Exhibit 99.1
                                                                    ------------



                                  Procept, Inc.
                               840 Memorial Drive
                         Cambridge, Massachusetts 02139


                                  CONFIDENTIAL
                                  ------------

                                November 2, 1998


Dr. H. Laurence Shaw
President and Chief Executive Officer
Pacific Pharmaceuticals, Inc.
6730 Mesa Ridge Road, Suite A
San Diego, CA  92121

         Re:  Letter of Intent
              ----------------

Dear Dr. Shaw:

         This letter is intended to confirm recent discussions between Procept,
Inc., a Delaware corporation ("Procept"), and Pacific Pharmaceuticals, Inc., a
Delaware corporation ("Pacific") regarding the terms which will form the basis
for our efforts to reach a definitive agreement regarding the proposed merger of
Pacific and Procept (the "Merger"). It is expressly agreed that, with the
limited exceptions of Sections 2 and 4, which shall be legally binding, this
letter does not constitute a firm proposal, offer or enforceable agreement to
consummate the Merger, is not legally binding on either of the parties and
imposes no duty or obligation on either of them to proceed with the proposed
transaction. In the event that a definitive agreement to consummate the Merger
is not signed by November 19, 1998, the binding provisions of Sections 2.1 shall
terminate, and the parties shall have no further obligations except as stated in
Sections 2.2 and 4.

         1. Preparation of Definitive Agreement. Counsel for Procept and for
Pacific will prepare a definitive agreement for submission to and approval by
the boards of directors and stockholders of each of Procept and Pacific and
Procept will thereby succeed to and acquire the business of Pacific (the
"Business"). Procept and Pacific acknowledge agreement in principle to the
following terms and conditions of the transaction:

                 1.1 Proposed Merger. For the consideration set forth below,
Pacific will merge with and into Procept. All of the outstanding capital stock,
options, warrants and other rights to acquire an interest in the capital
structure of Pacific will convert into the aggregate securities specified in
Section 1.2 below.

                 1.2 Consideration. On the date of the closing of the
transaction (the "Closing Date"), Procept shall deliver:

                           (a) to the Pacific stockholders 2,755,000 shares of
Procept Common Stock (of which the 1,287,647 shares of Procept Common Stock that
will be issued in the Merger to the holders of Pacific Preferred Stock shall be
accompanied by certain contractual rights identical to contractual rights held
by purchasers in Procept's 1998 private placement); and

<PAGE>


                           (b) to the holders of outstanding options and
warrants to purchase Pacific stock, options and warrants to purchase Procept
Common Stock exercisable for that number of shares of Procept Common Stock which
such option or warrant holder would have been entitled to receive if the
underlying Pacific shares had converted in the Merger, at an exercise price per
share equal to the aggregate exercise price of the Pacific option or warrant
exchanged divided by the number of shares of Procept Common Stock subject to the
new option or warrant, and otherwise having the same terms and conditions as the
Pacific option or warrant.

                 1.3 Certain Assumed Rights and Obligations. Each of Procept and
Pacific acknowledges that by virtue of the Merger, Procept will acquire the
equity interest of Pacific in BGDC and will be subject to the obligations of
Pacific to the other stockholders of BGDC.

                 1.4 Stockholder Approval; Fairness Opinions. Each of Procept
and Pacific will promptly seek stockholder approval of the Merger after the
execution of the definitive merger agreement. Prior to the solicitation of
proxies or consents from stockholders (or the mailing of an information
statement in lieu thereof), each of Procept and Pacific will obtain fairness
opinions from a reputable investment banking firm with respect to the Merger,
copies of which shall be provided to the stockholders of each company.

                 1.5 Form of Transaction, Tax and Accounting Treatment. The
final form of the transaction will be determined by Procept and Pacific after
consultation with their legal, tax and accounting advisors. It is currently
contemplated that the transaction will be tax-free to Procept, Pacific and their
respective stockholders. Procept anticipates the transaction will be recorded
using "purchase accounting."

                 1.6 Employment and Consulting Agreements. Certain Pacific
employees may enter into employment agreements or consulting and confidentiality
agreements. Prior to the execution of a definitive agreement, the parties shall
identify each such person by name and title and determine his or her term of
employment or consultation and compensation. Prior to the Closing Date, all of
such agreements will be completed and signed by all parties.

