<PAGE>
                                                                   Exhibit 10.33

                                 PROMISSORY NOTE

<TABLE>
<S>                <C>           <C>            <C>        <C>        <C>            <C>        <C>
------------------ ------------- -------------- ---------- ---------- -------------- ---------- ------------
Principal          Loan Date     Maturity       Loan No    Call/Coll  Account        Officer    Initials
------------------ ------------- -------------- ---------- ---------- -------------- ---------- ------------
$250,000.00        04-03-2002    01-15-2003                           8000249413
------------------ ------------- -------------- ---------- ---------- -------------- ---------- ------------
</TABLE>
References in the shaded area are for lender's use only and do not limit the
applicability of this document to any particular loan or item. Any item above
containing "***" has been omitted due to text length limitations.
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Borrower: Empyrean Bioscience, Inc.        Lender:  The Huntington National Bank
          23800 Commerce Park Rd. Suite A           Cleveland Commercial Lending
          Cleveland, OH  44122                      P.O. Box 1558 - HZ0325
                                                    Columbus, OH  43272-4195
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Principal Amount: $250,000.00   Initial Rate:  5.750%   Date of Note: 04/03/2002

PROMISE TO PAY. Empyrean Bioscience, Inc. ("Borrower") promises to pay to THE
HUNTINGTON NATIONAL BANK ("Lender"), or order, in lawful money of the United
States of America, the principal amount of Two Hundred Fifty Thousand & 00/100
Dollars ($250,000.00) together with interest on the unpaid outstanding principal
balance from April 3, 2002, until paid in full.

PAYMENT. Borrower will pay this loan in one principal payment of $250,000.00
plus interest on January 15, 2003. This payment due on January 15, 2003, will be
for all principal and all accrued interest not yet paid. In addition, Borrower
will pay regular monthly payments of all accrued unpaid interest due as of each
payment date, beginning April 15, 2002, with all subsequent interest payments to
be due on the same day of each month after that. Unless otherwise agreed or
required by applicable law, payments will be applied first to accrued unpaid
interest, then to principal, and any remaining amount to any unpaid collection
costs and late charges. The annual interest rate for this Note is computed on a
365/360 basis; that is, by applying the ratio of the annual interest rate over a
year of 360 days, multiplied by the outstanding principal balance, multiplied by
the actual number of days the principal balance is outstanding. Borrower will
pay Lender at Lender's address shown above or at such other place as Lender may
designate in writing.

VARIABLE INTEREST RATE. The interest rate on this Note is subject to change from
time to time based on changes in an index which is the Lender's Prime Commercial
Rate. As used herein, Prime Commercial Rate shall mean the rate established by
the Lender from time to time based on its consideration of economic, money
market, business and competitive factors, and it is not necessarily the Lender's
most favored rate. Subject to any maximum or minimum interest rate limitation
specified herein or by applicable law, any variable rate of interest on the
obligation evidenced hereby shall change automatically without notice to the
undersigned immediately with each change in the Prime Commercial Rate (the
"Index"). The Index is not necessarily the lowest rate charged by Lender on its
loans and is set by Lender in its sole discretion. If the Index becomes
unavailable during the term of this loan, Lender may designate a substitute
index after notifying Borrower. Lender will tell Borrower the current Index rate
upon Borrower's request. The interest rate change will not occur more often than
each day. Borrower understands that Lender may make loans based on other rates
as well. The Index currently is 4.750% per annum. The interest rate to be
applied to the unpaid principal balance of this Note will be at a rate of 1.000
percentage points over the Index, resulting in an initial rate of 5.750% per
annum. NOTICE: Under no circumstances will the interest rate on this Note be
more than the maximum rate allowed by applicable law.

PREPAYMENT. Borrower agrees that all loan fees and other prepaid finance charges
are earned fully as of the date of the loan and will not be subject to refund
upon early payment (whether voluntary or as a result of default), except as
otherwise required by law. Except for the foregoing, Borrower may pay without
penalty all or a portion of the amount owed earlier than it is due. Early
payments will not, unless agreed to by Lender in writing, relieve Borrower of
Borrower's obligation to continue to make payments under the payment schedule.
Rather, early payments will reduce the principal balance due. Borrower




<PAGE>

agrees not to send Lender payments marked "paid in full", "without recourse", or
similar language. If Borrower sends such a payment, Lender may accept it without
losing any of Lender's rights under this Note, and Borrower will remain
obligated to pay any further amount owed to Lender. All written communications
concerning disputed amounts, including any check or other payment instrument
that indicates that the payment constitutes "payment in full" of the amount owed
or that is tendered with other conditions or limitations or as full satisfaction
of a disputed amount must be mailed or delivered to: The Huntington National
Bank, Commercial Customer Support, 7450 Huntington Park Drive - HZ0326 Columbus,
OH 43235.

