WARRANT TO PURCHASE SHARES OF COMMON STOCK OF RAPTOR PHARMACEUTICALS CORP

Exhibit 4.2

WARRANT

TO PURCHASE SHARES OF COMMON STOCK

OF

RAPTOR PHARMACEUTICALS CORP.

THIS WARRANT AND THE UNDERLYING SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES OR ANY OTHER JURISDICTION. THE SECURITIES MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, HYPOTHECATED, TRANSFERRED OR ASSIGNED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER APPLICABLE SECURITIES LAWS, OR UNLESS OFFERED, SOLD, PLEDGED, HYPOTHECATED OR TRANSFERRED PURSUANT TO AN AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THOSE LAWS. THE COMPANY SHALL BE ENTITLED TO REQUIRE AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED TO THE EXTENT THAT SUCH OPINION IS REQUIRED PURSUANT TO THAT CERTAIN SECURITIES PURCHASE AGREEMENT UNDER WHICH THE SECURITIES WERE ISSUED.

WARRANT TO PURCHASE COMMON STOCK

of

RAPTOR PHARMACEUTICALS CORP.,

a Delaware corporation

Void after the date set forth in the first paragraph hereof

This certifies that, for value received, ______________, or registered assigns (“ Holder ”) is entitled, subject to the terms set forth below, to purchase from Raptor Pharmaceuticals Corp., a Delaware corporation (the “ Company ”), ______ shares of Common Stock, $0.001 par value, of the Company (such class of stock being referred to herein as “ Common Stock ”), as constituted on August 21, 2009 (the “Issue Date”), upon surrender of this Warrant, at the principal office of the Company referred to below, with the subscription form attached hereto duly executed, and simultaneous payment therefor in the form of consideration specified in Section 1 hereof, at the price of $0.35 per share (the “ Purchase Price ”). This Warrant is one of a series of warrants being issued pursuant to the terms of that certain Securities Purchase Agreement, dated August 21, 2009, by and among the Company and the original Holder of this Warrant and the other parties named therein (the “ Purchase Agreement ”). This Warrant must be exercised, if at all, prior to the earliest to occur of (i) the fifth anniversary of the Issue Date and (ii) the date of consummation of the acquisition of the Company (including, without limitation, any reorganization, merger or consolidation) that results in the stockholders

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of the Company immediately prior to such consummation date owning less than 50% of the voting power of the surviving entity or the date of consummation of the sale of all or substantially all of the assets of the Company or the date of dissolution or liquidation of the Company (each a “ Change of Control Transaction ”). Together, clause (i) and clause (ii) herein are referred to hereafter as the “Expiration Events.” The shares of Common Stock issued or issuable upon exercise of this Warrant are sometimes referred to as the “ Warrant Shares .” The term “ Warrants ” as used herein shall include this Warrant and any warrants delivered in substitution or exchange therefor as provided herein.

1.             Exercise . This Warrant may be exercised at any time or from time to time, on any business day, for all or part of the full number of Warrant Shares during the period of time described in the preceding paragraph, by surrendering it at the principal office of the Company, 9 Commercial Boulevard, Suite 200, Novato, California 94949, with the subscription form in the form attached hereto duly executed, together with payment for the Warrant Shares to be purchased, payable (a) in cash, cashier’s check and/or wire transfer of immediately available funds or (b) as set forth in Section 9 hereof. No other form of consideration shall be acceptable for the exercise of this Warrant. A Warrant shall be deemed to have been exercised immediately prior to the close of business on the date of its surrender for exercise together with delivery of payment therefor as provided above, and the person entitled to receive the shares of Common Stock issuable upon such exercise shall be treated for all purposes as the record holder of such shares as of the close of business on such date. As soon as practicable on or after such date, and in any event within 10 days thereof, the Company shall issue and deliver to the person or persons entitled to receive the same a certificate or certificates for the number of shares of Common Stock issuable upon such exercise. Upon any partial exercise, the Company will issue and deliver to Holder a new Warrant with respect to the Warrant Shares not previously purchased. No fractional shares of Common Stock shall be issued upon exercise of a Warrant. In lieu of any fractional share to which Holder would be entitled upon exercise, the Company shall pay cash equal to the product of such fraction multiplied by the then current fair market value of one share of Common Stock, as determined in good faith by the Company (the “ Common Stock Value ”).

