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                                                                  EXHIBIT 10.164

                   PRE-CLOSING BUSINESS ARRANGEMENT AGREEMENT
                   ------------------------------------------

         PRE-CLOSING BUSINESS ARRANGEMENT AGREEMENT (this "Agreement"), dated as
of May 6, 2002, by and among CERTIS U.S.A., L.L.C., a Delaware limited liability
company (the "Buyer"), ECOGEN INC., a Delaware corporation ("Ecogen"),
ECOGEN-BIO INC., a Delaware corporation ("Ecogen-Bio") and ECOGEN TECHNOLOGIES I
INCORPORATED, a Delaware corporation ("Ecogen-Tech" and collectively with Ecogen
and Ecogen-Bio, the "Sellers" and individually, a "Seller"). Capitalized terms
used herein and not otherwise defined shall have the meanings ascribed to such
terms in the Ecogen Asset Purchase Agreement dated May 6, 2002 by and among
Buyer and the Sellers (the "Asset Purchase Agreement").

                              W I T N E S S E T H :
                              - - - - - - - - - -

         WHEREAS, pursuant to the Asset Purchase Agreement the Buyer will
purchase from the Sellers, and the Sellers will sell to the Buyer certain assets
related to Bacillus thuringiensis ("Bt") bioinsecticides and insecticidal
nematodes Products (excluding Bt insecticide products known as CellCap(TM)
products), including those Products listed in Schedule A thereto (collectively,
the "Products");

         WHEREAS, the parties desire to provide for an orderly transfer of the
Purchased Assets and to maintain a market presence for the Products;

         WHEREAS, the Sellers desire to license to the Buyer, and the Buyer
desires to obtain a license, to manufacture, have manufactured, distribute,
market and sell each of the Products;

         NOW, THEREFORE, in consideration of the mutual representations and
warranties and covenants made herein, the Buyer and the Sellers, each intending
to be legally bound, hereby agree as follows:

                                    ARTICLE I

                          GRANT OF LICENSE; COMMISSION
                          ----------------------------

         Section 1.01 Grant of License. Upon execution of the Asset Purchase
Agreement and subject to the other provisions of this Agreement, the Sellers
shall grant the Buyer an exclusive (including with regard to the Sellers),
royalty-free, world-wide license, under the Sellers' right, title, and interest
in and to the Purchased Assets to manufacture, have manufactured, market,
distribute, sell each of the Products, provided, however such license shall be
subject to any rights previously granted by Ecogen under the Intrachem License
Agreement between Ecogen and Intrachem Bio (International) SA dated October 15,
2001.

         Section 1.02 Commission. In consideration of the rights granted herein
and subject to the terms and conditions set forth in this Agreement, the Buyer
shall pay the Sellers a commission equal to 10% of gross sales of Product sold
by the Buyer or its Affiliates from the date hereof until Closing.

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         Section 1.03 Payment of Commission. The Buyer shall pay to the Sellers
any commission due hereunder within five (5) days of the end of each month and
final payment shall be made at the Closing Date or as soon as practicable
thereafter. Such payment shall be accompanied by a statement showing (i) gross
sales for such month and (ii) the amount of the commission payable in respect of
such gross sales.

                                   ARTICLE II

                                    INVENTORY
                                    ---------

         Section 2.01 Inventory. From time to time, beginning from the date
hereof until the earlier of the termination of the license pursuant to Section
3.01 or the Closing of the Asset Purchase Agreement, the Sellers shall sell and
the Buyer shall purchase any or all of the Inventory for use in the manufacture
of the Products or for sale to third parties.

         Section 2.02 Payment. The Buyer shall pay to the Sellers the
corresponding value of such Inventory set forth in the Schedule 1.01(a)(i) of
the Asset Purchase Agreement within five (5) Business Days after purchasing such
Inventory and final payment shall be made at the Closing Date or as soon as
practicable thereafter. Payments by the Buyer for purchases of Inventory
hereunder shall result in a corresponding deduction in the amount of the
Purchase Price payable by Buyer at the Closing pursuant to Section 1.04(a) of
the Asset Purchase Agreement.

                                   ARTICLE III

                              TERM AND TERMINATION
                              --------------------

         Section 3.01 Term of License. The term of the license granted hereunder
shall commence upon the execution of the Asset Purchase Agreement and, unless
terminated earlier pursuant hereto, shall expire upon the Closing Date at which
time the Buyer shall be the owner of the licensed rights and any remaining
Inventory.

         Section 3.02 Termination Prior to Closing. In the event the Asset
Purchase Agreement is terminated prior to Closing of the Asset Purchase
Agreement, the exclusive license granted by the Sellers to Buyer hereunder shall
terminate and the Buyer shall immediately cease manufacture of the Products,
provided all unfinished Products may be completed and packaged. Thereafter the
Buyer shall have a six (6) month period from such termination to sell-off any
remaining Products and Inventory in the Buyer's possession. The Buyer's payment
of any commission during the such six (6) month sell-off period shall be made in
accordance with Section 1.03 hereof.

