Exhibit (a)(1)(B)
      
      
      LETTER OF TRANSMITTAL
      to Tender Shares of Common Stock
      of
      ZYNERBA PHARMACEUTICALS, INC.
      at
      $1.1059 per share, in cash, without interest and less any applicable tax withholding,
      plus, one non-tradable contingent value right (“CVR”) per share, which represents the contractual right to receive contingent payments in cash,
        without interest and less any applicable tax withholding, upon the achievement of certain specified milestones
      by
      XYLOPHONE ACQUISITION CORP.
      a wholly owned subsidiary of
      HARMONY BIOSCIENCES HOLDINGS, INC. 
      
        
            
              | THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME, ON SEPTEMBER 26, 2023, UNLESS THE OFFER IS EXTENDED OR EARLIER TERMINATED. | 
        
       
      
      The Depositary and Paying Agent for the Offer Is:
      
      
         If delivering by hand, mail, express mail, courier,
        or other expedited service:
        Equiniti Trust Company, LLC
        Operations Center
        Attn: Reorganization Department
        6201 15th Avenue
        Brooklyn, New York 11219
        
          For assistance call (877) 248-6417 or (718) 921-8317
         
       
      
      
      
          
            | THIS DOCUMENT IS IMPORTANT AND REQUIRES YOUR IMMEDIATE ATTENTION. | 
          
            | Voluntary Corporate Action: COY ZYNE | 
          
            | DESCRIPTION OF SHARES AND SHARE CERTIFICATES (IF ANY) TENDERED | 
          
            | Name(s) and Address(es) of Registered Owner(s) (If blank, please fill in exactly as name(s) appear(s) on share certificate(s)) |  | Shares and Share Certificates (if any) Tendered (Attach additional list if necessary) | 
          
            |  |  | Share Certificate Number(s)* | Total Number of Shares Represented By Shares Certificate(s)* |  | Number of Shares Tendered** | 
          
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            |  | Total Shares (Including Shares held electronically through the Direct Registration System at the Transfer Agent (DRS)) |  |  | 
          
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            | *  Need not be completed by book-entry shareholders. If tendering Shares represented by certificates, list each certificate on a separate line. **  Unless otherwise indicated, it will be assumed that all shares of common stock, par value $0.001 per share, of Zynerba Pharmaceuticals, Inc. represented by
                certificates described above are being tendered hereby. See Instruction 4. | 
      
       
      
       
      DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY. YOU MUST SIGN THIS LETTER OF TRANSMITTAL WHERE INDICATED BELOW, WITH A
        SIGNATURE GUARANTEE IF REQUIRED, AND COMPLETE EITHER THE INTERNAL REVENUE SERVICE FORM W-9 ACCOMPANYING THIS LETTER OF TRANSMITTAL OR AN APPLICABLE INTERNAL REVENUE SERVICE FORM W-8. SEE INSTRUCTION 8 BELOW.
       
      PLEASE READ THE INSTRUCTIONS ACCOMPANYING THIS LETTER OF TRANSMITTAL CAREFULLY BEFORE COMPLETING THIS LETTER OF TRANSMITTAL.
       
      IF YOU WOULD LIKE ADDITIONAL COPIES OF THIS LETTER OF TRANSMITTAL OR ANY OF THE OTHER OFFER DOCUMENTS, YOU SHOULD CONTACT THE INFORMATION AGENT, MACKENZIE PARTNERS, INC., TOLL-FREE AT (800)
        322-2885.
       
      You have received this Letter of Transmittal in connection with the tender offer by Xylophone Acquisition Corp., a Delaware corporation and a wholly owned subsidiary of Harmony Biosciences Holdings, Inc., a Delaware
        corporation, to purchase all of the issued and outstanding shares of common stock, par value $0.001 per share (the “Shares”), of Zynerba Pharmaceuticals, Inc., a Delaware corporation, in exchange for (a)
        $1.1059 per Share in cash (the “Closing Amount”) without interest and subject to deduction for any required withholding under applicable tax law, plus (ii) one
        non-tradable CVR per Share, which represents the contractual right to receive contingent payments in cash, without interest and less any applicable tax withholding, upon the achievement of certain specified milestones in accordance with the terms
        and subject to the conditions described in the Offer to Purchase, dated August 28, 2023.
       
      
      You should use this Letter of Transmittal to deliver to 
Equiniti Trust Company, LLC (the “
Depositary and Paying Agent”) Shares represented by
        stock certificates or Shares represented by direct registration system for tender. If you are delivering your Shares by book-entry transfer to an account maintained by the Depositary and Paying Agent at The Depository Trust Company (“
DTC”), you may use this Letter of Transmittal or you may use an Agent’s Message (as defined in Instruction 2 below). In this document, shareholders who deliver certificates representing their Shares are referred
        to as “
Certificate Shareholders.” Shareholders who deliver their Shares through book-entry transfer are referred to as “
Book-Entry Shareholders.” 
Delivery of documents to DTC will not constitute delivery to the Depositary and Paying Agent. 
      
