Exhibit 4.42

                            LINE OF CREDIT AGREEMENT

      This LINE OF CREDIT AGREEMENT (the "Agreement") is made as of April 15,
2002 between MILESTONE SCIENTIFIC INC., a Delaware corporation, with its
principal offices at 220 South Orange Avenue, Livingston, New Jersey 07039 (the
"Company"), and Leonard Osser ("Osser" or the "Lender"), having an address at
c/o MILESTONE SCIENTIFIC INC., 220 South Orange Avenue, Livingston, New Jersey
07039.

      WHEREAS, the Company desires to borrow from Lender and Lender desires to
lend to the Company up to an aggregate of $100,000 pursuant to a line of credit;

      NOW, THEREFORE, in consideration of the premises and the covenants herein
contained, each of the undersigned parties hereto agree as follows:

      1. Line of Credit. Lender hereby agrees to lend to the Company a principal
amount of $100,000 in the aggregate, at any time or times until January 2, 2003,
subject to the terms and conditions hereinafter set forth:

      The Company shall deliver to Lender, upon the borrowings of any funds
      under the line of credit, promissory notes (the "Notes") in the amounts
      borrowed, bearing a 6% interest. All outstanding Notes shall mature and be
      payable on April 2, 2003. The borrowings shall be made pursuant to a
      notice from the Company's Chief Financial Officer, that such borrowing is
      required for purposes related to the Company's ordinary course of
      business.

      2. Use of Proceeds. The proceeds from the line of credit will be used for
general corporate purposes.

      3. Legends. Lender consents to the placement of the following legend on
the Notes and shares of Common Stock issued in payment of principal and
interest, provided they are not then covered by an effective Registration
Statement:

      THIS SECURITY 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 SECURITY IS SUBJECT TO THE TERMS OF A LINE OF CREDIT AGREEMENT, DATED
AS OF APRIL 15, 2002, A COPY OF WHICH IS ON FILE AT THE EXECUTIVE OFFICES OF
MILESTONE SCIENTIFIC INC.

<PAGE>

      4. Notices. All notices, requests, demands and other communications which
are required to be or may be given under this Agreement to any party to any of
the other parties shall be in writing and shall be deemed to have been duly
given when (a) delivered in person, (b) the day following dispatch by an
overnight courier service (such as Federal Express or UPS, etc.) or (c) five (5)
days after dispatch by certified or registered first class mail, postage
prepaid, return receipt requested, to the party to whom the same is so given or
made. Any notice or other communication given hereunder shall be addressed to
the Company, at its principal offices as set forth above and to the Lenders at
his address indicated on the signature page hereto.

      5. Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of New York. The parties hereby agree that
any dispute which may arise between them arising out of or in connection with
this Agreement shall be adjudicated before a court located in New York City and
they hereby submit to the exclusive jurisdiction of the courts of the State of
New York located in New York, New York and of the federal courts in the Southern
District of New York with respect to any action or legal proceeding commenced by
any party, and irrevocably waive any objection they now or hereafter may have
respecting the venue of any such action or proceeding brought in such a court or
respecting the fact that such court is an inconvenient forum, relating to or
arising out of this Agreement or any acts or omissions relating to the sale of
the securities hereunder, and consent to the service of process in any such
action or legal proceeding by means of registered or certified mail, return
receipt requested, in care of the address set forth below or such other address
as the undersigned shall furnish in writing to the other.

      IN WITNESS WHEREOF, the undersigned parties have executed this Agreement
as of the day and year first above written.

                                          MILESTONE SCIENTIFIC INC.


                                          By: __________________________________
                                                Thomas Stuckey
                                                Chief Financial Officer


                                                ________________________________
                                                Leonard Osser


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