Requiremnt of re constitution of adrenaline & lignocaine at time of surgery

  • Adrenaline is unstable at normal or higher pH
  • Lignocaine is ionized at normal or higher pH and so more active (reason why sodium bicarbonate is added to moffet’s solution)
  • In dental cartridge, to maintain adrenaline stability –> low pH –>  but leads to low activity of lignocaine
  • In self pre constituted mixture, adrenaline being unstable becomes inactive à adrenaline effect lost –>  lignocaine systemic absorption faster –> pain intra operatively
  • Therefore, best is re constitution of mixture immediately before surgery