THIS
      WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE BEEN ACQUIRED
      FOR
      INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
      AMENDED (THE “ACT”), OR ANY STATE SECURITIES LAW. THIS WARRANT AND SUCH
      SECURITIES MAY NOT BE OFFERED, SOLD OR OTHERWISE PLEDGED, TRANSFERRED OR
      HYPOTHECATED IN THE ABSENCE OF SUCH REGISTRATION OR DELIVERY OF AN OPINION
      OF
      COUNSEL IN FORM AND SUBSTANCE REASONABLY SATISFACTORY TO THE COMPANY THAT SUCH
      OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE WITH THE
      ACT
      OR UNLESS SOLD IN FULL COMPLIANCE WITH RULE 144 UNDER THE ACT.




**Lev
      Pharmaceuticals, Inc.**




***Warrant
      for the Purchase of Shares of*** ***Common Stock***


No.****B2007-01
              900,000
                  Shares




FOR
      VALUE
      RECEIVED, Lev Pharmaceuticals, Inc., a Delaware corporation (the “ **Company** ”),
      hereby certifies that Mast Credit Opportunities I Master Fund, its designee
      or
      its permitted assigns is entitled to purchase from the Company, at any time
      or
      from time to time commencing on November 2, 2007 and prior to 5:00 P.M., New
      York City time, on November 1, 2010 (the “ **Exercise
      Period** ”),
      900,000 fully paid and non-assessable shares of common stock, $.01 pa value
      per
      share (the “ **Common
      Stock** ”),
      of
      the Company for a purchase price per share of $1.6576. Hereinafter, (i) said
      common stock of the Company, is referred to as the “ **Common
      Stock** ”;
      (ii)
      the shares of the Common Stock (subject to adjustment as set forth herein)
      purchasable hereunder or under any other Warrant (as hereinafter defined) are
      referred to as the “ **Warrant
      Shares** ”;
      (iii)
      the aggregate purchase price payable for the Warrant Shares purchasable
      hereunder is referred to as the “ **Aggregate
      Warrant Price** ”;
      (iv)
      the price payable for each of the Warrant Shares hereunder is referred to as
      the
“ **Per
      Share Warrant Price** ”;
      (v)
      this Warrant, any similar Warrants issued on the date hereof and any warrants
      hereafter issued in exchange or substitution for this Warrant or such similar
      Warrants are referred to as the “ **Warrants** ”;
      (vi)
      the holder of this Warrant is referred to as the “ **Holder** ”
and
      the
      holder of this Warrant and all other Warrants and Warrant Shares are referred
      to
      as the “ **Holders** ”
and
      Mast Capital Management, LLC, LLC is referred to as the “ **Holders’
      Agent** ”;
      and
      (vii) the then “ **Current
      Market Price** ”
per
      share of the Common Stock shall be deemed to be the
      average closing sale price of the Common Stock for the ten (10) Trading Days
      (as
      defined below) immediately prior
      to
      such date or, in case no such reported sales take place on such day, the average
      of the last reported bid and asked prices of the Common Stock on such day,
      in
      either case on the principal national securities exchange on which the Common
      Stock is admitted to trading or listed, or if not listed or admitted to trading
      on any such exchange, the representative closing sale price of the Common Stock
      as reported by the National Association of Securities Dealers, Inc. Automated
      Quotations System (“ **NASDAQ** ”),
      or
      other similar organization if NASDAQ is no longer reporting such information,
      or, if the Common Stock is not reported on NASDAQ, the closing share price
      for
      the Common Stock in the over-the-counter market as reported by the National
      Quotation Bureau or similar organization, or if not so available, the fair
      market value of the Common Stock as determined in good faith by the Company’s
      Board of Directors. A “ **Trading
      Day** ”
shall
      mean any day on which shares of the Company’s Common Stock are sold, or eligible
      for sale, on the respective exchange, quotation system or over-the-counter
      market. The Aggregate Warrant Price is not subject to
      adjustment.







