Document:

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                                                                    EXHIBIT 10.5

                               EXCHANGE AGREEMENT

         THIS AGREEMENT made and entered into as of the 24 day of July, 2000, by
and between MARC ISERI, (referred to herein as "HOLDER"), and WILLIAM ST.
LAURENT, or his assigns or affiliates (referred to herein as "St. Laurent");

                              W I T N E S S E T H :

         WHEREAS, HOLDER is the owner, free and clear of all liens or
encumbrances, of US $100,000 (One Hundred Thousand U.S. Dollars) face value
global medium term notes issued by Technology Acceptance Corp., a Cayman Islands
special purpose corporation, on April 16, 1998, copies of which are attached
hereto as Exhibit "A" (referred to herein as the "TAC Notes"); and

         WHEREAS, St. Laurent is the owner, free and clear of all liens and
encumbrances, of 16,000 (Sixteen Thousand) restricted shares of the common stock
of Vitech America, Inc., a Florida corporation (referred to herein as the
"Vitech Stock"); and

         WHEREAS, HOLDER desires to transfer the TAC Notes to St. Laurent in
exchange for the Vitech Stock, and St. Laurent desires to transfer the Vitech
Stock to HOLDER in exchange for the TAC Notes, subject to the terms and
conditions stated herein;

         NOW, THEREFORE, for and in consideration of the mutual promises herein
set forth, the receipt and sufficiency of which are hereby acknowledged, it is
hereby agreed as follows:

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         1.       Exchange. HOLDER hereby transfers all of its right, title and
interest in the TAC Notes to St. Laurent in exchange for all St. Laurent's
right, title and interest in and to the Vitech Stock, free and clear of all
liens and encumbrances.

         2.       Assignment. Upon execution hereof, HOLDER agrees to deliver
the TAC Notes to St. Laurent together with a fully executed bond power assigning
the TAC Notes to St. Laurent to allow, upon execution hereof, the transfer of
the TAC Notes to St. Laurent on the corporate records of Technology Acceptance
Corp. Upon execution hereof, St. Laurent agrees to deliver the Vitech Stock to
HOLDER together with a fully executed stock power assigning the Vitech Shares to
HOLDER to allow, upon execution hereof, the transfer of the Vitech Stock to
HOLDER on the corporate records of Vitech America, Inc..

         3.       No Broker or Finder. The parties hereto acknowledge that they
are not in any way obligated for a payment of fees or expenses to any broker or
finder in connection with the transaction contemplated by this Agreement.

         4.       Nondisclosure. The parties hereby agree to maintain the
existence of this Agreement as well as all of its terms and conditions (referred
to herein as the "Transaction Information") in confidence and to use at least
the same degree of care to maintain the Transaction Information as secret as it
uses in maintaining as secret its own proprietary and confidential information
but always using at least a reasonable degree of care. The parties will use or
disclose the Transaction Information only to the extent necessary to effectuate
the exchange called for herein, as reasonably required in connection with the
contemplated registration of the Vitech Stock as hereinafter agreed to in
writing by both parties or as required by law.

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         5.       Further Assurances. St. Laurent and HOLDER agree that each
shall, from time to time upon the reasonable request of the other party,
execute, acknowledge and deliver in proper form any instrument of conveyance or
further assurance necessary or desirable to perfect the consummation of the
within transaction.

         6.       Construction. The parties hereto agree that all matters
pertaining to the validity, construction and effect of this Agreement shall be
determined in accordance with the laws of the State of Florida. This Agreement
shall be binding upon and inure to the benefit of the parties hereto and their
respective successors and assigns.

         7.       Notice. All deliveries, notices, statements, requests and
demands given to or made upon any party hereto in accordance with the provisions
of this Agreement shall be made via messenger or nationally recognized courier
service or via telecopy to the following addresses or facsimile numbers or such
other addresses or facsimile numbers at which the parties shall from time to
time notify one another:

         If to HOLDER:
                  Marc Iseri
                  P.O. Box M
                  Ontario, OR 97914

         If to ST. LAURENT:
                  William St. Laurent
                  C/O Vitech America Inc.
                  2190 NW 89th Place
                  Miami, FL 33172

         8.       Counterparts. This Agreement may be executed in any number of
counterpart copies, each of which shall be deemed an original for all purposes,
but all of which shall constitute one and the same agreement.

