<PAGE>

                                                                   Exhibit 10.44

                             SECURED PROMISSORY NOTE

$301,000.00                                                San Diego, California

                                                               Date: May 1, 2003

                  FOR VALUE RECEIVED, the undersigned Ryer Enterprises, LLC, a
Nevada limited liability company ("Debtor"), promises to pay to the order of
Planet Polymer Technologies, Inc., a California corporation ("Holder"), at its
office in San Diego, California, or at such other place as may be designated in
writing by Holder, the principal sum of Three Hundred One Thousand Dollars
($301,000.00), with no interest thereon (except as stated herein). All sums
owing hereunder are payable in lawful money of the United States of America. Any
capitalized term not defined herein shall assume the meaning stated in the
Security Agreement between Debtor and Holder dated of even date herewith
("Security Agreement").

                  While no interest shall accrue on this Note (except as stated
herein) from the date set forth above (the "Commencement Date"), each party
hereto shall account for and report on its tax filing to the Internal Revenue
Service imputed interest (at the rate of seven percent (7%) per annum), if any,
required under applicable tax laws with regards to this Note.

                  The outstanding principal balance of this Note ("Principal"),
shall be due and payable in the following installments (each a "Principal
Payment"): (a) Twenty Five Thousand Dollars ($25,000.00) on or before May 1,
2003, and (b) Eleven Thousand Five Hundred Dollars ($11,500.00) on or before the
first day of each and every month for the period beginning June 1, 2003 through
May, 31, 2005, for a period of twenty-four (24) months (the "Period"). If any
Monthly Principal Payment hereunder is not paid on or before the fifth calendar
day of the month in which it becomes due, Debtor shall pay, at Holder's option,
a late or collection charge equal to ten percent (10%) of the amount of such
unpaid Monthly Principal Payment. As a consequence of any Default or Event of
Default under this Note or the Security Agreement, interest shall accrue at the
rate of ten percent (10%) per year (based upon a 360-day year) on the
outstanding Principal until such Default or Event of Default is cured.

                  At any time during the Period and so long as Ryer is not in
default on any payment due Planet, Ryer has the option to pre-pay the remaining
balance on the Purchase Price in full (the "Balance Pre-Payment") by paying to
Planet the net present value of the remaining unpaid monthly payments determined
using a discount rate equal to the then current yield on Two Year U.S. Treasury
Bills ("T-Bill Rate"). The T-Bill rate shall be that rate published in the Wall
Street Journal on the third business day preceding the date the Balance
Pre-Payment delivered to Planet.

                  This Note is secured by, among other things, the Security
Agreement pledging as collateral Debtor's entire interest in the Collateral
described therein.

                  If: (a) Debtor fails to pay when due any sums payable
hereunder; or (b) a Default occurs under the Security Agreement or under any
obligation secured thereby; or (c) the property covered by the Security
Agreement or any portion thereof or interest therein, is sold, transferred,
mortgaged, assigned, or encumbered, whether voluntarily or involuntarily or by
operation of law or otherwise, other than as expressly permitted by Holder in
writing; THEN Holder may, at its

<PAGE>

sole option, declare all sums owing under this Note immediately due and payable;
provided, however, that if any document related to this Note provides for
automatic acceleration of payment of sums owing hereunder, all sums owing
hereunder shall be automatically due and payable in accordance with the terms of
that document.

                  If any attorney is engaged by Holder to enforce or construe
any provision of this Note or the Security Agreement or as a consequence of any
Default or Event of Default under this Note or the Security Agreement, with or
without the filing of any legal action or proceeding, then Debtor shall
immediately pay on demand all attorneys' fees and all other costs incurred by
Holder, together with interest thereon from the date of such demand until paid
at the interest rate of ten percent (10%) per year, applied to the Principal
hereunder as if such unpaid attorneys' fees and costs had been added to the
Principal.

                  No previous waiver and no failure or delay by Holder in acting
with respect to the terms of this Note or the Security Agreement shall
constitute a waiver of any breach, default, or failure of condition under this
Note, the Security Agreement or the obligations secured thereby. A waiver of any
term of this Note, any of the Security Agreement or of any of the obligations
secured thereby must be made in writing and shall be limited to the express
written terms of such waiver. In the event of any inconsistencies between the
terms of this Note and the terms of any other document related to the loan
evidenced by this Note, the terms of this Note shall prevail.

