UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549


                                  SCHEDULE 13G


                  UNDER THE SECURITIES EXCHANGE ACT OF 1934(1)


                         SHEFFIELD PHARMACEUTICALS, INC.
                                (Name of Issuer)

                    COMMON STOCK, $0.001 PAR VALUE PER SHARE
                         (Title of Class of Securities)

                                    82123D408
                                 (CUSIP Number)

                                NOVEMBER 22, 2006
             (Date of Event Which Requires Filing of this Statement)


     Check the  appropriate  box to  designate  the rule  pursuant to which this
Schedule is filed:

          |_| Rule 13d-1(b)

          |X| Rule 13d-1(c)

          |_| Rule 13d-1(d)


-------------------

     (1) The  remainder  of this cover page shall be filled out for a  reporting
person's  initial  filing on this  form with  respect  to the  subject  class of
securities,  and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.

     The  information  required in the remainder of this cover page shall not be
deemed to be "filed"  for the purpose of Section 18 of the  Securities  Exchange
Act of 1934 or otherwise  subject to the  liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  SEE the
NOTES).





CUSIP No. 82123D408                  13G                      Page 2 of 10 Pages


--------- ----------------------------------------------------------------------
1.        NAME OF REPORTING PERSONS
          I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

          Ridgeback Capital Investments Ltd.          00-0000000
--------- ----------------------------------------------------------------------
2.        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP**            (a)  |_|
                                                                        (b)  |_|
--------- ----------------------------------------------------------------------
3.        SEC USE ONLY
--------- ----------------------------------------------------------------------
4.        CITIZENSHIP OR PLACE OF ORGANIZATION
          Cayman Islands
--------- ----------------------------------------------------------------------
 NUMBER OF      5.        SOLE VOTING POWER

  SHARES                  -0-
                --------  ------------------------------------------------------
BENEFICIALLY    6.        SHARED VOTING POWER

 OWNED BY                 5,569,693*
                --------  ------------------------------------------------------
   EACH         7.        SOLE DISPOSITIVE POWER

 REPORTING                -0-
                --------  ------------------------------------------------------
PERSON WITH     8.        SHARED DISPOSITIVE POWER

                          5,569,693*
--------- ----------------------------------------------------------------------
9.        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
          5,569,693*
--------- ----------------------------------------------------------------------
10.       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES
          CERTAIN  SHARES**                                             |_|
--------- ----------------------------------------------------------------------
11.       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
          11%
--------- ----------------------------------------------------------------------
12.       TYPE OF REPORTING PERSON**
          OO
--------- ----------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT


*Consists of 3,713,129 shares of common stock and 1,856,564 warrants to purchase
shares of common stock.





CUSIP No. 82123D408                  13G                      Page 3 of 10 Pages


--------- ----------------------------------------------------------------------
1.        NAME OF REPORTING PERSONS
          I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

          Ridgeback Capital Management LLC          42-1684320
--------- ----------------------------------------------------------------------
2.        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP**            (a)  |_|
                                                                        (b)  |_|
--------- ----------------------------------------------------------------------
3.        SEC USE ONLY
--------- ----------------------------------------------------------------------
4.        CITIZENSHIP OR PLACE OF ORGANIZATION
          Delaware
--------- ----------------------------------------------------------------------
 NUMBER OF      5.        SOLE VOTING POWER

  SHARES                  -0-
                --------  ------------------------------------------------------
BENEFICIALLY    6.        SHARED VOTING POWER

 OWNED BY                 5,569,693*
                --------  ------------------------------------------------------
   EACH         7.        SOLE DISPOSITIVE POWER

 REPORTING                -0-
                --------  ------------------------------------------------------
PERSON WITH     8.        SHARED DISPOSITIVE POWER

                          5,569,693*
--------- ----------------------------------------------------------------------
9.        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
          5,569,693*
--------- ----------------------------------------------------------------------
10.       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES
          CERTAIN  SHARES**                                             |_|
--------- ----------------------------------------------------------------------
11.       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
          11%
--------- ----------------------------------------------------------------------
12.       TYPE OF REPORTING PERSON**
          OO
--------- ----------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT


*Consists of 3,713,129 shares of common stock and 1,856,564 warrants to purchase
shares of common stock.