This
      Warrant, together with any warrants of like tenor, constituting in the aggregate
      Warrants to purchase 900,000 Warrant Shares, is being issued in connection
      with
      that certain Term
      Loan Agreement, dated as of November 2, 2007 (as it may be amended or modified
      from time to time the “ **Credit
      Agreement** ”)
      by and
      among the Company, its wholly-owned subsidiary, Lev Development Corp.
      (collectively, the “ **Borrowers** ”),
      the
      lenders from time to time party thereto (the “ **Lenders** ”),
      and
      Mast Capital Management, LLC as administrative agent and collateral agent (the
      “ **Agent** ”)





**1.**  **Exercise
      of Warrant** .





(a)  This
      Warrant may be exercised in whole at any time, or in part from time to time,
      by
      the Holder during the Exercise Period:





(i)  by
      the surrender of this Warrant (with the subscription form at the end hereof
      duly
      executed) at the address set forth in subsection 9(a) hereof, together with
      proper payment of the Aggregate Warrant Price, or the proportionate part thereof
      if this Warrant is exercised in part, with payment for the Warrant Shares made
      by certified or official bank check payable to the order of, or wire transfer
      of
      immediately available funds to, the Company; or





(ii)  by
      the surrender of this Warrant (with the cashless exercise form at the end hereof
      duly executed) (a “ **Cashless
      Exercise** ”)
      at the address set forth in subsection 9(a) hereof. Such presentation and
      surrender shall extinguish the Holder’s obligation to pay the Aggregate Warrant
      Price, or the proportionate part thereof if this Warrant is exercised in part.
      In the event of a Cashless Exercise, the Holder shall exchange its Warrant
      for
      that number of Warrant Shares subject to such Cashless Exercise as is equal
      to
      the product of (A) the number of Warrant Shares with respect to which this
      Warrant is being exercised multiplied by (B) a fraction, the numerator of which
      shall be the difference between the then Current Market Price and the Per Share
      Warrant Price, and the denominator of which shall be the then Current Market
      Price.





(b)  If
      this Warrant is exercised in part, this Warrant must be exercised for a number
      of whole shares of the Common Stock and the Holder is entitled to receive a
      new
      Warrant covering the Warrant Shares that have not been exercised and setting
      forth the proportionate part of the Aggregate Warrant Price applicable to such
      Warrant Shares. Upon surrender of this Warrant in connection with the exercise
      of this Warrant pursuant to the terms hereof, the Company will (i) issue a
      certificate or certificates in the name of the Holder for the largest number
      of
      whole shares of the Common Stock to which the Holder shall be entitled upon
      such
      exercise and, if this Warrant is exercised in whole, in lieu of any fractional
      share of the Common Stock to which the Holder shall be entitled, pay to the
      Holder cash in an amount equal to the fair value of such fractional share
      (determined in such reasonable manner as the Board of Directors of the Company
      shall determine), and (ii) deliver the other securities and properties
      receivable upon the exercise of this Warrant, or the proportionate part thereof,
      if this Warrant is exercised in part, pursuant to the provisions of this
      Warrant.


2




**2.**  **Reservation
      of Warrant Shares; Listing** .





The
      Company agrees that, prior to the expiration of this Warrant, the Company shall
      at all times (a) have authorized and in reserve, and shall keep available,
      solely for issuance and delivery upon the exercise of this Warrant, the shares
      of the Common Stock and other securities and properties as from time to time
      shall be receivable upon the exercise of this Warrant, free and clear of all
      restrictions on sale or transfer, other than under Federal or state securities
      laws, and free and clear of all preemptive rights and rights of first refusal
      and (b) if the Company hereafter lists its Common Stock on any national
      securities exchange, use its commercially reasonable efforts to keep the Warrant
      Shares authorized for listing on such exchange upon notice of
      issuance.





**3.**  **Certain
      Adjustments** .





(a)  In
      case
      the Company shall hereafter (i) pay a dividend or make a distribution on its
      Common Stock in shares of Common Stock, (ii) subdivide its outstanding shares
      of
      Common Stock into a greater number of shares or (iii) combine or reverse-split
      its outstanding shares of Common Stock into a smaller number of shares, then
      the
      Per Share Warrant Price and the number of Warrant Shares shall forthwith be
      proportionately decreased and increased, respectively, in the case of a
      subdivision, distribution or stock dividend, or proportionately increased and
      decreased, respectively, in the case of a combination or reverse stock split.
      The Aggregate Warrant Price payable for the then total number of Warrant Shares
      available for exercise under this Warrant shall remain the same. Adjustments
      made pursuant to this subsection 3(a) shall become effective on the record
      date
      in the case of a dividend or distribution, and shall become effective
      immediately after the effective date in the case of a subdivision, combination
      or reclassification. If such dividend, distribution, subdivision or combination
      is not consummated in full, the Per Share Warrant Price and Warrant Shares
      shall
      be readjusted accordingly.




