Triphenylphosphonium Cations of the Diterpenoid Isosteviol: Synthesis and Antimitotic Activity in a Sea Urchin Embryo Model

A series of novel triphenylphosphonium (TPP) cations of the diterpenoid isosteviol (<b>1</b>, 16-oxo-<i>ent</i>-beyeran-19-oic acid) have been synthesized and evaluated in an in vivo phenotypic sea urchin embryo assay for antimitotic activity. The TPP moiety was applied as a carrier to provide selective accumulation of a connected compound into mitochondria. When applied to fertilized eggs, the targeted isosteviol TPP conjugates induced mitotic arrest with the formation of aberrant multipolar mitotic spindles, whereas both isosteviol and the methyltriphenylphosphonium cation were inactive. The structure–activity relationship study revealed the essential role of the TPP group for the realization of the isosteviol effect, while the chemical structure and the length of the linker only slightly influenced the antimitotic potency. The results obtained using the sea urchin embryo model suggested that TPP conjugates of isosteviol induced mitotic spindle defects and mitotic arrest presumably by affecting mitochondrial DNA. Since targeting mitochondria is considered as an encouraging strategy for cancer therapy, TPP-isosteviol conjugates may represent promising candidates for further design as anticancer agents

Nanoparticle-Delivered 2‑PAM for Rat Brain Protection against Paraoxon Central Toxicity

Solid lipid nanoparticles (SLNs) are among the most promising nanocarriers to target the blood–brain barrier (BBB) for drug delivery to the central nervous system (CNS). Encapsulation of the acetylcholinesterase reactivator, pralidoxime chloride (2-PAM), in SLNs appears to be a suitable strategy for protection against poisoning by organophosphorus agents (OPs) and postexposure treatment. 2-PAM-loaded SLNs were developed for brain targeting and delivery via intravenous (iv) administration. 2-PAM–SLNs displayed a high 2-PAM encapsulation efficiency (∼90%) and loading capacity (maximum 30.8 ± 1%). Drug-loaded particles had a mean hydrodynamic diameter close to 100 nm and high negative zeta potential (−54 to −15 mV). These properties contribute to improve long-term stability of 2-PAM–SLNs when stored both at room temperature (22 °C) and at 4 °C, as well as to longer circulation time in the bloodstream compared to free 2-PAM. Paraoxon-poisoned rats (2 × LD₅₀) were treated with 2-PAM-loaded SLNs at a dose of 2-PAM of 5 mg/kg. 2-PAM–SLNs reactivated 15% of brain AChE activity. Our results confirm the potential use of SLNs loaded with positively charged oximes as a medical countermeasure both for protection against OPs poisoning and for postexposure treatment

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