Document:

<PAGE>

                                                                    Exhibit 10.5

                              AMENDED SCHEDULE TO
                           INDEMNIFICATION AGREEMENT

The Indemnification Agreements between Sunoco, Inc. and the directors and
executive officers named below are identical in all material respects.

     Officer                                Date of Agreement
     -------                                -----------------

Michael H. R. Dingus                        January 11, 1999
John G. Drosdick                            February 1, 1997
Bruce G. Fischer                            January 11, 1999
Deborah M. Fretz                            February 1, 1996
Thomas W. Hofmann                           February 1, 1996
Joseph P. Krott                             July 1, 1998
Michael S. Kuritzkes                        May 4, 2000
Joel H. Maness                              May 4, 2000
Michael J. McGoldrick                       January 11, 1999
Ann C. Mule                                 February 1, 1996
Paul A. Mulholland                          April 3, 2000
Rolf D. Naku                                January 11, 1999
Robert W. Owens                             February 6, 1997
Charles K. Valutas                          January 11, 1999

     Director                               Date of Agreement
     ----------                             -----------------
Raymond E. Cartledge                        February 1, 1996
Robert J. Darnall                           May 4, 2000
Mary Johnston Evans                         February 1, 1996
Ursula F. Fairbairn                         May 3, 2001
Thomas P. Gerrity                           February 1, 1996
Rosemarie B. Greco                          May 7, 1998
James G. Kaiser                             February 1, 1996
Robert D. Kennedy                           February 1, 1996
Norman S. Matthews                          May 12, 1999
R. Anderson Pew                             February 1, 1996
G. Jackson Ratcliffe                        May 7, 1998
Alexander B. Trowbridge                     February 1, 1996

                                       1<PAGE>

                                                                    Exhibit 10.1

                              BRIDGE LOAN AGREEMENT

         THIS BRIDGE LOAN AGREEMENT ("Agreement") is made and entered into this
26th day of July 2001 and made effective as of May 1, 2001 (the "Effective
Date"), by and among Optical Sensors Incorporated, a Delaware corporation (the
"Company"), with its principal place of business at 7615 Golden Triangle Drive,
Suite A, Eden Prairie, Minnesota 55344, and Circle F Ventures LLC ("Circle F").

         A. The Company currently needs capital to fund its operations until
such time as it is able raise additional equity capital.

         B. Circle F and/or one or more of its affiliates has advanced cash
funds to the Company and may, in its sole discretion, advance additional funds
to the Company on the terms and conditions set forth in this Agreement.

         Accordingly, in consideration of the foregoing, the mutual promises set
forth herein, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto agree as
follows:

1.       Loan Amount.

         (a)      Maximum Amount. On the terms and subject to the conditions
                  hereof, Circle F and/or one or more of its Affiliates (as such
                  term if defined in Rule 12b-2 of the General Rules and
                  Regulations under the Securities Exchange Act of 1934, as
                  amended (the "Exchange Act")) may advance, from time to time
                  in one or more installments, up to an aggregate of $1,500,000
                  to the Company. The parties acknowledge that Circle F or its
                  Affiliates have advanced an aggregate of $669,000 from the
                  Effective Date through and including the date hereof, which
                  such advances shall be subject to this Agreement. The party
                  making such an advance (an "Advance") is hereinafter referred
                  to as the "Investor." Advances may be made by an Investor at
                  such dates and in such amounts as the Company and the Investor
                  may agree.

         (b)      No Minimum Commitment. Notwithstanding any other provision in
                  this Agreement to the contrary, neither Circle F nor its
                  Affiliates shall have any obligation to make any minimum
                  number or amount of Advances to the Company.

2.       Issue of Convertible Promissory Note. Upon the execution of this
         Agreement, the Company agrees to issue, upon the receipt of an Advance,
         a convertible promissory note made payable to the order of Circle F in
         the form attached hereto as Exhibit A in the maximum principal amount
         of $1,500,000. The Note shall not bear interest and shall be due and
         payable in installments, with each installment becoming due one (1)
         year from the date of each Advance (the "Maturity Date") unless
         converted into shares of Common Stock of the Company prior to the
         applicable Maturity Date, and each installment payment being equal to
         the amount of the applicable Advance. After the thirtieth day
<PAGE>

         after a Note is issued, the Company shall have the right to prepay the
         Note, in whole or in part, at any time or from time to time, on ten
         (10) days' prior written notice to the applicable Investor, without
         premium or penalty pursuant to Section 1 of the Note.

