Abstract:
A topical composition for eye treatment of glaucoma, comprising a small but pharmaceutically effective amount of an analog of benzothiazole-2-sulfonamide. The most preferred compound is 6-hydroxyethoxy-2-benzothiazolesulfonamide. The invention also relates to a method of topically treating glaucoma with eye drops to reduce intraocular pressure. Finally, disclosed is a method of synthesis of the preferred and highly effective benzothiazole-2-sulfonamide analogs, particularly the 6-hydroxyethoxy-2-benzothiazolesulfonamide compound.

Description:
GRANT REFERENCE 
     This invention was made in part with government support under Contract No. 5 ROl EY No. 03297-02 awarded by the National Eye Institute. The government may have certain rights in this invention. 
    
    
     CROSS REFERENCE TO A RELATED INVENTION 
     This application is a continuation-in-part of copending, commonly assigned application Ser. No. 464,063, filed Feb. 13, 1983. 
    
    
     BACKGROUND OF THE INVENTION 
     Glaucoma, which some estimate affects 2 million adults over 40, is an impairment of vision caused by too much fluid pressure within the eye. 
     Surgical treatment for glaucoma is effective, however, it is expensive and some surgeons will use surgery only as a last resort. 
     Carbonic anhydrase inhibitors, prescribed orally work well to treat this disease, but they carry a host of side effects, from nausea to kidney stones. 
     Glaucoma stems from an excess of fluid behind the cornea, the three-layered tissue that acts as a window to let light enter. Fluid carrying nutrients such as potassium and glucose constantly wash the inside of the cornea to keep it healthy, much as tears wash the outside of the cornea. 
     In some middle-aged adults fluids build up faster than can be absorbed back into the blood, for one of two reasons: the ciliary body (a tiny tissue behind the iris) may excrete too much fluid, or the fluid may not drain off at the normal rate. 
     Either way, the excess fluid damages the optic nerve. At first a glaucoma victim usually experiences a subtle loss of peripheral vision--objects will seem to disappear from certain spots to the side. But glaucoma often leads to middle-age blindness. 
     Unfortunately, the two approaches to general drug usage in treating glaucoma--topical (dropped into the eye) and oral--each have a peculiar set of side effects. 
     To make the long journey, oral drugs must be dosed in very high concentration. One class of drugs, called carbonic anhydrase inhibitors, slow the formation of fluid by inhibiting a chemical reaction at the ciliary body. Along with their well-tested effectiveness, comes nausea, tingling in fingers and toes and other side effects. Oral drugs generally do not, however, cause side effects in the eye. 
     Certain topical drugs, while causing less systemic effects, on the other hand, can cause sever headaches and constrict the pupil, making the daytime appear dark. 
     Accordingly, there is a real and continuing need to develop an inhibitor drug that can be dropped into the eye instead of swallowed, thereby avoiding the present side effects. It is a primary objective of the present invention to develop a highly effective topical carbonic anhydrase inhibitor drug for treatment of glaucoma to reduce intraocular eye pressure, and at the same time, avoid the systemic side effects, commonly caused by oral drugs. 
     Another objective of the present invention is to develop a drug for topical treatment of glaucoma, which is not only effective, but which will also pass through the three layered cornea and still be effective enough to work on the ciliary body. 
     Another objective of the present invention is to develop a highly effective, topical drug treatment for glaucoma which is substantially non-harmful to the eye when topically applied. 
     An even further objective of the present invention is to develop an eye treating topical composition which is effective for glaucoma treatment. 
     A still further objective is to provide a convenient method of synthesis of 6-hydroxyethoxy-2-benzothiazolesulfonamide, which is a highly effective topical treatment of glaucoma. 
     A further specific objective of the present invention is to provide as a novel component 6-hydroxyethoxy-2-benzothiazolesulfonamide, in pharmaceutically effective amounts is a highly effective topical composition for eye drop treatment of glaucoma. 