(b)  In
      case
      of any capital reorganization or reclassification, any consolidation or merger,
      or any sale, transfer or other disposition of all or substantially all of its
      property, assets or shares to which the Company is a party, the Holder of this
      Warrant shall have the right thereafter to receive upon the exercise of this
      Warrant the kind and amount of securities, cash or other property which the
      Holder would have owned or have been entitled to receive immediately after
      such
      reorganization, reclassification, consolidation, merger or reorganization had
      this Warrant been exercised immediately prior to the effective date of such
      transaction and in any such case, if necessary, appropriate adjustment shall
      be
      made in the application of the provisions set forth in this Section 3 with
      respect to the rights and interests thereafter of the Holder of this Warrant
      to
      the end that the provisions set forth in this Section 3 shall thereafter
      correspondingly be made applicable, as nearly as may reasonably be, in relation
      to any shares of stock or other securities or property thereafter deliverable
      on
      the exercise of this Warrant. The above provisions of this subsection 3(b)
      shall
      similarly apply to successive reorganizations, reclassifications,
      consolidations, mergers or other dispositions. The Company shall require the
      issuer of any shares of stock or other securities or property thereafter
      deliverable on the exercise of this Warrant to be responsible for all of the
      agreements and obligations of the Company hereunder. Notice
      of
      any such reorganization, reclassification, consolidation or merger, shall be
      mailed to the Holders of Warrants not less than twenty (20) days prior to such
      event.




3




(c)  No
      adjustment in the Per Share Warrant Price shall be required unless such
      adjustment would require an increase or decrease of at least $0.01 per share
      of
      Common Stock; provided , however ,
      that any adjustments which by reason of this subsection 3(c) are not required
      to
      be made shall be carried forward and taken into account in any subsequent
      adjustment; provided , further ,
      however, that adjustments shall be required and made in accordance with the
      provisions of this Section 3 (other than this subsection 3(c)) not later than
      such time as may be required in order to preserve the tax-free nature of a
      distribution, if any, to the Holder of this Warrant or Common Stock issuable
      upon the exercise hereof. All calculations under this Section 3 shall be made
      to
      the nearest cent or to the nearest 1/100th of a share, as the case may be.
      Anything in this Section 3 to the contrary notwithstanding, the Company shall
      be
      entitled to make such reductions in the Per Share Warrant Price, in addition
      to
      those required by this Section 3, as it in its discretion shall deem to be
      advisable in order that any stock dividend, subdivision of shares or
      distribution of rights to purchase stock or securities convertible or
      exchangeable for stock hereafter made by the Company to its stockholders shall
      not be taxable.





(d)  Whenever
      the Per Share Warrant Price or the number of Warrant Shares is adjusted as
      provided in this Section 3 and upon any modification of the rights of a Holder
      of Warrants in accordance with this Section 3, the Company shall promptly
      prepare a brief statement of the facts requiring such adjustment or modification
      and the manner of computing the same and cause copies of such certificate to
      be
      mailed to the Holders of the Warrants. The Company may, but shall not be
      obligated to unless requested by the Holders’ Agent, obtain, at its expense, a
      certificate of a firm of independent public accountants of recognized standing
      selected by the Board of Directors (who may be the regular auditors of the
      Company) setting forth the Per Share Warrant Price and the number of Warrant
      Shares in effect after such adjustment or the effect of such modification,
      a
      brief statement of the facts requiring such adjustment or modification and
      the
      manner of computing the same and cause copies of such certificate to be mailed
      to the Holders of the Warrants.





(e)  If
      the Board of Directors of the Company shall declare any dividend or other
      distribution with respect to the Common Stock, the Company shall mail notice
      thereof to the Holders of the Warrants not less than twenty (20) days prior
      to the record date fixed for determining stockholders entitled to participate
      in
      such dividend or other distribution.





