactions.     

Supramolecular solvent microextraction of Sudan blue II in environmental samples prior to its spectrophotometric determination

A liquid phase microextraction method-based conformation of supramolecular assembly was developed for the separation and preconcentration of trace levels of Sudan blue II. Various analytical parameters such as pH, supramolecular solvent type and volume, sample volume and matrix effect etc. were optimised. Sudan blue II concentration in the extraction phase was determined by UV-visible spectrophotometer. Under the optimised conditions, detection limit and preconcentration factor was found as 2.16 µg L^?1 and 80, respectively. Relative standard deviation value was found 5%. The developed procedure was successfully applied for the determination of trace levels of Sudan blue II in environmental samples.     

L-proline derivatives based on a calix[4]arene scaffold as chiral organocatalysts for the direct asymmetric aldol reaction in water

Abstract

A new series of water-compatible proline catalysts (4–6) derived from calixarene bearing a hydrophobic nature have been synthesised. It was found that the compound 4 was a highly efficient organocatalyst for aldol reactions occurred in the water. Under optimised reaction conditions, high yields (up to 82%), good enantioselectivities (ee up to 81%) and high diastereoselectivities (dr up to 91:9) were obtained.     

Tuning the Selectivity of Biodegradable Antimicrobial Cationic Polycarbonates by Exchanging the Counter‐Anion

There is a growing interest in modern healthcare to develop systems able to fight antibiotic resistant bacteria. Antimicrobial cationic biodegradable polymers able to mimic antimicrobial peptides have shown to be effective against both Gram‐positive and Gram‐negative bacteria. In these systems, the hydrophilic–hydrophobic ratio and the cationic charge density play a pivotal role in defining the killing efficiency. Nevertheless, many of these antimicrobial polymers show relatively low selectivity as defined by the relative toxicity to mammalian cells or hemolysis relative to pathogens. In this study, a series of polycarbonates containing pendant quaternary ammoniums are used to understand the role of different counter‐anions including chloride, citrate, malonate, benzoate, acetate, lactate and trifluoroacetate, and the antibiotic penicillin on antimicrobial efficacy and selectivity. Interestingly, it is found that in spite of the strong antimicrobial activity of trifluoroacetate and benzoate anions, they prove to be much less hemolytic than chloride anion. It is believed that the proper selection of the anion could enhance the potential of antimicrobial polymers to fight against clinically relevant pathogenic infections, while concurrently mitigating harmful side effects.

     

Low‐Pressure Cobalt‐Catalyzed Enantioselective Hydrovinylation of Vinylarenes

An efficient and practical protocol for the enantioselective cobalt‐catalyzed hydrovinylation of vinylarenes with ethylene at low (1.2 bar) pressure has been developed. As precatalysts, stable [L₂CoCl₂] complexes are employed that are activated in situ with Et₂AlCl. A modular chiral TADDOL‐derived phosphine–phosphite ligand was identified that allows the conversion of a broad spectrum of substrates, including heterocyclic vinylarenes and vinylferrocene, to smoothly afford the branched products with up to 99 % ee and virtually complete regioselectivity. Even polar functional groups, such as OH, NH₂, CN, and CO₂R, are tolerated.     

Highly Selective and Sensitive Voltammetric Sensor Based on Ruthenium Nanoparticle Anchored Calix[4]amidocrown‐5 Functionalized Reduced Graphene Oxide: Simultaneous Determination of Quercetin,Morin and Rutin in Grape Wine

In this report, ruthenium nanoparticles (RuNPs) and calix[4]amidocrown‐5 (C4A5) were synthesized and grafted onto the surface of reduced graphene oxide (RGO) nanocomposite (RuNPs/C4A5/RGO). The morphologies of the nanocomposites were characterized by transmission electron microscope, scanning electron microscope, atomic force microscope, electrochemical impedance spectroscopy and x‐ray photoelectron spectroscopy. The electrochemical experiments were performed by cyclic voltammetry, electrochemical impedance spectroscopy and square wave voltammetry. The simultaneous determination of quercetin, rutin and morin was performed on glassy carbon electrode modified with RuNPs/C4A5/RGO (RuNPs/C4A5/RGO/GCE). The linearity ranges and the detection limits of QR, RT and MR were 1.0×10^?10–1.0×10^?8 M and 2.0×10^?11 M respectively.     

Electrochemical Genoassay Design for Allele‐Specific Detection of Toll‐Like Receptor‐2 Gene Polymorphism

An allele‐specific voltammetric genoassay for the detection of allele‐specific toll‐like receptor‐2 gene arg753gln polymorphism (TLR‐2) from polymerase chain reaction (PCR) amplified real samples was described in this study. Meldola blue (MDB), an intercalator molecule, was used as hybridization label. The wild‐type and mutant type oligonucleotide probes were immobilized onto disposable graphite electrode surfaces by covalent attachment method. The extent of hybridization between probe and target sequences was determined by using differential pulse voltammetry (DPV). As a result of the interaction between MDB and DNA at electrode surface, the MDB signal observed from probe sequence before hybridization and after hybridization with MM sequence is lower than that observed after hybridization with complementary sequence. The differences between the MDB reduction peaks obtained from probe modified, hybrid modified and MM modified electrode were used to detect TLR‐2 from PCR amplified real samples. The discrimination of homozygous and heterozygous alleles was also established by comparing the peak currents of MDB reduction signals. Numerous factors affecting the target hybridization and indicator binding reactions are optimized to maximize the sensitivity.