(-) AND (+) 10-(1-AZABICYCLO[2.2.2.]OCT-3-YL-METHYL)-10 H-PHENOTHIAZINE QUATERNARY AMMONIUM DERIVATIVES, PHARMACEUTICAL COMPOSITIONS CONTAINING THEM AND PROCESS FOR THEIR PREPARATION

Abstract: The description refers to dextrorotatory (+) and levorotatory (-) enantiomorphs of quaternary ammonium derivatives of 10-(1-azabicyclo[2.2.2.]oct-3-yl-methyl)-10 H-phenothiazine as per general formula (I), where R = C1-4 alkyl, cyclopropyl, X = halogen, dimethyl sulphate, p-toluenesulphonic acid as well as to the preparation of same and to the pharmaceutical compositions containing them.

Description: (-) and ( + ) 10- (l-azabicyclo[2.2.2. ]oct-3-yl-methyl ) -10 H- phenothiazine quaternary ammonium derivatives , pharmaceutical compositions containing them and process for their preparation Field of the Invention This invention refers to dextrorotatory (+) and levorotatory (-) enantiomorphs of 10- (l-azabicyclo[2.2.2. ]oct-3-yl-methyl) -10 H- phenothiazine quaternary ammonium derivatives as per the following general formula (I) where x R = C^_|ι alkyl, cyclopropyl X = halogen, dimethyl sulphate, p-toluenesulphonic acid as well as to the pharmaceutical compositions containing them. State of the Art The 10- (l-azabicyclo[2.2.2]oct-3-yl--_ethyl) -10 H-phenothiazine compound (internationally known as equitazine) as per the following formula (A) is acknowledged by literature (see, e.g., FR-A-203^ 605 and its antihistaminic properties are described herein. In patent EP-A-159 059 • the applicant described quaternary derivatives of the compound as per formula (A), in the form of racemic modif cations, endowed with a significant anti- bronchospastic activity. Detailed Description of the Invention Mequitazine quaternary derivatives (just as, on the other hand, mequitazine itself) exhibit an asymmetric carbon atom (position 3 of l-azabicyclo[2.2.2.]octane). Each racemic quaternary derivative thus consists of two (+) and (-) enantiomorphs in a 50:50 ratio. It has surprisingly been found that the enantiomorphs of the quaternary derivatives .of mequitazine as per formula (I) where R = C^_^ alkyl, cyclopropyl X = halogen, dimethyl sulphate, p-toluenesulphonic acid exhibit differing properties that make each of them particularly fit for respectively different treatments. According to the present invention, C j ^ alkyl means: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl. According to the present invention, halogen means: iodine, bromine, chlorine. In particular, it has been found that while both enantiomorphs as per general formula (I) are equally effective in respect of acetylcholine - a quite surprising property in itself - , the dextrorotatory (+) enantiomorph is significantly more effective in respect of histamine than the respective levorotatory ( - ) enantiomorph. Moreover, the dextrorotatory enantiomorph was found to be less toxic than the levorotatory. The dextrorotatory enantiomorph is thus being proposed hereby as an agent particularly suitable for the treatment of bronchoconstrictive and allergic diseases (in particular bronchial asthma and rhinitis) and of all pathologies involving histamine - one of the main mediators both of asthmatic bronchoconstriction and of the abnormal response of the mucous membrane of the nose in the case of allergic rhinitis - , or acetylcholine - which controls both the tone of respiratory system and the secretion of the mucous membrane of the nose. As is known, in fact, the mediators involved by asthmatic bronchoconstriction and rhinitis are many, the extent of their involvement depending on the type and progress of disease and on the patient as well. The fact that the dextrorotatory enantiomorph exhibits both activities at quite superimposable concentrations makes it particularly interesting as an instrument for the treatment of such diseases. In the preparation of enantiomorphs as per the invention, the racemic mixture of mequitazine (A) is resolved into the two respective dextro- and levorotatory enantiomorphs by the usual chromatographic separation techniques based on the use of chiral phases. In particular cellulose preparative chromatographic columns can be used, eluents being hexane/ethyl alcohol (9V6) , hexane/methyl alcohol (98/2) , hexane/ethyl alcohol/TEA (98/0.8/1.2) . The