<PAGE>
                                                                   EXHIBIT 10.14


                                 PROMISSORY NOTE

                   TO MASTER SECURITY AGREEMENT NO. _________

                              ____________________
                                     (DATE)

  FOR VALUE RECEIVED, PTC Therapeutics, Inc., a Delaware corporation, located at
  the address stated below ("MAKER") promises, jointly and severally if more
  than one, to pay to the order of OXFORD FINANCE CORPORATION or any subsequent
  holder hereof (each, a "PAYEE") at its office located at 133 N. FAIRFAX
  STREET, ALEXANDRIA, VA 22314 or at such other place as Payee or the holder
  hereof may designate, the principal sum of ____________________ DOLLARS
  ($____________________), with interest on the unpaid principal balance, from
  the date hereof through and including the dates of payment, at a fixed
  interest rate of ______ and _____ hundredths percent (____%) per annum, in
  ________ consecutive monthly installments of principal and interest as
  follows:

<TABLE>
<CAPTION>
        Periodic
        Installment                Amount
        _________________________________
<S>                                <C>
                                   $
</TABLE>


  each ("PERIODIC INSTALLMENT") and a final installment which shall be in the
  amount of the total outstanding principal and interest. The first Periodic
  Installment shall be due and payable on ____________________ and the following
  Periodic Installments and the final installment shall be due and payable on
  the same day of each succeeding _______________ (each, a "PAYMENT DATE"). Such
  installments have been calculated on the basis of a 360-day year of twelve
  30-day months. Each payment may, at the option of the Payee, be calculated and
  applied on an assumption that such payment would be made on its due date.
  Maker agrees to pay any initial partial month interest payment from the date
  of this Note to the first day of the following month ("Interim Interest").

  The acceptance by Payee of any payment which is less than payment in full of
  all amounts due and owing at such time shall not constitute a waiver of
  Payee's right to receive payment in full at such time or at any prior or
  subsequent time.

  The Maker hereby expressly authorizes the Payee to insert the date value is
  actually given in the blank space on the face hereof and on all related
  documents pertaining hereto.

  This Note may be secured by a security agreement, chattel mortgage, pledge
  agreement or like instrument (each of which is hereinafter called a "SECURITY
  AGREEMENT" AND ANY SECURITY AGREEMENT, THIS NOTE AND ANY OTHER DOCUMENT
  EVIDENCING OR SECURING THIS LOAN IS HEREINAFTER CALLED A "DEBT DOCUMENT").

  Time is of the essence hereof. If any installment or any other sum (not
  including any accelerated amount) due under this Note or any Security
  Agreement is not received when due, or within five (5) days thereafter, the
  Maker agrees to pay, in addition to the amount of each such installment or
  other sum, a late payment charge of five percent (5%) of the amount of said
  installment or other sum, but not exceeding any lawful maximum. If (i) Maker
  fails to make payment of any amount due hereunder within five (5) days after
  the due date; or (ii) Maker is in default under any Security Agreement, then
  the entire principal sum remaining unpaid, together with all accrued interest
  thereon and any other sum payable under this Note or any Security Agreement,
  at the election of Payee, shall immediately become due and payable, with
  interest thereon at the lesser of (x) two and one-half percent (2.5%) per
  annum plus the applicable non-default rate per annum under the Debt Documents;
  and (y) the maximum rate not prohibited by applicable law from the date of
  such accelerated maturity until paid (both before and after any judgment).

  Maker may prepay in full any indebtedness hereunder upon 5 days' notice to the
  Payee. The repayment shall be accompanied by payment of (i) all accrued and
  unpaid interest on the principal and the outstanding principal balance of this
  Note and (ii) a premium of 8% of the principal prepaid if such prepayment
  shall occur in Year 1, a premium of 6% of the principal prepaid if such
  prepayment shall occur in Year 2 and a premium of 4% of the principal prepaid
  if such prepayment shall occur in Year 3. There shall be no prepayment premium
  in Year 4 or thereafter. Year 1 will mean the period consisting of the 1st
  through the 12th installments under this Note and subsequent years will refer
  to the subsequent twelve monthly payment periods.

