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                                                                     Exhibit 4.3

THIS WARRANT AND ANY SHARES ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS
OF ANY STATE AND MAY NOT BE SOLD OR OFFERED FOR SALE IN THE ABSENCE OF AN
EFFECTIVE REGISTRATION STATEMENT OR AN OPINION OF COUNSEL OR OTHER EVIDENCE
ACCEPTABLE TO PSIVIDA LIMITED THAT REGISTRATION IS NOT REQUIRED.

                             FORM OF PSIVIDA LIMITED
                                WARRANT AGREEMENT

              VOID AFTER 5:00 P.M. NEW YORK TIME, SEPTEMBER 9, 2008

Issue Date: September 9, 2005

     1. Basic Terms. This warrant agreement (this "Warrant") certifies that, for
value received, the registered holder specified below or its registered assigns
(the "Holder") is the owner of a warrant of pSivida Limited, an Australian
company having its principal place of business at Level 12, BGC Centre, 28 The
Esplanade, Perth, WA 6000, Australia (the "Company"), subject to adjustments as
provided herein, to purchase ________________ American Depositary Shares of the
Company (the "Warrant Shares"), each representing ten ordinary shares of the
Company, from the Company at the price per share shown below (the "Exercise
Price").

          Holder: ______________________________

          Exercise Price per share: ______________________________

Except as specifically provided otherwise, all references in this Warrant to the
Exercise Price and the number of Warrant Shares purchasable hereunder are to the
Exercise Price and number of Warrant Shares after any adjustments are made
thereto pursuant to this Warrant.

     2. Shares Issuable. The Company represents that the Warrant Shares issuable
upon the exercise of this Warrant will at delivery be fully paid and
non-assessable and free from taxes, liens, encumbrances and charges with respect
to their purchase. The Company shall at all times reserve and hold available
sufficient shares to satisfy all conversion and purchase rights of outstanding
convertible securities, options and warrants of the Company, including this
Warrant.

     3. Method of Exercise; Fractional Shares. This Warrant is exercisable at
the option of the Holder at any time by surrendering this Warrant, on any
business day during

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the period (the "Exercise Period") beginning the business day after the issue
date of this Warrant specified above and ending at 5:00 p.m. (New York time)
three years after the issue date. This Warrant may not be exercised for fewer
than 5,000 Warrant Shares per exercise, as adjusted to reflect stock dividends,
stock splits, and other comparable changes. To exercise this Warrant, the Holder
shall surrender this Warrant at the principal office of the Company or that of
the Company's Depositary, together with the executed exercise form
(substantially in the form of that attached hereto) and together with payment
for the Warrant Shares purchased under this Warrant. Payment shall be made by
check payable to the order of the Company or by wire transfer. Promptly after
exercise, the Company shall deliver to the Company's Depositary a binding and
irrevocable instruction letter instructing the Depositary to issue to the Holder
an American Depositary Receipt representing the Warrant Shares issuable in
connection with that exercise. This Warrant is not exercisable with respect to a
fraction of a Warrant Share. In lieu of issuing a fraction of a share remaining
after exercise of this Warrant as to all full shares covered by this Warrant,
the Company shall either at its option (a) pay for the fractional share cash
equal to the same fraction at the fair market price for such share; or (b) issue
scrip for the fraction in the registered or bearer form entitling the Holder to
receive a certificate for a full American Depositary Share on surrender of scrip
aggregating a full share.

     4. Protection Against Dilution. Subject to the Listing Rules of Australian
Stock Exchange Limited, the number of Warrant Shares purchasable under this
Warrant, and the Exercise Price, shall be adjusted as set forth as follows. If
at any time or from time to time after the date of this Warrant, the Company:

          (i)  takes a record of the holders of its outstanding ordinary shares
               or American Depositary Shares for the purposes of entitling them
               to receive a dividend payable in, or other distribution of,
               ordinary shares or American Depositary Shares; or

          (ii) subdivides its outstanding ordinary shares or American Depositary
               Shares into a larger number of ordinary shares or American
               Depositary Shares; or

          (iii) combines its outstanding ordinary shares or American Depositary
               Shares into a smaller number of ordinary shares or American
               Depositary Shares;

then, and in each such case, the Exercise Price shall be adjusted to that price
determined by multiplying the Exercise Price in effect immediately prior to such
event by a fraction (A) the numerator of which is the total number of
outstanding ordinary shares or American Depositary Shares (as applicable)
immediately prior to such event and (B) the denominator of which is the total
number of outstanding ordinary shares or American Depositary Shares (as
applicable) immediately after such event.

