No abstract

As the consumption of aquatic products increased, the need for regulation of pesticide residues in aquatic products also emerged. Thus, in this study, a scheduled multiple reaction monitoring (sMRM) method employing a novel extraction and purification step based on QuEChERS with EDTA was developed for the simultaneous quantitation of 20 pesticides (alachlor, aldicarb, carbofuran, diazinon, dimethoate, dimethomorph, ethoprophos, ferimzone, fluridone, hexaconazole, iprobenfos, malathion, methidathion, methiocarb, phenthoate, phosalone, phosmet, phosphamidon, pirimicarb, and simazine) in aquatic products. Additionally, the present method was validated in the aspects of specificity, linearity (r ≥ 0.980), sensitivity (the limit of quantitation (LOQ) ≤ 5 ng/g), relative standard deviation, RSD (1.0% ≤ RSD ≤ 19.4%), and recovery (60.1% ≤ recovery ≤ 117.9%). Finally, the validated method was applied for the determination of the 20 pesticide residues in eel and shrimp purchased from local food markets. In the present study, QuEChERS with EDTA was successfully expanded to residual pesticide analysis for the first time. The present method could contribute to the rapid and successful establishment of the positive list system in South Korea.

Relatively few studies on time-related peptide losses have been reported and previous studies on the differential peptide recovery from a sample solution over a period had limitations. Thus, here, longitudinal peptide losses during sample solution storage in an autosampler vial over 145 h were assessed using nanoliquid chromatography and tandem mass spectrometry. In this study, hydrophilic peptide losses from a solution stored in a vial were observed regardless of materials of vials and the possibility of hydrophobic peptide losses brought by reasons other than hydrophobic peptide adsorption onto vials was found. Additionally, the preparation of a proteomics sample using 0.1% aqueous formic acid solution (0.1% FA) and a polypropylene vial, 0.1% FA and a glass vial, or the aqueous mixture of 5 M urea, 1 M thiourea, and 0.1% FA and a polymethylpentene vial proved to produce the most reliable longitudinal recovery of peptides from a solution stored in a vial.

A new Soluplus (polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer)-based supersaturable self-emulsifying drug delivery system (S-SEDDS) was formulated to enhance oral absorption of tacrolimus (FK506) with minimal use of oil, surfactant, and cosurfactant. A high payload supersaturable system (S-SEDDS) was prepared by incorporating Soluplus, as a precipitation inhibitor, to SEDDS consisting of Capmul MCM, Cremophor EL, and Transcutol (FK506:vehicle:Soluplus =1:15:1). In vitro dissolution profile and in vitro pharmacokinetic aspect of S-SEDDS in rats were comparatively evaluated with those of conventional SEDDS formulas containing four times greater content of vehicle components (FK506:vehicle =1:60). Both formulations formed spherical drug-loaded microemulsion <70 nm in size when in contact with aqueous medium. In an in vitro dissolution test in a nonsink condition, the amphiphilic polymer noticeably retarded drug precipitation and maintained >80% of accumulated dissolution rate for 24 hours, analogous to that from conventional SEDDS. Moreover, pharmacokinetic parameters of the maximum blood concentration and area under the curve from S-SEDDS formula in rats were not statistically different ( P >0.05) than those of conventional SEDDS. The results suggest that the Soluplus-based supersaturable system can be an alternative to achieve a comparable in vitro dissolution profile and in vivo oral absorption with conventional SEDDS, with minimal use of vehicle ingredients.

As the first step to discover protein disease biomarkers from saliva, global analyses of the saliva proteome have been carried out since the early 2000s, and more than 3,000 proteins have been identified in human saliva. Recently, ethnic differences in the human plasma proteome have been reported, but such corresponding studies on human saliva in this aspect have not been previously reported. Thus, here, in order to determine ethnic differences in the human saliva proteome, a Korean whole saliva (WS) proteome catalogue indexing 480 proteins was built and characterized through nLC-Q-IMS-TOF analyses of WS samples collected from eleven healthy South Korean male adult volunteers for the first time. Identification of 226 distinct Korean WS proteins, not observed in the integrated human saliva protein dataset, and significant gene ontology distribution differences in the Korean WS proteome compared to the integrated human saliva proteome strongly support ethnic differences in the human saliva proteome. Additionally, the potential value of ethnicity-specific human saliva proteins as biomarkers for diseases highly prevalent in that ethnic group was confirmed by finding 35 distinct Korean WS proteins likely to be associated with the top 10 deadliest diseases in South Korea. Finally, the present Korean WS protein list can serve as the first level reference for future proteomic studies including disease biomarker studies on Korean saliva.