     The method and manner of achieving each of the above objectives, as well as others, will become apparent from the detailed description of the invention which follows hereinafter. 
     SUMMARY OF THE INVENTION 
     As a new compound, 6-hydroxyethoxy-2-benzothiazolesulfonamide. Also, topical compositions for eye drop treatment of glaucoma which comprises a small but pharmaceutically effective amount of 6-hydroxyethoxy-2-benzothiazolesulfonamide. 
     The invention thus relates to a most preferred compound which is a compound falling into the general formula presented in our previous patent application, Ser. No. 464,563, filed Feb. 13, 1983. The invention further relates to a method of topically treating glaucoma with eye drops to reduce intraocular eye pressure; and finally, the invention relates to a method of synthesis of this preferred compound. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As heretofore mentioned, carbonic anhydrase inhibitors are known. However, the compounds are generally not effective because of the rather severe side effects previously mentioned. Studies have shown that when taken orally, because of the side effects, approximately 80% of the treated patients stop taking the drug treatment within two to three weeks. The side effects that they often report are short-term tingling of the extremities, gastrointestinal tract upset, kidney stones and some renal failure. 
     The mechanism of reaction of carbonic anhydrase inhibitors has been reported, and it is a combination of a diuretic effect and reduction of intraocular pressure in the eye. The compound useful for treatment in this invention functions to provide reduction of intraocular pressure, but does so without the commonly occurring side effects of oral drugs for treating glaucoma, or the commonly occurring side effects of topical drugs for glaucoma treatment. 
     The compound developed by the applicant and useful for the topical composition eye drop treatment of glaucoma, as described in this invention, is an analog of benzothiazole-2-sulfonamide, and is a carbonic anhydrase inhibitor. It has the following general formula: ##STR1## It is also to be understood that one may use an ophthalmologically acceptable salt of the above shown compound. Examples of acceptable salts include the alkali metal salts. 
     Of course, the compound is carried in an inert, noneye irritating, non-toxic eye drop diluent of conventional formulation. Such formulations are well known, and commonly referred to in, for example, the Physician&#39;s Desk Reference for Ophthalmology (1982 Edition, published by Medical Economics Company, Inc., Oridell, New Jersey), wherein numerous sterile ophthalmologic ocular solutions are reported, e.g., see pp. 112-114, which are incorporated by reference. 
     Preferably the amount of 6-hydroxyethoxy-2-benzothiazolesulfonamide present in the eye drop treatment composition is a concentration of from about 0.25% to about 5% by weight of the eye drop treating composition. Most preferably, the amount is from about 0.5% to about 3.0% by weight of the eye drop treating composition, and in tests conducted to date, highly effective compositions have used the compounds at the 1% and 3% suspension level. 
     As heretofore mentioned, while the diluent is not part of the present invention in that such diluents are known, it is preferred that the diluent be an isotonic eye treatment carrier, buffered to a pH within the range of from about 4.0 to about 8.0 and containing a small but effective amount of a wetting agent and an anti-bacterial agent. The preferred pH range is from about 6.8 to about 7.8. 
     Commonly used wetting agents are well known, and again are mentioned in the previously referred to pages of the Physician&#39;s Desk Reference for Ophthalmology. One suitable one is Tween, and in particular, Tween 80. Likewise, antibacterials are known and commonly employed in such compositions. Suitable anti-bacterials include the most preferred benzalkonium chloride and others as well such as, for example, chlorobutanol. The amount of wetting agent can range from .01% to .10%. 
     The amount of anti-bacterial can range from about 0.004% to about .02% by weight of the eye drop treating composition. 
