Notes
Slide Show
Outline
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Automation In Pharmaceutical Profiling
  • Edward Kerns, Li Di, Susan Petusky, Susan Li, Donna Huryn
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We Overlook Properties At Our Peril
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Pharmaceuticals - Holistic Model
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Changing Strategy in Discovery Aids Success
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Barrier Model Assists Assay Selection
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Barrier / Assay Model – In Vivo “ADME”
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Barriers Also Restrict Drug Leads In Vitro
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Lack of Information Can be Deadly
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“ADME” Is Not Just In Vivo Anymore
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Apply Property Data Throughout Discovery
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Focus on Properties With Impact
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Pharmaceutical Profiling:  Mission
  • Determine properties of compounds
    • Physicochemical, metabolic, toxicologic, pharmacokinetic
    • In silico, in vitro, in vivo
  • Deliver timely data in useful format
  • Apply data to benefit discovery
    • Enhance lead selection and optimization
    • Improve experiment planning & interpretation
      • Multidisciplinary collaboration
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Automation of Profiling Methods:  Examples
  • Integrity & Purity
  • Solubility
  • Permeability
  • Stability
  • CYP450 Inhibition
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Integrity & Purity
  • Right compound?
    • HTS compound may have degraded or be misidentified
    • Structure-Activity Relationships (SAR)


  • Purity high?
    • Impurities cause false activities and properties
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Integrity & Purity Schematic:  LC/UV/MS
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Permeability
  • Pass lipid membranes?
    • Absorption – Intestinal
    • Cells – Target tissue
    • Cells – In vitro bioassay


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Permeability Schematic:  PAMPA
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Permeability Profile:  PAMPA Detail
  • pION PSR4®
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PAMPA-BBB Assay
  • PAMPA Modification for BBB
    • Same instrumentation
    • Brain lipid
    • High correlation
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Solubility
  • Sufficient for GI absorption?
    • Improve with structure modification


  • Sufficient for bioassays?
    • Not be soluble at test concentration or during preparation
    • Correct activity (SAR)


  • Soluble during reagent preparation?
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Solubility Schematic
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Solubility Profile:  Detail
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Stability
  • Remain intact in discovery experiments?
    • Activity or inactivity due to degradation
    • Use conditions of activity experiments


  • Does clearance reduce exposure?
    • Modify structure to increase t1/2
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Stability:  Relevant Discovery Conditions
  • Metabolic   37o C, 0.25 hr (Liver)
  • Neutral   pH 7.4, 37o C, 24 hr (Assay Buffer)
  • Plasma   37o C, 4 hr (Blood)


  • Acid   pH 1.5, 37o C, 4 hr (Stomach)
  • Basic   pH 8, 37o C, 24 hr (Intestine)
  • Heat   pH 7.4, 45o C, 24 hr (Storage)
  • Light   pH 7.4, HI light, 24 hr (Light)
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Stability Schematic
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Microsomal Incubation: Plate Detail
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Stability Quantitation: FIA MS/MS
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Stability Profile: FIA MS/MS
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Stability Follow-up
  • Mechanism of degradation
    • Structure elucidation
    • Rapid LC/MS/MS
  • Synthesize stable structures
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CYP450 Inhibition
  • Inhibit CYP450 Isozyme(s)?
    • Potential Drug-Drug interactions
    • Safety concern
    • Product removal
    • Determine early to correct or drop series


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CYP450 Inhibition:  Experiment
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CYP450 Inhibition Schematic
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CYP450 Inhibition:  Detail
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Tactics for Properties in Discovery
  • Discovery activity assay barriers
  • Parallel activity and property evaluation
  • Iterative structure redesign
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Tactic: Understand Discovery Experiment Barriers
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Tactic:  Parallel Activity/Property Optimization
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Tactic:  Iterative Structure Redesign
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Future Directions
  • Enhanced assays (Q3)
    • Quickness
    • Quantity
    • Quality
  • Higher level automation
    • BMS, Pfizer, Eli Lilly
  • Enhanced property optimization
    • Guidance for medicinal chemists
    • Visualization & Consultation
    • IV/IV correlation software


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Conclusions
  • Many discovery problems are property-related
  • Property information enhances drug discovery
    • Planning, Interpreting, Modifying, Prioritizing, Diagnosing
  • Discovery scientists are learning to apply data
  • Continued improvement in assays is important
  • Automation enhances property assays
    • Quickness, Quantity, Quality
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Log P 2004 Symposium
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Acknowledgements
  • Wyeth
  • Li Di
  • Susan Petusky
  • Susan Li
  • Teresa Kleintop
  • Mark Tischler
  • Larry Mallis
  • Nelson Huang


  • Donna Huryn
  • Oliver McConnell
  • Guy Carter