MACROCHEM CORPORATION
                   CALCULATION FOR WEIGHTED AVERAGE NUMBER OF
                            COMMON SHARES OUTSTANDING

              WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING
                     FOR THE SIX MONTHS ENDED JUNE 30, 1996

                        CALENDAR DAYS IN THE PERIOD: 182

<TABLE>
<CAPTION>
                                                                            WEIGHTED
                                             COMMON     COMMON               AVERAGE
                                             SHARE      SHARES    DAYS OUT- NUMBER OF
DATE               DESCRIPTION              ACTIVITY  OUTSTANDING STANDING   SHARES
-------------------------------------------------------------------------------------
<S>                <C>                     <C>        <C>           <C>    <C>
  
DECEMBER 31, 1995  BALANCE                            13,129,321
January 22, 1996   Options Exercised          5,000   13,134,321    161    13,133,744
January 31, 1996   Unit Purchase Options 
                   Exercised                810,000   13,944,321    152    13,810,228
February 1, 1996   Unit Purchase Options 
                   Exercised                210,000   14,154,321    151    13,984,458
February 2, 1996   Unit Purchase Options 
                   Exercised                455,000   14,609,321    150    14,359,458
February 2, 1996   A Warrants Exercised     151,667   14,760,988    150    14,484,459
February 2, 1996   Options Exercised         15,000   14,775,988    150    14,496,821
February 5, 1996   Options Exercised          2,861   14,778,849    147    14,499,132
February 7, 1996   A Warrants Exercised       1,000   14,779,849    145    14,499,929
February 8, 1996   Options Exercised          1,000   14,780,849    144    14,500,149
February 9, 1996   AA Warrants Exercised     81,000   14,861,849    143    14,563,792
February 15, 1996  X Warrants Exercised       3,750   14,865,599    137    14,566,615
February 29, 1996  Options Exercised         30,000   14,895,599    123    14,586,890
February 29, 1996  A Warrants Exercised     200,000   15,095,599    123    14,722,060
February 29, 1996  X Warrants Exercised       1,000   15,096,599    123    14,722,736
March 1, 1996      X Warrants Exercised       1,000   15,097,599    122    14,723,406
March 4, 1996      Options Exercised          2,500   15,100,099    119    14,725,041
March 7, 1996      A Warrants Exercised     140,000   15,240,099    116    14,814,272
March 14, 1996     X Warrants Exercised      10,000   15,250,099    109    14,820,261
March 19, 1996     Options Exercised          5,000   15,255,099    104    14,823,118
March 21, 1996     A Warrants Exercised     100,000   15,355,099    102    14,879,162
April 4, 1996      Options Exercised         31,500   15,386,599     87    14,894,219
April 25, 1996     Options Exercised        120,000   15,506,599     66    14,937,736
May 7, 1996        Options Exercised          5,000   15,511,599     54    14,939,219

JUNE 30, 1996      WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING    14,939,219
                                                   NET LOSS               $(1,895,349)
                                                   NET LOSS PER SHARE     $     (0.13)
                                                                        
</TABLE>
                                                                     (Continued)
<PAGE>
                                                                      Exhibit 11
                                                                     (Continued)
              WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING
                     FOR THE SIX MONTHS ENDED JUNE 30, 1997

                        CALENDAR DAYS IN THE PERIOD: 181
<TABLE>
<CAPTION>
                                                                             WEIGHTED
                                             COMMON     COMMON               AVERAGE
                                             SHARE      SHARES    DAYS OUT-  NUMBER OF
   DATE                DESCRIPTION          ACTIVITY  OUTSTANDING STANDING   SHARES
-------------------------------------------------------------------------------------
<S>                <C>                       <C>      <C>           <C>    <C>