(f)  If,
      as a
      result of an adjustment made pursuant to this Section 3, the Holder of any
      Warrant thereafter surrendered for exercise shall become entitled to receive
      shares of two or more classes of capital stock or shares of Common Stock and
      other capital stock of the Company, the Board of Directors (whose determination
      shall be conclusive and shall be described in a written notice to the Holder
      of
      any Warrant promptly after such adjustment) shall determine ,
      in good faith, the
      allocation of the adjusted Per Share Warrant Price between or among shares
      or
      such classes of capital stock or shares of Common Stock and other capital
      stock.


4





**4.**  **Fully
      Paid Stock; Taxes** .
      The shares of the Common Stock represented by each and every certificate for
      Warrant Shares delivered on the proper exercise of this Warrant shall, at the
      time of such delivery, be duly authorized, validly issued and outstanding,
      fully
      paid and nonassessable, and not subject to preemptive rights or rights of first
      refusal imposed by any agreement to which the Company is a party, and the
      Company will take all such actions as may be necessary to assure that the par
      value, if any, per share of the Common Stock is at all times equal to or less
      than the then Per Share Warrant Price. The Company shall pay, when due and
      payable, any and all Federal and state stamp, original issue or similar taxes
      which may be payable in respect of the issue of any Warrant Share or any
      certificate thereof to the extent required because of the issuance by the
      Company of such security.





**5.**  **Registration
      Under Securities Act of 1933** .





(a)  The
      Holder shall be entitled to all of the rights and subject to all of the
      obligations regarding registration of the Warrant Shares, as described in that
      certain Registration Rights Agreement between the Company and the original
      holder hereof and dated as of the original issue date of this
      Warrant.





(b)  Until
      all of the Warrant Shares have been sold under a Registration Statement or
      pursuant to an exemption from registration under the Act, including pursuant
      to
      Rule 144, so long as the Company’s Common Stock remains registered under the
      Act, the Company shall use its commercially reasonable efforts to file with
      the
      Securities and Exchange Commission all current reports and the information
      as
      may be necessary to enable the Holder to effect sales of its shares in reliance
      upon Rule 144 promulgated under the Act.





**6.**  **Investment
      Intent; Limited Transferability.**





(a)  By
      accepting this Warrant, the Holder represents to the Company that it understands
      that this Warrant and any securities obtainable upon exercise of this Warrant
      have not been registered for sale under Federal or state securities laws and
      are
      being offered and sold to the Holder pursuant to one or more exemptions from
      the
      registration requirements of such securities laws. In the absence of an
      effective registration of such securities or an exemption therefrom, any
      certificates for such securities shall bear the legend set forth on the first
      page hereof; provided however, that following the effective date of the
      Registration Statement (as such term is defined in the Registration Rights
      Agreement), such legend may, at the request of the Holder, be removed from
      the
      certificates evidencing such Warrant Shares prior to the resale thereof and
      the
      Company will rescind any stop transfer orders with respect to such shares given
      to the Company’s transfer agent, provided that the Holder represents and
      covenants to the Company in writing (in a form reasonably acceptable to the
      Company and its counsel) that (1) such Holder will sell such Warrant Shares
      only
      pursuant to and in the manner contemplated by the Registration Statement,
      including the Plan of Distribution section contained therein, and otherwise
      in
      compliance with the Act, including the prospectus delivery requirements of
      such
      Act and (2) such other agreements or covenants as the Company or its counsel
      may
      reasonably request. Subject to the foregoing, at such time and to the extent
      a
      legend is no longer required for the Warrant Shares, the Company will use its
      best efforts to, no later than three (3) trading days following the delivery
      to
      the Company or the Company’s transfer agent by the holder of such Warrant Shares
      of a legended certificate representing such Warrant Shares (together with such
      accompanying documentation or representations as reasonably required by counsel
      to the Company), deliver or cause to be delivered a certificate representing
      such Warrant Shares that is free from the foregoing legend. The Holder
      understands that it must bear the economic risk of its investment in this
      Warrant and any securities obtainable upon exercise of this Warrant for an
      indefinite period of time, as this Warrant and such securities have not been
      registered under Federal or state securities laws and therefore cannot be sold
      unless subsequently registered under such laws, unless an exemption from such
      registration is available. The Holder further represents to the Company, by
      accepting this Warrant that it has full power and authority to accept this
      Warrant and make the representations set forth herein.




