Exhibit 99.1

[GRAPHIC OMITTED] IMPAX
                  LABORATORIES, INC.


Company Contacts:                       Investor Relations Contacts:
IMPAX Laboratories, Inc.                Lippert/Heilshorn & Associates, Inc.
- ------------------------                ------------------------------------
Barry R. Edwards, Co-CEO                Kim Sutton Golodetz (kgolodetz@lhai.com)
(215) 289-2220 Ext. 1771                (212) 838-3777
Larry Hsu, Ph.D. President              Bruce Voss (bvoss@lhai.com)
(510) 476-2000 Ext. 1111                (310) 691-7100
Cornel C. Spiegler, CFO                 www.lhai.com
(215) 289-2220 Ext. 1706                ------------
www.impaxlabs.com
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FINAL
12/30/03


              IMPAX COMMENTS ON SHIRE'S LAWSUIT RELATED TO GENERIC
                             VERSION OF ADDERALL XR


HAYWARD, Calif. (December 30, 2003) - IMPAX Laboratories, Inc. (NASDAQ NM: IPXL)
today announced that Shire Laboratories Inc., a subsidiary of Shire
Pharmaceuticals Group plc (Nasdaq: SHPGY; TSX: SHQ; LSE: SHP), has filed a
lawsuit against the Company in the United States District Court for the district
of Delaware alleging patent infringement related to IMPAX's filing of an
Abbreviated New Drug Application (ANDA) for a generic version of Adderall
XR(R)30mg Capsules.

Adderall XR is a once daily, extended-release, mixed salts of a single-entity
amphetamine product used for the treatment of Attention Deficit and
Hyperactivity Disorder (ADHD). According to NDCHealth, U.S. sales of Adderall XR
Capsules were approximately $550 million in the twelve months ended October 31,
2003.

The U.S. Food and Drug Administration (FDA) accepted for review IMPAX's
application to market a generic version of Shire's Adderall XR 30 mg capsules in
September 2003. IMPAX's submission included a Paragraph IV certification stating
the Company believes its product does not infringe upon Shire's listed patents.

Barry R. Edwards, Co-Chief Executive Officer of IMPAX Laboratories, commented,
"This type of lawsuit has become standard practice in the industry and we are
not surprised that Shire filed this action. It is a routine part of the process
we need to go through in getting these complex generic products to market. We
believe our product as formulated does not infringe upon Shire's patents and
will provide a safe, effective and affordable alternative in the marketplace. We
will proceed accordingly to defend our application."

IMPAX currently has 20 applications pending at the FDA, including four
tentatively approved, which address approximately $7.1 billion in U.S. branded
product sales for the 12 months ended October 31, 2003. Fifteen of these filings
were made under Paragraph IV of the Hatch-Waxman Amendments.



IMPAX Laboratories, Inc. is a technology based specialty pharmaceutical company
applying its formulation expertise and drug delivery technology to the
development of controlled-release and specialty generics in addition to the
development of branded products. IMPAX markets its generic products through its
Global Pharmaceuticals division and intends to market its branded products
through the IMPAX Pharmaceuticals division. Additionally, where strategically
appropriate, IMPAX has developed marketing partnerships to fully leverage its
technology platform. IMPAX Laboratories is headquartered in Hayward, California,
and has a full range of capabilities in its Hayward and Philadelphia facilities.
For more information, please visit the Company's Web site at: www.impaxlabs.com.

"Safe Harbor" statement under the Private Securities Litigation Reform Act of
1995:
To the extent any statements made in this news release contain information that
is not historical; these statements are forward-looking in nature and express
the beliefs and expectations of management. Such statements are based on current
expectations and involve a number of known and unknown risks and uncertainties
that could cause Impax's future results, performance or achievements to differ
significantly from the results, performance or achievements expressed or implied
by such forward-looking statements. Such risks and uncertainties include, but
are not limited to, Impax's ability to obtain sufficient capital to fund its
operations, the difficulty of predicting FDA filings and approvals, consumer
acceptance and demand for new pharmaceutical products, the impact of competitive
products and pricing, Impax's ability to successfully develop and commercialize
pharmaceutical products, Impax's reliance on key strategic alliances, the
uncertainty of patent litigation, the availability of raw materials, the
regulatory environment, dependence on patent and other protection for innovative
products, exposure to product liability claims, fluctuations in operating
results and other risks detailed from time to time in Impax's filings with the
Securities and Exchange Commission. Forward-looking statements speak only as to
the date on which they are made, and Impax undertakes no obligation to update
publicly or revise any forward-looking statement, regardless of whether new
information becomes available, future developments occur or otherwise.
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