LATE CHARGE. If a payment is 11 days or more late, Borrower will be charged
5.000% of the regularly scheduled payment.

INTEREST AFTER DEFAULT. Upon default, including failure to pay upon final
maturity, Lender, at its option, may, if permitted under applicable law,
increase the variable interest rate on this Note to 4.000 percentage points over
the Index. The interest rate will not exceed the maximum rate permitted by
applicable law.

DEFAULT. Each of the following shall constitute an event of default ("Event of
         Default") under this Note:

         Payment Default. Borrower fails to make any payment when due under this
         Note.

         Other Defaults. Borrower fails to comply with or to perform any other
         term, obligation, covenant or condition contained in this Note or in
         any of the related documents or to comply with or to perform any term,
         obligation, covenant or condition contained in any other agreement
         between Lender and Borrower.

         False Statements. Any warranty, representation or statement made or
         furnished to Lender by Borrower or on Borrower's behalf under this Note
         or the related documents is false or misleading in any material
         respect, either now or any the time made or furnished or becomes false
         or misleading at any time thereafter.

         Insolvency. The dissolution or termination of Borrower's existence as a
         going business, the insolvency of Borrower, the appointment of a
         receiver for any part of Borrower's property, any assignment for the
         benefit of creditors, any type of creditor workout, or the commencement
         of any proceeding under any bankruptcy or insolvency laws by or against
         Borrower.

         Creditor or Forfeiture Proceedings. Commencement of foreclosure or
         forfeiture proceedings, whether by judicial proceeding, self-help,
         repossession or any other method, by any creditor of Borrower or by any
         governmental agency against any collateral securing the loan. This
         includes a garnishment of any of Borrower's accounts, including deposit
         accounts, with Lender. However, this Event of Default shall not apply
         if there is a good faith dispute by Borrower as to the validity or
         reasonableness of the claim which is the basis of the creditor or
         forfeiture proceeding and if Borrower gives Lender written notice of
         the creditor or forfeiture proceeding and deposits with Lender monies
         or a surety bond for the creditor or forfeiture proceeding, in an
         amount determined by Lender, in its sole discretion, as being an
         adequate reserve or bond for the dispute.

         Events Affecting Guarantor. Any of the preceding events occurs with
         respect to any Guarantor of any of the indebtedness or any Guarantor
         dies or becomes incompetent, or revokes or disputes the validity of, or
         liability under, any guaranty of the indebtedness evidenced by this
         Note.

         Change in Ownership. Any change in ownership of twenty-five percent
         (25%) or more of the common stock of Borrower.

         Adverse Change. A material adverse change occurs in Borrower's
         financial condition, or Lender believes the prospect of payment or
         performance of this Note is impaired.



<PAGE>

         Insecurity. Lender in good faith believes itself insecure.

LENDER'S RIGHTS. Upon default, Lender may declare the entire unpaid principal
balance on this Note and all accrued unpaid interest immediately due, and then
Borrower will pay that amount.

ATTORNEYS' FEES; EXPENSES. Lender may hire or pay someone else to help collect
this Note if Borrower does not pay. Borrower will pay Lender that amount. This
includes, subject to any limits under applicable law, Lender's attorneys' fees
and Lender's legal expenses, whether or not there is a lawsuit, including
attorneys' fees, expenses for bankruptcy proceedings (including efforts to
modify or vacate any automatic stay or injunction), and appeals. If not
prohibited by applicable law, Borrower also will pay any court costs, in
addition to all other sums provided by law.

JURY WAIVER. Lender and Borrower hereby waive the right to any jury trial in any
action, proceeding, or counterclaim brought by either Lender or Borrower against
the other.

GOVERNING LAW. This Note will be governed  by, construed and enforced in
accordance with federal law and the laws of the State of Ohio. This Note has
been accepted by Lender in the State of Ohio.

CONFESSION OF JUDGMENT. Borrower hereby irrevocably authorizes and empowers any
attorney-at-law, including an attorney hired by Lender, to appear in any court
of record and to confess judgment against Borrower for the unpaid amount of this
Note as evidenced by an affidavit signed by an officer of Lender setting forth
the amount then due, attorneys' fees plus costs of suit, and to release all
errors, and waive all rights of appeal. If a copy of this Note, verified by an
affidavit, shall have been filed in the proceeding, it will not be necessary to
file the original as a warrant of attorney. Borrower waives the right to any
stay of execution and the benefit of all exemption laws now or hereafter in
effect. No single exercise of the foregoing warrant and power to confess
judgment will be deemed to exhaust the power, whether or not any such exercise
shall be held by any court to be invalid, voidable, or void; but the power will
continue undiminished and may be exercised from time to time as Lender may elect
until all amounts owing on this Note have been paid in full. Borrower waives any
conflict of interest that an attorney hired by Lender may have in acting on
behalf of Borrower in confessing judgment against Borrower while such attorney
is retained by Lender. Borrower expressly consents to such attorney acting for
Borrower in confessing judgment.

