New chiral and restricted-access materials containing glycopeptides as selectors for the high-performance liquid chromatographic determination of chiral drugs in biological matrices

Two new chiral and restricted-access materials containing glycopeptide antibiotics as chiral selectors (chiro-Glyco-RAM) were designed, suitable for the direct HPLC injection of biological fluids containing chiral drugs without any sample pre-treatment or pre-columns coupling. The external surface of the porous silica support was covered with a bio-compatible hydrophilic polymeric network (polyvinyl alcohol, PVA) while the chiral phase based on either teicoplanin (TE) or teicoplanin aglycone (TAG) was exclusively confined to the internal region. The chiro-Glyco-RAM supports were synthesized by the following steps: (a) introduction of 3-aminopropyl groups on 100 A pore size silica gel; (b) activation of the aminopropylated silica with 1,6-diisocyanatohexane; (c) functionalization of the external region of the porous silica with PVA; (d) covalent linking of TE/TAG to the internal surface. The average pore diameter of the chiro-Glyco-RAM supports, calculated by inverse size-exclusion chromatography (ISEC), was about 80 A and able to exclude macromolecules heavier than about 20,000 Da (such as the most abundant serum proteins) from the pores. The recovery of bovine serum albumin (BSA) was almost quantitative. HPLC analyses of model chiral drugs were performed using hydro-organic mobile phases consisting of an organic solvent (acetonitrile or methanol) and aqueous solutions of ammonium acetate (0.020 M) or ammonium formate (0.0025-0.0050 M).     

Synthesis and characterization of novel internal surface reversed-phase silica supports for high-performance liquid chromatography

An original synthetic method was developed for the preparation of a family of six novel deactivated restricted-access materials (RAMs), belonging to the group of the internal surface reversed-phase (ISRP) supports. The supports (ISRP-RAM phases A-F) have an alkyl-chain (14 methylenes) with two embedded ureido groups bound only to the internal surfaces of the porous silica, and polyvinyl alcoholic groups (PVA, 100,000-->22,000 molecular weight) chemically bound to the external surfaces. The average pore diameters of the prepared ISRP-RAM supports, calculated by inverse size-exclusion chromatography, ranged between 49 A and 88 A, and were able to exclude macromolecules heavier than about 24000 Da (such as serum proteins) from the pores. The novel supports were designed for the determination of a semi-synthetic anticancer drug of the camptothecin family in human plasma, but they represent universal ISRP-RAM supports not limited to such class of compounds.     

Detection and sequence determination of a new variant beta-lactoglobulin II from donkey

The sequence determination of a new variant of beta-LG II, detected as a minor component by reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry (RP-HPLC/ESI-MS) analysis of the whey fraction from a milk sample taken from an individual donkey belonging to the 'Ragusana' species of eastern Sicily, is reported. Direct RP-HPLC/ESI-MS analysis of the whey fraction from this milk sample allowed the identification of a new variant of beta-LG II, based on the determination of the M(r) of the intact protein. The new protein, with an experimentally determined M(r) of 18311 Da, was detected as a minor component in the whey fraction investigated. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)MS and RP-HPLC/ESI-MS/MS analyses of the tryptic digest of the new protein demonstrate that it presents two amino acid substitutions with respect to the sequence of beta-LG II A, namely a substitution Pro-->Cys at position 110, and a substitution Asp-->Gly at position 162. The disulfide bonds between the four cysteines, not directly determined in donkey's and horse's beta-LG II, were shown to occur between Cys(106)-Cys(120) and Cys(66)-Cys(161), as in other mammalian beta-LGs. The new beta-LG II variant from donkey was named D.     

The Different Facets of Triclocarban: A Review

In the late 1930s and early 1940s, it was discovered that the substitution on aromatic rings of hydrogen atoms with chlorine yielded a novel chemistry of antimicrobials. However, within a few years, many of these compounds and formulations showed adverse effects, including human toxicity, ecotoxicity, and unwanted environmental persistence and bioaccumulation, quickly leading to regulatory bans and phase-outs. Among these, the triclocarban, a polychlorinated aromatic antimicrobial agent, was employed as a major ingredient of toys, clothing, food packaging materials, food industry floors, medical supplies, and especially of personal care products, such as soaps, toothpaste, and shampoo. Triclocarban has been widely used for over 50 years, but only recently some concerns were raised about its endocrine disruptive properties. In September 2016, the U.S. Food and Drug Administration banned its use in over-the-counter hand and body washes because of its toxicity. The withdrawal of triclocarban has prompted the efforts to search for new antimicrobial compounds and several analogues of triclocarban have also been studied. In this review, an examination of different facets of triclocarban and its analogues will be analyzed.     