Upon each adjustment in the Exercise Price under this Warrant the number of
Warrant Shares purchasable under this Warrant will be adjusted by multiplying
the number of


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Warrant Shares by a fraction, the numerator of which is the Exercise Price
immediately prior to such adjustment and the denominator of which is the
Exercise Price in effect upon such adjustment.

     5. Adjustment for Reorganization, Consolidation, Merger, Etc.

          (a) During the Exercise Period, the Company shall, prior to
consummation of a consolidation with or merger into another corporation, or
conveyance of all or substantially all of its assets to any other corporation or
corporations, whether affiliated or unaffiliated (any such corporation being
included within the meaning of the term "successor corporation"), or entry into
any agreement to so consolidate, merge or convey assets, require the successor
corporation to assume, by written instrument delivered to the Holder, the
obligation to issue and deliver to the Holder such shares of stock, securities
or property as, in accordance with the provisions of Section 5(b), the Holder is
entitled to purchase or receive.

          (b) In the event of any capital reorganization or reclassification of
the stock of the Company (or any other corporation the stock or other securities
of which are at the time receivable on the exercise of this Warrant) during the
Exercise Period, or in the event that during the Exercise Period the Company (or
any such other corporation) consolidates with or merges into another corporation
or conveys all or substantially all its assets to another corporation, the
Holder, upon exercise, at any time after the consummation of such
reorganization, consolidation, merger or conveyance, will be entitled to
receive, in lieu of Warrant Shares (or stock of such other corporation), the
proportionate share of all stock, securities or other property issued, paid or
delivered for or on all of the stock of the Company (or such other corporation)
as is allocable to the Warrant Shares then called for by this Warrant as if the
Holder had exercised the Warrant immediately prior thereto, all subject to
further adjustment as provided in Section 4.

     6. Notice of Adjustment. On the happening of an event requiring an
adjustment of the Exercise Price or the shares purchasable under this Warrant,
the Company shall immediately give written notice to the Holder stating the
adjusted Exercise Price and the adjusted number and kind of securities or other
property purchasable under this Warrant resulting from the event and setting
forth in reasonable detail the method of calculation and the facts upon which
the calculation is based.

     7. Dissolution, Liquidation. In case of the voluntary or involuntary
dissolution, liquidation or winding up of the Company (other than in connection
with a reorganization, consolidation, merger, or other transaction covered in
Section 5) is at any time proposed, the Company shall give at least thirty days'
prior written notice to the Holder. Such notice shall contain the following: (a)
the date on which the transaction is to take place; (b) the record date (which
shall be at least thirty days after the giving of the notice) as of which
holders of Common Stock will be entitled to receive distributions as a result of
the transaction; (c) a brief description of the transaction, (d) a brief
description of the distributions to be made to holders of ordinary shares of the
Company as a result of the transaction; and (e) an estimate of the fair value of
the distributions. On the date of


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the transaction, if it actually occurs, this Warrant and all rights under this
Warrant will terminate.

     8. Rights of Holder. The Company shall deliver to the Holder all notices
and other information provided to holders of ordinary shares of the Company or
other securities issuable under this Warrant concurrently with the delivery of
such information to those holders. This Warrant does not entitle the Holder to
any voting rights or, except for the foregoing notice provisions, any other
rights as a shareholder of the Company. No dividends are payable or will accrue
on this Warrant or the Warrant Shares purchasable under this Warrant until, and
except to the extent that, this Warrant is exercised. Upon surrender of this
Warrant and payment of the Exercise Price as provided above, the person or
entity entitled to receive the Warrant Shares issuable upon such exercise shall
be treated for all purposes as the record holder of such shares as of the close
of business on the date of the surrender of this Warrant for exercise as
provided above. Upon the exercise of this Warrant, the Holder will have all of
the rights of a shareholder in the Company.

     9. Exchange for Other Denominations. This Warrant is exchangeable, on its
surrender by the Holder to the Company, for a new Warrant of like tenor and date
representing in the aggregate the right to purchase the balance of the number of
shares purchasable under this Warrant in denominations and subject to
restrictions on transfer contained herein, in the names designated by the Holder
at the time of surrender.

     10. Substitution. Upon receipt by the Company of evidence satisfactory (in
the exercise of reasonable discretion) to it of the ownership of and the loss,
theft or destruction or mutilation of the Warrant, and (in the case or loss,
theft or destruction) of indemnity satisfactory (in the exercise of reasonable
discretion) to it, and (in the case of mutilation) upon the surrender and
cancellation thereof, the Company will issue and deliver, in lieu thereof, a new
Warrant of like tenor.