     The compounds of this invention, providing that the molecular structures are as defined hereinbefore, are water soluable, but they also have a lipid solubility factor to allow transfer across the eye, and they have suitable structure to allow them to effectively function in the eye as carbonic anhydrase inhibitors. Their water solubility means ease of preparation for topical application, their lipid solubility characteristics mean effectiveness in transfer across the three corneal layer. 
     As will be explained hereinafter, the dosage amounts can vary, and no doubt will vary, but are well within routine experimentation of the treating physician. In some of the tests described hereinafter, the dosage for the topical application has been three drops, with one drop every two minutes. This has been found to be effective, but it is also reasonable to expect that other dosage levels will vary depending upon severity of the case. 
     The following examples are offered to further illustrate the synthesis of the compounds of this invention, the making of topical treatment compositions using the same, and to provide data showing decrease of intraocular pressure in the eyes of rabbits and cynomolgous monkeys. They are intended to further illustrate, but not necessarily limit the invention and it is understood that certain modifications and changes, both in technique and composition and structure, may be made, without departing from structure, function and operation of the invention. 
     EXAMPLES 
     EXAMPLE 1 
     Synthesis of 6-hydroxyethoxy-2-benzothiazolesulfonamide 
     The ammonium dithiocarbamate of 4-hydroxyethoxyaniline was prepared by mixing 95% ethanol (50ml) and concentrated ammonium hydroxide (17 ml) in a 3-necked flask equipped with an addition funnel and a thermometer, cooling the solution to -5° C. in an ice-methanol bath, and adding carbon disulfide (10 ml). A solution of 4-hydroxyethoxyaniline (15.7 g, 0.103 mol) in 95% ethanol (50 ml) was added over 30 minutes to the reaction mixture while maintaining a temperature of 0° C. The reaction was stirred for 3 hours at 0° C. and the precipitated product collected by vacuum filtration in a Buchner funnel. The product was washed with 95% ethanol (50 ml) followed by acetone (25 ml) and air dried at room temperature to give 15.3 g (60.5% yield) of ammonium 4-hydroxyethoxyphenyl dithiocarbamate: m. p. 94° -97° C. Ammonium 4-hydroxyethoxyphenyl dithiocarbamate (4.9 g, 0.02 mol) and sulfur (9.7 g, 0.022 mol) were triturated. The reaction mixture was combined in a 25 ml high pressure bomb and placed in a preheated oil bath at 190° C. A temperature of 190° -200° C. was maintained for a 2 hour period. The bomb was removed from the heating bath and cooled to room temperature. The gases generated by the reaction were passed through as aqueous 5.25% sodium hypochlorite solution. The orange oil was dissolved in aqueous 5% potassium hydroxide (100 ml) and diluted with water (50 ml). The product was precipitated by cooling to 0° C. and the pH adjusted to 5 with glacial acetic acid. The precipitated product was collected by vacuum filtration in a Buchner funnel give 1.5 g (33.0% yield) of 6-hydroxyethoxy-2-mercaptobenzothiazole. m. p. 162-165° C.; Anal. (C 9  H 9  NO 2  S 2 ) CHN. The sulfenamide was formed by reaction with aqueous sodium hydroxide and sodium hypochlorite and oxidized with m-chloroperoxybenzoic acid to yield the product in 55% yield. m. p. 155°-158° C.; Anal. (C 9  H 10  N 2  O 2  S 2 ) CHN. 
     EXAMPLE 2 
     Measurement of Intraocular Pressure 
     (&#34;Salted Rabbit Test&#34;) (IOP) 
     Rabbits (3-4 months old) were maintained on 0.3% sodium chloride solution in place of drinking water for 3 weeks prior to the determination of IOP because it has been shown that a diet deficient in sodium produces a variable response to this class of drugs. During this 3 week period numerous IOP measurements were made to familiarize the rabbits with this procedure. Baseline IOP measurements were determined by applanation tonometry following topical administration of 3 drops of 1% suspension of analog CAI inhibitor to one eye. The fellow eye received blank vehicle. The observer was masked. Each eye received 1 to 2 drops of proparacaine hydrochloride (0.5%) to anethetize the cornea prior to placing the sensor tip of the tonometer flot on the cornea. IOP measurements were determined over 180 minutes at 20 minute intervals. Changes in IOP were expressed as: 
     
