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                                                                    EXHIBIT 10.7

                          FIRST SUPPLEMENTAL INDENTURE

      This FIRST SUPPLEMENTAL INDENTURE (this "First Supplemental Indenture"),
dated as of June 29, 2004, is entered into by and between Viskase Companies,
Inc., a Delaware corporation (the "Company"), and Wells Fargo Bank N.A.
(successor by merger to Wells Fargo Bank Minnesota, N.A.), as trustee (the
"Trustee"). Capitalized terms used but not otherwise defined herein shall have
the meaning given to such terms in the Indenture.

                              W I T N E S S E T H:

      WHEREAS, the Company and the Trustee are parties to that certain
Indenture, dated as of April 3, 2003 (the "Indenture"), relating to the
Company's 8% Senior Subordinated Secured Notes due 2008 (the "2008 Notes").

      WHEREAS, Section 8.02 of the Indenture provides that the Company, when
authorized by a resolution of its Board of Directors, and the Trustee may, with
the written consent of the holders of at least a majority in aggregate principal
amount of the 2008 Notes outstanding, amend or supplement the Indenture, subject
to certain exceptions;

      WHEREAS, Section 11.03(g)(i) of the Indenture provides that the Company,
when authorized by a resolution of its Board of Directors, may request the
release of all of the Collateral from the Liens of the Security Agreement or any
other Liens created under the Indenture or related documents, with the written
consent of the holders of 66 2/3% in aggregate principal amount of the 2008
Notes outstanding;

      WHEREAS, Section 8.02(7) of the Indenture provides that the Company, when
authorized by a resolution of its Board of Directors, and the Trustee may, with
the written consent of the holders of 66 2/3% in aggregate principal amount of
the 2008 Notes outstanding, amend or waive the provisions of clause (g)(i) of
Section 11.03 of the Indenture;

      WHEREAS, the Company has solicited and obtained consents from holders of
approximately 79% of the outstanding 2008 Notes (the "Consents") with respect to
certain amendments to the Indenture and the release of all Collateral under the
Indenture and the Security Agreement (the "Proposed Amendments") pursuant to the
terms and conditions of eleven certain letter agreements (the "Letter
Agreements") (copies of which have been delivered to the Trustee) and as
contemplated hereby;

      WHEREAS, each Letter Agreement provides that the respective Consent to the
Proposed Amendments becomes operative upon payment by the Company of an amount
sufficient to pay the purchase price for the subject 2008 Notes; and

      WHEREAS, the Company has been authorized by a resolution of its Board of
Directors to enter into this First Supplemental Indenture and implement the
Proposed Amendments.

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      NOW, THEREFORE, in consideration of the premises and the mutual agreements
contained herein and for other good and valuable consideration, the receipt and
adequacy of which are hereby acknowledged, the parties hereto agree as follows
for the benefit of each other party and for the equal and ratable benefit of the
Holders of the 2008 Notes, the Company and the Trustee hereby agree as follows:

                                    ARTICLE 1

                                   AMENDMENTS

      Section 1.01. Amendments to Covenants. Upon delivery of a notice in the
form of Exhibit A hereto (the "Notice") by the Company to the Trustee that all
the Consents are operative (the "Notification Time"), the Indenture shall
thereupon automatically be amended as set forth below. The Notice may be
delivered via facsimile or email. Upon the Notification Time, the Indenture
shall automatically be amended to delete the following Articles and Sections in
their entirety (unless otherwise noted) and any and all references to such
Articles and Sections and any and all obligations thereunder shall be deleted
throughout the Indenture, and such references, Articles and Sections shall
thereafter be of no further force or effect:

      (a)   Section 3.03;

      (b)   Section 3.04;

      (c)   Section 3.05;

      (d)   Section 3.06;

      (e)   The first and third paragraphs of Section 3.07;

      (f)   Section 4.01; and

      (g)   Article 11.