3.       Conversion. The Investor shall have the right to convert all or any
         portion of principal balance under the Note, at the option of the
         Investor, into shares of Common Stock of the Company at any time after
         the date hereof, and from time to time after the date hereof. The
         conversion price of the Note shall be equal to $.25 per share;
         provided, however, that the conversion price for the portion of the
         principal amount of the Note, if any, representing Advances made after
         the date hereof and during thirty (30) day period preceding the date on
         which the Company completes a private placement of equity securities (a
         "Financing") shall be equal to the per share price of the securities
         sold in such Financing. Any principal payments made by the Company on
         the Note shall be applied against the Advances in the order in which
         the Advances were made. The shares of Common Stock issuable upon
         conversion of the Note are referred to as the "Conversion Securities."

4.       Representations and Warranties of the Company. The Company represents
         and warrants to Circle F as follows:

         (a)      Organization. The Company is a corporation duly organized,
                  validly existing and in good standing under the laws of the
                  State of Delaware and has the requisite corporate power and
                  authority to own, lease or operate its properties and to carry
                  on its business as it is now being conducted and as it is
                  proposed to be conducted. The Company has no subsidiaries or
                  direct or indirect ownership in any firm, corporation or
                  business which either, individually or in the aggregate, is
                  material to the business of the Company. The Company is
                  qualified to do business and is in good standing as a foreign
                  corporation in every jurisdiction in which its ownership of
                  property or conduct of business requires it so to be qualified
                  and in which the failure to so qualify would have a material
                  adverse effect on the financial condition or business of the
                  Company.

         (b)      Authorization. The Company has the corporate power and
                  authority to execute and deliver this Agreement and to perform
                  its obligations hereunder and thereunder, including the
                  issuance of the Notes and the Conversion Securities. This
                  Agreement has been duly authorized by all necessary corporate
                  action on behalf of the Company, has been duly executed and
                  delivered by authorized officers of the Company, is valid and
                  binding agreement on the part of the Company and is
                  enforceable against the Company in accordance with its terms,
                  except as the enforceability thereof may be limited by
                  bankruptcy, insolvency, moratorium, reorganization or other
                  similar laws affecting the enforcement of creditors rights
                  generally and to judicial limitations on the enforcement of
                  the remedy of specific performance and other equitable
                  remedies. The Notes, when issued pursuant to this Agreement,
                  will be duly authorized and represent valid and binding
                  agreements on the part of the Company enforceable against it
                  in accordance with their terms, except as the enforceability
                  thereof may be limited by bankruptcy, insolvency, moratorium,
                  reorganization or other similar laws

                                       2
<PAGE>

                  affecting the enforcement of creditors rights generally and to
                  judicial limitations on the enforcement of the remedy of
                  specific performance and other equitable remedies. All
                  corporate actions necessary for reservation and issuance of
                  the Conversion Securities has been taken. The Conversion
                  Securities when issued pursuant to conversion of the Notes
                  will be duly authorized, validly issued, fully paid and
                  nonassessable, free and clear of any and all liens, charges,
                  claims, encumbrances and preemptive rights.

         (c)      No Violation. Neither the execution and delivery of this
                  Agreement or any Notes by the Company, nor the performance by
                  the Company of its obligations hereunder or thereunder, nor
                  the consummation of the transactions contemplated hereby or
                  thereby will: (a) conflict with or result in any breach of any
                  provision of the Certificate of Incorporation or By-Laws of
                  the Company; (b) result in a default (or give rise to any
                  right of termination, cancellation or acceleration) under any
                  of the terms, conditions or provisions of any note, lease,
                  mortgage, license, agreement or other instrument or obligation
                  to which the Company is a party or by which any of its assets
                  may be bound, except for such defaults (or rights of
                  termination, cancellation or acceleration) as to which
                  requisite waivers or consents have been obtained or which, in
                  the aggregate, would not result in a material adverse effect
                  on the Company; (c) violate any order, writ, injunction,
                  decree, statute, rule or regulation applicable to the Company
                  or any of its assets, except for violations which would not
                  result in a material adverse effect on the Company; or (d)
                  result in the creation or imposition of any liens, charges or
                  encumbrances upon any assets of the Company.

