Drop Down List Split

In my drop down List, I combineed two columns Item_Name + ' ' + Item+Model to appear in my dropdownlist, However, when i try to insert my data Item_Name and Item_Model are still together when i save the information in the database and not split.. How do I fix this?
SqlDDL.InsertCommand = "INSERT INTO Inventory_History(Item_Name,Item_Model,Item_Quantity,MDDT,MDTM,Edited_by,Comments) select '" & ddlInventoryList.Text & "',Item_Quantity + '" & txtNewQuantity.Text & "','" & Today & "','" & TimeOfDay & "','" & Session("LOGINNAME") & "','" & txtComments.Text & "' From Inventory WHERE (Item_Name + ' ' + Item_Model = '" & ddlInventoryList.Text & "')" SqlDDL.Insert()