MCDOWELL <ME> TO MERGER WITH <INTERPHARM INC> McDowell Enterprises Inc said it has signed a definitive agreement to acquire an 80 pct interest in privately held Interpharm Inc for a 19.9 pct interest in McDowell. The company said subject to contigencies, including future sales and profit levels, McDowell could over a four-year period acquire 100 pct of Interpharm in exchange for up to 51 pct of McDowell's voting stock. It said the transaction is expected to be completed within 60 days, at which time the McDowell board would be restructured to include Interpharm management.