         (d)      SEC Reports. The Company has filed all reports, registration
                  statements and other filings with the Securities and Exchange
                  Commission (the "Commission") required to be filed by it
                  pursuant to the Securities Act of 1933, as amended (the
                  "Securities Act") and the Exchange Act. All such reports,
                  registration statements and other filings (including all
                  notes, exhibits and schedules thereto, all documents
                  incorporated by reference therein, and any amendments thereto)
                  are collectively referred to herein as the "SEC Reports." As
                  of their respective dates of filing with the Commission, the
                  SEC Reports complied in all material respects with all of the
                  rules and regulations of the Commission and did not contain
                  any untrue statement of a material fact or omit to state a
                  material fact required to be stated therein or necessary in
                  order to make the statements made therein, in light of the
                  circumstances under which they were made, not misleading.

         (e)      Financial Statements. The financial statements of the Company
                  included in the SEC Reports (the "Financial Statements") have
                  been prepared in accordance with United States generally
                  accepted accounting principles consistently applied and fairly
                  present the financial position of the Company at the dates
                  thereof and the results of the Company's operations and cash
                  flows for the periods then ended (subject, in the case of
                  unaudited statements, to normal adjustments and the omission
                  of footnotes). The Company has no material liabilities, known
                  or unknown, absolute, contingent or otherwise, except for (i)
                  liabilities that are set forth in the Financial Statements,
                  the notes thereto or the SEC Reports and (ii)

                                       3
<PAGE>

                  liabilities that have been incurred in the ordinary course of
                  business since the date of the most recent Financial
                  Statements.

         (f)      No Material Adverse Change. There have not been any changes in
                  the assets, properties, liabilities, financial condition,
                  business or operations of the Company from that reflected in
                  the Financial Statements except for (i) changes in the
                  ordinary course of business which have not been, either
                  individually or in the aggregate, materially adverse and (ii)
                  the Company's continued operating losses, negative cash flow
                  and negative stockholders' equity.

         (g)      Authorized Capital Stock. The authorized capital stock of the
                  Company is as set forth in the SEC Reports. The issued and
                  outstanding shares of capital stock of the Company have been
                  duly authorized, validly issued and are fully paid and
                  nonassessable. As of the date hereof, the Company has
                  outstanding options and warrants to purchase 1,824,084 shares
                  of Common Stock, convertible promissory notes in the aggregate
                  principal amount of One Million Six Hundred Fifty Thousand
                  Dollars ($1,650,000) (exclusive of Advances made prior to the
                  date hereof) and warrants to purchase an aggregate of
                  1,050,000 shares of Common Stock that are issuable upon
                  conversion of the foregoing convertible promissory notes.
                  Except as set forth in the preceding sentence, there are no
                  other outstanding warrants, options or other rights to acquire
                  any shares of capital stock of the Company, except for the
                  shares issued upon conversion of the Note and as disclosed in
                  the SEC Reports. All of the above securities of the Company
                  were issued in compliance with all applicable federal and
                  state securities laws and were not issued in violation of or
                  subject to any preemptive rights or other rights to subscribe
                  for or purchase securities. Except for Instrumentation
                  Laboratory Company ("IL"), no holder of any security of the
                  Company is entitled -- to any preemptive or similar rights to
                  purchase any securities of the Company.

         (h)      Intellectual Property. The Company owns or possesses adequate
                  rights to use all patents, patent rights, inventions,
                  trademarks, trade names, copyrights, licenses, domain names,
                  governmental authorizations, trade secrets and know-how that
                  are used or necessary for the conduct of its business; the
                  Company has not received any notice of, and has no knowledge
                  of, any infringement of or conflict with asserted rights of
                  others with respect to any patents, patent rights, inventions,
                  trademarks, trade names, copyrights, licenses, governmental
                  authorizations, trade secret or know-how that, individually or
                  in the aggregate, if the subject of an unfavorable decision,
                  ruling or finding, would have a material adverse effect on the
                  condition (financial or otherwise), earnings, operations or
                  business of the Company and its subsidiaries considered as a
                  whole.