2.             Payment of Taxes . All shares of Common Stock issued upon the exercise of a Warrant shall be duly authorized, validly issued and outstanding, fully paid and non-assessable. Holder shall pay all taxes and other governmental charges that may be imposed in respect of the issue or delivery thereof and any tax or other charge imposed in connection with any transfer involved in the issue of any certificate for shares of Common Stock in any name other than that of the registered Holder of this Warrant surrendered in connection with the purchase of such shares, and in such case the Company shall not be required to issue or deliver any stock certificate until such tax or other charge has been paid or it has been established to the Company’s satisfaction that no tax or other charge is due.

3.             Transfer and Exchange . Subject to the restrictions set forth in Section 8.1, this Warrant and all rights hereunder are transferable, in whole but not in part, only with the prior approval of the Company, which consent shall not be unreasonably withheld. If such a proposed transfer is so approved, this Warrant is transferable on the books of the Company maintained for such purpose at its principal office referred to above by Holder in person or by duly authorized attorney, upon surrender of this Warrant properly endorsed and upon payment of any necessary transfer tax or other governmental charge imposed upon such transfer. Each taker and holder of

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this Warrant, by taking or holding the same, consents and agrees that this Warrant, when endorsed in blank, shall be deemed negotiable and that when this Warrant shall have been so endorsed, the Holder hereof may be treated by the Company and all other persons dealing with this Warrant as the absolute owner hereof for any purpose and as the person entitled to exercise the rights represented hereby or to the transfer hereof on the books of the Company, any notice to the contrary notwithstanding; but until such transfer on such books, the Company may treat the registered Holder hereof as the owner for all purposes.

4.1           Adjustment for Reorganization, Consolidation, Merger . Other than in any case a Change of Control Transaction, in case of any reclassification of the Common Stock, or other securities issuable upon exercise of this Warrant, or in case of any reorganization of the Company (or, in each case, any other corporation, the stock or other securities of which are at the time receivable on the exercise of this Warrant) after the Issue Date, or in case, after such date, the Company (or any such other corporation) shall consolidate with or merge into another corporation, then and in each such case Holder, upon the exercise hereof as provided in Section 1 at any time after the consummation of such reorganization, consolidation, merger or conveyance, shall be entitled to receive, in lieu of the stock receivable upon the exercise of this Warrant prior to such consummation, the stock or other securities or property to which such Holder would have been entitled upon such consummation if such Holder had exercised this Warrant immediately prior thereto.

4.2           Adjustments for Dividends in Common Stock . If the Company at any time or from time to time after the Issue Date makes, or fixes a record date for the determination of holders of Common Stock entitled to receive, a dividend payable in additional shares of Common Stock, then and in each such event the Purchase Price then in effect shall be decreased as of the time of such issuance or, in the event such record date is fixed, as of the close of business on such record date, by multiplying the Purchase Price then in effect by a fraction (1) the numerator of which is the total number of shares of Common Stock issued and outstanding immediately prior to the time of such issuance or the close of business on such record date, and (2) the denominator of which shall be the total number of shares of Common Stock issued and outstanding immediately prior to the time of such issuance or the close of business on such record date plus the number of shares of Common Stock issuable in payment of such dividend; provided, however, that if such record date is fixed and such dividend is not fully paid on the date fixed therefor, the Purchase Price shall be recomputed accordingly as of the close of business on such record date and thereafter the Purchase Price shall be adjusted pursuant to this Section 4.2 as of the time of actual payment of such dividends.

4.3           Stock Split and Reverse Stock Split . If the Company at any time or from time to time after the Issue Date effects a subdivision of the outstanding Common Stock, the Purchase Price then in effect immediately before that subdivision shall be proportionately decreased and the number of shares of Common Stock theretofore receivable upon the exercise of this Warrant shall be proportionately increased. If the Company at any time or from time to time after the Issue Date combines the outstanding shares of Common Stock into a smaller number of shares, the Purchase Price then in effect immediately before that combination shall be proportionately increased and the number of shares of Common Stock theretofore receivable

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upon the exercise of this Warrant shall be proportionately decreased. Each adjustment under this Section 4.3 shall become effective at the close of business on the date the subdivision or combination becomes effective.

4.4           Accountants’ Certificate as to Adjustment . In each case of an adjustment in the Purchase Price or shares of Common Stock receivable on the exercise of this Warrant, the Company at its expense shall cause independent public accountants of recognized standing selected by the Company (who may be the independent public accountants then auditing the books of the Company) to compute such adjustment in accordance with the terms of this Warrant and prepare a certificate setting forth such ad