CUSIP No. 82123D408                 13G                      Page 4 of 10 Pages


--------- ----------------------------------------------------------------------
1.        NAME OF REPORTING PERSONS
          I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

          Wayne Holman
--------- ----------------------------------------------------------------------
2.        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP**            (a)  |_|
                                                                        (b)  |_|
--------- ----------------------------------------------------------------------
3.        SEC USE ONLY
--------- ----------------------------------------------------------------------
4.        CITIZENSHIP OR PLACE OF ORGANIZATION
          USA
--------- ----------------------------------------------------------------------
 NUMBER OF      5.        SOLE VOTING POWER

  SHARES                  -0-
                --------  ------------------------------------------------------
BENEFICIALLY    6.        SHARED VOTING POWER

 OWNED BY                 5,569,693*
                --------  ------------------------------------------------------
   EACH         7.        SOLE DISPOSITIVE POWER

 REPORTING                -0-
                --------  ------------------------------------------------------
PERSON WITH     8.        SHARED DISPOSITIVE POWER

                          5,569,693*
--------- ----------------------------------------------------------------------
9.        AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
          5,569,693*
--------- ----------------------------------------------------------------------
10.       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW 9 EXCLUDES
          CERTAIN  SHARES**                                             |_|
--------- ----------------------------------------------------------------------
11.       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
          11%
--------- ----------------------------------------------------------------------
12.       TYPE OF REPORTING PERSON**
          IN
--------- ----------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT


*Consists of 3,713,129 shares of common stock and 1,856,564 warrants to purchase
shares of common stock.





CUSIP No. 82123D408                  13G                      Page 5 of 10 Pages


ITEM 1(A).  NAME OF ISSUER.

     Sheffield Pharmaceuticals, Inc. (the "Company").

ITEM 1(B).  ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES.

     The Company's principal executive offices are located at 3985 Research Park
Drive, Ann Arbor, Michigan 48108.

ITEMS 2(A).  NAME OF PERSON FILING.

     This statement is filed on behalf of the following  persons with respect to
shares of common  stock of the Company  acquired,  and to be  acquired  upon the
exercise  of  warrants  acquired,  by such  persons  in a private  placement  of
securities by the issuer (the "Shares"):

     (i) Ridgeback  Capital  Investments Ltd., a Cayman limited company ("RCI"),
with respect to Shares beneficially owned by it;

     (ii) Ridgeback Capital Management LLC, a Delaware limited liability company
("RCM"), with respect to Shares beneficially owned by it; and

     (iii) Wayne Holman,  an individual and owner of RCM, with respect to Shares
beneficially owned by him.

     The  foregoing  persons are  hereinafter  referred to  collectively  as the
"Reporting  Persons." Any disclosures  herein with respect to persons other than
the Reporting Persons are made on information and belief after making inquiry to
the appropriate party.

ITEM 2(B).  ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE.

     The  address  of the  principal  business  office of each of the  Reporting
Persons is 430 Park Avenue, 12th Floor, New York, New York 10022.

ITEM 2(C).  CITIZENSHIP.

     RCI is a Cayman Island limited company. RCM is a Delaware limited liability
company. Wayne Holman is a United States citizen.

ITEM 2(D).  TITLE OF CLASS OF SECURITIES.

     Common stock , $0.001 par value per share.

ITEM 2(E).  CUSIP NUMBER.

     82123D408





CUSIP No. 82123D408                 13G                      Page 6 of 10 Pages


ITEM 3.

     If this  statement is filed pursuant to Rules 13d-1(b) or 13d- 2(b) or (c),
check whether the person filing is a:

     (a)  |_| Broker or dealer registered under Section 15 of the Act,

     (b)  |_| Bank as defined in Section 3(a)(6) of the Act,

     (c)  |_| Insurance Company as defined in Section 3(a)(19) of the Act,

     (d)  |_| Investment  Company  registered  under Section 8 of the Investment
          Company Act of 1940,

     (e)  |_| Investment Adviser in accordance with Rule 13d-1 (b)(1)(ii)(E),

     (f)  |_| Employee  Benefit Plan or Endowment Fund in accordance  with 13d-1
          (b)(1)(ii)(F),

     (g)  |_| Parent Holding  Company or control person in accordance  with Rule
          13d-1 (b)(1)(ii)(G),

     (h)  |_|  Savings  Association  as defined in Section  3(b) of the  Federal
          Deposit Insurance Act,

     (i)  |_| Church Plan that is excluded from the  definition of an investment
          company under Section 3(c)(14) of the Investment Company Act of 1940,

     (j)  |_| Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

     If this statement is filed pursuant to 13d-1(c), check this box:      |X|

ITEM 4.  OWNERSHIP.