      
          
            | ☐ | CHECK HERE IF TENDERED SHARES ARE BEING DELIVERED BY BOOK-ENTRY TRANSFER TO THE ACCOUNT MAINTAINED BY THE DEPOSITARY AND PAYING AGENT WITH DTC AND COMPLETE THE FOLLOWING (ONLY FINANCIAL
                INSTITUTIONS THAT ARE PARTICIPANTS IN DTC MAY DELIVER SHARES BY BOOK-ENTRY TRANSFER): | 
      
       
      
      
          
            |  | Name of Tendering Institution: | 
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            |  | DTC Participant Number: | 
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            |  |  |  | 
          
            |  | Transaction Code Number | 
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      NOTE:    SIGNATURES MUST BE PROVIDED BELOW
      PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY
       
      Ladies and Gentlemen:
       
      The undersigned hereby tenders to Xylophone Acquisition Corp., a Delaware corporation (the “Offeror”) and a wholly owned subsidiary of Harmony Biosciences Holdings, Inc., a
        Delaware corporation (“Parent”), the above-described shares of common stock, par value $0.001 per share (the “Shares”), of
        Zynerba Pharmaceuticals, Inc., a Delaware corporation (“Zynerba” or the “Company”), pursuant to the Offer to Purchase, dated August 28, 2023 (together with any
        amendments or supplements thereto, the “Offer to Purchase”), in exchange for (a) $1.1059 per Share in cash (the “Closing Amount”) without interest and subject to
        deduction for any required withholding under applicable tax law, plus (ii) one non-tradable CVR per Share, which represents the contractual right to receive contingent payments in cash, without interest and
        less any applicable tax withholding, upon the achievement of certain specified milestones in accordance with the terms and subject to the conditions described in the Offer to Purchase, receipt of which is hereby acknowledged, and this Letter of
        Transmittal (together with any amendments or supplements hereto, this “Letter of Transmittal” and, together with the Offer to Purchase, the “Offer”).
       
      On the terms and subject to the conditions of the Offer (including, if the Offer is extended or amended, the terms and conditions of such extension or amendment), subject to, and effective upon, acceptance for
        payment of the Shares validly tendered herewith and not validly withdrawn in accordance with the terms of the Offer, the undersigned hereby sells, assigns and transfers to, or upon the order of, the Offeror, all right, title and interest in and to
        all of the Shares being tendered hereby and any and all cash dividends, distributions, rights, other Shares or other securities issued or issuable in respect of such Shares on or after the date of acceptance of the tendered shares by the Offeror
        (other than those with a record date prior to such date) (collectively, “Distributions”). In addition, by executing and delivering this Letter of Transmittal (or taking action resulting in the delivery of an
        Agent’s Message), the undersigned hereby irrevocably appoints Depositary and Paying Agent the true and lawful agent and attorney-in-fact and proxy of the undersigned with respect to such Shares and any Distributions with full power of substitution
        and re-substitution (such proxy and power of attorney being deemed to be an irrevocable power coupled with an interest in the Shares tendered by this Letter of Transmittal) to the fullest extent of such shareholder’s rights with respect to such
        Shares and any Distributions (a) to deliver certificates representing Shares (the “Share Certificates”) and any Distributions, or transfer ownership of such Shares and any Distributions on the account books
        maintained by DTC, together, in either such case, with all accompanying evidence of transfer and authenticity, to or upon the order of, the Offeror, (b) to present such Shares and any Distributions for transfer on the books of Zynerba and (c) to
        receive all benefits and otherwise exercise all rights of beneficial ownership of such Shares and any Distributions, all in accordance with the terms and subject to the conditions of the Offer.
       
      By executing and delivering this Letter of Transmittal (or taking action resulting in the delivery of an Agent’s Message), the undersigned hereby irrevocably appoints each of the Offeror, its officers and any other
        designees of the Offeror the true and lawful agents and attorneys-in-fact and proxies of the undersigned, each with full power of substitution and re-substitution, to the full extent of such shareholder’s rights with respect to the Shares tendered
        hereby which have been accepted for payment and with respect to any Distributions. Each of the Offeror, its officers and any other designees of the Offeror will, with respect to the Shares and any associated Distributions for which the appointment
        is effective, be empowered to exercise all voting and any other rights of such shareholder, as they, in their sole discretion, may deem proper at any annual, special, adjourned or postponed meeting of Zynerba’s shareholders, by written consent in
        lieu of any such meeting or otherwise. This proxy and power of attorney shall be irrevocable and coupled with an interest in the tendered Shares. Such appointment is effective when, and only to the extent that, the Offeror accepts the Shares
        tendered with this Letter of Transmittal for payment pursuant to the Offer. Upon the effectiveness of such appointment, without further action, all prior powers of attorney, proxies and consents given by the undersigned with respect to such Shares
        and any associated Distributions will be revoked and no subsequent powers of attorney, proxies, consents or revocations may be given (and, if given, will not be deemed effective). The Offeror reserves the right to require that, in order for Shares
        to be deemed validly tendered, immediately upon the Offeror’s acceptance for payment of such Shares, the Offeror must be able to exercise full voting, consent and other rights, to the extent permitted under applicable law, with respect to such
        Shares and any associated Distributions, including voting at any meeting of shareholders or executing a written consent concerning any matter.
       
