Abstract:
Methods of antagonizing the effects of thromboxane A 2  in the circulatory system of an animal which comprises administering to said animal a nontoxic effective amount of N,N&#39;-bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide or a pharamaceutical acceptable salt thereof are valuable in the treatment of diseases in which thromboxane A 2  is a factor, such as thrombosis, endotoxic shock and cardiac anaphylaxis.

Description:
BACKGROUND OF THE INVENTION 
     Thromboxane A 2  (TxA 2 ), which is a product of the &#34;arachidonic acid cascade&#34;, has been found to be a very potent platelet aggregator and pulmonary and systemic vasoconstrictive agent. TxA 2  is produced by the conversion by thromboxane synthetase of the prostaglandin endoperoxide, and PGH 2 , which is a cyclooxygenase metabolite of arachidonic acid. TxA 2  has been suggested as an important mediator of thrombosis, endotoxic shock, pulmonary hypertension and cardiac anaphylaxis. By antagonizing the effects of TxA 2  in the circulatory system the compound of this invention is valuable in the treatment of diseases in which TxA 2  is a factor. 
     N,N&#39;-Bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide, which is disclosed and claimed in U.S. Pat. No. 4,315,935 as antagonizing the effects of slow reacting substance of anaphylaxis (SRS-A) on bronchial smooth muscle, has been discovered to be an end organ antagonist of TxA 2 . Therefore, it would be useful in the treatment of diseases in which TxA 2  is a factor. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to (1) a method of antagonizing the effects of thromboxane A 2  (TxA 2 ) in the circulatory system of an animal and (2) a method of inhibiting platelet aggregation in an animal which comprises administering to said animal a nontoxic effective amount of N,N&#39;-bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide or a pharmaceutically acceptable salt thereof. 
     The TxA 2  antagonist activity of N,N-bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide has been demonstrated both in vitro and in vivo. The test systems employed included: (a) antagonism of the contractions of isolated tracheal and lung parenchymal strips elicited by a stable thromboxane analog; (b) prevention of human platelet aggregation dependent on thromboxane and (c) antagonism of the bronchospasm elicited by a thromboxane mimic in vivo. The protocols and results of these test systems are shown below. 
     Antagonism of Contractions Elicited by Carbocyclic Thromboxane A 2  (CTA 2 ), a Synthetic Thromboxane Mimic 
     Isolated guinea pig tracheas or paired lung parenchymal strips were attached via silk suture to force displacement transducers for recording changes in isometric tension. The tissues were equilibrated for one hour in modified Krebs&#39; buffer at 37.5° C. and aerated with 95% O 2  /5% CO 2 . Then, the tissues were equilibrated for 30 additional minutes with N,N&#39;-bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide (Compound I) (1×10 -5  M) or buffer. Contraction of the tissues was then elicited by increasing the bath concentration of CTA 2  in a cumulative fashion. The contractile responses were recorded as changes in mg tension. 
     
         ______________________________________RESULTS:    CTA.sub.2 Con-          (+)    centration              Control       Compound ITissue   (M)       (mg tension)  (mg tension)______________________________________Lung     10.sup.-8  45.5 ± 11.4 (10)                            0 (10)parenchyma    10.sup.-7 103.5 ± 23.7 (10)                            0 (10)    10.sup.-6 181.5 ± 23.3 (10)                            0 (10)Trachea  10.sup.-8 0 (7)         0 (7)    10.sup.-7 125.0 ± 33.5 (7)                            0 (7)    10.sup.-6 360.0 ± 89.8 (7)                            42.9 ± 20.2 (7)______________________________________ Note: Each tissue receiving Compound I responded normally to challenge with reference contractile agonists: 1 × 10.sup.-3 M histamine on the lung parenchyma and 1 × 10.sup.-5 M carbachol on the trachea. The number in parentheses refers to the number of tissues studied. 
    