                 1.7 Registration of Shares; Restrictions on Resale. The shares
of Procept Common Stock delivered in the Merger will have been registered under
the Securities Act of 1933, as amended (the "Act"), on Form S-4. As a result,
the shares of Procept Common Stock will be freely tradable following the Merger,
subject to the provisions of Rule 145 under the Act.

                 1.8 Timing. It is the intention of the parties to sign the
definitive agreement no later than November 19, 1998.

                 1.9 Representations and Warranties. The definitive agreement
will contain representations and warranties to the extent customary for merger
transactions involving the acquisition of a public company.

                 1.10 Conditions to Closing. As proposed to be structured, the
signing of the definitive agreement is conditioned on the approval of the
transaction by the Boards of Directors of Procept and Pacific. The consummation
of the transactions to be set forth in the definitive agreement shall be subject
to the following additional terms and conditions:


                                       2
<PAGE>


                                  1.10.1 Each of Procept and Pacific shall have
                 received satisfactory responses to its requests for information
                 from the other party and each of the parties shall have
                 completed its customary due diligence review to its
                 satisfaction, including review of the financial results of the
                 Business of Procept and Pacific for the last five years.

                                  1.10.2 Pacific and Procept shall each have
                 received approval of their respective stockholders and all
                 other approvals, clearances and consents from any governmental
                 entities and other third parties necessary or desirable for the
                 consummation of the Merger and the Pacific shares shall be free
                 and clear of any lien or encumbrances. 

                                  1.10.3 Procept or its independent public
                 accountants shall have (i) completed a review of the revenues
                 and expenses of the Business; (ii) confirmed to Procept's
                 satisfaction that Pacific's financial statements fairly present
                 in all material respects the results of operations and cash
                 flows resulting from the Business in conformity with generally
                 accepted accounting principles; and (iii) confirmed to
                 Procept's satisfaction that Pacific's financial records are
                 adequate to permit Procept to fulfill its SEC financial
                 reporting obligations in connection with the exchange and in
                 connection with Procept's future registered financings without
                 unreasonable effort or expense.

                                  1.10.4 To the extent necessary, each holder of
                 an outstanding Pacific option or warrant shall consent to the
                 exchange of such option or warrant for an option or warrant
                 exercisable for Procept Common Stock, as contemplated by
                 Section 1.2(b) above.

                                  1.10.5 Pacific shall have exercised the option
                 agreement between BTI and Pacific and issued Pacific Common
                 Stock upon exercise thereof.

                                  1.10.6 Such other closing conditions as are
                 customary in a transaction of this type.

                 1.11 Expenses. The definitive agreement will contain provisions
whereby Procept and Pacific shall each bear their own costs if the transaction
is not consummated. If the transaction is consummated, Procept will discharge
expenses of both parties.

         2. Agreement not to Entertain other Offers. In consideration of the
efforts and expenses undertaken by both parties in pursuing the contemplated
Merger and other valuable consideration, the receipt and adequacy of which are
acknowledged, the parties agree as follows:

                 2.1 Until November 19, 1998 (or such earlier time as Procept
and Pacific agree to abandon the transactions contemplated by this Letter),
neither Pacific nor Procept nor any of their respective authorized
representatives may:


                                       3
<PAGE>


                 (i) directly or indirectly, solicit any proposal relating to
the acquisition by another party of all or any portion of the capital stock of
such company or substantially all of the assets of such company (whether by
merger or otherwise);

                 (ii) directly or indirectly, engage in any discussions or
negotiations with any other party regarding any such acquisition, or otherwise
encourage or facilitate any efforts by any other party to engage in such an
acquisition; or

                 (iii) sell, transfer or dispose of all or any portion of the
capital stock of such company or substantially all of the assets of such company
(whether by merger or otherwise);

provided however, that nothing in the foregoing shall restrict either company
from engaging in discussions with potential collaborative partners, subject to
such company disclosing to the other the identity of the party involved in such
discussions and the general nature thereof; and provided further that,
notwithstanding the foregoing, each such company and its authorized
representatives may participate in discussions or negotiations with, provide
information to, and consummate a transaction with, a third party which would
otherwise be prohibited by this section, if (A) such discussions or negotiations
had been commenced prior to the date hereof or if commenced after the date
hereof, were not solicited by or on behalf of such company and (B) such
discussions or negotiations were being continued or initiated after consultation
with and based upon written advice of independent legal counsel which determined
in good faith that such action is necessary for the Board of Directors of the
involved company to comply with its fiduciary duties to its stockholders under
applicable law.