      
      
      The undersigned hereby represents and warrants that the undersigned has full power and authority to tender, sell, assign and transfer the Shares tendered hereby and any Distributions and, when the same are accepted
        for payment by the Offeror, the Offeror will acquire good, marketable and unencumbered title thereto, free and clear of all liens, restrictions, charges and encumbrances, and that the same will not be subject to any adverse claim. The undersigned
        hereby represents and warrants that the undersigned is the registered owner of the Shares or the Share Certificate(s) have been endorsed to the undersigned in blank or the undersigned is a participant in DTC whose name appears on a security
        position listing participant as the owner of the Shares. The undersigned will, upon request, execute and deliver any additional documents deemed by the Depositary and Paying Agent or the Offeror to be necessary or desirable to complete the sale,
        assignment and transfer of the Shares tendered hereby and any Distributions. In addition, the undersigned shall promptly remit and transfer to the Depositary and Paying Agent for the account of the Offeror any and all Distributions in respect of
        the Shares tendered hereby, accompanied by appropriate documentation of transfer and, pending such remittance or appropriate assurance thereof, the Offeror shall be entitled to all rights and privileges as owner of any such Distributions and may
        withhold the entire purchase price or deduct from the purchase price the amount or value thereof, as determined by the Offeror in its sole discretion.
       
      It is understood that the undersigned will not receive payment for the Shares unless and until the Shares are accepted for payment and until the Share Certificate(s) owned by the undersigned are received by the
        Depositary and Paying Agent at the address set forth above, together with such additional documents as the Depositary and Paying Agent may require, or, in the case of Shares held in book-entry form, ownership of Shares is validly transferred on the
        account books maintained by DTC, and until the same are processed for payment by the Depositary and Paying Agent. It is understood that the method of delivery of the Shares, the Share Certificate(s) and all other required documents (including
        delivery through DTC) is at the option and risk of the undersigned and that the risk of loss of such Shares, Share Certificate(s) and other documents shall pass only after the Depositary and Paying Agent has actually received the Shares or Share
        Certificate(s) (including, in the case of a book-entry transfer, by Book-Entry Confirmation (as defined below)).
       
      All authority conferred or agreed to be conferred pursuant to this Letter of Transmittal shall not be affected by, and shall survive, the death or incapacity of the undersigned and any obligation of the undersigned
        hereunder shall be binding upon the heirs, executors, administrators, trustees in bankruptcy, personal representatives, successors and assigns of the undersigned. Except as stated in the Offer to Purchase, this tender is irrevocable.
       
      The undersigned understands that the acceptance for payment by the Offeror of Shares tendered pursuant to one of the procedures described in “Section 3—Procedures for Accepting the Offer and Tendering Shares” of the
        Offer to Purchase will constitute a binding agreement between the undersigned and the Offeror upon the terms and subject to the conditions of the Offer. The undersigned recognizes that under certain circumstances set forth in the Offer, the Offeror
        may not be required to accept for payment any Shares tendered hereby.
       
      The undersigned understands that the CVRs will not be transferable except (i) upon death of a CVR holder by will or intestacy; (ii) pursuant to a court order; (iii) by operation of law (including by consolidation or
        merger) or without consideration in connection with the dissolution, liquidation or termination of any corporation, limited liability company, partnership or other entity; (iv) in the case of CVRs held in book-entry or other similar nominee form,
        from a nominee to a beneficial owner and, if applicable, through an intermediary, as allowable by DTC; (v) if the CVR holder is a partnership or limited liability company, a distribution by the transferring partnership or limited liability company
        to its partners or members, as applicable; (vi) by instrument to an inter vivos or testamentary trust in which the CVRs are to be passed to beneficiaries upon the death of the settlor; or (vii) by a holder of CVRs, at such holder’s option, to
        Parent or any of its affiliates, in which case such transferring holder abandons all of such holder’s remaining rights in a CVR. The undersigned further understands that the CVRs will be issued in book-entry form only and will not be evidenced by a
        certificate or other instrument, will not have any voting or dividend rights and will not represent any equity or ownership interest in Parent or any constituent company to the Merger (as defined in the Offer to Purchase), will not be registered or
        listed for trading, and that no interest will accrue or be payable in respect of any of the amounts that may be payable on CVRs. The undersigned further understands that the CVRs will be governed by the terms and conditions of the CVR Agreement (as
        defined in the Offer to Purchase) and that holders of CVRs will have no greater rights against Parent than those accorded to general, unsecured creditors under applicable law.
       
