Exhibit 10.4

EMPLOYMENT AGREEMENT

This Employment Agreement (the “Agreement”), is entered into as of April 19, 2012 (the “Effective Date”), by and between Pacira Pharmaceuticals, Inc., a California corporation (the “Company”), and Lauren Riker (the “Employee”).

RECITALS

WHEREAS, the Company wishes to continue to employ the Employee, and the Employee desires to continue to be employed by the Company, for such purpose and upon the terms and conditions hereinafter provided; and

WHEREAS, the parties wish to establish the terms of the Employee’s future employment with the Company and set out fully their respective rights, obligations and duties.

AGREEMENT

In consideration of the promises and the terms and conditions set forth in this Agreement, the parties agree as follows:

1.                                       Title and Capacity.  The Company hereby agrees to continue to employ the Employee, and the Employee hereby accepts continued employment with the Company, under the terms set forth in this Agreement.  The Employee will serve as the Executive Director, Account and Reporting and Principal Accounting Officer of the Company and shall perform such duties as are ordinary, customary and necessary in such role.  The Employee will report directly to the Chief Financial Officer of the Company.  The Employee shall devote her full business time, skill and attention to the performance of her duties on behalf of the Company.

2.                                       Compensation and Benefits.

(a)                                  Salary.  The Company agrees to pay the Employee an annual base salary of Two Hundred Eleven Thousand and Five Hundred Twenty Dollars ($211,520) payable in accordance with Company’s customary payroll practice (the “Base Salary”).  The Employee’s Base Salary shall be reviewed periodically by the Chief Financial Officer or Chief Executive Officer of the Company; provided, however, that any such review will not necessarily result in an adjustment to the Employee’s Base Salary.

(b)                                 Bonus.  The Employee is eligible to receive, in addition to the Base Salary and subject to the terms hereof and at the full discretion of the Chief Financial Officer and/or Chief Executive Officer, a targeted incentive bonus of twenty-five percent (25%) of Base Salary (the “Targeted Incentive Bonus”).  The Targeted Incentive Bonus shall be based on the Employee’s and the Company’s performance during the applicable fiscal year.  The Targeted Incentive Bonus criteria or “goals” will be determined by agreement between the Chief Financial Officer and/or Chief Executive Officer and the Employee at beginning of each fiscal year.  The award of the Target Incentive Bonus may be in an amount either above or below the amount specified by the Chief Financial Officer and/or Chief Executive Officer at the beginning of each

fiscal year based on the ultimate performance assessed by the Chief Financial Officer and/or Chief Executive Officer

The Targeted Incentive Bonus, if awarded, shall be payable in the first payroll period in 2013, but in no event later than March 15, 2013.  Targeted Incentive Bonuses for subsequent years shall be determined and approved by the Chief Financial Officer and/or Chief Executive Officer in their sole discretion.

All salary and bonuses shall be subject to all applicable withholdings and deductions.

(c)                                  Stock Options.  On May 11, 2011, the Company granted to the Employee stock options (each an “Option” and collectively, the “Options”) to purchase an aggregate of forty thousand (40,000) shares of the Company’s common stock, $0.001 par value per share (the “Option Shares”), pursuant to the Company’s 2011 Stock Option/Stock Issuance (the “Plan”).  The exercise price, vesting schedule and other terms for each of the Options are set forth in the notice of grant and option agreement for each such Option and the Options are subject to accelerated vesting as set forth in Section 3 hereof.  Additional equity incentives, if any, shall be determined by the Board (or a committee thereof) in its sole discretion.  All share figures set forth herein shall be subject to adjustment for stock splits, stock dividends, stock combinations, recapitalizations and similar events.

(d)                                 Benefits.  The Employee(and, where applicable, the employee’s qualified dependents) will be eligible to participate in health insurance and other employee benefit plans and policies established by the Company for its employees from time to time on substantially the same terms as are made available to other such employees of the Company generally.  The Employee’s participation (and the participation of the Employee’s qualified dependents) in the Company’s benefit plans and policies will be subject to the terms of the applicable plan documents and the Company’s generally applied policies, and the Company in its sole discretion may from time to time adopt, modify, interpret or discontinue such plans or policies.

