Diese Präsentation wurde erfolgreich gemeldet.
Wir verwenden Ihre LinkedIn Profilangaben und Informationen zu Ihren Aktivitäten, um Anzeigen zu personalisieren und Ihnen relevantere Inhalte anzuzeigen. Sie können Ihre Anzeigeneinstellungen jederzeit ändern.

ruthin 230512

222 Aufrufe

Veröffentlicht am

  • Als Erste(r) kommentieren

  • Gehören Sie zu den Ersten, denen das gefällt!

ruthin 230512

  1. 1. Design and Biological Evaluation of Heterocyclic Quinolones Targeting Plasmodium Falciparum Type II NADH:Quinone Oxidoreductase (PfNDH2) Peter Gibbons
  2. 2. Introduction to the WT Project. 2 • Urgent need for new antimalarial drugs with novel mechanisms of action to deliver effective control and eradication programmes. • Parasite resistance to all existing antimalarial classes, including artemisinins, has been reported during their clinical use. • Failure to develop new antimalarials with novel mechanisms of action that circumvent the current resistance challenges will contribute to a resurgence in the disease. • New antimalarials with dual mechanism of action against two respiratory enzymes (PfNDH2 and bc1 ) would be advantageous against multi-drug resistant P. falciparum parasites. • Known inhibitor of PfNDH2 target, hydroxy-2-dodecyl-4-(1H)-quinolone (HDQ).
  3. 3. Why target PfNDH2? • Novel mechanism of action ? (i)Mitochondria is a proven drug target (e.g. atovaquone) with curative activity against circulating intra-erythrocytic parasites, Curative activity against liver stage parasites for prophylaxis and Curative activity against gametocytes reducing transmission (at least against stages I- III). (ii)PfNDH2 is key electron donor for the respiratory chain 3 NADH Dihroorotate G-3-P Succinate Malate PfNDH2 N P ΔΨm + e- III H+ e- c QH2 ETC DHOD G3PD SQR MQO >90 % <<1% ~ 1% ~1% <<1%
  4. 4. 4 Mono aryl Quinolones identified from HTS and initial SAR work. • Structural modifications (e.g. Cl at 7 position of A ring and methyl substituent at 3-position) led to generation of 60 compounds including lead compound CK-2-68, 31 nM against 3D7 and 16 nM against PfNDH2. • ClogP needed to be reduced and aqueous solubility enhanced in order to administer drug in suitable vehicle, without the need for a pro-drug approach. • Incorporation of a pyridine group reduces ClogP, improves aqueous solubility, and possible salt formation.
  5. 5. 5 Medicinal Chemistry Strategy for the Discovery of SL-2-25 and SL-2-64
  6. 6. Chemistry Goals Medicinal Chemistry • Focus is to enhance inherent antimalarial potency whilst increasing solubility • Incorporation of heterocycles to reduce ClogP/logD, disruption of planarity and introduction of solubilising groups • 2-Aryl Series central focus 6 OCF3 6a 14a
  7. 7. General Synthesis of Quinolone Target Molecules. 7 • Heterocycle incorporation to reduce ClogP. Chemistry easier with no O or CH2 linker between the two rings within the side chain. Would activity be maintained? • Pyridine ring incorporated into side chain, optimal A ring and terminal aryl ring substituents investigated. • Methodology allows for the rapid synthesis of Quinolone analogues to probe the SAR.
  8. 8. Yields for the Synthesis of Target Quinolones. 8
  9. 9. Target Quinolones continued. 9
  10. 10. Synthesis of Hydroxyl Quinolones in A ring and side chain. 10 • Presence of OH in both the A ring of the Quinolone core and terminal aryl group investigated. • Possible attachment position for Pro-drug strategy if aqueous solubility of parent Quinolone not satisfactory.
  11. 11. Substitution at 3-position of Quinolone core with Esters and methyl alcohol. 11 • 3-Methyl alcohol Quinolones prepared with pro-drug strategy in mind, however inherently unstable at 3-position of quinolone core.
  12. 12. 3-Chloro Quinolones. 12
  13. 13. Incorporation of Morpholine group and Aza Quinolones. 13 • Enhance aqueous solubility and allow possibility of salt formation.
  14. 14. Extended side chain Morpholine Quinolones and piperazine linker analogues.. 14
  15. 15. Phosphate and Morpholine Pro-drugs. 15
  16. 16. In Vitro Antimalarial of Bisaryl Quinolones vs 3D7 16 • No linker is well tolerated • High degree of substitution in side chain close to the quinolone core is poorly tolerated. (8a, 940 nM, flexibility of side chain key to activity?) • 4-OCF3 group optimal terminal group (12a, 59 nM) • 3-position methyl group favoured (Me > CH2OH > CO2Et)