      
      
      Unless otherwise indicated herein under “Special Payment Instructions,” please issue the check for the aggregate Common Cash Amount in the name(s) of, and/or return any Share Certificates representing Shares not
        tendered or accepted for payment to, the registered owner(s) appearing under “Description of Shares Tendered.” Similarly, unless otherwise indicated under “Special Delivery Instructions,” please mail the check for the aggregate Common Cash Amount
        and/or return any Share Certificates representing Shares not tendered or accepted for payment (and accompanying documents, as appropriate) to the address(es) of the registered owner(s) appearing under “Description of Shares Tendered.” In the event
        that both the “Special Delivery Instructions” and the “Special Payment Instructions” are completed, please issue the check for the aggregate Common Cash Amount and/or issue or return any Share Certificates representing Shares not tendered or
        accepted for payment (and any accompanying documents, as appropriate) in the name of, and deliver such check and/or return such Share Certificates (and any accompanying documents, as appropriate) to, the person or persons so indicated. Unless
        otherwise indicated herein in the box titled “Special Payment Instructions,” please credit any Shares tendered hereby or by an Agent’s Message and delivered by book-entry transfer, but which are not purchased, by crediting the account at DTC
        designated above. The undersigned recognizes that the Offeror has no obligation pursuant to the Special Payment Instructions to transfer any Shares from the name of the registered owner thereof if the Offeror does not accept for payment any of the
        Shares so tendered. All payments regarding the CVRs will be made subject to the terms and conditions of the CVR Agreement.
       
      
      
          
            |  |  |  | 
          
            | SPECIAL DELIVERY INSTRUCTIONS (See Instructions 1, 5 and 6) |  | SPECIAL PAYMENT INSTRUCTIONS (See Instructions 1, 5 and 6) | 
          
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            | To be completed ONLY if Share Certificate(s) not tendered or not accepted for payment and/or the check for the aggregate Common Cash Amount of Shares accepted for payment
                are to be delivered in the name of someone other than the undersigned. Issue to:   ‘ Check        ‘ Certificate |  | To be completed ONLY if Share Certificate(s) not tendered or not accepted for payment and/or the check for the aggregate Common Cash Amount of Shares accepted for payment
                are to be issued in the name of someone other than the undersigned. Issue to:   ‘ Check        ‘ Certificate | 
          
            | Name: |  |  | Name |  | 
          
            |  | (Please Print) |  |  | (Please Print) | 
          
            | Address |  |  | Address |  | 
          
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            | (Include Zip Code) |  | (Include Zip Code) | 
          
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            | (Taxpayer Identification or Social Security Number) (See Specific Instructions to Internal Revenue Service Form W-9 included in this Letter of Transmittal)   |  |  | 
      
      
      
      
      
          
            | IMPORTANT—SIGN HERE | 
          
            | (Please also complete the Internal Revenue Service Form W-9 accompanying this Letter of Transmittal or the appropriate | 
          
            | Internal Revenue Service Form W-8, as applicable) | 
          
            | (Signature of Shareholder(s)) | 
          
            | Sign Here: | 
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            | Sign Here: |  | 
          
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            | (Must be signed by registered owner(s) exactly as name(s) appear(s) on Share Certificate(s) or on a security position listing or by person(s) authorized to become registered owner(s) by certificates and
                documents transmitted herewith. If signature is by trustees, executors, administrators, guardians, attorneys-in-fact, officers of corporations or others acting in a fiduciary or representative capacity, please set forth full title and see
                Instruction 5. For information concerning signature guarantees, see Instruction 1.) | 
          
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            | Name(s): |  | 
          
            | (Please Print) | 
          
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            | Address: |  | 
          
            | (Include Zip Code) | 
          
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            | Daytime Area Code and Telephone Number: |  | 
          
            | Taxpayer Identification or Social Security No: |  | 
          
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            | GUARANTEE OF SIGNATURE(S) (For use by Eligible Institutions only; see Instructions 1 and 5) | 
          
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            | Address: |  | 
          
            | (Include Zip Code) | 
          
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            | Name: |  | 
          
            | (Please Type or Print) | 
          
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            | Daytime Area Code and Telephone Number: | 
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      Place medallion guarantee in space below:
       
      
      
      Instructions
      Forming part of the terms and conditions of the Offer
       
      1. Guarantee of signatures. Except as otherwise provided below, all signatures on this Letter of Transmittal must be guaranteed by a financial institution (including most commercial banks, savings and loan
        associations and brokerage houses) that is a member in good standing of a recognized Medallion Program approved by the Securities Transfer Association, Inc., including the Security Transfer Agents Medallion Program, the New York Stock Exchange
        Medallion Signature Program and the Stock Exchanges Medallion Program (each, an “Eligible Institution”). Signatures on this Letter of Transmittal need not be guaranteed (a) if this Letter of Transmittal is
        signed by the registered owner(s) (which term, for purposes of this document, includes any participant in DTC whose name appears on a security position listing as the owner of the Shares) of Shares tendered herewith, owners powers are not signed by
        trustees, executors, administrators, guardians, attorneys-in-fact, officers of corporations or others acting in a fiduciary or representative capacity and such registered owner has not completed the box titled “Special Payment Instructions” or the
        box titled “Special Delivery Instructions” on this Letter of Transmittal or (b) if such Shares are tendered for the account of an Eligible Institution. See Instruction 5.
       