                  Debtor hereby waives presentment, demand, notice of dishonor,
notice of default or delinquency, notice of acceleration, notice of protest and
nonpayment, notice of costs, expenses or losses and interest thereon, notice of
late charges, and diligence in taking any action to collect any sums owing under
this Note or in proceeding against any of the rights or interests in or to
properties securing payment of this Note. Time is of the essence with respect to
every provision hereof. This Note shall be construed and enforced in accordance
with the laws of the State of California, except to the extent that Federal laws
preempt the laws of the State of California, and all persons and entities in any
manner obligated under this Note consent to the jurisdiction of any Federal or
State Court within the State of California, County of San Diego, having proper
venue and also consent to service of process by any means authorized by
California or Federal law.

                                    DEBTOR:
                                    Ryer Industries, LLC, a Nevada limited
                                    liability company

                                    By:___________________________________

                                    Its: _________________________________

<PAGE>

                                                               08/04/2003 Page 1

Compound Period................  :   Monthly

Nominal Annual Rate............  :    7.000%
Effective Annual Rate..........  :    7.229%
Periodic Rate..................  :   0.5833%
Daily Rate.....................  :  0.01918%

CASH FLOW DATA

<TABLE>
<CAPTION>
Event               Start Date           Amount    Number  Period    End Date
--------------------------------------------------------------------------------
<S>                 <C>                <C>         <C>     <C>       <C>
1 Loan              05/01/2003         256,853.64     1
2 Payment           06/01/2003          11,500.00    24    Monthly   05/01/2005
</TABLE>

AMORTIZATION SCHEDULE - Normal Amortization

<TABLE>
<CAPTION>
      Date             Payment       Interest      Principal      Balance
---------------------------------------------------------------------------
<S>                  <C>            <C>           <C>            <C>
Loan 05/01/2003                                                  256,853.64
   1 06/01/2003       11,500.00      1,498.31      10,001.69     246,851.95
   2 07/01/2003       11,500.00      1,439.97      10,060.03     236,791.92
   3 08/01/2003       11,500.00      1,381.29      10,118.71     226,673.21
   4 09/01/2003       11,500.00      1,322.26      10,177.74     216,495.47
   5 10/01/2003       11,500.00      1,262.89      10,237.11     206,258.36
   6 11/01/2003       11,500.00      1,203.17      10,296.83     195,961.53
   7 12/01/2003       11,500.00      1,143.11      10,356.89     185,604.64
2003 Totals           80,500.00      9,251.00      71,249.00

   8 01/01/2004       11,500.00      1,082.69      10,417.31     175,187.33
   9 02/01/2004       11,500.00      1,021.93      10,478.07     164,709.26
  10 03/01/2004       11,500.00        960.80      10,539.20     154,170.06
  11 04/01/2004       11,500.00        899.33      10,600.67     143,569.39
  12 05/01/2004       11,500.00        837.49      10,662.51     132,906.88
  13 06/01/2004       11,500.00        775.29      10,724.71     122,182.17
  14 07/01/2004       11,500.00        712.73      10,787.27     111,394.90
  15 08/01/2004       11,500.00        649.80      10,850.20     100,544.70
  16 09/01/2004       11,500.00        586.51      10,913.49      89,631.21
  17 10/01/2004       11,500.00        522.85      10,977.15      78,654.06
  18 11/01/2004       11,500.00        458.82      11,041.18      67,612.88
  19 12/01/2004       11,500.00        394.41      11,105.59      56,507.29
2004 Totals          138,000.00      8,902.65     129,097.35

  20 01/01/2005       11,500.00        329.63      11,170.37      45,336.92
  21 02/01/2005       11,500.00        264.47      11,235.53      34,101.39
  22 03/01/2005       11,500.00        198.92      11,301.08      22,800.31
  23 04/01/2005       11,500.00        133.00      11,367.00      11,433.31
  24 05/01/2005       11,500.00         66.69      11,433.31           0.00
2005 Totals           57,500.00        992.71      56,507.29

Grand Totals         276,000.00     19,146.36     256,853.64
</TABLE>