     Inhibition of Human Platelet Aggregation 
     Platelet-rich plasma (PRP) and platelet-poor plasma (PPP) are prepared from citrated blood of drug-free human volunteers and are stored at room temperature for at least 30 minutes before use. Each PRP sample is preincubated two minutes at 37° C. prior to addition of N,N-bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide (Compound I) or agonists; Compound I is preincubated for 1 minute prior to addition of agonist. A dose response is determined for each agonist, and a concentration which gives a biphasic response is selected. Compounds are tested for inhibition of the response (control response) generated by this agonist concentration. A time is selected, and the height at which the various curves intersect this time line is measured and expressed in mm (a measure of light transmittance). The difference between the response of the control and that with inhibitor present is used to calculate percent inhibition. This value is plotted against inhibitor concentrations to determine the IC 50   (the inhibitory concentration of Compound I which inhibits aggregation by 50%). 
     Compound I inhibits both the primary and secondary wave of platelet aggregation induced by: collagen, arachidonic acid and U-44069, a structural prostaglandin endoperoxide analog, yet functional thromboxane A 2  mimic. It also inhibits secondary aggregation induced by platelet activating factor and the calcium ionophore, A23187. The IC 50  for all these agonists are as follows: 
     
         ______________________________________Agonist          IC.sub.50 (μM)______________________________________Inhibition of Primary PhaseArachidonic acid 19Collagen         10U-44069          2.5Inhibition of Secondary PhaseU-44069          1.7A23187           12Platelet Activating            4.5Factor (PAF)______________________________________ 
    
     Protection in a Drug-Induced Canine Bronchospasm 
     N,N-Bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide (Compound I) had a protective effect in canine bronchoconstriction induced by U-44069. Bronchopulmonary responses to these agents were measured by computer analyses in 5 spontaneously breathing, anesthetized mongrel dogs. In a dose range of 0.3-3.0 μg/kg i.v., the endoperoxide analog produced dose-related alterations in pulmonary airway resistance, dynamic lung compliance, expiratory airflow rate, tidal volume and respiratory frequency. Pretreatment with Compound I (5.0 mg/kg i.v.) produced an inhibition of the bronchospasm with a characteristic shift to the right of the control U-44069 curve. Inhibition by Compound I occurred in all pulmonary parameters calculated. 
     
         ______________________________________               Increase in  Decrease in               resistance to                            ability of     U-44069   movement of air                            lungs to expand     Dose      into the lungs                            easilyDrug      (μg/kg i.v.)               (%)          (%)______________________________________resting baseline     0            0U-44069   0.3       67           28     1.0       333          56     3.0       549          70pretreat  0.3       14            5with      1.0       30           13Compound I     3.0       56           28(5 mg/kg),then repeatU-44069______________________________________ 
    
     It is clear from the above data that N,N&#39;-bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide antagonizes the effect of thromboxane A 2  and inhibits the aggregation of platelets. 
     The methods in accordance with the instant invention comprises administering to an animal in need of: (1) antagonism of the effects of thromboxane A 2  ; or (2) the inhibition of platelet aggregation the compound N,N&#39;-bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide or a pharmaceutically acceptable salt thereof, usually combined with a pharmaceutical carrier, in a nontoxic effective amount of about 50 to about 500 mg of the compound. The route of administration is preferably parenteral. For parenteral administration the pharmaceutical composition will be in the form of a sterile injectable liquid such as an ampul or an aqueous or nonaqueous liquid suspension. For convenience equal doses will be administered 1 to 4 times daily with the daily dosage regimen being selected from about 50 to 2000 mg. 
     The pharmaceutical preparations are made following the conventional techniques of the pharmaceutical chemist as appropriate to the desired end product. The following example illustrates the preparation of such a composition used in the method of the instant invention. 
     N,N&#39;-Bis[7-(3-chlorobenzeneaminosulfonyl)-1,2,3,4-tetrahydroisoquinolyl]disulfonylimide is dissolved in sterile water at a concentration of 0.5 percent and placed in an sterile ampul for parenteral administration.