(e)                                  Expenses.  The Company will reimburse the Employee for all reasonable and necessary expenses incurred by the Employee in connection with the Company’s business, in accordance with the applicable Company policy as may be amended from time to time.

(f)                                    Vacation and Holidays.  The Employee shall be eligible for thirty (30 days’ paid vacation/flexible time off per calendar year subject to the applicable terms and conditions of the Company’s vacation policy and applicable law.

(g)                                 Termination of Benefits.  Except as set forth in Section 3 or as otherwise specified herein or in any other agreement between the Employee and the Company, if the Employee’s employment is terminated by the Company for any reason, with or without Cause (as defined below), or if the Employee resigns the Employee’s employment voluntarily, with or without Good Reason (as defined below), no compensation or other payments will be paid or provided to the Employee for periods following the date when such a termination of employment is effective, provided that any rights the Employee may have under the Company’s benefit plans

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shall be determined under the provisions of such plans.  If the Employee’s employment terminates as a result of the Employee’s death or disability, no compensation or payments will be made to the Employee other than those to which the Employee may otherwise be entitled under the benefit plans of the Company.

3.                                       Compensation and Benefits Upon Termination of Employment.  Upon termination of the Employee’s employment (such date of termination being referred to as the “Termination Date”), the Company will pay the Employee the compensation and benefits as described in this Section 3.

(a)                                  General Benefits Upon Termination.  The Company will pay the Employee on or about the Termination Date all salary and vacation/personal time off pay, if any, that has been earned or accrued through the Termination Date and that has not been previously paid.

(b)                                 Termination without “Cause” or for “Good Reason”.  In the event that the Company terminates the Employee’s employment without Cause (as defined below) or, in the event the Employee terminates her employment for Good Reason (as defined below), in each case, (i) the Employee shall be entitled to receive (A) continuing payments of the then effective Base Salary for a period of nine (9) months beginning on the Payment Commencement Date and payable in accordance with the Company’s payroll policies and (B) the benefits set forth in Section 3(e), and (ii) the Employee shall be entitled to acceleration of vesting of such number of Option Shares as would have vested in the nine (9) month period following the Termination Date had the Employee continued to be employed by the Company for such period, provided, however that in each case the receipt of such payments and benefits is expressly contingent upon the Employee’s execution and delivery of a severance and release of claims agreement drafted by and satisfactory to counsel for the Company (the “Release”) which Release must be executed and become effective within sixty (60) days following the Termination Date.  The payments and benefits shall be paid or commence on the first payroll period following the date the Release becomes effective (the “Payment Commencement Date”).  Notwithstanding the foregoing, if the 60th day following the Termination Date occurs in the calendar year following the termination, then the Payment Commencement Date shall be no earlier than January 1st of such subsequent calendar year.  The provision of payments and benefits pursuant to this Section shall be subject to the terms and conditions set forth on Exhibit A.

(c)                                  Termination without “Cause” or for “Good Reason” Prior to or Following a Change of Control.  In the event that the Company terminates the Employee’s employment without Cause (as defined below) or, in the event the Employee terminates her employment for Good Reason (as defined below), in each case, within thirty (30) days prior to, or twelve (12) months following, the consummation of a Change of Control, then (i) the Employee shall be entitled to receive (A) continuing payments of the then effective Base Salary for a period of nine (9)months beginning on the Payment Commencement Date and payable in accordance with the Company’s payroll policies and (B) the benefits set forth in Section 3(e), and (ii) acceleration of vesting of one hundred percent (100%) of the then unvested Option Shares, provided, however that in each case: (x), the receipt of such payments and benefits is expressly contingent upon the Employee’s execution and delivery of a Release as described above drafted by and satisfactory to counsel for the Company, which Release must be executed and become effective within sixty

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(60) days following the Termination Date.  The provision of payments and benefits pursuant to this Section shall be subject to the terms and conditions set forth in Exhibit A.