3,5-Dinitrobenzoyl-9-amino-9-deoxy-9-epiquinine as Pirkle-Anion Exchange Hybrid-Type Chiral Selector in High-Performance Liquid Chromatography

A new chiral stationary phase was designed by introducing 9-amino-9-deoxy-9-epiquinine, one of the most versatile organocatalysts in asymmetric synthesis, as chiral scaffold. The derivatization of its amino group with the 3,5-dinitrobenzoyl (DNB) fragment provided hydrogen bonding and π–π donor/acceptor systems in addition to the quinoline and quinuclidine moieties having two nitrogen atoms with different basicities. The selector offers multiple interaction sites in both typical of the Pirkle-type phases and classical of weak-anion-exchanger phases. The immobilization step took place through thiol-ene addition onto 3-mercaptopropyl-silica gel and gave a grafting density of 180 µmol of chiral selector per gram of silica. A silica with reduced particle size (Daisogel silica, pore size 120 Å, particle size 2.5 µm, and specific surface area 343 m² g^?1) has been employed to improve the efficiency and the speed of separations. The chiral stationary phase was packed in a small format column (50 × 4.6 mm) that allowed, by van Deemter analysis, 180,000 plates/m and approximately 5.1 µm of plate height. The ability of chiral discrimination was then studied with more than 30 test compounds using both polar-organic and normal phase conditions. In polar-organic mode, N-protected amino acids, α-aryloxy carboxylic acids, as well the non-steroidal anti-inflammatory profens were analyzed. Interesting results were obtained in normal phase elution, where the chiral selector behaves like a Pirkle-type stationary phase. Aryl amides, esterified DNB-amino acids, benzodiazepines, and binaphthol were well resolved with a very good peak symmetry and in short analysis time (mainly in less than 5 min).     

Relative stereochemistry of a diterpene from Salvia cinnabarina

The relative stereochemistry of 3,4-secoisopimara-4(18),7,15-triene-3-oic acid, a diterpenoid with antispasmodic, hypotensive and antibacterial activities isolated from Salvia cinnabarina, was determined by an X-ray diffraction analysis of a single crystal of a suitable crystalline derivative.     

Urinary profile of methylprednisolone acetate metabolites in patients following intra-articular and intramuscular administration

A study on urinary metabolites of methylprednisolone acetate (MPA) has been performed by liquid chromatography–electrospray ionization–tandem mass spectrometry (LC-ESI-MS/MS) in precursor ion scanning (PIS) and neutral loss (NL) modes. Patients suffering from joint inflammation have been treated with Depo-Medrol? (MPA marketed suspension, 40 mg) intra-articularly (IA) and after a wash-out period, intramuscularly (IM) at the same dose. Urine samples have been collected after both the administration routes. Metabolites were identified in PIS mode by setting the fragment ion at m/z 161 which is specific for MPA, methylprednisolone (MP), methylprednisolone hemisuccinate, and in NL mode by selecting the losses of 54, 72, 176 and 194 Da. The MP-related structure of each target ion detected in both the MS modes was then confirmed by MS/MS acquisitions, and by accurate mass experiments. By using this approach, 13 MPA metabolites (M1–M13) have been identified, nine already reported in the literature and four unknown and for which the chemical structures have been proposed. No differences in the metabolic pattern of MPA when administered IM or IA were observed. The relative abundances of metabolites compared with the internal standard (MP-D2) were monitored by multiple reaction monitoring analysis for 19 days after both the administration routes.     

Protein expression patterns associated with advanced stage ovarian cancer

This is a comparative proteomic study on biopsies from patients with ovarian cancer to identify potential diagnostic/prognostic biomarkers in both healthy and tumor tissue, interstitial fluid (normal interstitial fluid and tumoral interstitial fluid and peritoneal effusion. Protein expression/identification was evaluated by 2-DE and MS analysis: six proteins showed differential expression in tumoral interstitial fluid and tumor tissue compared to normal interstitial fluid and healthy tissue: five were found to be downregulated and identified as galectin 3, glutathione S-transferase A-2, retinol binding protein 1, phosphatidylethanolamine-binding protein and annexin 5, while the calgranulin, was significantly upregulated in all pathological samples, including the ascitic fluid. Validation of S100A8 overexpression in carcinoma tissue was obtained by immunohistochemistry. To our knowledge, this is the first study to report an over-expression of calgranulin by 2-DE associated with MS/MS analysis on surgical biopsy. The reduced expression of galectin 3 and retinol binding protein 1 in cystic fluid and serum of patients with early stage disease is confirmed in this study. The results highlight alterations in proteins that control cell-cycle progression and apoptosis, as well as factors that modulate the activity of signal transduction pathways. Moreover, this study suggests that calgranulin expression may be used as a diagnostic and/or prognostic biomarker.