      Section 1.02. Amendments to Events of Default. Upon the Notification Time,
the Indenture shall thereupon automatically be amended to delete the following
Sections in their entirety and any and all references to such Sections and any
and all obligations thereunder shall be deleted throughout the Indenture, and
such references and Sections shall thereafter be of no further force or effect:

      (a)   Section 5.01(a) (3);

      (b)   Section 5.01(a) (4);

      (c)   Section 5.01(a) (7); and

      (d)   Section 5.01(a) (8).

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      Section 1.03. Release of all Liens on the Collateral. Upon the
Notification Time, the Indenture shall thereupon automatically be amended to
release the Collateral from the Liens of the Security Agreement and any other
Liens created under the Indenture and any related documents, including, without
limitation, termination of the Security Agreement and release of the Company
from all obligations thereunder. Exhibit B, the Security Agreement, shall be
deleted in its entirety.

      Section 1.04. Definition of Senior Debt. Upon the Notification Time, the
term "Senior Debt" as defined in the Indenture shall be amended to be defined as
follows:

      "Senior Debt" means all present and future Obligations of the Company for
borrowed money or evidenced by notes, debentures, bonds or other similar
instruments and Obligations of the Company under and in connection with one or
more working capital loan facilities now or hereafter in existence, including
without limitation principal, interest (including without limitation interest
accruing after the commencement of a case under the Bankruptcy Code, regardless
of whether such interest is paid), fees, costs and expenses (including without
limitation fees, costs and expenses incurred in enforcing the rights of the
holders thereof) and all other amounts payable in connection therewith, so long
as such indebtedness does not explicitly provide that it is on a parity with or
subordinated in right of payment to the Subordinated Debt, and any refinancing,
refunding, renewal, replacement or recreation thereof.

      Section 1.05 Default on Senior Debt. Upon the Notification Time, Section
10.03(a) of the Indenture shall be amended as follows:

      "The Company may not directly or indirectly make any payment or
distribution to the Trustee or any Holder in respect of any Obligations with
respect to the Subordinated Debt and may not directly or indirectly acquire from
the Trustee or any Holder any Subordinated Debt for cash or property (other than
(A) Permitted Junior Securities and (B) payments and other distributions made
from any discharge of this Indenture pursuant to Article 7 hereof) until all
Principal and other Obligations with respect to, and included in, the Senior
Debt have been paid in full in cash or cash equivalents if:

            (i)  any default with respect to the Senior Debt (including any
      default in the payment of any principal or other Obligations with respect
      to, and included in, Senior Debt) occurs and is continuing;

            (ii) a default, other than a payment default, on Senior Debts occurs
      and is continuing that then permits holders of the Senior Debt to
      accelerate its maturity and the Trustee receives a notice of the default
      (a "Payment Blockage Notice") from a Person who may give it pursuant to
      Section 10.11 hereof. If the Trustee receives any such Payment Blockage
      Notice, no subsequent Payment Blockage Notice shall be effective for
      purposes of this Section unless and until at least 360 days shall have
      elapsed since the first date upon which the immediately prior Payment
      Blockage Notice was effective. No nonpayment default that existed or was
      continuing on the date of delivery of any Payment Blockage Notice to the

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      Trustee shall be, or be made, the basis for a subsequent Payment Blockage
      Notice unless such default shall have been waived for a period of not less
      than 60 days."

      Section 1.06 Removal of Certain Definitions. Upon the Notification Time,
the following defined terms shall be deleted in their entirety and any and all
references to such defined terms shall be deleted throughout the Indenture:

            i.    Lien;

            ii.   Offer to Purchase (Section 11.03);

            iii.  Purchase Amount (Section 11.03); and

            iv.   Security Agreement (Exhibit B).