(d)                                 Definitions.

(i)                                     “Change of Control” means (A) a merger or consolidation of either the Company or Pacira, Inc., a Delaware corporation (“Parent”) into another entity in which the stockholders of the Company or Parent (as applicable) do not control fifty percent (50%) or more of the total voting power of the surviving entity (other than a reincorporation merger);  (B) the sale, transfer or other disposition of all or substantially all of the Company’s assets in liquidation or dissolution of the Company; or (C) the sale or transfer of more than fifty percent (50%) of the outstanding voting stock of the Company.  In the case of each of the foregoing clauses (A), (B) and (C), a Change of Control as a result of a financing transaction of the Company or Parent shall not constitute a Change of Control for purposes of this Agreement

(ii)                                  “Cause” means (A) the Employee’s failure to substantially perform her duties to the Company after there has been delivered to the Employee written notice setting forth in detail the specific respects in which the Chief Financial Officer and/or Chief Executive Officer believes that the Employee has not substantially performed her duties and, if the Company reasonably considers the situation to be correctable, a demand for substantial performance and opportunity to cure, giving the Employee thirty (30) calendar days after he receives such notice to correct the situation; (B) the Employee’s having engaged in fraud, misconduct, dishonesty, gross negligence or having otherwise acted in a manner injurious to the Company or in intentional disregard for the Company’s best interests; (C) the Employee’s failure to follow reasonable and lawful instructions from the Chief Financial Officer and/or Chief Executive Officer and the Employee’s failure to cure such failure after receiving twenty (20) days advance written notice; (D) the Employee’s material breach of the terms of this Agreement or the Employee Proprietary Information and Inventions Assignment Agreement or any other similar agreement that may be in effect from time to time; or (E) the Employee’s conviction of, or pleading guilty or nolo contendere to, any misdemeanor involving dishonesty or moral turpitude or related to the Company’s business, or any felony.

(iii)                               “Good Reason” means the occurrence of any one or more of the following events without the prior written consent of the Executive:  (A) any material reduction of the then effective Base Salary other than in accordance with this Agreement or which reduction is not related to a cross-executive team salary reduction; (B) any material breach by the Company of this Agreement; or (C) a material reduction in the Employee’s responsibilities or duties, provided that in the case of clause (C), a mere reassignment following a Change of Control to a position that is substantially similar to the position held prior to the Change of Control transaction shall not constitute a material reduction in job responsibilities or duties; provided, however, that no such event or condition shall constitute Good Reason unless (x) the Employee gives the Company a written notice of termination for Good Reason not more than ninety (90) days after the initial existence of the condition, (y) the grounds for termination (if susceptible to correction) are not corrected by the Company within thirty (30) days of its receipt of such notice and (z) the Termination Date occurs within one (1) year following the Company’s receipt of such notice.

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(e)                                  Benefits Continuation.  If the Employee’s employment is terminated pursuant to Section 3(b) or Section 3(c) and provided that the Employee is eligible for and elects to continue receiving group health and dental insurance pursuant to the federal “COBRA” law, 29 U.S.C. § 1161 et seq., the Company will, for a twelve (12) month period following the Payment Commencement Date (the “Benefits Continuation Period”), continue to pay the share of the premium for such coverage that is paid by the Company for active and similarly-situated employees who receive the same type of coverage.  The remaining balance of any premium costs shall be paid by the Employee on a monthly basis for as long as, and to the extent that, the Employee remains eligible for COBRA continuation.  Notwithstanding the above, in the event the Employee becomes eligible for health insurance benefits from a new employer during the Benefits Continuation Period, the Company’s obligations under this Section 3(e) shall immediately cease and the Employee shall not be entitled to any additional monthly premium payments for health insurance coverage.  Similarly, in the event the Employee becomes eligible for dental insurance benefits from a new employer during the Benefits Continuation Period, the Company’s obligations under this Section 3(e) shall immediately cease and the Employee shall not be entitled to any additional monthly premium payments for dental insurance.  The Employee hereby represents that he will notify the Company in writing within three (3) days of becoming eligible for health or dental insurance benefits from a new employer during the Benefits Continuation Period

(f)                                    Death.  This Agreement shall automatically terminate upon the death of the Employee and all monetary obligations of Company under Section 2 of this Agreement shall be pro rated to the date of death and paid to the Employee’s estate.

