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hERG Assay

hERG assays on Human Embry­onic Kid­ney (HEK) cells:

Reg­u­la­tory study (ICH S7B)

IKr cur­rent inhi­bi­tion has been shown to pro­long the car­diac action poten­tial, a phe­nom­e­non asso­ci­ated with increased risk of QT inter­val pro­lon­ga­tion, who can lead to poten­tially fatal ven­tric­u­lar tach­yarhyth­mia called Tor­sades de Pointe. Inhi­bi­tion of hERG chan­nel by phar­ma­ceu­ti­cals is the pri­mary cause of drug-​induced QT pro­lon­ga­tion. A large num­ber of drugs have been with­drawn from the mar­ket or dur­ing late stage clin­i­cal tri­als due to these car­diotoxic effects, there­fore it’s impor­tant to iden­tify poten­tial inhibitory effects early in drug discover.

Muta­tion LQT2: LONG QT

Stan­dard hERG assay pro­to­col:
  • GLP com­pli­ant
  • man­ual patch-​clamp technique
  • 6 treated cells and 6 con­trol cells
  • 3 or 4 increas­ing cumu­la­tive con­cen­tra­tions of assay compound
  • exper­i­ment con­duced at room tem­per­a­ture or at more phys­i­o­log­i­cal tem­per­a­ture (35°C)
  • Stim­u­la­tion protocol:


Mea­sured para­me­ters:
  • Ampli­tude of the tail cur­rent upon repo­lar­iza­tion to –40 mV (pA)
  • Ampli­tude of the base cur­rent at –80 mV (pA)
  • Inhi­bi­tion of hERG tail cur­rent amplitude (%)
  • IC50 value
Ref­er­ence com­pounds or pos­i­tive con­trols

REFERENCE

COM­POUNDS hERG

IC50
E– 4031 32.3 nM

Quini­dine

0.3 µM
Fle­caïnide 0.7 µM
Sotalol 69.0 µM
Ziprasi­done 0.2 µM
Amio­darone 27.9 nM
Dofetilide 10.8 nM
Cis­apride 26.1 nM