Patent Application
20090180969
This application claims priority to European Patent Application No. 08000602.6, filed on Jan. 15, 2008, which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to pharmaceutical formulations suitable to be administered by pressurized metered dose inhalers (pMDIs) which are useful for the prevention and/or treatment of an obstructive airways disease. The present invention also relates to processes for the preparation of such a formulation, and to a pressurized metered dose inhaler filled with said pharmaceutical formulation. The present invention further relates to methods for the prevention and/or treatment of an obstructive airways disease.
2. Discussion of the Background
Quaternary ammonium salts acting as muscarinic receptors antagonists are currently used in therapy to induce bronchodilation for the treatment of respiratory diseases and in particular inflammatory or obstructive airway diseases such as asthma and chronic obstructive pulmonary disease (COPD).
For treating chronic diseases, it is often desirable to utilize antimuscarinic drugs with a long-lasting effect. This ensures that the concentration of the active substance necessary for achieving the therapeutic effect is present in the lungs for a long period of time, without the need for the active substance to be administered repeatedly and too frequently.
In particular, it would be highly desirable to utilize antimuscarinic drugs which are therapeutically efficacious upon administration by inhalation once a day. In order to fulfill such a requirement, antimuscarinic drugs shall exhibit good selectivity for M3 muscarinic receptors, and slow dissociation from them.
Recently it has been reported that tiotropium bromide, the first drug of a new generation of antimuscarinic drugs, exhibits a very slow dissociation from M3 receptors. This behaviour is thought to account for its long lasting activity. However, tiotropium bromide still retains a slow dissociation kinetics for the M2 muscarinic receptors. Since M2 receptors are a major population in the cardiac muscle, a therapy with said drug might be accompanied by undesired cardiac side effects.
The quaternary ammonium salt of 3-[[[(3-fluorophenyl)[(3,4,5-trifluoro phenyl)methyl]amino]carbonyl]oxy]-1-[2-oxo-2-(2-thienyl)ethyl]-1-azoniabicyclo[2.2.2]octane (hereinafter referred to as compound 1) is a compound which has been disclosed in the co-pending Patent Application no. PCT/EP2007/057585, which is incorporated herein by reference in its entirety. The compound 1 has the following chemical structure:
wherein X− is a pharmaceutically acceptable anion, preferably selected from the group consisting of chloride, bromide, iodide, sulfate, phosphate, methanesulfonate, nitrate, maleate, acetate, citrate, fumarate, tartrate, oxalate, succinate, benzoate, and p-toluenesulfonate. In particular the chloride salt of compound 1, has been found to be equieffective to tiotropium bromide in terms of receptor potency and duration of action, but significantly short-acting on the M2 receptors.
Accordingly, it is one object of the present invention to provide novel pharmaceutical formulations suitable to be administered by pressurized metered dose inhalers (pMDIs) which are useful for the prevention and/or treatment of an obstructive airways disease.
It is another object of the present invention to provide novel processes for the preparation of such a formulation.
It is another object of the present invention to provide novel pressurized metered dose inhaler which contain such a pharmaceutical formulation.
It is another object of the present invention to provide novel methods for the prevention and/or treatment of an obstructive airways disease.
These and other objects, which will become apparent during the following detailed description, have been achieved by the inventors' discovery that pharmaceutical formulations suitable for aerosol administration by a pressurized metered dose inhaler (pMDI) which comprise a pharmaceutically acceptable salt of 3-[[[(3-fluorophenyl)[(3,4,5-trifluoro phenyl)methyl]amino]carbonyl]oxy]-1-[2-oxo-2-(2-thienyl)ethyl]-1-azoniabicyclo[2.2.2]octane (compound 1) and a propellant are effective for the prevention and/or treatment of an obstructive airways disease.
Thus, in a first embodiment, the present invention provides pharmaceutical formulations suitable for aerosol administration by a pressurized metered dose inhaler (pMDI) which comprise a pharmaceutically acceptable salt of 3-[[[(3-fluorophenyl)[(3,4,5-trifluoro phenyl)methyl]amino]carbonyl]oxy]-1-[2-oxo-2-(2-thienyl)ethyl]-1-azoniabicyclo[2,2,2]octane (compound 1) and a propellant.
In a particular embodiment, said pharmaceutical formulation may be in the form of suspension of particles of micronized crystalline compound 1 in said propellant.
In an alternative embodiment, the pharmaceutical formulation may be in the form of solution wherein compound 1 is dissolved in a mixture of said propellant and a suitable amount of a co-solvent such as ethanol.
According to another aspect, the present invention provides a pressurized metered dose inhaler (pMDI) comprising a canister filled with the pharmaceutical formulation of the invention, and a metering valve for delivering a daily therapeutically effective dose of the active ingredient.
The invention also relates to the use of one of the formulations described before as a medicament.
In a further aspect, the present invention provides the use of the formulation described before for the prevention and/or treatment of an inflammatory or obstructive airways disease such as asthma or chronic obstructive pulmonary disease (COPD).
In a still further aspect, the present invention provides a method of preventing and/or treating an inflammatory or obstructive airways disease such as asthma or chronic obstructive pulmonary disease (COPD), which comprises administration by inhalation of an effective amount of one of the formulations described before.