(g)                                 Disability.  The Company may terminate the Employee’s employment if the Employee is unable to perform any of the duties required under this Agreement for a period of three (3) consecutive months due to a “Total and Permanent Disability”.  The term “Total and Permanent Disability” shall mean the existence of a permanent physical or mental illness or injury, which renders the Employee incapable of performing any material obligations or terms of this Agreement.  Any dispute regarding the existence of a Total and Permanent Disability shall be resolved by a panel of three (3) physicians, one selected by Company, one selected by the Executive, and the third selected by the other two physicians.  A termination of employment pursuant to this Section 3(f) shall constitute a termination for Cause.

4.                                       At-Will Employment.  The Employee will be an “at-will” employee of the Company, which means the employment relationship can be terminated by either the Employee or the Company for any reason, at any time, with or without prior notice and with or without cause.  The Company makes no promise that the Employee’s employment will continue for any particular period of time, nor is there any promise that it will be terminated only under particular circumstances.  No raise or bonus, if any, shall alter the Employee’s status as an “at-will” employee or create any implied contract of employment.  Discussion of possible or potential benefits in future years is not an express or implied promise of continued employment.  No manager, supervisor or officer of the Company has the authority to change the Employee’s status as an “at-will” employee.  The “at-will” nature of the employment relationship with the Employee can only be altered by a written resolution approved by the Board.

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5.                                       Non-Solicitation.

(a)                                  Non-Solicit.  The Employee agrees that during the term of the Employee’s employment with the Company, and for a period of twelve (12) months immediately following the termination of the Employee’s employment with the Company for any reason, whether with or without Cause or Good Reason, the Employee shall not either directly or indirectly solicit, induce, recruit or encourage any of the Company’s or its affiliates’ employees or consultants to terminate such employee’s or consultant’s relationship with the Company or its affiliates, or attempt to solicit, induce, recruit, encourage or take away employees or consultants of the Company or any of its affiliates, either for the Employee or for any other person or entity except such restrictions shall not apply to any employee who was at any time an employee or consultant of Stack Pharmaceuticals, Inc.  Further, during the Employee’s employment with the Company or any of its affiliates and at any time following termination of the Employee’s employment with the Company or any of its affiliates for any reason, with or without Cause or Good Reason, the Employee shall not use any confidential information of the Company or any of its affiliates to attempt to negatively influence any of the Company’s or any of its affiliates’ clients or customers from purchasing Company products or services or to solicit or influence or attempt to influence any client, customer or other person either directly or indirectly, to direct such person’s or entity’s purchase of products and/or services to any person, firm, corporation, institution or other entity in competition with the business of the Company or any of its affiliates.

(b)                                 Specific Performance.  In the event of the breach or threatened breach by the Employee of this Section 5, the Company, in addition to all other remedies available to it at law or in equity, will be entitled to seek injunctive relief and/or specific performance to enforce this Section 5.

6.                                       Director and Officer Liability Insurance; Indemnification.  During the term of the Employee’s employment hereunder, the Employee shall be entitled to the same indemnification and director and officer liability insurance as the Company and its affiliates maintain for other corporate officers.

7.                                       Proprietary Information and Inventions Assignment Agreement.  The Employee has executed and delivered the Company’s standard Employee Proprietary Information and Inventions Assignment Agreement or similar agreement and the Employee represents and warrants that the Employee shall continue to be bound and abide by such Employee Proprietary Information and Inventions Assignment Agreement or similar agreement.