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                                   ARTICLE IV

                                  MISCELLANEOUS
                                  -------------

         Section 4.01 Notices. All notices, requests, claims, demands and other
communications required or permitted to be given under this Agreement shall be
in writing and shall be delivered by hand or sent by confirmed facsimile (with
the original to follow by first class mail, postage prepaid) or sent, postage
prepaid, by registered or certified mail or internationally recognized overnight
courier service and shall be deemed given when so delivered by hand, facsimile,
mail or overnight courier service at the following addresses (or at such other
address for a party as shall be specified by like notice):

                 (a)      if to the Buyer, to

                       Certis USA
                       9145 Guilford Road
                       Suite 175
                       Columbia, MD 21046
                       Attention: President
                       Telecopy: (301) 604-7015

                       with a copy to:

                       Pillsbury Winthrop LLP
                       One Battery Park Plaza
                       New York, NY 10004
                       Attention: Donald G. Kilpatrick
                       Telecopy: (212) 858-1500

                 (b)      if to the Sellers, to

                       Ecogen Inc.
                       2000 West Cabot Blvd. #170
                       Langhorne, PA 19047-1811
                       Attention: James P. Reilly, Jr.
                       President and Chief Executive Officer
                       Telecopy: (215) 757-3339

                       with a copy to:

                       Blank Rome Comisky and McCauley LLP
                       The Chrysler Building, 405 Lexington Avenue
                       New York, NY 10174
                       Attention: Emanuel J. Adler
                       Telecopy: (212) 885-5001

         Section 4.02 Severability. If any term or other provision of this
Agreement is invalid, illegal or incapable of being enforced by any Applicable
Law, or public policy, all other

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conditions and provisions of this Agreement shall nevertheless remain in full
force and effect. Upon such determination that any term or other provision is
invalid, illegal or incapable of being enforced, such term or other provision
will be interpreted so as to best accomplish the intent of the parties within
the limits of Applicable Law.

         Section 4.03 Counterparts. This Agreement may be executed in one or
more counterparts, all of which shall be considered one and the same agreement
and shall become effective when one or more counterparts have been signed by
each of the parties and delivered to the other parties.

         Section 4.04 No Third-Party Beneficiaries. Nothing in this Agreement,
express or implied, is intended to confer on any Person other than the parties
hereto and their respective permitted successors and assigns, any rights,
remedies, obligations or liabilities under or by reason of this Agreement.

         Section 4.05 Amendments. No modification or amendment of this Agreement
and no waiver of any of the terms or conditions hereof shall be valid or binding
unless made in writing and executed by all of the parties hereto.

         Section 4.06 Assignment; Successors in Interest. (a) Neither this
Agreement nor any of the rights, interests or obligations under this Agreement
shall be assigned, in whole or in part, by operation of law or otherwise by any
of the parties without the prior written consent of the other parties, except
that the Buyer may, in its sole discretion, assign any of or all of its rights,
interests and obligations under this Agreement to any wholly-owned subsidiary of
Mitsui & Co. (U.S.A.), Inc., but no such assignment shall relieve the Buyer of
any of its obligations under this Agreement. Any purported assignment in
violation of this Section 4.06 shall be void. Subject to the preceding
sentences, this Agreement will be binding upon, inure to the benefit of, and be
enforceable by, the parties and their respective successors and assigns.

         (b) In the event that any of the Sellers sells, transfers or leases all
or substantially all of its assets, or is not the surviving corporation in any
merger, consolidation or other business combination in which it may enter with
any Person, such Seller will cause such purchaser or surviving corporation, as
the case may be, to assume such Seller's obligations under this Agreement upon
the consummation of any such transaction, so long as any of such obligations
remain outstanding, unpaid or unperformed.

         Section 4.07 Governing Law. Pursuant to Section 5-1401 of the New York
General Obligations Law, this Agreement shall be governed by, and construed in
accordance with, the laws of the State of New York without giving effect to any
choice or conflict of law provision or rule (whether of the State of New York or
any other jurisdiction) that would cause the application of the laws of any
jurisdiction other than the State of New York.

         Section 4.08 Arbitration. (a) Any dispute, controversy or claim arising
out of or relating to this Agreement that cannot be resolved between the Buyer
and the Sellers shall be resolved in accordance with the procedures specified in
this Section 4.08, which shall constitute the sole and exclusive procedures for
the resolution of such disputes.

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         (b) The Buyer and the Sellers agree to use commercially reasonable
efforts to settle promptly any disputes or claims arising out of or relating to
this Agreement through negotiations conducted in good faith between
representatives of each party having authority to reach such a settlement. All
negotiations pursuant to this Section 4.08 shall be confidential and shall be
treated as compromise and settlement negotiations and shall not be admissible
for any purposes in any subsequent arbitration.

