Modulating the Inclusive and Coordinating Ability of Thiacalix[4]arene and Its Antenna Effect on Yb³-Luminescence via Upper-Rim Substitution<xref rid="fn+-20221012160304-1908848" ref-type="fn">+</xref>

The present work introduces the series of thiacalix[4]arenes (H4L) bearing different upper-rim substituents (R = H, Br, NO2) for rational design of ligands providing an antenna-effect on the NIR Yb3+-centered luminescence of their Yb3+ complexes. The unusual inclusive self-assembly of H3L− (Br) through Brπ interactions is revealed through single-crystal XRD analysis. Thermodynamically favorable formation of dimeric complexes [2Yb3+:2HL3−] leads to efficient sensitizing of the Yb3+ luminescence for H4L (Br, NO2), while poor sensitizing is observed for ligand H4L (H). X-ray analysis of the single crystal separated from the basified DMF solutions of YbCl3 and H4L(NO2) has revealed the transformation of the dimeric complexes into [4Yb3+:2L4−] ones with a cubane-like cluster structure. The luminescence characteristics of the complexes in the solutions reveal the peculiar antenna effect of H4L(R = NO2), where the triplet level at 567 nm (17,637 cm−1) arisen from ILCT provides efficient sensitizing of the Yb3+ luminescence

Surface modification of pralidoxime chloride-loaded solid lipid nanoparticles for enhanced brain reactivation of organophosphorus-inhibited AChE: pharmacokinetics in rat

The nanotechnological approach is an innovative strategy of high potential to achieve reactivation of organophosphorus-inhibited acetylcholinesterase in central nervous system. It was previously shown that pralidoxime chloride-loaded solid lipid nanoparticles (2-PAM-SLNs) are able to protect the brain against pesticide (paraoxon) central toxicity. In the present work, we increased brain AChE reactivation efficacy by PEGylation of 2-PAM-SLNs using PEG-lipid N-(carbonyl-methoxypolyethylene glycol-2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine, sodium salt) (DSPE-PEG2000) as a surface-modifier of SLNs. To perform pharmacokinetic study, a simple, sensitive (LLOQ 1.0ng/ml) high-performance liquid chromatography tandem mass spectrometry with atmospheric pressure chemical ionization by multiple reaction monitoring mode (HPLC-APCI-MS) was developed. The method was compared to mass spectrometry with electrospray ionization. The method was validated for linearity, accuracy, precision, extraction recovery, matrix effect and stability. Acetophenone oxime was used as the internal standard for the quantification of 2-PAM in rat plasma and brain tissue after intravenous administration. 2-PAM-DSPE-PEG2000-SLNs of mean size about 80nm (PDI=0.26), zeta-potential of 55mV and of high in vitro stability, prolonged the elimination phase of 2-PAM from the bloodstream more than 3 times compared to free 2-PAM. An increase in reactivation of POX-inhibited human brain acetylcholinesterase up to 36.08±4.3% after intravenous administration of 2-PAM-DSPE-PEG2000-SLNs (dose of 2-PAM is 5mg/kg) was achieved. The result is one of the first examples where this level of brain acetylcholinesterase reactivation was achieved. Thus, the implementation of different approaches for targeting and modifying nanoparticles surface gives hope for improving the antidotal treatment of organophosphorus poisoning by marketed reactivators.This research (the HPLC-MS part of this work) was carried out using facilities of the CSF-SAC FRC KSC RAS was financial support from the government assignment for FRC Kazan Scientific Center of Russian Academy of Sciences to D.N.B., I.Kh.R, V.M.B. This work (the part preparation, characterization, and stability, release analysis, reactivation of brain AChE in vivo of 2-PAM-DSPE-PEG2000-SLNs) was supported by Russian Science Foundation (project N◦ 19-73-30012) to T.N. P., E.A.B., I.V.Z., K.A.P. The authors are indebted to Prof. L.Ya. Zakharova who initiated this work. They express to her their thanks for her interest and constant support. The authors are indebted to Prof. Patrick Masson (KFU, Kazan) for his critical reading and editing of the manuscript. The authors are grateful to Dr. Sofya V. Lushchekina (Emanuel Institute RAS, Moscow) for her assistanceinfo:eu-repo/semantics/publishedVersio