DECEMBER 31, 1996  BALANCE                            15,601,274
January 14, 1997   A Warrants Exercised         100   15,601,374    168    15,601,367
January 23, 1997   Unit Purchase Options 
                   Exercised                 30,000   15,631,374    159    15,627,720
January 29, 1997   Unit Purchase Options 
                   Exercised                 30,000   15,661,374    153    15,653,080
January 29, 1997   Options Exercised          3,334   15,664,708    153    15,655,898
January 31, 1997   X Warrnts Exercised        1,000   15,665,708    151    15,656,732
February 3, 1997   Options Exercised         13,000   15,678,708    148    15,667,362
February 5, 1997   Options Exercised          2,000   15,680,708    146    15,668,975
February 7, 1997   A Warrants Exercised       1,000   15,681,708    144    15,669,771
February 7, 1997   AA Warrants Exercised      1,000   15,682,708    144    15,670,566
February 7, 1997   Options Exercised          3,000   15,685,708    144    15,672,953
February 10, 1997  Options Exercised          1,000   15,686,708    141    15,673,732
February 10, 1997  X Warrants Exercised      25,000   15,711,708    141    15,693,207
February 14, 1997  A Warrants Exercised      17,000   15,728,708    137    15,706,075
February 18, 1997  Options Exercised          1,500   15,730,208    133    15,707,177
February 19, 1997  Options Exercised         12,000   15,742,208    132    15,715,928
February 24, 1997  Options Exercised            667   15,742,875    127    15,716,396
February 25, 1997  A Warrants Exercised      25,000   15,767,875    126    15,733,799
February 25, 1997  Unit Purchase Options
                   Exercised                 30,000   15,797,875    126    15,754,683
March 4, 1997      Unit Purchase Options
                   Exercised                 30,000   15,827,875    119    15,774,407
March 6, 1997      Options Exercised          1,000   15,828,875    117    15,775,054
March 14, 1997     Options Exercised          5,000   15,833,875    109    15,778,065
March 18, 1997     Unit Purchase Options
                   Exercised                 60,000   15,893,875    105    15,812,871
March 18, 1997     Options Exercised          7,000   15,900,875    105    15,816,932
March 21, 1997     X Warrants Exercised       6,000   15,906,875    102    15,820,313
March 28, 1997     A Warrants Exercised      25,000   15,931,875     95    15,833,435
April 14, 1997     Unit Purchase Options 
                   Exercised                 60,000   15,991,875     77    15,858,960
April 18, 1997     A Warrants Exercised      15,000   16,006,875     73    15,865,009
April 23, 1997     X Warrants Exercised      15,000   16,021,875     68    15,870,645
May 12, 1997       X Warrants Exercised      23,000   16,044,875     50    15,876,998
May 15, 1997       A Warrants Exercised      25,000   16,069,875     47    15,883,490
June 5, 1997       Shares Issued for Service 16,000   16,085,875     26    15,885,788
June 10, 1997      A Warrants Exercised       1,000   16,086,875     21    15,885,904
June 13, 1997      Unit Purchase Options 
                   Exercised                 60,000   16,146,875     18    15,891,871
June 16, 1997      Options Exercised          1,000   16,147,875     15    15,891,954
June 27, 1997      Options Exercised          2,500   16,150,375      4    15,892,009

JUNE 30, 1997      WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING    15,892,009
                                                     NET LOSS             $(1,816,505)
                                                     NET LOSS PER SHARE   $     (0.11)
                                                                                             
</TABLE>
                                                                     (Continued)
<PAGE>
                                                                     EXHIBIT 11 
                                                                     (Continued)

              WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING
                    FOR THE THREE MONTHS ENDED JUNE 30, 1996

                         CALENDAR DAYS IN THE PERIOD: 91
<TABLE>
<CAPTION>

                                                                            WEIGHTED
                                             COMMON     COMMON               AVERAGE
                                             SHARE      SHARES    DAYS OUT- NUMBER OF
   DATE                DESCRIPTION          ACTIVITY  OUTSTANDING STANDING   SHARES                                      OUTSTANDING
-------------------------------------------------------------------------------------
<S>                <C>                       <C>      <C>            <C>   <C>

MARCH 31, 1996     BALANCE                            15,355,099
april 4, 1996      Options Exercised         31,500   15,386,599     88    15,385,561
April 25, 1996     Options Exercised         20,000   15,506,599     67    15,473,912
May 7, 1996        Options Exercised          5,000   15,511,599     55    15,476,934

JUNE 30, 1996      WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING    15,476,934
                                                     NET LOSS            $ (1,146,753)
                                                     NET LOSS PER SHARE  $      (0.07)
                                                                    
</TABLE>

              WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING
                    FOR THE THREE MONTHS ENDED JUNE 30, 1997

                         CALENDAR DAYS IN THE PERIOD: 91

<TABLE>
<CAPTION>
                                                                            WEIGHTED
                                             COMMON     COMMON               AVERAGE
                                             SHARE      SHARES    DAYS OUT- NUMBER OF
   DATE                DESCRIPTION          ACTIVITY  OUTSTANDING STANDING   SHARES                                      OUTSTANDING
-------------------------------------------------------------------------------------
<S>                <C>                       <C>      <C>            <C>   <C>

MARCH 31, 1997     BALANCE                            15,931,875
April 14, 1997     Unit Purchase Options 
                   Exercised                 60,000   15,991,875     78    15,983,304
April 18, 1997     A Warrants Exercised      15,000   16,006,875     74    15,995,501
April 23, 1997     X Warrants Exercised      15,000   16,021,875     69    16,006,875
May 12, 1997       X Warrants Exercised      23,000   16,044,875     50    16,019,512
May 15, 1997       A Warrants Exercised      25,000   16,069,875     47    16,032,424
June 5, 1997       Shares Issued for 
                   Services                  16,000   16,085,875     26    16,036,996
June 10, 1997      A Warrants Exercised       1,000   16,086,875     21    16,037,227
June 13, 1997      Unit Purchase Options 
                   Exercised                 60,000   16,146,875     18    16,049,095
June 16, 1997      Options Exercised          1,000   16,147,875     15    16,049,260
June 27, 1997      Options Exercised          2,500   16,150,375      4    16,049,370

JUNE 30, 1997      WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING    16,049,370
                                                     NET LOSS            $ (1,104,189)
                                                     NET LOSS PER SHARE  $      (0.07)
                                                                               
</TABLE>
                                                                     (Concluded)