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         9.       Entire Agreement. This Agreement constitutes the entire
agreement and understanding of St. Laurent and HOLDER, and no contemporaneous or
subsequent oral agreement or statements shall alter or modify the terms and
provisions hereof unless agreed thereto by the parties in writing. There are no
promises or representations upon which any party hereto has relied in the
execution of this Agreement which are not contained herein.

         10.      Severability. In the event any provision of this Agreement
shall be held invalid or unenforceable by any court of competent jurisdiction,
such holding shall not invalidate or render unenforceable any other provision
hereof.

         11.      Pronouns and Headings. As used herein, all pronouns shall
include the masculine, feminine, neuter, singular and plural thereof wherever
the context and facts require such construction. The headings, titles and
subtitles herein are inserted for convenience of reference only and are to be
ignored in any construction of the provisions hereof.

         12.      No Reliance. The Parties to this Agreement acknowledge and
agree that neither has relied on any representation of the other, or upon
representation from any other person or entity, referring or relating in any way
to this transaction, other than the representations and warranties specifically
contained in this Agreement. The Parties to this Agreement further acknowledge
and agree that they were represented by their own counsel in connection with
this Agreement, were afforded the opportunity to conduct due diligence, were
afforded the opportunity to seek financial advice and were otherwise allowed to
fully analyze the transactions. No party has relied upon the other or any of the
other's representatives concerning the value, worth or any other aspect of the
securities described herein, except the representations and warranties
specifically contained in this Agreement.

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         13.      Understanding of Relationship. HOLDER acknowledges and
understands that St. Laurent is related to officers, directors and/or principals
of Vitech, TAC and other related entities and that St. Laurent owns greater than
10% of the shares of common stock of Vitech and owns a majority of the TAC
Notes. HOLDER further acknowledges and agrees that St. Laurent's relationship
with Vitech, TAC and their respective officers, directors and principals and
related companies shall not provide any basis, right or reason to assert any
claim, of whatever nature, against St. Laurent. HOLDER acknowledges and agrees
that it has had full opportunity to investigate St. Laurent's relationship with
Vitech, TAC and their respective officers, directors and principals and related
companies and hereby waives any and all rights and/or claims which it had, has
or may have which in any way relate to the relationship between St. Laurent and
Vitech, TAC and their related companies, officers, directors and/or principals.

         14.      Mutual Releases. Except for the breach of this Agreement, each
party, on behalf of themselves and their respective administrators, successors,
agents, attorneys, assigns, employees and affiliates hereby releases and forever
discharges, waives and relinquishes the other party, its administrators,
successors, agents, attorneys, officers, directors, employees, assigns and
affiliates from any and all claims, demands, lawsuits, causes of action,
obligations, damages, debts, liabilities, sums of money, including attorneys'
fees and costs, whether in law or in equity, whether known or unknown
(collectively, "Claims"), occurring at any time prior to and including the date
hereof. Each party further covenants not to sue and agrees not to assert any
claim or other legal proceeding against the other parties released herein, in
any court or other jurisdiction, based on any events, whether known or unknown,
which are the subject of the release contained in this Section 13. For purposes
of this release, Vitech America Inc., Intercontinental Telecommunications
Corporation, Technology Acceptance Corporation and Bahia Tech shall be
considered affiliates of WSL.

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         IN WITNESS WHEREOF, the parties hereto have set their respective hands
as of the date first above written.