         IOP change=IOP (dosed eye - control eye).sub.t -IOP (dosed eye prior to administration - control eye).sub.t=O 
    
     Intraocular pressure (IOP) measurements of 6-hydroxyethoxy-2-benzothiazole sulfonamide in rabbits a  maintained on 3% sodium chloride drinking water following topical instillation. b ,c 
    
    
    
     
         ______________________________________Time after dosing          Ave. change in(minutes)      IOP (mm Hg) Probability.sup.d______________________________________0              0           --20             -0.2        N.S.40             -1.1        0.0760             -1.1        0.0480             -0.8        0.12100            -1.2        0.04120            -0.5        N.S.140            0.2         N.S.160            0.3         N.S.180            -0.2        N.S.______________________________________ .sup.d N.S. = nonsignificant, reported values represent probability that the reduction in IOP is due to chance, from student&#39;s t test 
    
     EXAMPLE 3 
     As demonstrated in the earlier examples, the compound of the present invention has been demonstrated to inhibit carbonic anhydrase, using the rabbit as the test species. Because there are certain differences in the eyes of rabbits and man, it was desired to test topical carbonic anhydrase inhibition by the compound of the present invention in a subhuman primate species to confirm the presence of activity by this route. The cynomologous monkey was chosen to represent the species. Because drug effects on intraocular pressure are sometimes less dramatic or not demonstrable using an eye that is normotensive, a test protocol known as the &#34;DeSantis&#34; test was developed. It involves testing the carbonic anhydrase inhibitor effects in eyes made hypertensive by laser treatment. In particular, argon laser energy was delivered to the trabecular meshwork of cynomologous monkeys which resulted in an elevation of the intraocular pressure as measured by pneumatonometry. After the eye was allowed to recover from the inflammatory process which accompanied the laser treatment, it was used to test the subject drugs. Experimental results of these tests are reported below. 
     Intraocular pressure (IOP) was determined using an Alcon Pneumatonograph after light corneal anesthesia with proparacaine, before and at 1, 3 and 7 hours after installation of drug to both eyes of each of six cynomologous monkeys per group. The right eyes of these monkeys had been given laser trabeculoplasty several months prior to this experiment which resulted in ocular hypertension. Animals were trained to sit in restraint chairs and to accept the pressure measurement. Following the measurement, residual anesthetic was washed out with saline. 
     Data for the intraocular pressure studies are presented in the attached tables, where the lasered eyes but not the normal eyes show significant reduction of intraocular pressure compared to control animals. 
     In the tables below &#34;OD&#34; refers to ocular dexter, and &#34;OS&#34; refers to ocular sinnister. This is simply another way of saying right and left eye. The designation number in the lefthand column of each table refers to the designation number assigned to each monkey. &#34;SE&#34; refers to standard error. Table 1 shows in the first instance a control treatment of the lasered eye with a gel without the active compound of the invention. In the second instance it shows the treatment of the same eye with the drug, that is with 6-hydroxyethoxy-2-benzothiazolesulfonamide. In the third instance it shows a left eye control and in the fourth instance treatment of the left eye with the drug. 
     
                                           TABLE 1__________________________________________________________________________1.0% 6-Hydroxyethoxy-2-benzothiazolesulfonamide Gel                 IOP (mmHg)MONKEY                TIME   TIME     TIME#          EYE         TREATMENT                 (HR)                     IOP                        (HR)                            IOP  (HR)                                     IOP__________________________________________________________________________53         OD CONTROL 0   48 3   48   7   5348         OD CONTROL 0   57 3   57   7   5849         OD CONTROL 0   29 3   28   7   2851         OD CONTROL 0   48 3   40   7   4750         OD CONTROL 0   38 3   31   7   35186        OD CONTROL 0   38 3   35   7   36MEAN                      43.0   39.8     42.8S.E.                      4.0    4.5      4.8MEAN % CHANGE                    -7.8     -1.1S.E.                             3.3      2.756         OD DRUG    0   38 3   34   7   3447         OD DRUG    0   25 3   23   7   2555         OD DRUG    0   28 3   23   7   2463         OD DRUG    0   46 3   36   7   4652         OD DRUG    0   35 3   30   7   33187        OD DRUG    0   48 3   40   7   41MEAN                      36.7   31.0     33.8S.E.                      3.8    2.9      3.5MEAN % CHANGE                    -14.9    -7.5S.E.                             2.0      2.753         OS CONTROL 0   32 3   27   7   3148         OS CONTROL 0   22 3   25   7   2449         OS CONTROL 0   25 3   27   7   2851         OS CONTROL 0   27 3   34   7   3250         OS CONTROL 0   28 3   26   7   28186        OS CONTROL 0   27 3   27   7   31MEAN                      26.8   27.7     29.0S.E.                      1.4    1.3      1.2MEAN % CHANGE                    +4.1     +8.6S.E.                             6.1      3.556         OS DRUG    0   33 3   34   7   3447         OS DRUG    0   19 3   20   7   2555         OS DRUG    0   24 3   25   7   2863         OS DRUG    0   23 3   25   7   2252         OS DRUG    0   20 3   19   7   19187        OS DRUG    0   33 3   38   7   41MEAN                      25.3   26.8     28.2S.E.                      2.5    3.1      3.3MEAN % CHANGE                    +5.2     +11.1S.E.                             2.7      6.3__________________________________________________________________________ **NOTE: Percent change values are calculated from individual animal data and may not reflect changes of mean IOP. 
    
