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                             SPECIMEN CERTIFICATE

                             CALLABLE COMMON STOCK


The securities of Spiros Development Corporation II, Inc., a Delaware company
(the "Company") evidenced hereby are subject to an option of the holder of a
majority of the Special Common Stock of the Company, as described in the Amended
and Restated Certificate of Incorporation of the Company, to purchase such
securities at an agreed upon price, exercisable by notice given at any time
beginning on the closing date of the offering of the Callable Common Stock, par
value $0.001 per share (the "Callable Common Stock"), of Spiros Development
Corporation II, Inc. and the warrants (the "Warrants") to purchase common shares
of Dura Pharmaceuticals, Inc. ("Dura") which comprise the Units, (the "Unit
Offering") and ending on the earlier of (i) December 31, 2002, (ii) the 90th day
after the date the Company provides such holder with quarterly financial
statements of the Company showing cash or cash equivalents of less than
$5,000,000 or (iii) the date of termination by the Company of that certain
Technology License Agreement, Development Agreement or Manufacturing and
Marketing Agreement dated on or about December 22, 1997.  Copies of the
Amended and Restated Certificate of Incorporation of the Company are available
at the offices of the Company, 7475 Lusk Boulevard, San Diego, California
92121, Attention:  Mitchell R. Woodbury and will be furnished to any shareholder
of the Company on request and without cost.

         Until December 31, 1999 or such earlier date as the Purchase Option is
exercised or expires unexercised (the "Separation Date"), the shares of Callable
Common Stock represented by this Certificate may be traded, exchanged, or
otherwise transferred only together with the Warrant issued herewith.  The
holder hereof may, but need not, submit this Certificate for the removal of this
legend after the Separation Date.


                       SPIROS DEVELOPMENT CORPORATION II, INC.
                 Incorporated Under The Laws of the State of Delaware

                                CALLABLE COMMON STOCK

                 FULLY PAID AND NON-ASSESSABLE CALLABLE COMMON STOCK,
                             PAR VALUE OF $.001 PER SHARE
                      OF SPIROS DEVELOPMENT CORPORATION II, INC.

                                   CUSIP 848936100
                         See Reverse For Certain Definitions


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THIS CERTIFIES that

is the owner of           Callable Common Stock of

SPIROS DEVELOPMENT CORPORATION II, INC. (the "Company"), transferable on the
books of the Company by the holder hereof, in person or by duly authorized
attorney, upon surrender of this Certificate properly endorsed.  This
certificate and the shares represented hereby are subject to the laws of
Delaware, and to the Amended and Restated Certificate of Incorporation of the
Company as now or hereafter amended (copies of which are on file at the offices
of the Company and the Transfer Agent), which are made a part hereof with the
same force and effect as if they were set forth herein, to all of which the
holder, by acceptance hereof, assents.  This certificate is not valid unless
countersigned by the Transfer Agent and registered by the Registrar.

         IN WITNESS WHEREOF, the Company has caused the facsimile signatures of
its duly authorized officers and the facsimile of its corporate seal to be
hereunto affixed.

Dated:


Countersigned and Registered:


Transfer Agent and Registrar


By: ____________________
    Name:
    Title:


                        Authorized Officer       Authorized Officer


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            [FORM OF REVERSE OF SPIROS DEVELOPMENT CORPORATION II, INC.'S
                                CALLABLE COMMON STOCK]

                       SPIROS DEVELOPMENT CORPORATION II, INC.

         The Company will furnish without charge to each shareholder who so
requests a copy of the powers, designations, preferences and relative,
participating, optional or other special rights of each class of shares of the
Company or series thereof, and the qualifications, limitations or restrictions
of such preferences and/or rights.


The following abbreviations, when used in the inscription on the face of this
certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

TEN COM  -  as tenants in common

TEN ENT  -  as tenants by the entireties

JT TEN   -  as joint tenants with right of survivorship and not as tenants in
            common

UNIF GIFT MIN ACT...............Custodian..............................
                (cust)                       (Minor)
                under Uniform Gifts to Minors Act
               ....................................................
                                             (State)

Additional abbreviations may also be used though not in the above list.


         For Value Received, __________________ hereby sells, assigns and
transfers unto


Please insert Social Security
or other identifying number
of assignee


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                      Please print or typewrite name and address
                        including postal zip code of assignee




                                                                          Shares

represented by the within Certificate, and do hereby irrevocably constitute and
appoint


attorney, to transfer the said same on the books of the within named Company,
with full power of substitution in the premises.

Dated:


                                       Signature



                                       Signature

                             Notice:  The signature to this assignment must
                             correspond with the name as written upon the face
                             of the Certificate, in every particular, without
                             alteration or enlargement, or any change whatever.

In presence of:


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Important:              All signatures must be guaranteed by a firm which is a
                        financial institution and a member of the Securities
                        Transfer Agent's medallion Program ("STAMP"), the Stock
                        Exchange Medallion Program ("SEMP") or the New York
                        Stock Exchange, Inc. Medallion Signature Program
                        ("MSP").


Signature Guarantee:
                        Name of Firm


                        Authorized Signature


                        Name of Authorized Signatory
                        (Please print)


                        Address of Firm



                        Area Code and Telephone Number of Firm