HOLDER

By: /s/ MARC ISERI MD                         /s/ WILLIAM ST. LAURENT
   -----------------                          -----------------------
   MARC ISERI                                 WILLIAM ST. LAURENT

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                                                                    EXHIBIT 10.6

                              VITECH AMERICA, INC.
                            2190 Northwest 89th Place
                              Miami, Florida 33172

                                                           Date: August 14, 2000

The Equity Group Inc.
800 Third Avenue, 36th Floor
New York, NY 10022
Attn: Robert Goldstein, President

Dear Mr. Goldstein:

         Vitech America, Inc. (the "Corporation") is pleased to award you an
Option to purchase an aggregate of 20,000 shares of the Corporation's Common
Stock pursuant to the provisions of the 1996 Stock Option Plan (the "Plan").
This letter will describe the Option granted to you. Your signature on this
letter is an acknowledgment to us that you have read and understand this
Agreement and the Plan and that you agree to abide by its terms.

         1.       Mutual Intent. It is important to the Corporation that the
Optionee be encouraged to enhance the value of the Corporation and its
subsidiaries through Optionee's services to the Corporation and its
subsidiaries. Accordingly, the Corporation desires to afford the Optionee the
opportunity to purchase shares of the Corporation's Common Stock as hereinafter
provided.

         2.       Type of Option. The Option being granted is considered a
non-qualified stock option as it relates to Section ss.422 of the Internal
Revenue Code of 1996, as amended.

         3.       Rights and Privileges. Subject to the conditions hereinafter
set forth, the Corporation grants you the right to purchase 20,000 shares of
Stock at $5.50 per share. The right to purchase all shares accrues on the one
year anniversary of the date hereof.

         4.       Time of Exercise. The Option may be exercised at any time and
from time to time after August 14, 2001 and on or before August 14, 2005.

         5.       Method of Exercise. The Options shall be exercised by written
notice to the Corporation at the Corporation's principal place of business. The
notice shall set forth the number of shares of Stock to be acquired and shall
contain a check payable to the undersigned in full payment for the shares to be
purchased.

         6.       Registration Rights. The Corporation shall prepare and file
with the Securities and Exchange Commission, a Registration Statement on Form
S-3 (or if the Corporation is not eligible to register for resale of the Stock
on Form S-3, such registration shall be on another appropriate form in
accordance herewith) for the resale of the shares of common stock underlying
this option in accordance with the method or methods of distribution thereof as
specified by the undersigned, and use its best efforts to cause the Registration
Statement to become and remain effective prior to August 14, 2001 and until the
option is exercised and all the underlying shares have been sold, but no later
than August 14, 2005. The Company will be responsible to pay for all
registration costs and fees including all related attorney, auditor or other
expenses.

         7.       Termination of Option. To the extent not exercised, the Option
shall terminate five (5) years from the date of grant.

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         8.       Securities Laws. The Option and the shares of Stock underlying
the Option have not been registered under the Securities Act of 1933, as amended
(the "Act"). The Corporation has no obligations to ever register the Option or
the shares of Stock underlying the Option. All shares of Stock acquired upon the
exercise of the Option shall be "restricted securities" as that term is defined
in Rule 144 promulgated under the Act. The certificate representing the shares
shall bear an appropriate legend restricting their transfer. Such shares cannot
be sold, transferred, assigned or otherwise hypothecated without registration
under the Act or unless a valid exemption from registration is then available
under applicable federal and state securities laws and the Corporation has been
furnished with an opinion of counsel satisfactory in form and substance to the
Corporation that such registration is not required.

         9.       Date of Grant. The Option shall be treated as having been
granted to you on the date of this letter even though you may sign it at a later
date.

         10.      Counterparts. This Agreement shall be executed in multiple
counterparts, each of which when considered together, comes to one and the same
Agreement.

         11.      Integration. This Agreement supersedes all prior agreements
understanding between the undersigned and the Optionee related to the subject
matter hereof.

                                Very truly yours,

                                VITECH AMERICA, INC.

                                By: /s/ Edward A. Kelly
                                   ---------------------------
                                Name: Edward A. Kelly
                                Title: Chief Financial Officer

AGREED AND ACCEPTED THIS

14 day of August, 2000

The Equity Group Inc.

By: /s/ Robert Goldstein
   ---------------------
Name:
Title:

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