  The Maker and all sureties, endorsers, guarantors or any others (each such
  person, other than the Maker, an "OBLIGOR") who may at any time become liable
  for the payment hereof jointly and severally consent hereby to any and all
  extensions of time, renewals, waivers or modifications of, and all
  substitutions or releases of, security or of any party primarily or
  secondarily liable on this Note or any Security Agreement or any term and
  provision of either, which may be made, granted or consented to by Payee, and
  agree that suit may be brought and maintained against any one or more of them,
  at the election of Payee without joinder of


IMPORTANT NOTICE:
THIS INSTRUMENT CONTAINS A CONFESSION OF JUDGMENT PROVISION WHICH CONSTITUTES A
WAIVER OF IMPORTANT RIGHTS YOU MAY HAVE AS A DEBTOR AND ALLOWS THE CREDITOR TO
OBTAIN A JUDGMENT AGAINST YOU WITHOUT ANY FURTHER NOTICE.

                                  PAGE 1 OF 4
<PAGE>
  any other as a party thereto, and that Payee shall not be required first to
  foreclose, proceed against, or exhaust any security hereof in order to enforce
  payment of this Note. The Maker and each Obligor hereby waives presentment,
  demand for payment, notice of nonpayment, protest, notice of protest, notice
  of dishonor, and all other notices in connection herewith, as well as filing
  of suit (if permitted by law) and diligence in collecting this Note or
  enforcing any of the security hereof, and agrees to pay (if and to the extent
  permitted by law) all reasonable expenses incurred in collection, including
  Payee's reasonable actual attorneys' fees. Maker and each Obligor agrees that
  fees not in excess of twenty percent (20%) of the amount then due shall be
  deemed reasonable.

  Maker and Payee intend to strictly comply with all applicable federal and
  Virginia laws, including applicable usury laws (or the usury laws of any
  jurisdiction whose usury laws are deemed to apply to the Note or any other
  Debt Document despite the intention and desire of the parties to apply the
  usury laws of the Commonwealth of Virginia). Accordingly, the provisions of
  this paragraph shall govern and control over every other provision of this
  Note or any other Debt Document which conflicts or is inconsistent with this
  Section, even if such provision declares that it controls. As used in this
  paragraph, the term "INTEREST" includes the aggregate of all charges, fees,
  benefits or other compensation which constitute interest under applicable law,
  provided that, to the maximum extent permitted by applicable law, (a) any
  non-principal payment shall be characterized as an expense or as compensation
  for something other than the use, forbearance or detention of money and not as
  interest, and (b) all interest at any time contracted for, reserved, charged
  or received shall be amortized, prorated, allocated and spread, in equal parts
  during the full term of the obligations. In no event shall Maker or any other
  person be obligated to pay, or Payee have any right or privilege to reserve,
  receive or retain, (a) any interest in excess of the maximum amount of
  non-usurious interest permitted under the laws of the Commonwealth of Virginia
  or the applicable laws (if any) of the United States or of any other state, or
  (b) total interest in excess of the amount which Payee could lawfully have
  contracted for, reserved, received, retained or charged had the interest been
  calculated for the full term of the obligations. On each day, if any, that the
  interest rate (the "Stated Rate") called for under this Note or any other Debt
  Document exceeds the maximum non-usurious rate, the rate at which interest
  shall accrue shall automatically be fixed by operation of this sentence at the
  maximum non-usurious rate for that day. Thereafter, interest shall accrue at
  the Stated Rate unless and until the Stated Rate again exceeds the maximum
  non-usurious rate, in which case, the provisions of the immediately preceding
  sentence shall again automatically operate to limit the interest accrual rate
  to the maximum non-usurious rate. The daily interest rates to be used in
  calculating interest at the maximum non-usurious rate shall be determined by
  dividing the applicable maximum non-usurious rate by the number of days in the
  calendar year for which such calculation is being made. None of the terms and
  provisions contained in this Note or in any other Debt Document which directly
  or indirectly relate to interest shall ever be construed without reference to
  this paragraph, or be construed to create a contract to pay for the use,
  forbearance or detention of money at an interest rate in excess of the maximum
  non-usurious rate. If the term of any obligation is shortened by reason of
  acceleration of maturity as a result of any Default or by any other cause, or
  by reason of any required or permitted prepayment, and if for that (or any
  other) reason Payee at any time, including but not limited to, the stated
  maturity, is owed or receives (and/or has received) interest in excess of
  interest calculated at the maximum non-usurious rate, then and in any such
  event all of any such excess interest shall be canceled automatically as of
  the date of such acceleration, prepayment or other event which produces the
  excess, and, if such excess interest has been paid to Payee, it shall be
  credited pro tanto against the then-outstanding principal balance of Maker's
  obligations to Payee, effective as of the date or dates when the event occurs
  which causes it to be excess interest, until such excess is exhausted or all
  of such principal has been fully paid and satisfied, whichever occurs first,
  and any remaining balance of such excess shall be promptly refunded to its
  payor.