  17. 17. In Vitro Antimalarial Activities of Bicyclic Quinolones vs 3D7 17 • Small X groups e.g. Cl, F, OH well tolerated, larger groups e.g CF3, OCF3, SO2Me not tolerated e.g. (8h 75 nM vs 8l > 1000 nM). Hydroxyl Y group not tolerated (11a and 11b). Sub at 4 position favoured over 2 and 3 position.
  18. 18. In Vitro Antimalarial Activities of Other Bicyclic Quinolones vs 3D7 18
  19. 19. Continued. 19 • One pyridine ring 8b (54 nM) favoured over two pyridine rings 8v (370 nM) • OCF3 optimal terminal substituent e.g. 8w (40 nM) vs 8x (279 nM) • Incorporation of morpholine/piperazine group generally leads to a loss of activity.
  20. 20. In vivo activity 20 In Vivo Peters Standard 4-day test- Oral Administration • SL-2-25 some solubility issues in SSV, compound dosed as suspension and reduced % parasite clearance observed. Fully dissolved in DET (proof of concept) 100 % parasite kill Achieved at 20 mg/Kg. • Phosphate salt of SL-2-25 and morpholine Pro-drug 100 % parasite kill in SSV. • Phosphate Pro-drug of SL-2-25 (compound 55) dosed in sodium carbonate solution with 100 % parasite kill at 20 mg/Kg.
  21. 21. In vivo activity 21 • Peters standard 4 day test performed in Liverpool – oral dosing once daily
  22. 22. Initial PK data consistent with once daily oral dosing 22 SL-2-25S (20 mg/kg) Cmax 3.7 µg/mL, Tmax 7.0 h,T ½ 9.9 h, Vd 3970.8 mL/kg, AUC0-t 69.3 µg/h/mL and a ClT of 276.3 mL/h/kg. SL2-99 (20 mg/kg) Cmax 8.1 µg/mL, Tmax 7.0 h, half life (T ½) of 20.3 h, a volume of distribution Vd of 2875.6 mL/kg, an area under the curve of AUC0-t 167.2 µg/h/mL and a calculated total clearance ClT was 98.0 mL/h/kg.
  23. 23. FIGURE Plasma Concentration-Time profile of SL-2-25 in male Wistar rats after administration of a single oral dose of SL-2-25-S (5 mg/kg (n=4)) SL-2-25-S Cmax (µg/ml) 3.1 Tmax (h) 7 AUC0-t (µg.h/ml) 57.9 T1/2 (h) 10.6 Vd (ml/kg) 1261.4 ClT (ml/h/kg) 82.1 Pharmacokinetic parameters calculated using Pk solutions 2.0 software SL-2-25; Oral Profile in Rats following 5 mg/kg (po) TABLE
  24. 24. 24 Solubility Compound Structure Solubility (µM) pH=7.4 pH=4.5 pH=1 Atovaquone <0.01 <0.01 1st generation Pyridone (GW844520) 0.02 0.2 2nd generation Pyridone (GSK9321121A) 1.0 2.7 SL-2-25 (Sl-2-25.H3PO4) 0.04 (0.08) 0.08 (0.12) 18 (42) WDH-1U-4 <0.01 0.3 Kinetic Solubility Assay Performed at Biofocus
  25. 25. Conclusions 25 • 4-6 step synthesis of a range of heterocyclic quinolones with potent antimalarial activity both in vitro and in vivo. • Several compounds within the series proven to be potent against novel PfNDH2 enzymatic target. • Lead compound SL-2-25 demonstrates outstanding antimalarial activity, reduced ClogP, and improved solubility. • SL-2-25 has antimalarial activity of 54 nM vs 3D7, PfNDH2 activity of 15 nM and an ED50 / ED90 of 1.87 / 4.72 mg / Kg when formulated as the phosphoric acid salt.
  26. 26. Future Work: SAR Development of Pyrazole and Pyridoxyl Series - Solubility/ Activity Improvements 26 • Optimisation of side chain to improve solubility and drug delivery is key. • Initially SAR around leads CK-3-22 and WDH-1W-5 will be explored. • CH2 linker in WDH-1W-5 is a possible site of metabolism alternatives including CH2CH2, C=O, CF2, oxygen and no linker will be investigated. N H O N Cl MeO OCF3 PG227 IC50 (3D7) = 27 nM
  27. 27. Future Work: Further Lead Optimisation-Solubility 27 N H O N N OCF3 WDH-1W-5 N H O N N OCF3 WDH-2Q-3 IC50 (3D7) = 148 nM IC50 (PfNDH2) = IP IC50 (3D7) = 74 nM IC50 (PfNDH2) = 49.1 nM Solubility =0.01 uM Solubility = 0.4 uM @ pH = 7.4 Solubility = 21 uM @ pH =7.4 2 x solubility of GSK pyridone at pH = 7.4 105 x more soluble at pH =1 20 x more soluble than GSK second generation pyridone at pH = 1 N H O N OCF3 SL-2-25 IC50 (3D7) = 54 nM N H O N CF3 Solubility = 0.04 uM @ pH = 7.4 Solubility = 18 uM @ pH = 1 Solubility = 1 uM @ pH = 7.4 Solubility = > 44 uM @ pH = 1 25 x increase in solubility at pH = IC50 (3D7) = 109 nM 7.4 1000 x increase in solubility at pH = 1 @ pH = 7.4 40 x increase in solubility at pH = 7.4 2100 x increase in solubility at pH = 1 Pyrazole isomer 3-Me N H O O N O 5-Membered Heterocyles Torsion Angle Effect in C/D Ring Extended Solubilising Group 2.4 uM @ pH =7.4 42 uM @ pH = 1 IC50 (3D7) = 300 nM • Side Chain Modifications – to reduce/optimise CLogP and enhance solubility. •Three Proof of Principle Examples Now Established Solubility = 0.4 uM @ pH = 7.4 Solubility = 21 uM @ pH = 1

×