Exhibit 4.10

THIS NOTE HAS BEEN ACQUIRED FOR INVESTMENT PURPOSES ONLY AND MAY NOT BE SOLD,
TRANSFERRED OR OTHERWISE DISPOSED OF UNTIL (I) A REGISTRATION STATEMENT UNDER
THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), SHALL HAVE BECOME EFFECTIVE
WITH RESPECT THERETO OR (II) RECEIPT BY THE COMPANY OF AN OPINION OF COUNSEL
REASONABLY SATISFACTORY TO THE COMPANY TO THE EFFECT THAT REGISTRATION UNDER THE
ACT IS NOT REQUIRED IN CONNECTION WITH SUCH PROPOSED TRANSFER NOR IS IN
VIOLATION OF ANY APPLICABLE STATE SECURITIES LAWS. THIS LEGEND SHALL BE ENDORSED
UPON ANY NOTE ISSUED IN EXCHANGE FOR THIS NOTE.

THIS NOTE IS SUBJECT TO THE TERMS OF A PURCHASE AGREEMENT, DATED AS OF JANUARY
31, 2000, A COPY OF WHICH IS ON FILE AT THE EXECUTIVE OFFICES OF MILESTONE
SCIENTIFIC INC.

                            MILESTONE SCIENTIFIC INC.
                       10% SENIOR SECURED PROMISSORY NOTE

$25,000                                                         January 31, 2000
                                                          Livingston, New Jersey

            FOR VALUE RECEIVED, MILESTONE SCIENTIFIC INC., a Delaware
corporation (the "Company" or "Maker") with its principal executive office at
220 South Orange Avenue, Livingston, New Jersey 07039, promises to pay to
STRATEGIC RESTRUCTURING PARTNERSHIP LP, having an address at 1114 Avenue of the
Americas, New York, New York (the "Payee" or the "holder of this Note"), or
registered assigns, the principal amount of TWENTY FIVE THOUSAND DOLLARS
($25,000) in such coin or currency of the United States of America as at the
time of payment shall be legal tender for the payment of public and private
debts, or such other form as shall be acceptable by the Payee in its sole and
absolute discretion together with interest as set forth in Section 1 of this
Note at such times and in such amounts as set forth in Section 2 of this Note,
at Payee's address designated above or at such other place as the Payee shall
have notified the Company in writing at least five (5) days before such payment
is due.

            This Note is one of a series of similar notes (collectively referred
to as the "Notes") issued pursuant to a Purchase Agreement between the Company
and Payee, dated as of January 31, 2000 (the "Agreement"), a copy of which is
available for inspection at the Company's principal office. This Note is
entitled to the benefit of certain terms, conditions, covenants and agreements
contained in the Agreement. Unless otherwise specifically provided herein to the
contrary, capitalized terms used herein shall have the same meaning ascribed to
such terms in the Agreement.

      1. Interest.

            A. Except as otherwise provided in Paragraph B of this Section 1,
interest on the principal amount hereof shall accrue at the rate of 10% per
annum (the "Basic Rate") from

<PAGE>

the date hereof until paid in full. Interest shall be payable semiannually in
arrears on June 15 and December 15 of each year commencing June 15, 2000 (each
such date, an "Interest Payment Date").

            B. (a) If an Event of Default (as defined in the Agreement) shall
have occurred and shall continue while this Note is outstanding, interest on the
unpaid principal balance of this Note shall accrue at a rate equal to the
greater of (i) 3% over the interest rate otherwise then in effect or (ii) the
maximum rate permitted by law (such rate is hereinafter referred to as the
"Default Rate").

                  (b) In the event a registration statement covering any shares
of the Company's Common Stock (as defined below) that may be issued as payment
of interest due on this Note or on exercise of certain warrants being issued
simultaneously with the Notes (collectively, the "Registerable Securities") is
not effective on or before July 15, 2000, in accordance with the terms of a
Registration Rights Agreement between the Company and the Payee, dated even date
herewith, interest on the principal amount hereof shall accrue at the rate of
16% per annum from such date until the earlier of (x) the effective date of a
registration statement covering the Registerable Securities or (y) the date on
which the Registerable Securities are salable pursuant to Rule 144 promulgated
under the Securities Act of 1933, as amended, during a period of not more than
90 days.