      2. Delivery of Letter of Transmittal and certificates or book-entry confirmations. This Letter of Transmittal is to be completed by shareholders either if Share Certificates are to be forwarded herewith
        or, unless an Agent’s Message is utilized, if tenders are to be made pursuant to the procedures for tender by book-entry transfer set forth in “Section 3—Procedures for Accepting the Offer Tendering Shares” of the Offer to Purchase. For any
        Eligible Institution, a manually executed facsimile of this document may be used in lieu of the original. Share Certificates representing all physically tendered Shares, or confirmation of any book-entry transfer into the Depositary and Paying
        Agent’s account at DTC of Shares tendered by book-entry transfer (“Book Entry Confirmation”), as well as this Letter of Transmittal properly completed and duly executed with any required signature guarantees,
        unless an Agent’s Message in the case of a book-entry transfer is utilized, and any other documents required by this Letter of Transmittal, must be received by the Depositary and Paying Agent at one of its addresses set forth herein on or prior to
        the Expiration Date (as defined in the Offer to Purchase). Please do not send your Share Certificates directly to the Offeror, Parent or Zynerba.
       
      A properly completed and duly executed Letter of Transmittal (or, with respect to Eligible Institutions, a manually executed facsimile thereof) must accompany each such delivery of Share Certificates to the
        Depositary and Paying Agent.
       
      The term “Agent’s Message” means a message, transmitted by DTC to, and received by, the Depositary and Paying Agent and forming part of a Book-Entry Confirmation, which states
        that DTC has received an express acknowledgment from the participant in DTC tendering the Shares which are the subject of such Book-Entry Confirmation that such participant has received and agrees to be bound by the terms of the Letter of
        Transmittal and that the Offeror may enforce such agreement against the participant.
       
      THE METHOD OF DELIVERY OF THE SHARES, THIS LETTER OF TRANSMITTAL AND ALL OTHER REQUIRED DOCUMENTS, INCLUDING DELIVERY THROUGH DTC, IS AT THE ELECTION AND RISK OF THE TENDERING SHAREHOLDER. DELIVERY OF ALL SUCH
        DOCUMENTS WILL BE DEEMED MADE AND RISK OF LOSS OF THE CERTIFICATES REPRESENTING SHARES WILL PASS, ONLY WHEN ACTUALLY RECEIVED BY THE DEPOSITARY AND PAYING AGENT (INCLUDING, IN THE CASE OF A BOOK-ENTRY TRANSFER, BY BOOK-ENTRY CONFIRMATION).
       
      IF THE DELIVERY IS BY MAIL, IT IS RECOMMENDED THAT ALL SUCH DOCUMENTS BE SENT BY PROPERLY INSURED REGISTERED MAIL WITH RETURN RECEIPT REQUESTED. IN ALL CASES, SUFFICIENT TIME SHOULD BE ALLOWED TO ENSURE TIMELY
        DELIVERY.
       
      
      No alternative, conditional or contingent tenders will be accepted. All tendering shareholders, by execution of this Letter of Transmittal (or, with respect to Eligible Institutions, a manually executed facsimile
        thereof), waive any right to receive any notice of the acceptance of their Shares for payment.
       
      
      
      All questions as to validity, form and eligibility of the surrender of any Share Certificate hereunder will be determined by the Offeror (which may delegate power in whole or in part to the Depositary and Paying
        Agent) in its sole and absolute discretion, which determination shall be final and binding. The Offeror reserves the right to waive any irregularities or defects in the surrender of any Shares or Share Certificate(s). A surrender will not be deemed
        to have been made until all irregularities have been cured or waived.
       
      3. Inadequate space. If the space provided herein is inadequate, the certificate numbers, the number of Shares represented by such Share Certificates and/or the number of Shares tendered should be listed
        on a separate schedule attached hereto and separately signed on each page thereof in the same manner as this Letter of Transmittal is signed.
       
      4. Partial tenders (applicable to certificate shareholders only). If fewer than all the Shares evidenced by any Share Certificate delivered to the Depositary and Paying Agent are to be tendered, fill in
        the number of Shares which are to be tendered in the column titled “Number of Shares Tendered” in the box titled “Description of Shares Tendered.” In such cases, new certificate(s) for the remainder of the Shares that were evidenced by the old
        certificate(s) but not tendered will be sent to the registered owner, unless otherwise provided in the appropriate box on this Letter of Transmittal, as soon as practicable after the Expiration Date. All Shares represented by Share Certificates
        delivered to the Depositary and Paying Agent will be deemed to have been tendered unless otherwise indicated.
       
      5. Signatures on Letter of Transmittal; stock powers and endorsements. If this Letter of Transmittal is signed by the registered owner(s) of the Shares tendered hereby, the signature(s) must correspond
        with the name(s) as written on the face of the Share Certificate(s) without alteration or any other change whatsoever.
       
      If any Shares tendered hereby are owned of record by two or more joint owners, all such owners must sign this Letter of Transmittal.
       