5




(b)  The
      Holder, by its acceptance of this Warrant, represents to the Company that it
      is
      acquiring this Warrant and will acquire any securities obtainable upon exercise
      of this Warrant for its own account for investment and not with a view to,
      or
      for sale in connection with, any distribution thereof in violation of the Act.
      The Holder agrees, by acceptance of this Warrant, that this Warrant and any
      such
      securities issuable
      under this Warrant will
      not
      be sold or otherwise transferred unless
      (i) a registration statement with respect to such transfer is effective under
      the Act and any applicable state securities laws or (ii) such sale or transfer
      is made pursuant to one or more exemptions from the Act.





(c)  In
      addition to the limitations set forth in Section 1 and in accordance with the
      legend on the first page hereof, this Warrant may not be sold, transferred,
      assigned or hypothecated by the Holder except in compliance with the provisions
      of the Act and the applicable state securities “blue sky” laws, and is so
      transferable only upon the books of the Company which it shall cause to be
      maintained for such purpose. The Company may treat the registered Holder of
      this
      Warrant as it appears on the Company’s books at any time as the Holder for all
      purposes. The Company shall permit any Holder of a Warrant or its duly
      authorized attorney, upon written request during ordinary business hours, to
      inspect and copy or make extracts from its books showing the registered Holders
      of Warrants. All Warrants issued upon the transfer or assignment of this Warrant
      will be dated the same date as this Warrant, and all rights of the holder
      thereof shall be identical to those of the Holder unless, in each case,
      otherwise prohibited by applicable law.





(d)  The
      Holder has been afforded (i) the opportunity to ask such questions as it has
      deemed necessary of, and to receive answers from, representatives of the Company
      concerning the terms and conditions of the Warrants or the exercise of the
      Warrants; and (ii) the opportunity to request such additional information which
      the Company possesses or can acquire without unreasonable effort or
      expense.





(e)  The
      Holder did not (i) receive or review any advertisement, article, notice or
      other
      communication published in a newspaper or magazine or similar media or broadcast
      over television or radio, whether closed circuit, or generally available; or
      (ii) attend any seminar, meeting or investor or other conference whose attendees
      were, to such Holder’s knowledge, invited by any general solicitation or general
      advertising.


6




(f)  The
      Holder is an “accredited investor” within the meaning of Regulation D under the
      Act. Such Holder is acquiring the Warrants for its own account and not with
      a
      present view to, or for sale in connection with, any distribution thereof in
      violation of the registration requirements of the Act, without prejudice,
      however, to such Holder’s right, subject to the provisions of this Warrant, at
      all times to sell or otherwise dispose of all or any part of such Warrants
      and
      Warrant Shares.





(g)  Either
      by reason of such Holder’s business or financial experience or the business or
      financial experience of its professional advisors (who are unaffiliated with
      and
      who are not compensated by the Company or any affiliate, finder or selling
      agent
      of the Company, directly or indirectly), such Holder has the capacity to protect
      such Holder’s interests in connection with the transactions contemplated by this
      Warrant and the Credit Agreement .
      The Holder, by its acceptance of this Warrant, represents to the Company that
      it
      is able to fend for itself, can bear the economic risk of its investment and
      has
      such knowledge and experience in financial or business matters that it is
      capable of evaluating the merits and risks of the investment in this Warrant.
      Holder also represents it has not been organized for the purpose of acquiring
      this Warrant.




**7.**  **Loss,
      etc., of Warrant** .
      Upon receipt of evidence reasonably satisfactory to the Company of the loss,
      theft, destruction or mutilation of this Warrant, and of indemnity reasonably
      satisfactory to the Company, if lost, stolen or destroyed, and upon surrender
      and cancellation of this Warrant, if mutilated, the Company shall execute and
      deliver to the Holder a new Warrant of like date, tenor and
      denomination.





**8.**  **Warrant
      Holder Not Stockholder** .
      This Warrant does not confer upon the Holder any right to vote on or consent
      to
      or receive notice as a stockholder of the Company, as such, in respect of any
      matters whatsoever, nor any other rights or liabilities as a stockholder, prior
      to the exercise hereof; this Warrant does, however, require certain notices
      to
      Holders as set forth herein.