            C. Interest as aforesaid shall be calculated on the basis of actual
number of days elapsed over a year of 360 days.

            D. At the option of the Company, interest shall be payable either in
cash or in shares of the Company's common stock, par value $.001 per share (the
"Common Stock"), valued at the average closing bid price per share of Common
Stock for the five trading days ending the day prior to the Interest Payment
Date.

      2. Principal Payments. The Company shall, not later than 30 days after the
end of each calendar quarter, make principal payments on the Notes in an
aggregate amount equal to the number "Wand" equipment units sold during the
preceding calendar quarter multiplied by $77.00 per unit. The aggregate
principal amount payable on the Notes shall be allocated to each Note in the
ratio which the then outstanding balance on each Note bears to the total
outstanding balance of all Notes. The entire remaining outstanding principal
amount of this Note shall be due and payable on the Maturity Date (as defined
below).

      3. Maturity. This Note shall mature, and the entire unpaid principal
amount hereof and all accrued but unpaid interest thereon, shall be due in full
on June 30, 2001 (the "Maturity Date").

      4. Security. This Note is a secured by raw material, work in process and
finished goods inventories and certain proceeds thereof of the Company pursuant
to a Security Agreement dated even date herewith.


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<PAGE>

      5. Priority. The payment of the entire principal amount of this Note, and
the accrued but unpaid interest hereon, shall be senior in right of payment to
all other indebtedness of the Company whether incurred prior or subsequent to
the date hereof other than (i) any purchase money obligations incurred by the
Company in connection with the purchase of property in the ordinary course of
business, (ii) all payment obligations of the Company pursuant to any
capitalized lease entered into by the Company, (iii) all payables incurred by
the Company in the ordinary course of its business and (iv) the Company's 3%
Convertible Notes.

      6. Events of Default and Remedies.

            A. Events of Default. Each of the following events is herein
referred to as an Event of Default:

                  (i) if any representation or warranty made herein, or in the
Agreement, or in any report, certificate, financial statement or other
instrument furnished in connection with this Note or the Agreement, shall be
false, inaccurate or misleading in any material respect when made or when deemed
made hereunder;

                  (ii) any default in the payment of any principal or interest
hereunder when the same shall be due and payable, whether at the due date
thereof or by acceleration or otherwise;

                  (iii) any material default in the due observance or
performance of any other covenant, condition or agreement to be observed or
performed pursuant to the terms hereof or the Agreement, and the continuance of
such default unremedied for a period of twenty (20) days after written notice
thereof to the Company setting forth in reasonable detail the circumstances of
such Event of Default;

                  (iv) if the Company shall: (A) apply for or consent to the
appointment of a receiver, trustee, custodian or liquidator of it or any of its
properties, (B) admit in writing its inability to pay its debts as they mature,
(C) make a general assignment for the benefit of creditors, (D) be adjudicated a
bankrupt or insolvent or be the subject of an order for relief under Title 11 of
the United States Code, or (E) file a voluntary petition in bankruptcy, or a
petition or an answer seeking reorganization or an arrangement with creditors or
to take advantage or any bankruptcy, reorganization, insolvency, readjustment of
debt, dissolution or liquidation law or statute, or an answer admitting the
material allegations of a petition filed against him or it in any proceeding
under any such law, or (vi) take or permit to be taken any action in furtherance
of or for the purpose of effecting any of the foregoing;

                  (v) if any order, judgment or decree shall be entered, without
the application, approval or consent of the Company, by any court of competent
jurisdiction, approving a petition seeking reorganization of the Company, or
appointing a receiver, trustee, custodian or liquidator of any of the Company,
or of all or any substantial part of its assets, and such order, judgment or
decree shall continue unstayed and in effect for any period of sixty (60)
consecutive days;


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<PAGE>

                  (vi) there shall be a default (taking into account lapse of
notice, written notice to the Company or both) under any bond, debenture, note
or other evidence of indebtedness for money borrowed or under any mortgage,
indenture or other instrument under which there may be issued or by which there
may be secured or evidenced any indebtedness for money borrowed by the Company,
whether existing on the date hereof or created subsequent to the date hereof,
which default relates to the obligation to pay the principal of or interest on
any such indebtedness and the effect of such default is to cause such
indebtedness to become due prior to its stated maturity; or

                  (vii) if final judgment(s) for the payment of money in excess
of $200,000 individually or $250,000 in the aggregate shall be rendered against
the Company, and the same shall remain undischarged or unbonded for a period of
thirty (30) consecutive days, during which execution shall not be effectively
stayed.