      If any tendered Shares are registered in the names of different holder(s), it will be necessary to complete, sign and submit as many separate Letters of Transmittal (or, with respect to Eligible Institutions, a
        manually executed facsimile thereof) as there are different registrations of such Shares.
       
      If this Letter of Transmittal or any certificates or stock powers are signed by trustees, executors, administrators, guardians, attorneys-in-fact, officers of corporations or others acting in a fiduciary or
        representative capacity, such persons should so indicate when signing, and proper evidence satisfactory to the Offeror of their authority so to act must be submitted, or in lieu of such document signatures must be guaranteed by an Eligible
        Institution. See Instruction 1.
       
      If this Letter of Transmittal is signed by the registered owner(s) of the Shares listed and transmitted hereby, no endorsements of Share Certificates or separate stock powers are required unless payment is to be made
        to, or Share Certificates representing Shares not tendered or accepted for payment are to be issued in the name of, a person other than the registered owner(s). Signatures on such Share Certificates or stock powers
          must be guaranteed by an Eligible Institution.
       
      If this Letter of Transmittal is signed by a person other than the registered owner(s) of the Share(s) listed, the Share Certificate(s) must be endorsed or accompanied by the appropriate stock powers, in either case,
        signed exactly as the name or names of the registered owner(s) or holder(s) appear(s) on the Share Certificate(s). Signatures on such Share Certificates or stock powers must be guaranteed by an Eligible Institution.
       
      
      6. Special payment and delivery instructions. If a check is to be issued in the name of, and/or Share Certificates representing Shares not tendered or accepted for payment are to be issued or returned to,
        a person other than the signer(s) of this Letter of Transmittal or if a check and/or such certificates are to be mailed to a person other than the signer(s) of this Letter of Transmittal or to an address other than that shown in the box titled
        “Description of Shares Tendered” above, the appropriate boxes on this Letter of Transmittal should be completed.
       
      7. Requests for assistance or additional copies. Questions or requests for assistance may be directed to the Information Agent at its address and telephone number set forth below or to your broker, dealer,
        commercial bank or trust company. Additional copies of the Offer to Purchase, this Letter of Transmittal and other tender offer materials may be obtained from the Information Agent, which may be contacted at the telephone numbers, mailing address
        and email address as set forth on the back cover of this Letter of Transmittal, and will be furnished at the Offeror’s expense.
       
      
      
      8. Tax forms. Under U.S. federal income tax laws, the Depositary and Paying Agent will be required to withhold a portion of the amount of any payments made to certain shareholders pursuant to the Offer
        unless certain requirements are met. To avoid such backup withholding, each tendering shareholder or payee that is a “U.S. Holder” (as defined in the Offer to Purchase, but including solely for the purpose of this Letter of Transmittal a U.S.
        partnership) must provide the Depositary and Paying Agent with such shareholder’s or payee’s correct taxpayer identification number (“TIN”) and certify, under penalty of perjury, that such shareholder or
        payee is not subject to such backup withholding and otherwise comply with applicable requirements of the backup withholding rules by completing the attached Internal Revenue Service (“IRS”) Form W-9. A U.S.
        Holder that fails to provide the correct taxpayer identification number on IRS Form W-9 and other required information or an adequate basis for exemption from backup withholding will be subject to backup withholding at a rate of 24% and may be
        subject to penalties imposed by the IRS. See the enclosed copy of the IRS Form W-9 and the instructions to IRS Form W-9.
       
      A Non-U.S. Holder (as defined in the Offer to Purchase) should submit to the Depositary and Paying Agent the appropriate IRS Form W-8 to establish an applicable withholding exemption from backup withholding. In the
        case of Non-U.S. Holders for which IRS Form W-8BEN is the appropriate form, IRS Form W-8BEN requires a Non-U.S. Holder to provide such Non-U.S. Holder’s name and address, along with certain other information, and to certify, under penalties of
        perjury, that such Non-U.S. Holder is not a U.S. Person. Non-U.S. Holders may obtain an IRS Form W-8BEN and instructions (or other appropriate IRS Form W-8) from the Depositary and Paying Agent upon request or from the IRS’s website (www.irs.gov).
        The failure of a Non-U.S. Holder to provide the appropriate IRS Form W-8 may result in backup withholding at a rate of 24% on some or all of the payments made to such stockholder pursuant to the Offer.
       
      Backup withholding is not an additional tax. Rather, the U.S. federal income tax liability of persons subject to backup withholding will be reduced by the amount of tax withheld. If withholding results in an
        overpayment of taxes, a refund or credit may be obtained from the IRS provided that the required information is furnished to the IRS.
       
      All Zynerba shareholders are urged to consult their own tax advisors to determine whether they are exempt from these backup withholding requirements and to determine which IRS form should be used
        to avoid backup withholding.
       
      NOTE: FAILURE TO COMPLETE AND RETURN THE IRS FORM W-9 OR APPROPRIATE IRS FORM W-8 MAY RESULT IN BACKUP WITHHOLDING ON ANY PAYMENTS MADE TO YOU PURSUANT TO THE OFFER.
       
