How medicinal chemists learned about log P

Design, synthesis and anti-tumor evaluation of plinabulin derivatives as potential agents targeting β-tubulin

Plinabulin is a promising microtubule destabilizing agent in phase 3 clinical stage for treating non-small cell lung cancer. However, the high toxicity and the poor water solubility of plinabulin limited its use and more plinabulin derivatives need to be explored. Here, two series of 29 plinabulin derivatives were designed, synthesized and evaluated for their anti-tumor effect against three types of cancer cell lines. Most of derivatives exerted obvious inhibition to the proliferation of the cell lines tested. Among them, compound 11c exerted stronger efficiency than plinabulin, and the reason might be the additional hydrogen bond between the nitrogen atom of the indole ring in compound 11c and Gln134 of β-tubulin. Immunofluorescence assay showed that compound 11c at 10 nM significantly disrupted tubulin structure. Compound 11c also significantly induced G2/M cell cycle arrest and apoptosis in dose dependent manner. These results suggest that compound 11c might be a potential candidate for cancer treatment as antimicrotubule agent.

μPESI-MS/MS System for Screening and Quantitating Drugs in Plasma Samples

Recently, we developed a novel microprobe electrospray ionization (μPESI) source and its coupled MS (μPESI-MS/MS) system. Here, we aimed to widely validate the μPESI-MS/MS method for quantitative analysis of drugs in plasma samples. Furthermore, the relationship between the quantitative performance of the μPESI-MS/MS method and the physicochemical properties of target drugs was analyzed. The μPESI-MS/MS methods for quantitative analysis of 5 representative drugs with a relatively wide range of molecular weight, pK_a, and log P values were developed and validated. The results showed that the linearity, accuracy, and precision of these methods met the requirements of the European Medicines Agency (EMA) guidance. Then a total of 75 drugs from plasma samples were primarily detected using the μPESI-MS/MS methods, among which 48 drugs could be quantitatively measured. Logistics regression suggested that drugs with significantly greater log P and physiological charge had better quantitative performance using the μPESI-MS/MS method. Collectively, these results clearly demonstrate the practical application of the μPESI-MS/MS system as a rapid approach to the quantitative analysis of drugs in plasma samples.

Polymer drug conjugates containing memantine, tacrine and cinnamic acid: promising nanotherapeutics for the treatment of Alzheimer's disease

AIM

To prepare polymer-drug conjugates containing a combination of memantine, tacrine, and E)-N-(3-aminopropyl)cinnamide, promising therapeutics for the treatment of neurodegenerative disorders.

METHODS

The conjugates were characterised by ¹HNMR, particle size analysis, SEM, LC-MS, TEM/EDX, and XRD, followed by in vitro anti-acetylcholinesterase and drug release studies.

RESULTS

¹H NMR analysis revealed successful drug conjugation with drug mass percentages in the range of 1.3-6.0% w/w. The drug release from the conjugates was sustained for 10 h in the range of 20-36%. The conjugates' capability to inhibit acetylcholinesterase (AChE) activity was significant with IC₅₀ values in the range of 13-44.4 µm which was more effective than tacrine (IC₅₀ =1698.8 µm). The docking studies further confirmed that the conjugation of the drugs into the polymer improved their anti-acetylcholinesterase activity.

CONCLUSION

The drug release profile, particle sizes, and in vitro studies revealed that the conjugates are promising therapeutics for treating neurodegenerative disorders.

A phenotype-directed chemical screen identifies ponalrestat as an inhibitor of the plant flavin monooxygenase YUCCA in auxin biosynthesis

Plant development is regulated by both synergistic and antagonistic interactions of different phytohormones, including a complex crosstalk between ethylene and auxin. For instance, auxin and ethylene synergistically control primary root elongation and root hair formation. However, a lack of chemical agents that specifically modulate ethylene or auxin production has precluded precise delineation of the contribution of each hormone to root development. Here, we performed a chemical genetic screen based on the recovery of root growth in ethylene-related Arabidopsis mutants with constitutive "short root" phenotypes (eto1-2 and ctr1-1). We found that ponalrestat exposure recovers root elongation in these mutants in an ethylene signal-independent manner. Genetic and pharmacological investigations revealed that ponalrestat inhibits the enzymatic activity of the flavin-containing monooxygenase YUCCA, which catalyzes the rate-limiting step of the indole-3-pyruvic acid branch of the auxin biosynthesis pathway. In summary, our findings have identified a YUCCA inhibitor that may be useful as a chemical tool to dissect the distinct steps in auxin biosynthesis and in the regulation of root development.