8.                                       Attention to Duties; Conflict of Interest.  While employed by the Company, the Employee shall devote the Employee’s full business time, energy and abilities exclusively to the business and interests of the Company, and shall perform all duties and services in a faithful and diligent manner and to the best of the Employee’s abilities. The Employee shall not, without the Company’s prior written consent, render to others services of any kind for compensation, or engage in any other business activity that would materially interfere with the performance of the Employee’s duties under this Agreement. The Employee represents that the Employee has no other outstanding commitments inconsistent with any of the terms of this Agreement or the services to be rendered to the Company.  While employed by the Company, the Employee shall

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not, directly or indirectly, whether as a partner, employee, creditor, shareholder, or otherwise, promote, participate or engage in any activity or other business competitive with the Company’s business. The Employee shall not invest in any company or business which competes in any manner with the Company, except those companies whose securities are listed on reputable securities exchanges in the United States or European Union.

9.                                       Miscellaneous.

(a)                                  Severability.  If any provision of this Agreement shall be found by any arbitrator or court of competent jurisdiction to be invalid or unenforceable, then the parties hereby waive such provision to the extent that it is found to be invalid or unenforceable and to the extent that to do so would not deprive one of the parties of the substantial benefit of its bargain.  Such provision shall, to the extent allowable by law and the preceding sentence, be modified by such arbitrator or court so that it becomes enforceable and, as modified, shall be enforced as any other provision hereof, all the other provisions continuing in full force and effect.

(b)                                 No Waiver.  The failure by either party at any time to require performance or compliance by the other of any of its obligations or agreements shall in no way affect the right to require such performance or compliance at any time thereafter.  The waiver by either party of a breach of any provision hereof shall not be taken or held to be a waiver of any preceding or succeeding breach of such provision or as a waiver of the provision itself.  No waiver of any kind shall be effective or binding, unless it is in writing and is signed by the party against whom such waiver is sought to be enforced.

(c)                                  Assignment.  This Agreement and all rights hereunder are personal to the Employee and may not be transferred or assigned by the Employee at any time.  The Company may assign its rights, together with its obligations hereunder, to any parent, subsidiary, affiliate or successor, or in connection with any sale, transfer or other disposition of all or substantially all of its business and assets; provided, however, that any such assignee assumes the Company’s obligations hereunder.

(d)                                 Withholding.  All sums payable to the Employee hereunder shall be reduced by all federal, state, local and other withholding and similar taxes and payments required by applicable law.

(e)                                  Entire Agreement.  This Agreement, including the agreements referred to herein (which are deemed incorporated by reference herein) constitute the entire and only agreement and understanding between the parties governing the terms and conditions of employment of the Employee with the Company and this Agreement supersedes and cancels any and all previous contracts, arrangements or understandings with governing the terms and conditions of the Employee’s employment by the Company. In the event of any conflict between the terms of any other agreement between the Employee and the Company entered into prior to the Effective Date, the terms of this Agreement shall control.

(f)                                    Amendment.  This Agreement may be amended, modified, superseded, cancelled, renewed or extended only by an agreement in writing executed by both parties hereto.

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(g)      Headings.  The headings contained in this Agreement are for reference purposes only and shall in no way affect the meaning or interpretation of this Agreement.  In this Agreement, the singular includes the plural, the plural included the singular, the masculine gender includes both male and female referents, and the word “or” is used in the inclusive sense.

(h)                                 Notices.  Any notices provided hereunder must be in writing and shall be deemed effective upon the earlier of personal delivery (including, personal delivery by facsimile transmission or the third day after mailing by first class mail) to the Company at its primary office location and to the Employee at her address as listed on the Company payroll (which address may be changed by written notice).

(i)                                     Counterparts.  This Agreement may be executed in two or more counterparts, each of which shall be deemed to be an original but all of which, taken together, constitute one and the same agreement.