         (i)      Securities Laws. Subject to the accuracy of the
                  representations of Circle F in Section 5, no consent,
                  authorization, approval, permit or order of or filing with any
                  governmental or regulatory authority is required under current
                  laws and regulations in connection with the execution and
                  delivery of this Agreement or the offer, issuance, sale or
                  delivery to the Investors of the Notes or the Conversion
                  Securities other than the filing with the Commission of a Form
                  D pursuant to

                                       4
<PAGE>

                  Regulation D under the Securities Act, and the qualification
                  thereof, if required, under applicable state securities laws,
                  which qualification has been or will be effected as a
                  condition of the sale of the Shares and the issuance of the
                  Conversion Securities. Under the circumstances contemplated by
                  this Agreement, the offer, issuance, sale and delivery of the
                  Note will not, under current laws and regulations, require
                  compliance with the prospectus delivery or registration
                  requirements of the Securities Act.

         (j)      Litigation. There are no actions, suits, proceedings or
                  investigations pending or, to the best of the Company's
                  knowledge, threatened against the Company or any of its
                  properties before or by any court or arbitrator or any
                  governmental body, agency or official in which there is a
                  reasonable likelihood (in the judgment of the Company) of an
                  adverse decision that (a) would have a material adverse effect
                  on the Company's properties or assets or the business of the
                  Company as presently conducted or proposed to be conducted or
                  (b) would impair the ability of the Company to perform in any
                  material respect its obligations under this Agreement. The
                  Company is not in default with respect to any judgment, order
                  or decree of any court or governmental agency or
                  instrumentality which, individually or in the aggregate, would
                  have a material adverse effect on the assets, properties or
                  business of the Company.

         (k)      Properties. The Company has good and marketable title to all
                  the properties and assets reflected as owned in the Financial
                  Statements, subject to no lien, mortgage, pledge, charge or
                  encumbrance of any kind except (i) those, if any, reflected in
                  such Financial Statements, or (ii) those which are not
                  material in amount and do not adversely affect the use made
                  and promised to be made of such property by the Company. The
                  Company holds its leased properties under valid and binding
                  leases, with such exceptions as are not materially significant
                  in relation to the business of the Company. The Company owns
                  or leases all such properties as are necessary to its
                  operations as now conducted or as proposed to be conducted.

         (l)      Brokers or Finders. To the knowledge of the Company, no
                  person, firm or corporation has or will have, as a result of
                  any act or omission of the Company, any right, interest or
                  valid claim against the Investor for any commission, fee or
                  other compensation as a finder or broker in connection with
                  the transactions contemplated by this Agreement. The Company
                  shall indemnify and hold the Investor harmless for any claims
                  made for any commission, fee or other compensation concerning
                  the transactions contemplated by this Agreement.

5.       Representations and Warranties of the Investor. Circle F represents and
         warrants to the Company as follows:

         (a)      Any Notes will purchased for investment for Circle F's own
                  account and not with the view to, or for resale in connection
                  with, any distribution or public offering thereof. Circle F
                  understands that neither the Note nor the Conversion
                  Securities have been registered under the Securities Act or
                  any state securities laws by

                                       5
<PAGE>

                  reason of their contemplated issuance in transactions exempt
                  from the registration requirements of the Securities Act and
                  applicable state securities laws and that the reliance of the
                  Company and others upon these exemptions is predicated in part
                  upon this representation by Circle F. Circle F further
                  understands that the Notes and the Conversion Securities may
                  not be transferred or resold without registration under the
                  Securities Act and any applicable state securities laws, or
                  pursuant to an exemption from the requirements of the
                  Securities Act and applicable state securities laws.

         (b)      Circle F's principal place of business is located at the
                  address set forth on the signature page hereto. Circle F
                  qualifies as an "accredited investor," as defined in Rule 501
                  of Regulation D under the Securities Act. Circle F
                  acknowledges that the Company has made available to Circle F
                  at a reasonable time prior to the execution of this Agreement
                  the opportunity to ask questions and receive answers
                  concerning the business, operations and financial condition of
                  the Company and the terms and conditions of the sale of
                  securities contemplated by this Agreement and to obtain any
                  additional information requested by such Investor. Circle F is
                  able to bear the loss of its entire investment in the Shares
                  and the Conversion Securities and has such knowledge and
                  experience of financial and business matters that he is
                  capable of evaluating the merits and risks of the investment
                  to be made pursuant to this Agreement. However, neither the
                  foregoing nor any other due diligence investigation conducted
                  by Circle F or on its behalf shall limit, modify or affect the
                  representations and warranties of the Company set forth in
                  Section 4 of this Agreement or the right of Circle F to rely
                  thereon.