      9. Lost, destroyed, mutilated or stolen share certificates. If any Share Certificate has been lost, destroyed, mutilated or stolen, the shareholder should promptly notify Zynerba’s stock transfer agent,
        Equiniti Trust Company, LLC, (the “Transfer Agent”), at (877) 248-6417 or (718) 921-8317. The shareholder will then be instructed as to the steps that must be taken in order to replace the Share Certificate.
        This Letter of Transmittal and related documents cannot be processed until the procedures for replacing lost, mutilated, destroyed or stolen Share Certificates have been followed. You are urged to contact the
          Transfer Agent immediately in order to receive further instructions and for a determination of whether you will need to post a bond and to permit timely processing of this documentation. This Letter of Transmittal and related documents cannot be
          processed until the procedures for replacing lost, destroyed or stolen Share Certificates have been followed.
       
      10. Waiver of conditions. Subject to the terms and conditions of the Merger Agreement (as defined in the Offer to Purchase) and the applicable rules and regulations of the Securities and Exchange
        Commission, the conditions of the Offer may be waived by Parent or the Offeror in whole or in part at any time and from time to time in its sole discretion.
       
      IMPORTANT: THIS LETTER OF TRANSMITTAL (OR, WITH RESPECT TO ELIGIBLE INSTITUTIONS, A MANUALLY EXECUTED FACSIMILE COPY THEREOF) OR AN AGENT’S MESSAGE, TOGETHER WITH SHARE CERTIFICATE(S) OR BOOK-ENTRY
        CONFIRMATION AND ALL OTHER REQUIRED DOCUMENTS MUST BE RECEIVED BY THE DEPOSITARY AND PAYING AGENT ON OR PRIOR TO THE EXPIRATION DATE.
       
      
      
      IMPORTANT TAX INFORMATION
       
      Under current U.S. federal income tax law, a shareholder who tenders Share Certificates that are accepted for exchange may be subject to backup withholding. In order to avoid such backup withholding, a shareholder
        who is a U.S. Holder (as defined in the Offer to Purchase, but including solely for the purpose of this Letter of Transmittal a U.S. Partnership) must provide the Depositary and Paying Agent with such shareholder’s correct taxpayer identification
        number and certify that such shareholder is not subject to such backup withholding by completing the IRS Form W-9 provided herewith. In general, if a shareholder is an individual, the taxpayer identification number is the Social Security number of
        such individual. If the Depositary and Paying Agent is not provided with the correct taxpayer identification number or an adequate basis for an exemption, the shareholder may be subject to a penalty imposed by the IRS, and any consideration such
        shareholder receives may be subject to backup withholding at the applicable rate (currently 24%). For further information concerning backup withholding and instructions for completing the IRS Form W-9 (including how to obtain a taxpayer
        identification number if you do not have one and how to complete the IRS Form W-9 if the Share Certificates are held in more than one name), consult the enclosed IRS Form W-9 and the instructions thereto.
       
      Certain shareholders (including certain foreign individuals) are not subject to these backup withholding requirements. To prevent backup withholding, a foreign shareholder must submit a statement, signed under
        penalties of perjury, attesting to that shareholder’s exempt status, on a properly completed applicable IRS Form W-8, or successor form. Such IRS forms can be obtained from the Depositary and Paying Agent or downloaded from the IRS website at
        http://www.irs.gov.
       
      Failure to complete the IRS Form W-9 or applicable IRS Form W-8 will not, by itself, cause the stock certificates to be deemed invalidly tendered, but may require the Depositary and Paying Agent to withhold on any
        payments made pursuant to the Offer. Backup withholding is not an additional federal income tax. Rather, the federal income tax liability of a person subject to backup withholding will be reduced by the amount of tax withheld. If withholding
        results in an overpayment of taxes, a refund may be obtained provided that the required information is furnished to the IRS.
       
      NOTE: FAILURE TO COMPLETE AND RETURN THE IRS FORM W-9 (OR AN APPLICABLE IRS FORM W-8) MAY RESULT IN BACKUP WITHHOLDING ON ANY PAYMENTS MADE TO YOU PURSUANT TO THE OFFER. PLEASE REVIEW THE ENCLOSED IRS FORM W-9 AND
        THE INSTRUCTIONS THERETO FOR ADDITIONAL DETAILS.
       
      
      The Depositary and Paying Agent for the Offer is:
      
        If delivering by hand, mail, express mail, courier,
      or other expedited service:
      Equiniti Trust Company, LLC
      Operations Center
      Attn: Reorganization Department
      6201 15th Avenue
      Brooklyn, New York 11219
      For assistance call (877) 248-6417 or (718) 921-8317
      
      
      
      Any questions or requests for assistance or additional copies of the Offer to Purchase, the Letter of Transmittal and other tender offer materials may be directed to the Information Agent at its telephone number and location listed below. You
        may also contact your broker, dealer, commercial bank, trust company or other nominee for assistance concerning the Offer.
       
