Sub Macro1()
Dim c As Range, j&, t
'Suppression doublons
Range("A1:B" & Val("Staple") + 1600).RemoveDuplicates Columns:=1, Header:=xlNo
j = 1
For Each c In Range("B1:B" & Cells(Rows.Count, 1).End(xlUp).Row)
t = Split(VBA.Trim(c.Text), ",")
Cells(j, "D").Resize(UBound(t) + 1) = Application.Transpose(t)
Cells(j, "C").Resize(UBound(t) + 1) = Cells(c.Row, "A")
Erase t
j = Cells(Rows.Count, 4).End(xlUp).Row + 1
Next
End Sub