     A repeat in order to test the accuracy of the data for the same monkeys was conducted six days later and is reported in Table 2. 
     
                                           TABLE 2__________________________________________________________________________1.0% 6-Hydroxyethoxy-2-benzothiazolesulfonamide Gel(Six Days Later)                 IOP (mmHg)MONKEY                TIME   TIME     TIME#          EYE         TREATMENT                 (HR)                     IOP                        (HR)                            IOP  (HR)                                     IOP__________________________________________________________________________53         OD DRUG    0   51 3   38   7   3648         OD DRUG    0   52 3   50   7   4849         OD DRUG    0   34 3   29   7   2862         OD DRUG    0   38 3   35   7   3760         OD DRUG    0   28 3   27   7   24186        OD DRUG    0   30 3   26   7   32MEAN                      38.8   34.2     34.2S.E.                      4.2    3.7      3.4MEAN % CHANGE                    -11.5    -10.8S.E.                             3.4      5.156         OD CONTROL 0   46 3   36   7   4647         OD CONTROL 0   30 3   38   7   3355         OD CONTROL 0   28 3   25   7   2763         OD CONTROL 0   38 3   36   7   3452         OD CONTROL 0   47 3   48   7   52187        OD CONTROL 0   43 3   39   7   32MEAN                      38.7   37.0     37.3S.E.                      3.3    3.0      3.9MEAN % CHANGE                    -3.0     -3.2S.E.                             6.7      5.653         OS DRUG    0   30 3   29   7   2748         OS DRUG    0   22 3   23   7   2349         OS DRUG    0   22 3   26   7   2862         OS DRUG    0   25 3   23   7   2760         OS DRUG    0   27 3   27   7   24186        OS DRUG    0   24 3   24   7   27MEAN                      25.0   25.3     26.0S.E.                      1.3    1.0      0.8MEAN % CHANGE                    +1.9     +5.2S.E.                             3.7      5.956         OS CONTROL 0   33 3   36   7   3447         OS CONTROL 0   19 3   20   7   1955         OS CONTROL 0   23 3   24   7   2263         OS CONTROL 0   22 3   23   7   2752         OS CONTROL 0   19 3   21   7   22187        OS CONTROL 0   32 3   33   7   35MEAN                      24.7   26.2     26.5S.E.                      2.6    2.7      2.7MEAN % CHANGE                    +6.2     +7.8S.E.                             1.2      4.2__________________________________________________________________________ **NOTE: Percent change values are calculated from individual animal data and may not reflect changes of mean IOP. 
    
     
                                           TABLE 3__________________________________________________________________________3.0% 6-Hydroxyethoxy-2-benzothiazolesulfonamide Gel                 IOP (mmHg)MONKEY                TIME   TIME     TIME     TIME#          EYE         TREATMENT                 (HR)                     IOP                        (HR)                            IOP  (HR)                                     IOP  (HR)                                              IOP__________________________________________________________________________182        OD DRUG    0   50 1   45   3   41   7   37189        OD DRUG    0   35 1   33   3   20   7   23194        OD DRUG    0   33 1   30   3   30   7   25207        OD DRUG    0   55 1   52   3   57   7   5550         OD DRUG    0   40 1   35   3   32   7   33212        OD DRUG    0   44 1   50   3   45   7   40MEAN                      42.8   40.8     37.5     35.5S.E.                      3.5    3.8      5.3      4.7MEAN % CONTROL                   -4.9     -14.0    -18.5S.E.                             3.8      7.0      5.161         OD CONTROL 0   62 1   62   3   65   7   60191        OD CHANGE  0   52 1   59   3   55   7   62206        OD CONTROL 0   55 1   53   3   59   7   48177        OD CONTROL 0   60 1   57   3   50   7   65199        OD CONTROL 0   55 1   55   3   52   7   50192        OD CONTROL 0   50 1   55   3   42   7   40MEAN                      55.7   56.8     53.8     54.2S.E.                      1.9    1.3      3.2      4.0MEAN % CHANGE                    +2.5     -3.4     -2.9S.E.                             3.1      4.5      5.9187        OS DRUG    0   27 1   25   3   23   7   23189        OS DRUG    0   24 1   29   3   27   7   25194        OS DRUG    0   22 1   24   3   23   7   20207        OS DRUG    0   26 1   30   3   28   7   2950         OS DRUG    0   30 1   24   3   25   7   29212        OS DRUG    0   24 1   24   3   25   7   26MEAN                      25.5   26.0     25.2     25.3S.E.                      1.1    1.1      0.8      1.4MEAN % CHANGE                    +1.7     -0.4     -0.6S.E.                             3.1      5.0      4.261         OS CONTROL 0   20 1   20   3   21   7   25191        OS CONTROL 0   29 1   27   3   25   7   27206        OS CONTROL 0   26 1   26   3   25   7   28177        OS CONTROL 0   25 1   16   3   20   7   23199        OS CONTROL 0   23 1   26   3   27   7   25192        OS CONTROL 0   28 1   26   3   27   7   23MEAN                      25.2   23.5     24.2     25.2S.E.                      1.4    1.8      1.2      0.8MEAN % CHANGE                    -6.2     -3.2     +1.4S.E.                             6.7      5.4      6.3__________________________________________________________________________ **NOTE: Percent change values are claculated from individual animal data and may not reflect changes of mean IOP. 
    