DISHONORED ITEM FEE. Borrower will pay a fee to Lender of $15.00 if Borrower
makes a payment on Borrower's loan and the check or preauthorized charge with
which Borrower pays is later dishonored.

RIGHT OF SETOFF. To the extent permitted by applicable law, Lender reserves a
right of setoff in all Borrower's accounts with Lender (whether checking,
savings, or some other account). This includes all accounts Borrower holds
jointly with someone else and all accounts Borrower may open in the future.
However, this does not include any IRA or Keogh accounts, or any trust accounts
for which setoff would be prohibited by law. Borrower authorizes Lender, to the
extent permitted by applicable law, to charge or setoff all sums owing on the
debt against any and all such accounts.

FINANCIAL STATEMENTS. Borrower agrees to furnish from time to time on the
request of the Lender true and complete financial statements and such other
information as the Lender may reasonably require.

PROCESSING FEE. Borrower shall pay to Lender on the date of this Note a
processing fee in the amount of $0.00. Lender and Borrower agree that the fee
shall be fully earned by Lender on the date of this Note.

PRIOR NOTE. This note is in renewal and replacement of a certain Promissory Note
dated December 19, 2001, in the original principal amount of 250,000.00 executed
and delivered by Borrower and Lender.

SUCCESSOR INTERESTS. The terms of this Note shall be binding upon Borrower, and
upon Borrower's heirs, personal representatives, successors and assigns, and
shall inure to the benefit of lender and its successors and assigns.


<PAGE>


GENERAL PROVISIONS. If any part of this Note cannot be enforced, this fact will
not affect the rest of the Note. Borrower does not agree or intend to pay, and
Lender does not agree or intend to contract for, charge, collect, take, reserve
or receive (collectively referred to herein as "charge or collect"), any amount
in the nature of interest or in the nature of a fee for this loan, which would
in any way or event (including demand, prepayment, or acceleration) cause Lender
to charge or collect more for this loan than the maximum Lender would be
permitted to charge or collect by federal law or the law of the State of Ohio
(as applicable). Any such excess interest or unauthorized fee shall, instead of
anything stated to the contrary, be applied first to reduce the principal
balance of this loan, and when the principal has been paid in full, be refunded
to Borrower. Lender may delay or forgo enforcing any of its rights or remedies
under this Note without losing them. Borrower and any other person who signs,
guarantees or endorses this Note, to the extent allowed by law, waive
presentment, demand for payment, and notice of dishonor. Upon any change in the
terms of this Note, and unless otherwise expressly stated in writing, no party
who signs this Note, whether as maker, guarantor, accommodation maker or
endorser, shall be released from liability. All such parties agree that Lender
may renew or extend (repeatedly and for any length of time) this loan or release
any party or guarantor or collateral; or impair, fail to realize upon or perfect
Lender's security interest in the collateral; and take any other action deemed
necessary by Lender without the consent of or notice to anyone. All such parties
also agree that Lender may modify this loan without the consent of or notice to
anyone other than the party with whom the modification is made. The obligations
under this Note are joint and several.

PRIOR TO SIGNING THIS NOTE, BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS OF
THIS NOTE, INCLUDING THE VARIABLE INTEREST RATE PROVISIONS. BORROWER AGREES TO
THE TERMS OF THE NOTE.

BORROWER ACKNOWLEDGES RECEIPT OF A COMPLETED COPY OF THIS PROMISSORY NOTE.

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NOTICE: FOR THIS NOTICE "YOU" MEANS THE BORROWER AND "CREDITOR" AND "HIS" MEANS
LENDER.

WARNING - BY SIGNING THIS PAPER YOU GIVE UP YOUR RIGHT TO NOTICE AND COURT
TRIAL. IF YOU DO NOT PAY ON TIME A COURT JUDGMENT MAY BE TAKEN AGAINST YOU
WITHOUT YOUR PRIOR KNOWLEDGE AND THE POWERS OF A COURT CAN BE USED TO COLLECT
FROMYOU REGARDLESS OF ANY CLAIMS YOU MAY HAVE AGAINST THE CREDITOR WHETHER FOR
RETURNED GOODS, FAULTY GOODS, FAILURE ON HIS PART TO COMPLY WITH THE AGREEMENT,
OR ANY OTHER CAUSE.
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BORROWER:

EMPYREAN BIOSCIENCE, INC.

By: /s/ Brenda K. Brown
    -------------------
    Brenda K. Brown, Vice President/
    CFO of Empyrean Bioscience, Inc.