     The percentages used herein are calculated  based on the 48,680,515  Common
Shares reported to be outstanding by the Issuer,  plus an aggregate of 1,856,564
shares  assumed  issued upon the exercise of warrants held by the filing person.
As of the  close of  business  on  November  22,  2006,  the  Reporting  Persons
beneficially  owned  shares of the  Company's  common  stock in the  amounts and
percentages listed below:

     A.   RIDGEBACK CAPITAL INVESTMENTS LTD.

     (a)  Amount beneficially owned: 5,569,693

     (b)  Percent of class: 11.0%

     (c)  (i) Sole power to vote or direct the vote: -0-

          (ii) Shared power to vote or direct the vote: 5,569,693





CUSIP No. 82123D408                 13G                      Page 7 of 10 Pages


          (iii) Sole power to dispose or direct the disposition: -0-

          (iv) Shared power to dispose or direct the disposition: 5,569,693

     B.   RIDGEBACK CAPITAL MANAGEMENT LLC

     (a)  Amount beneficially owned: 5,569,693

     (b)  Percent of class: 11%

     (c)  (i) Sole power to vote or direct the vote: -0-

          (ii) Shared power to vote or direct the vote: 5,569,693

          (iii) Sole power to dispose or direct the disposition: -0-

          (iv) Shared power to dispose or direct the disposition: 5,569,693

     C.   WAYNE HOLMAN

     (a)  Amount beneficially owned: 5,569,693

     (b)  Percent of class: 11%

     (c)  (i) Sole power to vote or direct the vote: -0-

          (ii) Shared power to vote or direct the vote: 5,569,693

          (iii) Sole power to dispose or direct the disposition: -0-

          (iv) Shared power to dispose or direct the disposition: 5,569,693

     Wayne  Holman  and RCM do not  own  any  Shares  directly.  Pursuant  to an
investment management agreement,  RCM maintains investment and voting power with
respect to the securities  held by RCI. Wayne Holman  controls RCM. By reason of
the provisions of Rule 13d-3 of the Securities Exchange Act of 1934, as amended,
Wayne  Holman  and RCM  may be  deemed  to own  beneficially  all of the  Shares
(constituting  approximately 11% of the shares  outstanding).  Both Wayne Holman
and RCM disclaim  beneficial  ownership of any of the securities covered by this
statement, except to the extent of any pecuniary interest therein.

ITEM 5.  OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

     If this  statement  is being  filed to report  the fact that as of the date
hereof the reporting  person has ceased to be the beneficial  owner of more than
five percent of the class of securities, check the following.   |_|





CUSIP No. 82123D408                 13G                      Page 8 of 10 Pages


ITEM 6.  OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

     To the knowledge of the Reporting Persons, no other person has the right to
receive or the power to direct the receipt of  dividends  from,  or the proceeds
from the sale of, a number of the Shares which represents more than five percent
of the number of outstanding shares of the Shares.

ITEM 7.  IDENTIFICATION  AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
         SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.

     Not Applicable.

ITEM 8.  IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

     Not Applicable.

ITEM 9.  NOTICE OF DISSOLUTION OF GROUP.

     Not Applicable.

ITEM 10.  CERTIFICATIONS.

     Each of the Reporting Persons hereby makes the following certification:

     By signing  below I certify  that,  to the best of my knowledge and belief,
the  securities  referred  to above were not  acquired  and are not held for the
purpose of or with the effect of  changing  or  influencing  the  control of the
issuer of the  securities  and were not acquired and are not held in  connection
with or as a participant in any transaction having that purpose or effect.





CUSIP No. 82123D408                  13G                      Page 9 of 10 Pages


                                    SIGNATURE

         After reasonable  inquiry and to the best of my knowledge and belief, I
certify that the information  set forth in this statement is true,  complete and
correct.

DATED:November 29, 2006

                                                              *
                                           By: ---------------------------------
                                               Wayne Holman, individually


                                              RIDGEBACK CAPITAL INVESTMENTS LTD.

                                                              *
                                           By: ---------------------------------
                                               Name: Wayne Holman
                                               Title: Director


                                              RIDGEBACK CAPITAL MANAGEMENT LLC

                                                              *
                                           By: ---------------------------------
                                               Name: Wayne Holman
                                               Title: Managing Member


*By: /s/ Bud Holman
     -----------------------------
     Bud Holman, Attorney-in-Fact
     Power of attorney filed as an exhibit hereto





CUSIP No. 82123D408                  13G                     Page 10 of 10 Pages


                                  EXHIBIT INDEX


EXHIBIT NUMBER    EXHIBIT DESCRIPTION
--------------    -------------------
24.1              Power of Attorney

99.1              Joint Filing Agreement