     
                                           TABLE 4__________________________________________________________________________3.0% 6-Hydroxyethoxy-2-benzothiazolesulfomaide Gel                 IOP (mmHg)MONKEY                TIME   TIME     TIME     TIME#          EYE         TREATMENT                 (HR)                     IOP                        (HR)                            IOP  (HR)                                     IOP  (HR)                                              IOP__________________________________________________________________________48         OD CONTROL 0   49 1   47   3   43   7   44180        OD CONTROL 0   39 1   38   3   38   7   40198        OD CONTROL 0   34 1   35   3   35   7   41206        OD CONTROL 0   52 1   50   3   43   7   5753         OD CONTROL 0   50 1   55   3   52   7   57210        OD CONTROL 0   53 1   45   3   48   7   45MEAN                      46.2   45.0     43.2     47.3S.E.                      3.2    3.0      2.5      3.1MEAN % CHANGE             0.0    -2.1     -5.8     +3.6S.E.                      0.0    3.4      3.5      5.7190        OD DRUG    0   38 1   37   3   33   7   35177        OD DRUG    0   55 1   50   3   47   7   55194        OD DRUG    0   37 1   32   3   29   7   35202        OD DRUG    0   42 1   30   3   21   7   28203        OD DRUG    0   50 1   53   3   45   7   38205        OD DRUG    0   46 1   40   3   55   7   32MEAN                      44.7   40.3     38.3     37.2S.E.                      2.9    3.8      5.2      3.8MEAN % CHANGE             0.0    -10.1    -15.0    -16.8S.E.                      0.0    4.8      9.1      5.848         OS CONTROL 0   21 1   23   3   22   7   30180        OS CONTROL 0   29 1   27   3   27   7   25198        OS CONTROL 0   27 1   26   3   28   7   28206        OS CONTROL 0   23 1   28   3   26   7   2753         OS CONTROL 0   35 1   30   3   29   7   28210        OS CONTROL 0   25 1   25   3   25   7   25MEAN                      26.7   26.5     26.2     27.2S.E.                      2.0    1.0      1.0      0.8MEAN % CHANGE             0.0    +1.1     -0.4     +5.0S.E.                      0.0    5.2      4.3      9.3190        OS DRUG    0   24 1   25   3   27   7   28177        OS DRUG    0   20 1   16   3   18   7   20194        OS DRUG    0   18 1   23   3   20   7   23202        OS DRUG    0   30 1   28   3   25   7   28203        OS DRUG    0   21 1   24   3   21   7   20205        OS DRUG    0   27 1   27   3   25   7   27MEAN                      23.3   23.8     22.7     24.3S.E.                      1.9    1.7      1.4      1.6MEAN % CHANGE             0.0    3.3      -1.8     5.5S.E.                      0.0    6.8      4.8      5.6__________________________________________________________________________ **NOTE: Percent change values are calculated from individual animal data and may not reflect changes of mean IOP. 
    
     From an examination of the data presented in this example, as well as Tables 1-4, it can be seen that 6-hydroxyethoxy-2-benzothiazolesulfonamide is an effective treating composition for topical treatment of glaucoma in mammalian species such as rabbits and in subhuman primates such as cynomologous monkeys.