X0202 4 2004-06-01 0 0001003642 IMPAX LABORATORIES INC IPXL 0001245196 HSIAO CHARLES C/O IMPAX LABORATORIES, INC. 30381 HUNTWOOD AVENUE HAYWARD CA 94544 1 0 0 0 Sale of common stock 2004-06-07 2004-06-07 4 S 0 25000 21.8463 D 4560207 D Sale of common stock 2004-06-07 2004-06-07 4 S 0 275000 21.0767 D 4285207 D Purchase common stock through employee stock purchase plan 2004-06-01 2004-06-09 4 P 0 107 18.6448 A 4285314 D Sale of common stock 2004-06-07 2004-06-07 4 S 0 25000 21.8463 D 275000 D Sale of common stock 2004-06-07 2004-06-07 4 S 0 275000 21.0767 D 0 D Date notified. from Pamela & Charles Hsiao Charitable Remainder Unitrust (common stock includes 500,370 shares of common stock held in trust for the benefit of J. Hsiao's children and 250,185 shares of common stock held in trust for the benefit of R. Hsiao's children.) Charles Hsiao 2004-06-09