so obtained enantiomorphs are then quaternized with reagents, as described in the examples hereinunder given by way of indication, not of limitation. Enantiomorphs as per the invention result to be particularly useful in the preparation of pharmaceutical compositions for topical use (mainly by inhalation and intranasal administration) or for oral administration. A type of pharmaceutical formulations suitable for the administration of the active ingredient according to the invention is conveyed in Example 3 hereinunder by way of indication, not of limitation. EXAMPLE 1 (-)-l-Methyl-3-(10-H-phenothiazine-lO-yl-methyl)-1-azoniabicyclo 2.2.2.1 octane iodide [(I) R = CH 3 ; X = I " ] 35 g (0.1 mole) of the mequitazine (-) enantiomorph obtained by preparative chromatographic chiral-phase column separation from the mequitazine racemic mixture is suspended in 200 ml acetonitrile. The suspension is kept under stirring for 10 minutes to homogenization. 50 ml (0.2 mole) methyl iodide is added; the solution thus obtained is heated to 50"C and is kept at this temperature for 16 hours. The reaction mixture is allowed to cool to 20 * C, then to 0-4 * C and kept at this temperature for 48 hours. Solid crystals are vacuum filtered, washed on filter with ethyl ether, then vacuum dried at 50 * C to constant weight. 42 g of the desired product is obtained (90 yield) as cream- coloured solid crystals having the following chemo-physical properties: HPLC Nucleosil C lg ®150x4.6 column eluent: MeOH/CHgCN NH^PO/ j 0.425? = 43/25/32 flow rate: 0.5 ml/min A = 254 nα injection: 4 ζ in methyl alcohol unit peak at r.t.: 6.4 m.p.: 142-144 * C [αjD 201 -21.3" (I CH 3 0H concentr.) Elementary analysis for C2JH26IN2S C H I calculated 54.31 5-59 27-35 found 54.06 5-60 27.20 NMR (CDC1 3 ): 7-21-6.84 (2m, 8H, [1*,2',3\4\6 « ,7',8',9']); 4.27-3-93 (m, 2H. [9]); 9-93-3-46 (m, 6H [2,6.7]); 3-21 (s, 3H, [10]); 2.71 (m. 1H. [3]); 2.30 (d. 1H [4]); 1-99-1-77 (2m, 4H. [5.8]) 13 C NMR (CDC1 3 ): 144.62 (C-9'a, C-10'a); 127-77 (C-1-, C-4\ C-6', c-9'); 126.97 (C-4'a. C-5'a); 123.26 (C-2', C-8' 116.25 (C-3', C-7'); 60.49 (C-9); 57-38 (C-6); 57-21 (C-7); 52-54 (C-3); 48.30 (C-2); 32.06 (C-10); 24.87 (C-8); 20.90 (C-4); 19-57 (C-5). The product -optical purity was assayed on free basis by HPLC with chiral-phase column column CHIRACEL O.D.® eluent hexane/ethyl alcohol * 94/6 flow rate 0.5 ml/min. = 254 nm injection 4 V in hexane/ethyl alcohol peak 98* at r.t. 15-03 EXAMPLE 2 (♦)-l-methyl-3-(10-H-phenothiazine-lO-yl-methyl)-1 azoniabicyclo [2.2.2.] octane iodide [(I) R = CH3; X = I " ] 28 g (0.08 mole) of the mequitazine (+) enantiomorph obtained by preparative chromatographic chiral-phase column separation from the mequitazine racemic mixture is suspended in 160 ml acetonitrlle. The suspension is kept under stirring for 10 minutes to homogenization. 40 ml (0.64 mole) methyl iodide is added; the solution thus obtained is heated to 50 * C and is kept at this temperature for 16 hours. The reaction mixture is allowed to cool to 20 * C, then to 0-4 * C and kept at this temperature for 48 hours. Solid crystals are vacuum filtered, washed on filter with ethyl ether, then vacuum dried at 50 * C to constant weight. 35 g of the desired product is obtained (94? yield) as cream- coloured solid crystals having the following chemo-physical properties: !_ NMR; 13 C NMR: as per Example 1 HPLC as per Example 1 chiral-phase HPLC: peak at r.t. 16.73 (97X) m.p.: 142-145 * C [α] D 20 + 21 * (1% CH 3 0H concentr.) Elementary analysis for C21H26IN2S C H I calculated 54.31 5-59 27-35 found 54-00 5-62 27-18 In vitro tests EXAMPLE 3 A pharmaceutical formulation consisting of active ingredient [(+) or (-) compound as 5 per formula (I)] 100 g sorbitan trioleate (Arlacel 85 R ) 20 mg Freon 11 R 3.380 mg Freon 12-ll4 R (65:35) 10.500 mg was placed in a metering valve type small cylinder. The above preparation allows the administration of single 50 to 200 0 μg active ingredient metered doses. Activity Tests Enantiomorphs as per Examples 1 and 2 were comparatively studied to ascertain their pharmacotoxicologic properties, with special regard 5 to the following aspects: acetylcholine and histamine antagonism on guinea pig's isolated trachea, guinea pig's broncoconstriction inhibition