  THE MAKER HEREBY UNCONDITIONALLY WAIVES ITS RIGHTS TO A JURY TRIAL OF ANY
  CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT OF, DIRECTLY OR INDIRECTLY,
  THIS NOTE, ANY OF THE RELATED DOCUMENTS, ANY DEALINGS BETWEEN MAKER AND PAYEE
  RELATING TO THE SUBJECT MATTER OF THIS TRANSACTION OR ANY RELATED
  TRANSACTIONS, AND/OR THE RELATIONSHIP THAT IS BEING ESTABLISHED BETWEEN MAKER
  AND PAYEE. THE SCOPE OF THIS WAIVER IS INTENDED TO BE ALL ENCOMPASSING OF ANY
  AND ALL DISPUTES THAT MAY BE FILED IN ANY COURT (INCLUDING, WITHOUT
  LIMITATION, CONTRACT CLAIMS, TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL OTHER
  COMMON LAW AND STATUTORY CLAIMS.) THIS WAIVER IS IRREVOCABLE, MEANING THAT IT
  MAY NOT BE MODIFIED EITHER ORALLY OR IN WRITING, AND THE WAIVER SHALL APPLY TO
  ANY SUBSEQUENT AMENDMENTS, RENEWALS, SUPPLEMENTS OR MODIFICATIONS TO THIS
  NOTE, ANY RELATED DOCUMENTS, OR TO ANY OTHER DOCUMENTS OR AGREEMENTS RELATING
  TO THIS TRANSACTION OR ANY RELATED TRANSACTION. IN THE EVENT OF LITIGATION,
  THIS NOTE MAY BE FILED AS A WRITTEN CONSENT TO A TRIAL BY THE COURT.

  This Note, any Security Agreement and all other Debt Documents constitute the
  entire agreement of the Maker and Payee with respect to the subject matter
  hereof and supersedes all prior understandings, agreements and
  representations, express or implied.

  No variation or modification of this Note, or any waiver of any of its
  provisions or conditions, shall be valid unless in writing and signed by an
  authorized representative of Maker and Payee. Any such waiver, consent,
  modification or change shall be effective only in the specific instance and
  for the specific purpose given.


IMPORTANT NOTICE:
THIS INSTRUMENT CONTAINS A CONFESSION OF JUDGMENT PROVISION WHICH CONSTITUTES A
WAIVER OF IMPORTANT RIGHTS YOU MAY HAVE AS A DEBTOR AND ALLOWS THE CREDITOR TO
OBTAIN A JUDGMENT AGAINST YOU WITHOUT ANY FURTHER NOTICE.
<PAGE>
  Any provision in this Note or any Security Agreement which is in conflict with
  any statute, law or applicable rule shall be deemed omitted, modified or
  altered to conform thereto.

  Upon receipt of an affidavit of an officer of Payee as to the loss, theft,
  destruction or mutilation of this Note or any Debt Document which is not of
  public record, and, in the case of any such loss, theft, destruction or
  mutilation, upon surrender and cancellation of such Note or other Debt
  Document, Maker will issue, in lieu thereof, a replacement Note or other Debt
  Document in the same principal amount thereof and otherwise of like tenor.

  It is understood and agreed that this Note and all of the Debt Documents were
  negotiated and have been or will be delivered to Payee in the Commonwealth of
  Virginia, which State the parties agree has a substantial relationship to the
  parties and to the underlying transactions embodied by this Note and the Debt
  Documents. Maker agrees to furnish to Payee at Payee's office in Alexandria,
  VA, all further instruments, certifications and documents to be furnished
  hereunder. The parties also agree that if collateral is pledged to secure the
  debt evidenced by this Note, that the state or states in which such collateral
  is located each have a substantial relationship to the parties and to the
  underlying transaction embodied by this Note and the Debt Documents.