         (c) Any dispute arising out of or relating to this Agreement which has
not been resolved by negotiations as provided in subsection (b) of this Section
4.08, within forty-five (45) days from the date that such negotiations shall
have been first requested by any party hereto, shall be settled by arbitration
before a panel of three (3) independent and impartial arbitrators (the
"Arbitration Panel") in accordance with the then current Commercial Arbitration
Rules of the American Arbitration Association, except to the extent such rules
are inconsistent with this Agreement, in which case the provisions of this
Agreement shall be followed. The Buyer and the Sellers each shall select one (1)
member of the Arbitration Panel, who shall jointly select the third member of
the Arbitration Panel. In no case shall there be any ex parte communications
between any party hereto and any member of the Arbitration Panel regarding any
dispute between the parties. If the Buyer or the Sellers refuses to participate
in good faith in negotiations as provided in subsection (b) of this Section
4.08, the Buyer or the Sellers, as the case may be, may initiate arbitration at
any time after such refusal without waiting for the expiration of the forty-five
(45) day period. Except as provided in subsection (d) of this Section 4.08,
relating to provisional remedies, the Arbitration Panel shall decide all aspects
of any dispute brought to them, including attorney disqualification and the
timeliness of the making of any claim. The Arbitration Panel shall have the
discretion to order a pre-hearing exchange of information by the parties,
including the production of requested documents, the exchange of testimony of
proposed witnesses, and the examination by deposition of parties. The
Arbitration Panel shall not have the authority to make any ruling, finding or
award that does not conform to the terms and conditions of this Agreement.

         (d) The Buyer or the Sellers may, without prejudice to any negotiation
or arbitration procedures, proceed to any court of competent jurisdiction to
obtain provisional judicial relief if, in the Buyer's or the Sellers'
discretion, as the case may be, such action is necessary to avoid imminent
irreparable harm or to preserve the status quo pending the conclusion of the
dispute procedures specified in this Section 4.08.

         (e) The site of any arbitration brought pursuant to this Agreement
shall be New York, NY, and the language in which the arbitration shall be
conducted, including all writings relating thereto (including the award of the
Arbitration Panel), shall be in English. All discovery activities shall be
completed within sixty (60) days after the initial meeting of the Arbitration
Panel. The award of the Arbitration Panel shall be (i) final and binding upon
the parties, (ii) issued within ninety (90) days after the initial meeting of
the Arbitration Panel, (iii) in writing and (iv) set forth the factual and legal
bases for such award. The Arbitration Panel is to award attorneys' fees and the
cost of the arbitration to the prevailing party. Judgment on the award rendered
by the Arbitration Panel may be entered and enforced in any court having
jurisdiction thereof in accordance with the New York Convention on Arbitration.

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         Section 4.09 Interpretation. (a) (a) Unless the context otherwise
requires, (i) each term defined in this Agreement has the meaning ascribed to
it, (ii) "or" is disjunctive but not necessarily exclusive, (iii) words in the
singular include the plural and vice versa. The headings contained in this
Agreement are for reference purposes only and shall not affect in any way the
meaning or interpretation of this Agreement. Whenever the words "include,"
"includes" or "including" are used in this Agreement, they shall be deemed to be
followed by the words "without limitation."

              (b) In the event of an ambiguity or question of intent or
interpretation, this Agreement shall be construed as if drafted jointly by the
parties and no presumption or burden of proof shall arise favoring or
disfavoring any party by virtue of the extent to which any such party or its
counsel participated in the drafting of any provision hereof or by virtue of the
extent to which any such provision is inconsistent with any prior draft hereof.

              (c) All references to "$" or dollar amounts are to lawful currency
of the United States of America.

              (d) All documents and correspondence relating to this Agreement
shall be in the English language.

         Section 4.10 Waiver. The failure of any of the parties to enforce at
any time any of the provisions of this Agreement shall in no way be construed to
be a waiver of any such provision, nor in any way to affect the validity of this
Agreement or any part hereof or thereof or the right of any party thereafter to
enforce each and every such provision. No waiver of any breach of or
non-compliance with this Agreement shall be held to be a waiver of any other
subsequent breach or non-compliance.

         Section 4.11 Payments. Unless otherwise provided, all payments required
to be made pursuant to this Agreement shall be made in U.S. Dollars in the form
of cash or by wire transfer or immediately available funds to an account
designated by the party receiving such payment.

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     IN WITNESS WHEREOF, the parties hereto have duly executed this Agreement,
all as of the date first written above.

                            ECOGEN INC.




                            By:  /s/ James P. Reilly, Jr.
                                 -----------------------------------------------
                                 James P. Reilly, Jr.
                                 President, Chairman and Chief Executive Officer


                            ECOGEN-BIO, INC.




                            By:  /s/ James P. Reilly, Jr.
                                 -----------------------------------------------
                                 James P. Reilly, Jr.
                                 President, Chairman and Chief Executive Officer


                            ECOGEN TECHNOLOGIES I INC.




                            By:  /s/ James P. Reilly, Jr.
                                 -----------------------------------------------
                                 James P. Reilly, Jr.
                                 President, Chairman and Chief Executive Officer


                            CERTIS U.S.A., L.L.C.




                            By:  /s/ Dennis S. Banasiak
                                 -----------------------------------------------
                                 Dennis S. Banasiak
                                 President and Chief Executive Officer

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