      
      The Information Agent for the Tender Offer is:
      
      
      
      
      
      1407 Broadway
      New York, New York 10018
      (212) 929-5500
      or
      Call Toll-Free (800) 322-2885
       
      Email: tenderoffer@mackenziepartners.com
       
      
      
      
        Form W-9(Rev. October 2018)Request for Taxpayer Identification Number and CertificationDepartment of
            the Treasury Internal Revenue Service ▶Go to
          www.irs.gov/FormW9 for instructions and the latest information.Give Form to the requester. Do not send to the IRS.Print or type. See Specific
              Instructions on page 3.1 Name (as shown on your income tax return). Name is required on this line; do not leave this line blank.2 Business
            name/disregarded entity name, if different from above3 Check appropriate box for federal tax classification of the person whose name is entered on line 1. Check only one
            of the following seven boxes. Individual/sole proprietor or single-member LLC C CorporationS CorporationPartnershipTrust/estateLimited liability company. Enter the tax classification (C=C corporation, S=S corporation, P=Partnership) ▶ Note: Check the appropriate box in the line above for the tax classification of the single-member owner. Do not check LLC if the LLC is classified
            as a single-member LLC that is disregarded from the owner unless the owner of the LLC is another LLC that is not disregarded from the owner for U.S. federal tax purposes. Otherwise, a single-member LLC
            that is disregarded from the owner should check the appropriate box for the tax classification of its owner.Other (see instructions) ▶ 5 Address
            (number, street, and apt. or suite no.) See instructions.6 City, state, and ZIP codeRequester’s name and address (optional)7 List account number(s) here
            (optional)Taxpayer Identification Number (TIN)Enter your TIN in the appropriate box. The TIN
              provided must match the name given on line 1 to avoid backup withholding. For individuals, this is generally your social security number (SSN). However, for a resident alien, sole proprietor, or disregarded entity, see the instructions for
              Part I, later. For other entities, it is your employer identification number (EIN). If you do not have a number, see How to get a TIN, later.Note: If the account
              is in more than one name, see the instructions for line 1. Also see What Name and Number To Give the Requester for guidelines on whose number to enter.Social security numberorEmployer identification number –CertificationUnder penalties of perjury, I certify that:1. The number shown on this form is my correct taxpayer identification number (or I am waiting for a number to be issued to me); and2. I am not
              subject to backup withholding because: (a) I am exempt from backup withholding, or (b) I have not been notified by the Internal Revenue Service (IRS) that I am subject to backup withholding as a result of a failure to report all interest or
              dividends, or (c) the IRS has notified me that I am no longer subject to backup withholding; and3. I am a U.S. citizen or other U.S. person (defined below); and4. The FATCA code(s) entered on this form (if any) indicating that I am exempt
              from FATCA reporting is correct.Certification instructions. You must cross out item
              2 above if you have been notified by the IRS that you are currently subject to backup withholding because you have failed to report all interest and dividends on your tax return. For real estate transactions, item 2 does not apply. For
              mortgage interest paid, acquisition or abandonment of secured property, cancellation of debt, contributions to an individual retirement arrangement (IRA), and generally, payments other than interest and dividends, you are not required to sign
              the certification, but you must provide your correct TIN. See the instructions for Part II, later.Sign HereSignature of U.S. person ▶Date ▶General InstructionsSection references are to the Internal Revenue Code unless otherwise noted.Future developments. For the latest information about developments related to Form W-9 and its
              instructions, such as legislation enacted after they were published, go to www.irs.gov/FormW9.Purpose of FormAn individual or entity (Form W-9 requester) who is required to file an information return with the IRS must obtain your
              correct taxpayer identification number (TIN) which may be your social security number (SSN), individual taxpayer identification number (ITIN), adoption taxpayer identification number (ATIN), or employer identification number (EIN), to report
              on an information return the amount paid to you, or other amount reportable on an information return. Examples of information returns include, but are not limited to, the following.• Form 1099-INT (interest earned or paid)• Form 1099-DIV
              (dividends, including those from stocks or mutual funds)• Form 1099-MISC (various types of income, prizes, awards, or gross proceeds)• Form 1099-B (stock or mutual fund sales and certain other transactions by brokers)• Form 1099-S (proceeds
              from real estate transactions)• Form 1099-K (merchant card and third party network transactions)• Form 1098 (home mortgage interest), 1098-E (student loan interest), 1098-T (tuition)• Form 1099-C (canceled debt)• Form 1099-A (acquisition or
              abandonment of secured property)Use Form W-9 only if you are a U.S. person (including a resident alien), to provide your correct TIN. If you do not
              return Form W-9 to the requester with a TIN, you might be subject to backup withholding. See What is backup withholding, later.Cat. No. 10231XForm W-9 (Rev. 10-2018)4 Exemptions
              (codes apply only to certain entities, not individuals; see instructions on page 3):Exempt payee code (if any)Exemption from FATCA reporting code (if any)(Applies
              to accounts maintained outside the U.S.)