  MAKER AGREES THAT THE PAYEE OF THIS NOTE SHALL HAVE THE OPTION BY WHICH STATE
  LAWS THIS NOTE SHALL BE GOVERNED AND CONSTRUED: (A) THE LAWS OF THE
  COMMONWEALTH OF VIRGINIA; OR (B) IF COLLATERAL HAS BEEN PLEDGED TO SECURE THE
  DEBT EVIDENCED BY THIS NOTE, THEN BY THE LAWS OF THE STATE OR STATES WHERE THE
  COLLATERAL IS LOCATED, AT PAYEE'S OPTION. THIS CHOICE OF STATE LAWS IS
  EXCLUSIVE TO THE PAYEE OF THIS NOTE. MAKER SHALL NOT HAVE ANY OPTION TO CHOOSE
  THE LAWS BY WHICH THIS NOTE SHALL BE GOVERNED. MAKER AND GUARANTORS HEREBY
  CONSENT TO THE EXERCISE OF JURISDICTION OVER IT BY ANY FEDERAL COURT SITTING
  IN VIRGINIA OR ANY VIRGINIA COURT SELECTED BY PAYEE, FOR THE PURPOSES OF ANY
  AND ALL LEGAL PROCEEDINGS ARISING OUT OF OR RELATING TO THE NOTE, THE LOAN
  AGREEMENT AND ALL OTHER DOCUMENTS. MAKER AND GUARANTORS IRREVOCABLY WAIVE, TO
  THE FULLEST EXTENT PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR
  HEREAFTER HAVE TO THE LAYING OF VENUE OF ANY SUCH PROCEEDING BROUGHT IN ANY
  SUCH COURT, ANY CLAIM BASED ON THE CONSOLIDATION OF PROCEEDINGS IN SUCH COURTS
  IN WHICH PROPER VENUE MAY LIE IN DIVERGENT JURISDICTIONS, AND ANY CLAIM THAT
  ANY SUCH PROCEEDING BROUGHT IN ANY SUCH COURT HAS BEEN BROUGHT IN AN
  INCONVENIENT FORUM. MAKER AND GUARANTORS HEREBY IRREVOCABLY WAIVE, TO THE
  FULLEST EXTENT PERMITTED BY LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY
  LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS NOTE, THE OTHER DOCUMENTS
  OR THE TRANSACTIONS CONTEMPLATED THEREBY.

  Confession of Judgment. In the event that this Note or any installment under
  this Note is not paid when due or within five days thereafter, whether by
  maturity or acceleration, Maker hereby appoints and constitutes Cindi E. Cohen
  and Lauri E. Cleary, either of whom may act (a Virginia attorney) as Maker's
  duly constituted attorney-in-fact to confess judgment pursuant to the
  provisions of Section 8.01-431 et seq. of the Code of Virginia of 1950, as
  amended, against Maker for all principal and interest due and payable under
  this Note, together with reasonable attorneys' fees and collection fees as
  provided in this Note (to the extent permitted by law), which judgment shall
  be confessed in the Clerk's Office of the Circuit Court of the City of
  Alexandria and/or Fairfax and/or Arlington Counties, Virginia. Maker shall,
  upon Payee's request, name such additional or alternative persons designated
  by Payee as Maker's duly constituted attorney-in-fact to confess judgment
  against Maker pursuant to the above Section. Upon request of Payee, Maker also
  shall agree to the designation of any additional circuit courts in the
  Commonwealth of Virginia in which judgment may be confessed against Maker. No
  single exercise of the power to confess judgment shall be deemed to exhaust
  the power and no judgment against fewer than all the persons constituting
  Maker shall bar any subsequent action or judgment against any one or more of
  such persons against whom judgment has not been obtained on this Note.


                                        PTC Therapeutics, Inc.

 ________________________               By:  _______________________
 (Witness)
 ________________________               Name:___________________________
 (Print name)
 ________________________               Title:______________________
 (Address)
                                        Federal Tax ID #: 04-3416587

                                        Address: 100 Corporate Court
                                                 South Plainfield, NJ 07080

IMPORTANT NOTICE:
THIS INSTRUMENT CONTAINS A CONFESSION OF JUDGMENT PROVISION WHICH CONSTITUTES A
WAIVER OF IMPORTANT RIGHTS YOU MAY HAVE AS A DEBTOR AND ALLOWS THE CREDITOR TO
OBTAIN A JUDGMENT AGAINST YOU WITHOUT ANY FURTHER NOTICE.

                                  PAGE 3 OF 4
<PAGE>
IMPORTANT NOTICE:
THIS INSTRUMENT CONTAINS A CONFESSION OF JUDGMENT PROVISION WHICH CONSTITUTES A
WAIVER OF IMPORTANT RIGHTS YOU MAY HAVE AS A DEBTOR AND ALLOWS THE CREDITOR TO
OBTAIN A JUDGMENT AGAINST YOU WITHOUT ANY FURTHER NOTICE.

                                  PAGE 4 OF 4