         (c)      This Agreement has been duly authorized by all necessary
                  action on the part of Circle F, has been duly executed and
                  delivered by Circle F and is a valid and binding agreement of
                  Circle F.

         (d)      Circle F will not permit any of its Affiliates to become an
                  Investor pursuant to this Agreement unless and until such
                  Affiliate agrees to be bound by the terms of this Agreement,
                  including without limitation the representations and
                  warranties contained in this Section 5, which such
                  representations and warranties shall be true and accurate with
                  respect to such Affiliate at the time such Affilate makes an
                  Advance hereunder.

6.       Registration Rights. The Company shall register the Conversion
         Securities with Securities and Exchange Commission on any registration
         statement filed by the Company pursuant to Section 7 of the Securities
         Purchase Agreement, dated as of August 11, 2000, between the Company
         and the Investor.

7.       Miscellaneous.

         (a)      The Company will file with the Commission, on a timely basis,
                  all SEC Reports required to be filed under the Exchange Act
                  and any other documents required to meet the public
                  information requirements of Rule 144(c) under the Securities
                  Act.

                                       6
<PAGE>

         (b)      This Agreement and the rights and obligations of the parties
                  hereunder shall not be assignable, in whole or in part, by the
                  Company without the prior written consent of the Investor.
                  This Agreement and the rights and obligations of the parties
                  hereunder shall not be assignable, in whole or in part, by the
                  Investor without the prior written consent of the Company,
                  except that the Investor may assign its rights under this
                  Agreement to any affiliate without the prior written consent
                  of the Company. This Agreement shall inure to the benefit of
                  and be binding upon and be enforceable by the successors and
                  permitted assigns of the parties hereto. Neither this
                  Agreement nor any provision hereof may be amended, modified,
                  waived or discharged without the written consent of the
                  parties hereto.

         (c)      This Agreement, including the exhibits attached hereto,
                  constitutes the entire agreement of the parties relative to
                  the subject matter hereof and supersedes any and all other
                  agreements and understanding, whether written or oral,
                  relative to the matters discussed herein.

         (d)      All representations and warranties contained herein shall
                  survive after the execution and delivery of this Agreement for
                  a period of two (2) years from the Effective Date. All
                  covenants and agreements which by their terms are to be
                  performed after the Effective Date will survive indefinitely,
                  unless such covenants and agreements by their terms expire at
                  an earlier date, in which case they will expire on such
                  earlier date.

         (e)      All notices, requests, consents and other communications
                  required or permitted hereunder shall be in writing and shall
                  be given in writing by personal delivery, facsimile,
                  commercial air delivery service or by registered or certified
                  mail, postage prepaid, return receipt requested, addressed to
                  the Company at the address set forth in the introductory
                  paragraph to this Agreement and to the Investor at the
                  addresses set forth on the signature page hereto, or at such
                  other address as the respective parties may designate by like
                  notice from time to time. Notices so given shall be effective
                  upon the earlier of: (a) receipt by the party to which notice
                  is given (which, in the instance of a facsimile, shall be
                  deemed to have occurred at the time that the machine
                  transmitting the facsimile verifies a successful transmission
                  of the facsimile); (b) on the fifth business day following the
                  date such notice was deposited in the mail; or (c) on the
                  second business day following the date such notice was
                  delivered to a commercial air delivery service.

         (f)      This Agreement shall be construed and enforced in accordance
                  with the laws of the State of Minnesota.

         (g)      This Agreement may be executed in two or more counterparts,
                  each of which shall be deemed an original, but all of which
                  together shall constitute one and the same instrument. This
                  Agreement may be executed by facsimile.

                          [NEXT PAGE IS SIGNATURE PAGE]

                                       7
<PAGE>

         IN WITNESS WHEREOF, the Company and the Investor have executed this
Agreement effective as of the date first written above.

                                      OPTICAL SENSORS INCORPORATED

                                      By
                                         --------------------------------------
                                         Paulita LaPlante,
                                         President and Chief Executive Officer

                                      CIRCLE F VENTURES LLC

                                      By
                                         --------------------------------------

                                      Its
                                         --------------------------------------

                                      Address:
                                      17797 North Perimeter Drive
                                      Suite 105
                                      Scottsdale, Arizona 85255

                                       8

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00028-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00028-of-00352.parquet"}]]