(j)                                     Governing Law, Forum Selection, Jury Waiver.  This Agreement and the rights and obligations of the parties hereto shall be construed in accordance with the laws of the State of New Jersey without giving effect to the principles of conflict of laws.  Any action, suit or other legal proceeding that is commenced to resolve any matter arising under or relating to any provision of this Agreement shall be commenced only in a court of the State of New Jersey (or, if appropriate, a federal court located within District of New Jersey ), and the Company and the Employee each consents to the jurisdiction of such a court.  Both the Company and the Employee expressly waive any right that any party either has or may have to a jury trial of any dispute arising out of or in any way related to the Employee’s employment with or termination from the Company.

[Remainder of Page Intentionally Left Blank]

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IN WITNESS WHEREOF, the Company and the Employee have executed this Employment Agreement as of the date first above written.

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EXHIBIT A

PAYMENTS SUBJECT TO SECTION 409A

1.                                       Subject to this Exhibit A, any severance payments and benefits that may be due under the Agreement shall begin only upon the date of the Employee’s “separation from service” (determined as set forth below) which occurs on or after the termination of the Employee’s employment.  The following rules shall apply with respect to distribution of the severance payments and benefits, if any, to be provided to the Employee under the Agreement, as applicable:

(a)                                   It is intended that each installment of the severance payments and benefits under the Agreement provided under shall be treated as a separate “payment” for purposes of Section 409A.  Neither the Company nor the Employee shall have the right to accelerate or defer the delivery of any such payments or benefits except to the extent specifically permitted or required by Section 409A.

(b)                                  If, as of the date of the Employee’s “separation from service” from the Company, the Employee is not a “specified employee” (within the meaning of Section 409A), then each installment of the severance payments or benefits shall be made on the dates and terms set forth in the Agreement.

(c)                                   If, as of the date of the Employee’s “separation from service” from the Company, the Employee is a “specified employee” (within the meaning of Section 409A), then:

(i)                                        Each installment of the severance payments and benefits due under the Agreement that, in accordance with the dates and terms set forth herein, will in all circumstances, regardless of when the Employee’s separation from service occurs, be paid within the short-term deferral period (as defined under Section 409A) shall be treated as a short-term deferral within the meaning of Treasury Regulation Section 1.409A-1(b)(4) to the maximum extent permissible under Section 409A and shall be paid at the time set forth in the Agreement; and

(ii)                                     Each installment of the severance payments and benefits due under the Agreement that is not described in this Exhibit A, Section 1(c)(i) and that would, absent this subsection, be paid within the six-month period following the Employee’s “separation from service” from the Company shall not be paid until the date that is six months and one day after such separation from service (or, if earlier, the Employee’s death), with any such installments that are required to be delayed being accumulated during the six-month period and paid in a lump sum on the date that is six months and one day following the Employee’s separation from service and any subsequent installments, if any, being paid in accordance with the dates and terms set forth herein; provided, however, that the preceding provisions of this sentence shall not apply to any installment of payments and benefits if and to the maximum extent that that such installment is deemed to be paid under a

separation pay plan that does not provide for a deferral of compensation by reason of the application of Treasury Regulation 1.409A-1(b)(9)(iii) (relating to separation pay upon an involuntary separation from service).  Any installments that qualify for the exception under Treasury Regulation Section 1.409A-1(b)(9)(iii) must be paid no later than the last day of the Employee’s second taxable year following the taxable year in which the separation from service occurs.

2.                                       The determination of whether and when the Employee’s separation from service from the Company has occurred shall be made and in a manner consistent with, and based on the presumptions set forth in, Treasury Regulation Section 1.409A-1(h).  Solely for purposes of this Exhibit A , Section 2, “Company” shall include all persons with whom the Company would be considered a single employer under Section 414(b) and 414(c) of the Code.

3.                                       The Company makes no representation or warranty and shall have no liability to the Employee or to any other person if any of the provisions of the Agreement (including this Exhibit) are determined to constitute deferred compensation subject to Section 409A but that do not satisfy an exemption from, or the conditions of, that section.

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