Sub AddHLink()
Dim oRng As Range
Dim strLink As String
    Set oRng = ActiveDocument.Range
    With oRng.Find
        Do While .Execute(FindText:="([A-Z]{2}) ([0-9]{4,}) ([A-Z0-9]{1,2})", MatchWildcards:=True)
            strLink = oRng.Text
            strLink = Replace(strLink, Chr(32), "")
            strLink = "https://www.google.co.in/patents/" & strLink & "?cl=en \t _blank"
            oRng.Text = ""
            ActiveDocument.Fields.Add oRng, wdFieldHyperlink, strLink, False
            oRng.Fields.Update
            oRng.Collapse 0
        Loop
    End With
lbl_Exit:
    Set oRng = Nothing
    Exit Sub
End Sub