Subquery decorrelation

The following query has a high cost (over 4 million), uses a nested
loop join and runs much slower than I would like. Does anyone know if
is possible to rewrite this query more efficiently (probably without
the correlated subquery)? If so, could you please show me how.

 SELECT *
  FROM p1
  WHERE recdt = (
      SELECT MAX ( recdt )
        FROM p2
        WHERE p1.script = p2.script
          AND p1.param = p2.param
          AND p1.hostname = p2.hostname
          AND p1.item = p2.item
          AND p2.flags NOT IN ( ? ) )
    AND p1.script = ?
    AND p1.param = ?
    AND p1.hostname = ?
    AND p1.flags NOT IN ( ? );

Thanks in advance.