<PAGE>   1
CONTACTS FOR CHIREX:                               CONTACT FOR GLAXO
                                                   WELLCOME MEDIA ENQUIRIES:
IN THE U.S.                                        Martin Sutton
Michael A. Griffith                                Manager
Chief Financial Officer                            Corporate Communications
ChiRex Inc.                                        London
(617) 431-2200                                     011-44-171-493-4060

Marcia A. Kean
Executive Vice President
Feinstein Kean Partners Inc.
(617) 577-8110

IN THE U.K.
Alan R. Clark
Chairman and CEO
ChiRex Inc.
011-44-191-250-0471

FOR IMMEDIATE RELEASE

              CHIREX TO BUY GLAXO WELLCOME PHARMACEUTICAL FACILITY
                               AT ANNAN, SCOTLAND

-- PURCHASE INCLUDES FIVE YEAR CONTRACT VALUED AT UP TO $450 MILLION OVER FIVE
     YEARS TO SUPPLY KEY INTERMEDIATES AND ACTIVE INGREDIENTS --

Wellesley, Massachusetts and Dudley, Northumberland, England, July 7, 1997 --
ChiRex Inc. (Nasdaq: CHRX), a leading pharmaceutical Contract Manufacturing
Organization, and Glaxo Wellcome plc announced today that they have signed a
letter of intent for ChiRex to acquire Glaxo Wellcome's cGMP pharmaceutical
production facility at Annan, Scotland. As part of the proposed agreement, Glaxo
Wellcome will award ChiRex a five year contract of up to $450 million (pound
sterling 270 million), of which $250 million (pound sterling 150 million) is
guaranteed, to supply certain pharmaceutical intermediates and active
ingredients.

"Glaxo Wellcome has more than 15 years of positive experience with the ChiRex
team, and we have found them to be both reliable and dedicated to the highest
quality of product manufacturing," said David Pulman, Ph.D., Director of
International Actives Supply, Glaxo Wellcome. "We view this five year supply
agreement as the continuation of a long-term relationship with an organization
that has an exciting combination of manufacturing expertise and innovative
technologies," Dr. Pulman added.

"This agreement is of major strategic importance to ChiRex," said Alan R. Clark,
Chairman and CEO of ChiRex. "It significantly expands our production capacity,
and ensures a major revenue stream into the next decade. Moreover, it positions
us to produce ingredients for some of the most significant compounds in the
healthcare industry, and to accelerate the commercialization of several of our
proprietary chiral building blocks that are rapidly emerging from the ChiRex
development pipeline.
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                          ChiRex Purchases Glaxo Wellcome Manufacturing Facility
                                                                          Page 2

We are extremely pleased to enhance our long-standing relationship with Glaxo
Wellcome."

The proposed agreement calls for ChiRex to purchase all of the buildings, land
and equipment at the 154-acre Annan, Scotland property, encompassing three main
production buildings, for pound sterling 40 million (approximately $66 million),
plus certain working capital. Under the agreement, ChiRex will continue to
manufacture products currently made at Annan and plans to invest pound
sterling 30 million (approximately $48 million) over five years to accommodate
newly contracted products and to modify the facility for general purpose
manufacturing. ChiRex intends to use senior bank debt as a source of capital for
the facility purchase and modification. The sale is expected to close later this
year, and ChiRex anticipates retaining a substantial majority of the 170
individuals currently employed at the facility.

ChiRex is a Contract Manufacturing Organization serving the outsourcing needs of
the pharmaceutical industry through its extensive pharmaceutical fine chemical
manufacturing and process development capabilities and proprietary technologies.
For fiscal year 1996 ended December 31, 1996, the Company reported total
revenues of $89.8 million, of which $50.1 million represented core revenues. The
Company supports and supplements the in-house development and manufacturing
capabilities of its pharmaceutical and biotechnology customers with a broad
range of fully-integrated services, accelerating the time from drug discovery to
commercialization. ChiRex currently produces 54 products, of which 29 are core
products, in its world-class, cGMP manufacturing facilities located in Dudley,
Northumberland, England. ChiRex holds 54 patents and patent applications in the
field of chiral chemistry.

Glaxo Wellcome is a research-based company committed to fighting disease by
bringing innovative medicines and services to patients throughout the world and
to the healthcare providers who serve them.

This press release contains forward-looking statements regarding the
transaction, which is subject to completion of definitive documentation and
other prerequisites for the debt financing arrangements, the receipt of required
regulatory and other consents and licenses, the definitive agreement between the
parties, and other customary conditions. This release also contains
forward-looking statements regarding the future operation of the facility,
assuming the transaction is completed. These statements involve risks and
uncertainties including, but not limited to, successful transfer of the
facility, the cost and timing of capital improvements, the ability to operate
the facility efficiently, product development and manufacturing risks, changes
in demand for Glaxo Wellcome's products and for ChiRex's products due to
competition or other changes in the market, developments regarding licensing and
intellectual property rights, changes in environmental and other regulations,
and other risks identified in ChiRex's Securities and Exchange Commission
filings. Actual results may differ materially from expected results. ChiRex
undertakes no obligation to publicly release any revisions to these
forward-looking statements to reflect events or circumstances after the date
hereof.

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