            B. Remedies. Upon the occurrence of any Event of Default, and at all
times thereafter during the continuance thereof: (i) this Note shall, at the
option of the holder thereof, in accordance with Section 13.11 of the Agreement
(except in the case of Sections 7(A)(iv) and (v) hereof, the occurrence of which
shall automatically effect acceleration, regardless of any action or forbearance
in respect of any prior or ongoing default or event of default which may be
inconsistent with such automatic acceleration), become immediately due and
payable, both as to principal, interest and premium, without presentment,
demand, protest or notice of any kind, all of which are hereby expressly waived,
anything contained herein or in the Agreement to the contrary notwithstanding,
(ii) all outstanding obligations under this Note, and all other outstanding
obligations on which the applicable interest rate is determined by reference to
the interest rate under this Note, shall bear interest at the default rate of
interest provided herein, (iii) the holder of this Note may file suit against
the Company on the Note and/or seek specific performance or injunctive relief
hereunder (whether or not a remedy exists at law or is adequate), (iv) the
holder of this Note shall have the right, in accordance with this Note to
exercise any and all remedies as such holder may determine in such holder's
discretion (without any requirement of marshalling of assets, or other such
requirement).

      7. Miscellaneous.

            A. Parties in Interest. All covenants, agreements and undertakings
in this Note binding upon the Company or the Payee shall bind and inure to the
benefit of the permitted successors and assigns of the Company and the Payee,
respectively, whether so expressed or not. Any transferee or transferees of this
Note, by their acceptance hereof, assume the obligations of the Payee in the
Agreement with respect to the conditions and procedures for transfer of this
Note.

            B. Notices. All notices, requests, consents and demands shall be
given or made, and shall become effective, in accordance with the Agreement
executed by the Payee and the Company.

            C. Construction. This Note shall be construed and enforced in
accordance with, and the rights of the parties shall be governed by, the laws of
the State of New York and


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<PAGE>

any applicable laws of the United States of America, without giving effect to
the conflicts or choice of law principles thereof.

            D. Enforceability. Maker acknowledges that this Note and Maker's
obligations hereunder are and shall at all times continue to be absolute and
unconditional in all respects, and shall at all times be valid and enforceable
irrespective of any other agreements or circumstances of any nature whatsoever
which might otherwise constitute a defense to this Note and the obligations of
Maker evidenced hereby, unless otherwise expressly evidenced in a writing duly
executed by the holder hereof.

            E. Payment. If the date for any payment due hereunder would
otherwise fall on a day which is not a Business Day, such payment or expiration
date shall be extended to the next following Business Day with interest payable
at the applicable rate specified herein during such extension. "Business Day"
shall mean any day other than a Saturday, Sunday, or any day which shall be in
the City of New York a legal holiday or a day on which banking institutions are
authorized by law to close.

            F. Waiver and Set-off. Maker hereby waives diligence, presentment,
demand, protest and notice of any kind whatsoever. The nonexercise by Payee of
any of its rights hereunder in any particular instance shall not constitute a
waiver thereof in that or any subsequent instance. The Payee, in addition to any
other right available to it under applicable law, shall have the right, at its
option, to immediately set off against this Note any monies owed by the Payee in
any capacity to Maker, whether or not due, upon the occurrence of any Event of
Default, even though such charge is made or entered on the books of Payee
subsequent to those events.

            G. Lost Documents. Upon receipt by the Company of evidence
satisfactory to it of the loss, theft, destruction or mutilation of this Note or
any Note exchanged for it, and (i) in the case of loss, theft or destruction, of
indemnity satisfactory to it and (ii) in the case of mutilation, of surrender
for cancellation of such Note, and, in any case, upon reimbursement to the
Company of all reasonable expenses incidental thereto, the Company will make and
deliver in lieu of such Note a new Note of like tenor and principal amount and
dated as of the original date of this Note.


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<PAGE>

      IN WITNESS WHEREOF, this Note has been executed and delivered on the date
specified above by the duly authorized representative of the Company.

                                    MILESTONE SCIENTIFIC INC.


                                    by: _____________________________
                                          Leonard Osser, Chairman and
                                          Chief Executive Officer


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