                 2.2 In the event that during the period between the date hereof
and November 19, 1998, either Pacific or Procept breaches its obligations under
Section 2.1 or engages in discussions or negotiations with, provides information
to, or consummates a transaction with a third party, which activity would have
been a breach of Section 2.1 but for the second proviso of such section, then,
unless a definitive agreement relating to the Merger is subsequently executed by
the parties hereto, on the earlier of (i) the consummation of any such
transaction with a third party or (ii) December 31, 1998, such company shall pay
the other a termination fee in the amount of $50,000, in immediately available
funds to an account designated by the recipient party. The parties acknowledge
and agree that the provisions for payment of such a termination fee are included
herein in order to induce each party to enter into this agreement and to
reimburse the non-terminating party for incurring the costs and expenses related
to the contemplated Merger. No more than one termination fee shall be paid by
any party hereunder. The parties hereto agree that any termination fee that is
paid or due hereunder shall be deemed to be liquidated damages designed to
reasonably compensate the recipient party for the loss incurred by the
terminating party's actions.

                 2.3 Any definitive agreement between the parties regarding the
Merger shall include a provision parallel to Sections 2.1 and 2.2 hereof,
provided that (i) the obligations of Section 2.1 shall continue until the
earlier of the closing of the Merger or the termination of such definitive
agreement, and (ii) the termination fee shall be in the amount of $150,000 and
shall be payable in the event of a breach by a party of the definitive Merger
agreement or a 


                                       4
<PAGE>


recommendation by the Board of Directors of a party that such company's
stockholders approve or accept a transaction with a third party of the type
described in clause (iii) of Section 2.1.

         3. Investigation of Business and Operations of Pacific. Pending the
preparation, execution and delivery of the definitive agreement and continuing
until the Closing Date or termination of this Letter of Intent (i) Pacific will
cause officers and representatives of Pacific (including without limitation
Pacific's firm of independent certified public accountants) to furnish access to
such books and records of Pacific during normal business hours as Procept, its
representatives or agents, may reasonably request in connection with its review
and investigation of the business and operations, assets and liabilities of
Pacific and the market potential for the Business, and (ii) Procept will cause
its officers and representatives (including without limitation, Procept's firm
of independent certified public accountants) to furnish access to such books and
records of Procept during normal business hours as Pacific, its representatives
or agents, may reasonably request in connection with the review and
investigation by it or the Stockholders of the business and operations, assets
and liabilities of Procept.

         4. Confidentiality. As provided in the Confidentiality Agreement
between the parties, the existence and the terms of this Letter of Intent and
the transactions contemplated herein shall be maintained in confidence by the
parties hereto. Except to the extent required by law, all public announcements,
notices or other communications regarding such matters to third parties shall
require the prior approval of Procept and Pacific.

         5. General. This Letter of Intent is executed and shall be governed by,
and construed and enforced (to the extent the Sections are stated herein to be
enforceable) in accordance with, the laws of The Commonwealth of Massachusetts.

         If you determine that the foregoing is satisfactory in principle, we
would appreciate acknowledgment of that determination by the execution and
delivery to us of the enclosed copy of this letter.

         We look forward to your favorable consideration of this letter.

                                          Very truly yours,

                                          PROCEPT, INC.


                                          /s/ John F. Dee
                                          -------------------------------------
                                          John F. Dee
                                          President and Chief Executive Officer



                                       5
<PAGE>



      The foregoing is agreed to and accepted as of the date first set forth
above.


                                          PACIFIC PHARMACEUTICALS, INC.



                                          /s/ H. Laurence Shaw
                                          -------------------------------------
                                          Dr. H. Laurence Shaw
                                          President and Chief Executive Officer




                                       6