**9.**  **Communication** .
      No notice or other communication under this Warrant shall be effective or deemed
      to have been given unless, the same is in writing and is mailed by first-class
      mail, postage prepaid, or via recognized overnight courier with confirmed
      receipt, addressed to:





(a)  the
      Company at Lev Pharmaceuticals, Inc., 675 Third Avenue, Suite 2200, New York,
      NY
      10017, Attn: Chief Executive Officer, or other such address as the Company
      has
      designated in writing to the Holder; or


(b)  the
      Holder at the address in the Credit Agreement, or other such address as the
      Holder has designated in writing to the Company.





**10.**  **Headings** .
      The headings of this Warrant have been inserted as a matter of convenience
      and
      shall not affect the construction hereof.





**11.**  **Applicable
      Law** .
      This Warrant shall be governed by and construed in accordance with the law
      of
      the State of New York without giving effect to the principles of conflicts
      of
      law thereof.


7




**12.**  **Amendment,
      Waiver, etc** .
      Except as expressly provided herein, neither this Warrant nor any term hereof
      may be amended, waived, discharged or terminated other than by a written
      instrument signed by the party against whom enforcement of any such amendment,
      waiver, discharge or termination is sought; provided, however, that any
      provisions hereof may be amended, waived, discharged or terminated upon the
      written consent of the Company and the Holders’ Agent.





*
      * * * *


8





**IN
      WITNESS WHEREOF,** the Company has caused this Warrant to be signed by the undersigned duly
      authorized officer as of November 2, 2007.








**Lev
      Pharmaceuticals, Inc.**











By: /s/
      Joshua D. Schein


Name:  Joshua
      D. Schein


Title: Chief
      Executive Officer








**SUBSCRIPTION**  ***(cash)***





The
      undersigned, ___________________, pursuant to the provisions of the foregoing
      Warrant, hereby agrees to subscribe for and purchase ____________________ shares
      of the Common Stock of Lev Pharmaceuticals, Inc. covered by said Warrant, and
      makes payment therefor in full at the price per share provided by said
      Warrant.






Dated:
              
              Signature:Address:







**CASHLESS
      EXERCISE**





The
      undersigned _____________, pursuant to the provisions of the foregoing Warrant,
      hereby elects to exchange its Warrant for ___________________ shares of Common
      Stock of Lev Pharmaceuticals, Inc. pursuant to the Cashless Exercise provisions
      of the Warrant.





Dated:
                
                Signature:Address:


**ASSIGNMENT**





FOR
      VALUE RECEIVED _______________ (“ **Assignor** ”)
      hereby sells, assigns and transfers unto ____________________ (“ **Transferee** ”)
      the foregoing Warrant and all rights evidenced thereby, and does irrevocably
      constitute and appoint _____________________, attorney, to transfer said Warrant
      on the books of Lev Pharmaceuticals, Inc. By acceptance of the foregoing
      Warrant, Transferee shall become a Holder under said Warrant and subject to
      the
      rights, obligations and representations of Holder set forth in said
      Warrant.





ASSIGNOR:




Dated:
                
                Signature:Address:





TRANSFEREE:


Dated:
                
                Signature:Address:





**PARTIAL
      ASSIGNMENT**





FOR
      VALUE RECEIVED _______________ (“ **Assignor** ”)
      hereby assigns and transfers unto ____________________ (“ **Transferee** ”)
      the right to purchase _______ shares of Common Stock of Lev Pharmaceuticals,
      Inc. covered by the foregoing Warrant, and a proportionate part of said Warrant
      and the rights evidenced thereby, and does irrevocably constitute and appoint
      ____________________, attorney, to transfer such part of said Warrant on the
      books of Lev Pharmaceuticals, Inc. By acceptance of the proportionate part
      of
      foregoing Warrant, Transferee shall become a Holder under said proportionate
      part of said Warrant and subject to the rights, obligations and representations
      of Holder set forth in said Warrant.





ASSIGNOR:




Dated:
                
                Signature:Address:





TRANSFEREE:




Dated:
                
                Signature:Address: