BMP SUNSTONE CORPORATION 12.5% MARCH CASH SECURED CONVERTIBLE NOTE DUE

Exhibit 4.3

BMP SUNSTONE CORPORATION
12.5% MARCH CASH SECURED CONVERTIBLE NOTE DUE
JULY 1, 2011

     THIS NOTE is one of a series of duly authorized and issued notes of BMP Sunstone Corporation, a Delaware corporation (the “ Company ”), designated as its 12.5% March Cash Secured Convertible Note due July 1, 2011, in the aggregate principal amount of up to $6,350,000 (the “ Notes ”).

     FOR VALUE RECEIVED, the Company promises to pay to the order of [ ] or his registered assigns (the “ Holder ”), the principal sum of [ ] Dollars ($[ ]) (the “ Original Principal Amount ”), on July 1, 2011 (the “ Maturity Date ”), or such earlier date as the Notes are required or permitted to be repaid as provided hereunder, and to pay interest to the Holder on the then outstanding principal amount of this Note in accordance with the provisions hereof. Notwithstanding the foregoing, the Company hereby unconditionally promises to pay to the order of the Holder interest on any principal or interest payable hereunder that shall not be paid in full when due, whether at the time of any stated interest payment date or maturity or by prepayment, acceleration or declaration or otherwise, for the period from and including the due date of such payment to but excluding the date the same is paid in full, at a rate of 18% per annum (but in no event in excess of the maximum rate permitted under applicable law).

     Interest payable under this Note shall be computed on the basis of a year of 360 days and actual days elapsed (including the first day but excluding the last day) occurring in the period for which interest is payable.

     Payments of principal and interest shall be made in lawful money of the United States of America to the Holder at its address as provided in Section 10 or by wire transfer to such account specified from time to time by the Holder hereof for such purpose as provided in Section 10.

     1.  Definitions . In addition to the terms defined elsewhere in this Note, (a) capitalized terms that are not otherwise defined herein have the meanings given to such terms in the Note Exchange Agreement, dated as of the date hereof, between the Company and the Holder (the “ Note Exchange Agreement ”), and (b) the following terms have the meanings indicated:

     “ Bankruptcy Event ” means that the Company or any Subsidiary shall commence, or there shall be commenced against the Company or any Subsidiary under any applicable bankruptcy or insolvency laws as now or hereafter in effect or any successor thereto, or the Company or any Subsidiary commences any other proceeding under any reorganization, arrangement, adjustment of debt, relief of debtors, dissolution, insolvency or liquidation or similar law of any jurisdiction whether now or hereafter in effect relating to the Company or any Subsidiary or there is commenced against the Company or any Subsidiary any such bankruptcy, insolvency or other proceeding which remains undismissed for a period of sixty-one (61) days; or the Company or any

Subsidiary is adjudicated insolvent or bankrupt; or any order of relief or other order approving any such case or proceeding is entered; or the Company or any Subsidiary suffers any appointment of any custodian, private or court appointed receiver or the like for it or any substantial part of its property which continues undischarged or unstayed for a period of sixty one (61) days; or the Company or any Subsidiary makes a general assignment for the benefit of creditors; or the Company or any Subsidiary shall fail to pay, or shall state that it is unable to pay, or shall be unable to pay, its debts generally as they become due; or the Company or any Subsidiary shall call a meeting of its creditors with a view to arranging a composition, adjustment or restructuring of its debts; or the Company or any Subsidiary shall by any act or failure to act expressly indicate its consent to, approval of or acquiescence in any of the foregoing; or any corporate or other action is taken by the Company or any Subsidiary for the purpose of effecting any of the foregoing.

     “ Business Day ” means any day except Saturday, Sunday and any day that shall be a federal legal holiday or a day on which banking institutions in the Commonwealth of Pennsylvania are authorized or required by law or other governmental action to close.

     “ Change of Control ” means the occurrence of (i) an acquisition after the date hereof by an individual or legal entity or “group” (as described in Rule 13d-5(b)(1) promulgated under the Exchange Act) of effective control (whether through legal or beneficial ownership of capital stock of the Company, by contract or otherwise) of in excess of fifty percent (50%) of the voting securities of the Company (except that the acquisition of voting securities by the Holder or any current holder of convertible securities of the Company shall not constitute a Change of Control for purposes hereof); (ii) a replacement at one time or over time of more than one-half of the members of the board of directors of the Company which is not approved by a majority of those individuals who are members of the board of directors on the date hereof (or by those individuals who are serving as members of the board of directors on any date whose nomination to the board of directors was approved by a majority of the members of the board of directors who are members on the date hereof); (iii) the merger or consolidation of the Company with or into another entity as a result of which the holders of the voting securities of the Company immediately before such merger or consolidation do not hold fifty percent (50%) or more of the voting securities of the surviving or resulting entity; (iv) the sale of fifty percent (50%) or more of the assets of the Company and its subsidiaries on a consolidated basis; or (v) the execution by the Company of an agreement to which the Company is a party or by which it is bound, providing for any of the events set forth above in (i), (ii), (iii) or (iv).

     “ Closing Market Price ” means the quoted sale price of the Common Shares as of the close of trading on the Nasdaq Global Market or any other national securities exchange, market or trading or quotation facility on which the Common Shares is then listed or quoted.

     “ Majority in Interest ” means the holders of greater than fifty percent (50%) of the aggregate principal amount of Notes then outstanding.

     “ Prepayment Price ” for any Notes which shall be subject to prepayment pursuant to Section 6, means the amount equal to the sum of the then outstanding principal amount of this Note being prepaid pursuant to Section 6 plus all accrued but unpaid interest on such outstanding principal amount of this Note.

     “ Qualified Offering ” shall mean the issuance after the date hereof of equity securities of the Company or securities convertible into equity securities in one or more offerings to investors resulting in the receipt of proceeds, net of all commissions, by the Company in an aggregate amount of at least twelve million six hundred seventy two thousand four hundred sixty three dollars ($12,672,463).

     “ Subsidiary ” means (i) any “significant subsidiary,” as defined in Item 1-02(w) of Regulation S-X promulgated by the Securities and Exchange Commission, of the Company and (ii) Sunstone China Limited (formerly named Hong Kong Fly International Health Care Limited), a Hong Kong corporation (“Sunstone China”).

     2.  Interest . The Company shall pay interest to the Holder on the aggregate then outstanding principal amount of this Note at the rate of 12.5% per annum, payable quarterly in arrears on each April 1, July 1, October 1 and January 1, except if such date is not a Business Day, in which case such interest shall be payable on the next succeeding Business Day (each, an “ Interest Payment Date ”). The first Interest Payment Date shall be April 1, 2009.

     3.  Ranking and Covenants .

     (a) Other than the 10.0% Senior Secured Promissory Notes Due May 1, 2009, no indebtedness of the Company is senior to this Note in right of payment, whether with respect to interest, damages or upon liquidation or dissolution or otherwise. The Company will not, and will not permit any Subsidiary to, directly or indirectly, enter into, create, incur, assume or suffer to exist any indebtedness of any kind, on or with respect to any of its property or assets now owned or hereafter acquired or any interest therein or any income or profits therefrom, that is not subordinated in all respects to the Company’s obligations under the Notes, other than (i) indebtedness secured by purchase money security interests (which will be senior only as to the underlying assets covered thereby), (ii) indebtedness under capital lease obligations (which will be senior only as to the assets covered thereby), (iii) indebtedness to any commercial bank or other institutional lender of commercial loans, (iv) the Notes, 12.5% Secured Convertible Note due July 1, 2011, 12.5% March Exchange Secured Convertible Note due July 1, 2011 or the 10.0% Senior Secured Promissory Notes Due May 1, 2009, or (v) any renewal, refinancing or replacement of indebtedness contemplated by clause (i) through (iv) above; provided, however, in no event shall the terms of any renewal, refinancing or replacement of the 10.0% Senior Secured Promissory Notes Due May 1, 2009 be more favorable than the terms of this Note.

     (b) So long as any Notes are outstanding, the Company shall maintain in an escrow account established pursuant to the terms of the Interest Escrow Agreement (as defined in the Note Exchange Agreement), (i) at all times after the date of transfer of the applicable funds as contemplated by Section 1.2.4 of the Note Exchange Agreement until April 1, 2009, an amount equal to the amount transferred pursuant to Section 1.2.4 of the Note Exchange Agreement, (ii) at all times after April 1, 2009 until the earlier of the closing date of a Qualified Offering or

July 1, 2009, an amount equal to (A) the amount transferred pursuant to Section 1.2.4 of the Note Exchange Agreement minus (B) the amount to be paid pursuant to Section 1.2.3 of the Note Exchange Agreement and (iii) at all times after the earlier of the closing date of a Qualified Offering or July 1, 2009, an amount equal to the interest to be paid with respect to all the Notes then outstanding on the next two succeeding Interest Payment Dates.

     (c) So long as any Notes are outstanding, (i) the Company shall own 100% of the issued and outstanding shares of capital stock or equity securities of Sunstone China, and (ii) Sunstone China shall own 100% of the issued and outstanding shares of capital stock or equity securities of Sunstone Pharmaceutical Co., Ltd., a Hong Kong corporation.

     (d) So long as any Notes are outstanding, the Company shall not declare or pay any cash dividend or distribution without the prior written consent of a Majority in Interest.

     4.  Registration of Notes . The Company shall register the Notes upon records to be maintained by the Company for that purpose (the “ Note Register ”) in the name of each record holder thereof from time to time. The Company may deem and treat the registered Holder of this Note as the absolute owner hereof for the purpose of any payment of interest or principal hereon, and for all other purposes, absent actual notice to the contrary.

     5.  Registration of Transfers and Exchanges . The Company shall register the transfer of any portion of this Note in the Note Register upon surrender of this Note to the Company at its address for notice set forth herein. Upon any such registration or transfer, a new Note, in substantially the form of this Note (any such new Note, a “ New Note ”), evidencing the portion of this Note so transferred shall be issued to the transferee and a New Note evidencing the remaining portion of this Note not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Note by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations of a Holder of a Note. This Note is exchangeable for an equal aggregate principal amount of Notes of different authorized denominations, as requested by the Holder surrendering the same. No service charge or other fee will be imposed in connection with any such registration of transfer or exchange. Notwithstanding anything herein to the contrary, the Company shall not be required at any time to register any transfer to a transferee and any transfer shall be void and of no force or effect unless the Note has been registered under the Securities Act or the Company has received an opinion of counsel reasonably acceptable to it stating that such transfer is exempt from the registration and prospectus delivery requirements of the Securities Act.

     6.  Prepayment .

     (a) At any time on or following a Change of Control and delivery of a written notice to the Company (the date such notice is delivered to the Company, the “ Notice Date ”), the Noteholder shall be entitled to demand prepayment of all or any portion of the outstanding principal amount of this Note plus any accrued and unpaid interest thereon for an amount in cash equal to the Prepayment Price.

     (b) The Prepayment Price shall be due on the fifteenth Business Day immediately following the Notice Date. If any portion of the Prepayment Price shall not be timely paid by the

Company, interest shall accrue thereon at the rate of 18% per annum (or the maximum rate permitted by applicable law, whichever is less) until the Prepayment Price plus all such interest is paid in full, which payment shall constitute liquidated damages and not a penalty.

     7.  Events of Default .

     (a) “ Event of Default ” means any one of the following events (whatever the reason and whether it shall be voluntary or involuntary or effected by operation of law or pursuant to any judgment, decree or order of any court, or any order, rule or regulation of any administrative or governmental body):

          (i) (A) any default in the payment of any principal amount of the Notes, as and when the same becomes due and payable (whether on a date specified for the payment of interest or the date on which the obligations under the Note mature or by acceleration, redemption, prepayment or otherwise), (B) any default in the payment of interest in respect of any Notes, no later than the third Business Day after such interest become due and payable (whether on a date specified for the payment of interest or the date on which the obligations under the Note mature or by acceleration, redemption, prepayment or otherwise), (C) any default by the Company in the performance of its covenants set forth in paragraphs 3(b) or 3(c) of this Note or (D) any default by the Company in the performance of any of its other covenants and obligations under this Note not listed in clauses (A), (B) or (C) above, which defaults remain uncured fifteen (15) Business Days after the Company receives written notice thereof from the Holder or a representative of the Holder;

          (ii) the Company or any Subsidiary defaults in any of its obligations under any other note or any mortgage, credit agreement or other facility, indenture agreement, factoring agreement or other instrument under which there may be issued, or by which there may be secured or evidenced, any indebtedness for borrowed money or money due under any long term leasing or factoring arrangement of the Company or any Subsidiary in an amount exceeding $1,000,000, whether such indebtedness now exists or is hereafter created, and such default results in such indebtedness becoming or being declared due and payable prior to the date on which it would otherwise become due and payable;

          (iii) any default by the Company of any of its obligations pursuant to the Note Exchange Agreement, the Pledge Agreement, the Interest Escrow Agreement or the Share Escrow Agreement; or

          (iv) the occurrence of a Bankruptcy Event.

     (b) At any time or times that an Event of Default has occurred and is continuing, (1) the full unpaid principal amount of this Note, together with interest and other amounts owing in respect thereof, to the date of acceleration shall become immediately due and payable in cash, and (2) while a non-payment default is continuing, the Note shall bear interest at a rate of 15% per annum (but in no event in excess of the maximum rate permitted under applicable law).

     (c) In connection with any Event of Default, the Holder need not provide and the Company hereby waives any pre