WO1993003029A1

WO1993003029A1 - (-) 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

Info

Publication number: WO1993003029A1
Application number: PCT/EP1992/001759
Authority: WO
Inventors: Raffaello Giorgi; Alessandro Subissi; Luigi Turbanti
Original assignee: Laboratori Guidotti S.P.A.
Priority date: 1991-08-07
Filing date: 1992-08-03
Publication date: 1993-02-18
Also published as: EP0599896A1; CZ24894A3; IT1251161B; SK11594A3; FI940530A; ITMI912225A0; ECSP920859A; CN1071667A; ZA925852B; MX9204539A; JPH06509570A; FI940530A0; PT100765A; HUT66570A; AU2417392A; HU9400273D0; MA22611A1; CA2114844A1; ITMI912225A1; BG98439A

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- (1-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_1-4 alkyl, cyclopropyl

X = halogen, dimethyl sulphate, p-toluenesulphonic acid

as well as to the pharmaceutical compositions containing them.

State of the Art

The 10- (1-azabicyclo[2.2.2]oct-3-yl-methyl) -10 H-phenothiazine compound (internationally known as mequitazine) 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 modifications, 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 1-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_1-4 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_1-4 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 (94/6) , 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

(-)-1-Methyl-3-(10-H-phenothiazine-10-yl-methyl)-1-azoniabicyclo

[2.2.2. ] octane iodide [(I) R = CH₃; 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 50ºC and is kept at this temperature for 16 hours. The reaction mixture is allowed to cool to 20ºC, then to 0-4ºC and kept at this temperature for 48 hours. Solid crystals are vacuum filtered, washed on filter with ethyl ether, then vacuum dried at

50ºC 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 C₁₈®150x4.6 column

eluent: MeOH/CH₃CN/NH₄PO₄ 0.425% = 43/25/32

flow rate: 0.5 ml/min λ = 254 nm

injection: 4 γ in methyl alcohol unit peak at r.t.: 6.4

m.p.: 142-144ºC

[α]D^20: -21.3º (1% CH₃OH concentr.)

Elementary analysis for C₂₁H₂₆IN₂S

C H I N S

calculated 54.31 5-59 27-35 6.03 6.89 found 54.06 5-60 27.20 5.94 6.80

1H NMR (CDCl₃): 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])

¹³C NMR (CDCl₃): 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. λ = 254 nm

injection 4 γ in hexane/ethyl alcohol

peak 98% at r.t. 15-03

EXAMPLE 2

(+)-1-methyl-3-(10-H-phenothiazine-10-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 50ºC and is kept at this temperature for 16 hours. The reaction mixture is allowed to cool to 20ºC, then to 0-4ºC and kept at this temperature for 48 hours. Solid crystals are vacuum filtered, washed on filter with ethyl ether, then vacuum dried at 50ºC to constant weight.

35 g of the desired product is obtained (94? yield) as cream- coloured solid crystals having the following chemo-physical properties:

1H NMR; ¹³C NMR: as per Example 1

HPLC as per Example 1

chiral-phase HPLC: peak at r.t. 16.73 (97%)

m.p.: 142-145ºC

[α]_D 20 + 21º (1% CH₃OH concentr.)

Elementary analysis for C₂₁H₂₆IN₂S

C H I N S

calculated 54.31 5-59 27-35 6.03 6.89

found 54-00 5-62 27-18 5-96 6.82 In vitro tests

EXAMPLE 3

A pharmaceutical formulation consisting of

active ingredient [(+) or (-) compound as

per formula (I)] 100 mg sorbitan trioleate (Arlacel 85^R) 20 mg

Freon 11^R 3.380 mg

Freon 12-114^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 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 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 histamine competitive antagonists on guinea pig's trachea. Anyway, while both enantiomorphs are equally effective in respect of acetylcholine (pA₂7-96 and 7-81 for levorotatory and dextrorotatory enantiomorphs, respectively, the dextrorotatory enantiomorph (+) (pA₂8.05) is significantly more effective than the levorotatory (-) (pA₂ 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^-1, respectively).

Tαxicologic Tests

The acute toxicity test referred to i.v. administration to mice showed that the dextrorotatory enantiomorph (+) [LD₅₀ and fiducial limits at 95%: 3-65 (3-45-3-86) mg kg^-1] 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 pA₂

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

ED₅₀ (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

1. (-) 10-(1-azabicyclo[2.2.2.]oct-3-yl-methyl)-10 H-phenothiazine quaternary ammonium derivatives as per the following general formula

(I)

where

R = C_1-4 alkyl, cyclopropyl

X = halogen, dimethyl sulphate, p-toluenesulphonic acid.

2. (+) 10-(1-azabicyclo[2.2.2.]oct-3-yl-methyl)-10 H-phenothiazine quaternary ammonium derivativvs as per the following general formula

(I)

where R and X are as per claim 1.

3. Enantiomorphs as per claims 1 and 2, where R = CH₃ and X = I.

4. Enantiomorphs as per claims 1 and 2, where R = CH₃ and X = Cl.

5. Enantiomorphs as per claims 1 and 2, where R = CH₃ and X = Br.

6. Enantiomorphs as per claims 1 and 2, where R = CH₃ and X = dimethyl sulphate.

7. Enantiomorphs as per claims 1 and 2, where R = CH₃ 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

R = C_1-4 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 -(1-azabicyclo[2.2.2.]oct-3-yl-methyl)-10 H-phenotiazine quaternary ammonium derivatives of formula (I)

where

R = C_1-4 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.