<?xml version="1.0" encoding="US-ASCII"?>
<!-- Generated by Broadridge Transform (tm) - http://www.broadridge.com -->
<!-- Created: Thu Jul 16 03:39:21 UTC 2026 -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
  <roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#PvpAdjustmentsOnly" roleURI="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all"/>
  <definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" xlink:type="extended">
    <loc xlink:type="locator" xlink:label="ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember"/>
    <loc xlink:type="locator" xlink:label="qnrx_EquityAwardsAdjustmentsChangeInFairValueOfAwardsGrantedInPriorYearsForfeitedDuringCurrentYearMember" xlink:href="qnrx-20251231.xsd#qnrx_EquityAwardsAdjustmentsChangeInFairValueOfAwardsGrantedInPriorYearsForfeitedDuringCurrentYearMember"/>
<!-- [WMV7][018KzxNKGTVQb8qqZMH0NPm2jhyIpy7w2ckS5sZat0KH8gH1Pjpyeljqjv0xlfY+W/0jKPa5zCvDbWpWBH8SGNjArwFyKNjG63rylLN6lP/l+HfLeF3STo21tTANlAY4w7M2y6csPNzEOY4B7+/q/3Cj3GMpuLZxMuft1Lz/3iqSd/j3hT/xq+wverKLpFg61sB7SOCrmKy+eFLZESYLFwTh05hf6862tG4tYtedQIDDrAjMOD+vFi07/4DuRpy/TN1dHWvIBAdK8XphD9qVDhvkHehSOLuBDPFPGe3R89sLGu9vr7A6sA2OQsp3UVSIb2MfrA1/Fg==] CSR-->
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember" xlink:to="qnrx_EquityAwardsAdjustmentsChangeInFairValueOfAwardsGrantedInPriorYearsForfeitedDuringCurrentYearMember" order="1" xbrldt:closed="true"/>
  </definitionLink>
</linkbase>