induced by acetylcholine and histamine (Konzett-Roessler method), acute toxicity in mice. Results demonstrated that both enantiomorphs are acetylcholine and Q histamine competitive antagonists on guinea pig's trachea. Anyway, while both enantiomorphs are equally effective in respect of acetylcholine (pA 7-96 and 7-8l for levorotatory and dextrorotatory enantiomorphs, respectively, the dextrorotatory enantiomorph (+) ( A 8.05) is significantly more effective than the levorotatory (-) ( pA 2 7-09) in respect of histamine. The in vitro results were confirmed by the in vivo tests, which demonstrated that the two enantiomorphs are equally effective in inhibiting bronchocostriction from acetylcholine, while the dextrorotatory (+) enantiomorph is significantly more effective than the levorotatory (-) in inhibiting bronchoconstriction from histamine (ED50: 63 and 239 nmole kg " , respectively). Tαxicologic Tests The acute toxicity test referred to i.v. administration to mice showed that the dextrorotatory enantiomorph (+) [LDCQ and fiducial limits at 95? 3-65 (3-45-3-86) mg kg ] is significantly less toxic than the levorotatory enantiomorph (-) [2.68 (2.61-2.74) mg kg "1 ]. TABLE 1 In Vitro Tests Acetylcholine and histamine antagonism, on guinea pig's isolated trachea Acetylcholine Histamine pA 2 Levorotatory enantiomorph (-) - [Example 1] 7-96 7-09 Dextrorotatory enantiomorph (+) [Example 2] 7.8l 8.05 In Vivo Tests Inhibition of guinea pig's bronchospasm from acetylcholine and histamine Acetylcholine Histamine ED 50 (nmole kg "1 ) Levorotatory enantiomorph (-) [Example 1] 65 239 Dextrorotatory enantiomorph (+) [Example 2] 71 63 Acute Toxicity in Mice LD50 (mg kg "1 and fiducial limits at 95?) Levorotatory enantiomorph (-) [Example 1] 2.68 (2.61-2.74) Dextrorotatory enantiomorph (♦) [Example 2] 3-65 (3-45-3-86)

Claims: CLAIMS 1. (-) 10-(l-azabicyclo[2.2.2.]oct-3-yl-methyl)-10 H-phenothiazine quaternary ammonium derivatives as per the following general formula (I) where R * c ι_j j alkyl, cyclopropyl X = halogen, dimethyl sulphate, p-toluenesulphonic acid. 2. (+) 10-(l-azabicyclo[2.2.2.]oct-3-yl-methyl)-10 H-phenothiazine quaternary ammonium derivatives as per the following general formula where R and X are as per claim 1. 3- Enantiomorphs as per claims 1 and 2, where R = CH and X * I. 4. Enantiomorphs as per claims 1 and 2, where R = CHo and X = Cl. 5. Enantiomorphs as per claims 1 and 2, where R = CH, and X = Br. 6. Enantiomorphs as per claims 1 and 2, where R = CH 3 and X = dimethyl sulphate. 7- Enantiomorphs as per claims 1 and 2, where R = CHa and X = p- toluenesulphonic acid. 8. Process for the preparation of (-) and ( + ) 10 - (1- azabicyclo[2.2.2.]oct-3-yl-methyl)-10 H-phenotiazine quaternary ammonium derivatives of formula (I) where x " R = c ~l\ alkyl. cyclopropyl X = halogen, dimethyl sulphate, p-toluenesulphonic acid wherein the racemicic mixture of mequitazine (A) is resolved into the two respective dextro- and levorotatory enantiomorphs through chromatoghrapic separation techniques using chiral phases, and the so obtained enantiomorphs are quaternized with the suitable reagents. 9. Pharmaceutical compositions containing a dextrorotatory (+) enantiomorph as active ingredient, as per claims 2-7. 10. Pharmaceutical compositions containing a levorotatory (-) enantiomorph as active ingredient, as per claims 1, 3-7. 11. Process for preparing a pharmaceutical composition according to claims 9 and 10 wherein a pharmaceutical effective amount of a (+) or (-) 10 -(l-azabicyclo[2.2.2.]oct-3-yl-methyl)-10 H-phenotiazine quaternary ammonium derivatives of formula (I) R = Ci.ii.. alkyl, cyclopropyl X = halogen, dimethyl sulphate, p-toluenesulphonic acid is mixed with the suitable carriers for the preparation of compositions useful for topical use or oral administration. 12. Use of compositions as per claim 9. for bronchial asthma and rhinitis treatment. 13. Use of compositions as per claim 10, for bronchial asthma and rhinitis treatment.

Inventors: GIORGI RAFFAELLO, SUBISSI ALESSANDRO, TURBANTI LUIGI, GIORGI, RAFFAELLO, SUBISSI, ALESSANDRO, TURBANTI, LUIGI
Applicants: GUIDOTTI & C SPA LABOR, LABORATORI GUIDOTTI S.P.A.
Application year: 1992
Main classification: A61K31
IPC codes: A61K31, A61P11, A61P37, C07D453