     11. Restrictions on Transfer; Registration Rights. Neither this Warrant nor
the Warrant Shares issuable on exercise of this Warrant have been registered
under the Securities Act of 1933, as amended, or any other securities laws (the
"Acts"). Neither this Warrant nor the Warrant Shares purchasable hereunder may
be sold, transferred, pledged or hypothecated in the absence of (a) an effective
registration statement for this Warrant or the American Depositary Shares
purchasable hereunder under the Acts, or (b) an opinion of counsel reasonably
satisfactory to the Company that registration is not required under the Acts.
Transfer of this Warrant and the Warrant Shares is further subject to the terms
of the Securities Purchase Agreement between the Holder and the Company dated
the date of this Warrant. If the Holder seeks an opinion as to transfer without
registration from Holder's counsel, the Company shall provide such factual
information to Holder's counsel as Holder's counsel reasonably requests for the
purpose of rendering such opinion. Any certificate evidencing Warrant Shares
purchased hereunder will bear a legend describing the restrictions on transfer
contained in this Section 11 unless, in the opinion of counsel reasonably
acceptable to the Company, the shares need no longer to be subject to the
transfer restrictions.


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     12. Transfer. Except as otherwise provided in this Warrant, this Warrant is
transferable only on the books of the Company by the Holder in person or by
attorney, on surrender of this Warrant, properly endorsed.

     13. Recognition of Holder. Prior to due presentment for registration of
transfer of this Warrant, the Company shall treat the Holder as the person
exclusively entitled to receive notices and otherwise to exercise rights under
this Warrant. All notices required or permitted to be given to the Holder shall
be in writing and shall be given by first class mail, postage prepaid, addressed
to the Holder at the address of the Holder appearing in the records of the
Company.

     14. Payment of Taxes. The Company shall pay all taxes and other
governmental charges, other than applicable income taxes, that may be imposed
with respect to the issuance of Warrant Shares pursuant to the exercise of this
Warrant.

     15. Headings. The headings in this Warrant are for purposes of convenience
in reference only, shall not be deemed to constitute a part of this Warrant, and
shall not affect the meaning or construction of any of the provisions of this
Warrant.

     16. Miscellaneous. This Warrant may not be changed, waived, discharged or
terminated except by an instrument in writing signed by the Company and the
Holder. This Warrant shall inure to the benefit of and shall be binding upon the
successors and assigns of the Company. Under no circumstances may this Warrant
be assigned by the Holder.

     17. Governing Law. This Warrant shall be governed by and construed in
accordance with the laws of the State of New York without giving effect to its
principles governing conflicts of law.

                                        PSIVIDA LIMITED


                                        By:
                                            ------------------------------------
                                            Gavin Rezos
                                            Managing Director


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                                PSIVIDA LIMITED
                                FORM OF TRANSFER

             (To be executed by the Holder to transfer the Warrant)

For value received the undersigned registered holder of the attached Warrant
hereby sells, assigns, and transfers the Warrant to the Assignee(s) named below:

<TABLE>
<CAPTION>
                                                  Number of Shares
                                                     Subject to
Names of Assignee   Address   Taxpayer ID No.   Transferred Warrant
-----------------   -------   ---------------   -------------------
<S>                 <C>       <C>               <C>

</TABLE>

The undersigned registered holder further irrevocably appoints _________________
___________________________________ attorney (with full power of substitution)
to transfer this Warrant as aforesaid on the books of the Company.


Date:
      -----------------------           ----------------------------------------
                                        Signature


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                                 PSIVIDA LIMITED
                                  EXERCISE FORM

                    (To be executed by the Holder to purchase
               American Depositary Shares pursuant to the Warrant)

The undersigned holder of the attached Warrant hereby: (1) irrevocably elects to
exercise purchase rights represented by such Warrant for, and to purchase,
___________ American Depositary Shares of pSivida Limited, an Australian
company, and encloses a check or has wired payment of $_________________________
therefor; (2) requests that an American Depositary Receipt representing those
American Depositary Shares be issued in the name of the undersigned; and (3) if
such number of shares is not all of the shares purchasable under this Warrant,
that a new Warrant of like tenor for the balance of the remaining shares
purchasable under this Warrant be issued.


Date:
      -----------------------           ----------------------------------------
                                        Signature


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