                                    ARTICLE 2

                          EFFECTIVENESS; OPERATIVENESS

      This First Supplemental Indenture will become operative upon but only upon
the Notification Time. Upon the Notification Time, the Indenture shall be
modified and amended in accordance with this First Supplemental Indenture, and
all the terms and conditions of both shall be read together as though they
constitute one instrument, except that, in case of conflict, the provisions of
this First Supplemental Indenture will control. The Indenture, as modified and
amended by this First Supplemental Indenture, is hereby ratified and confirmed
in all respects and shall bind every holder of 2008 Notes. In case of conflict
between the terms and conditions contained in the 2008 Notes and those contained
in the Indenture, as modified and amended by this First Supplemental Indenture,
the provisions of the Indenture, as modified and amended by this First
Supplemental Indenture, shall control.

                                    ARTICLE 3

                      CONFLICT WITH THE TRUST INDENTURE ACT

      If any provision of this First Supplemental Indenture limits, qualifies or
conflicts with any provision of the Trust Indenture Act of 1939 (the "TIA") that
is required under the TIA to be part of and govern any provision of this First
Supplemental Indenture, the provision of the TIA shall control. If any provision
of this First Supplemental Indenture modifies or excludes any provision of the
TIA that may be so modified or excluded, the provision of the TIA shall be
deemed to apply to the Indenture as so modified or to be excluded by this First
Supplemental Indenture.

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                                    ARTICLE 4

                                  SEVERABILITY

      In case any provision in this First Supplemental Indenture shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

                                    ARTICLE 5

                                    HEADINGS

      The Article and Section headings of this First Supplemental Indenture have
been inserted for convenience of reference only, are not to be considered a part
of this First Supplemental Indenture and shall in no way modify or restrict any
of the terms or provisions hereof.

                                    ARTICLE 6

                 BENEFITS UNDER THE FIRST SUPPLEMENTAL INDENTURE

      Nothing in this First Supplemental Indenture or the 2008 Notes, express or
implied, shall give to any Person, other than the parties hereto and thereto and
their successors hereunder and thereunder and the holders of the 2008 Notes, any
benefit of any legal or equitable right, remedy or claim under the Indenture,
this First Supplemental Indenture or the 2008 Notes.

                                    ARTICLE 7

                                   SUCCESSORS

      All agreements of the Company and the Trustee in this First Supplemental
Indenture shall bind their respective successors.

                                    ARTICLE 8

                                   THE TRUSTEE

      The Trustee shall not be responsible in any manner whatsoever for or in
respect of the validity or sufficiency of this First Supplemental Indenture or
for or in respect of the recitals contained herein, all of which are made solely
by the Company.

                                    ARTICLE 9

               CERTAIN DUTIES AND RESPONSIBILITIES OF THE TRUSTEE

      In entering into this First Supplemental Indenture, the Trustee shall be
entitled to the benefit of every provision of the Indenture relating to the
conduct or affecting the

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liability or affording protection to the Trustee, whether or not elsewhere
herein so provided.

                                   ARTICLE 10

                                  GOVERNING LAW

      THIS FIRST SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK AS APPLIED TO CONTRACTS MADE
AND PERFORMED WITHIN THE STATE OF NEW YORK, WITHOUT REGARD TO PRINCIPLES OF
CONFLICTS OF LAW. Each of the parties hereto agrees to submit to the
jurisdiction of the courts of the State of New York in any action or proceeding
arising out of or relating to this First Supplemental Indenture.

                                   ARTICLE 11

                              COUNTERPART ORIGINALS

      The parties may sign any number of copies of this First Supplemental
Indenture. Each signed copy shall be an original, but all of them together
represent one and the same agreement.

                                     * * * *

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      IN WITNESS WHEREOF, the parties hereto have caused this First Supplemental
Indenture to be duly executed, all as of the date first above written.

                             VISKASE COMPANIES, INC.

                                 /s/ Gordon S. Donovan
                             ---------------------------------------------------

                             Name: Gordon S. Donovan

                             Title: Vice President and Chief Financial Officer

WELLS FARGO BANK, N.A., as Trustee.

   /s/ Jane Y. Schweiger
-----------------------------

Name: Jane Y. Schweiger

Title: Vice President

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