Thus, a salt of compound 1 may provide significant therapeutic benefit in the treatment of respiratory diseases such as asthma and COPD (chronic obstructive pulmonary disease), when administered by inhalation.
Antimuscarinic drugs are currently administered to the respiratory tract by inhalation by means of pressurized metered dose inhalers (pMDIs) which use a hydrofluoroalkane (HFA) propellant to expel the active ingredient as an aerosol, or by means of dry powder inhalers (DPIs).
Thus, the aim of the present invention is to provide a HFA based aerosol composition that comprises a pharmaceutically acceptable salt of 3-[[[(3-fluorophenyl)[(3,4,5-trifluoro phenyl)methyl]amino]carbonyl]oxy]-1-[2-oxo-2-(2-thienyl)ethyl]-1-azoniabicyclo[2.2.2]octane as active ingredient.
Optimally, said formulation shall be homogeneous, chemically and physically stable and shall be able of providing a therapeutically active dose of the active ingredient.
In the context of the present invention, the terms “active drug”, “active ingredient”, “active”, “active compound”, “active substance”, and “therapeutic agent” are synonymous and used interchangeably.
The terms “muscarinic receptor antagonists”, “antimuscarinic drugs”, and “anticholinergic drugs” are synonymous and used interchangeably.
As used herein, the expressions “% w/w” and “% w/v” mean the weight percentage of the component with respect to the total weight or the total volume of the composition, respectively. The “% w/w” corresponding to the “% w/v” can be calculated by determining the density of the vehicle.
By “daily therapeutically effective dose” it is meant the quantity of active ingredient administered at one time by inhalation upon actuation of the inhaler. Said daily dose may be delivered in one or more actuations, preferably one actuation (shot) of the inhaler.
By “actuation” it is meant the release of the active ingredient from the device by a single activation (e.g. mechanical or breath).
As used herein the term “substantially optically pure” means an active ingredient having an optical purity higher than 95% w/w, preferably higher than 98% w/w.
As used herein the term “mass median diameter” means the diameter of 50 percent by weight of the particles.
As used herein, the term “co-solvent” means a substance having a higher polarity than that of the propellant, and a vapor pressure at 25° C. not less than 3 kPa, more preferably not less than 5 kPa.
As used herein, the term “low volatility component” means a component of the formulation having a vapor pressure at 25° C. lower than that of the co-solvent, and preferably not more than 0.1 kPa.
As used herein, the term “apparent pH” refers to the pH value of a non aqueous medium such as that consisting of a HFA propellant and ethanol. It can be determined according to procedures known to the person skilled in the art.
As used herein, the term “strong concentrated” refers to an acid which is 100% ionized in an aqueous solution and which is used in a concentration equal to or higher than 1M.
As used herein, the expression “formulation chemically stable” means a formulation wherein the stability and the shelf-life of the active ingredient meet the requirements of the ICH Guideline QIA referring to “Stability Testing of new Active Substances (and Medicinal Products)”.
As used herein, in the context of the suspension formulations, the expression “physically stable” refers to formulations which exhibit substantially no growth in particle size or change in crystal morphology of the active ingredient over a prolonged period, are readily redispersible, and upon redispersion, do not flocculate so quickly as to prevent reproducing dosing of the active ingredient.
As used herein, in the context of the solution formulations, the expression “physically stable” refers to formulations which exhibit substantially no visually detectable precipitation of the active ingredient over a prolonged period, for example over at least three months, preferably for at least 6 months.
Thus, in a first embodiment, the present invention provides novel pharmaceutical formulations suitable to be used for aerosol administration by a pressurized metered dose inhaler (pMDI) comprising a pharmaceutically acceptable salt of 3-[[[(3-fluorophenyl)[(3,4,5-trifluoro phenyl)methyl]amino]carbonyl]oxy]-1-[2-oxo-2-(2-thienyl)ethyl]-1-azoniabicyclo[2.2.2]octane (compound 1) as active ingredient, and a propellant. The compound 1 has the following chemical structure:
wherein the X− is a pharmaceutically acceptable anion, preferably selected from the group consisting of chloride, bromide, iodide, sulfate, phosphate, methanesulfonate, nitrate, maleate, acetate, citrate, fumarate, tartrate, oxalate, succinate, benzoate, and p-toluenesulfonate. Compound 1 is preferably used in the form of its chloride salt.
Any pressure-liquefied propellant may be used, preferably a hydrofluoroalkane (HFA) propellant. Examples of HFA propellants include 1,1,1,2-tetrafluoroethane (HFA134a) and 1,1,1,2,3,3,3-heptafluoro-n-propane (HFA227) and mixtures thereof. The preferred propellant is 1,1,1,2-tetrafluoroethane (HFA134a).
The pharmaceutical formulations according to the present invention, depending on volume of the metering valve to be used, may suitably comprise from about 0.02 mg to about 2 mg of compound 1 per ml, preferably from 0.1 mg to 0.8 mg per ml.
It will be apparent to those skilled in the art that compound 1 displays an asymmetric carbon on the quinuclidine ring, and hence may be in the form of a mixture of two optical stereoisomers, (3R)- and (3S)-stereoisomers. In the preferred embodiments, compound 1 is in the form of the substantially pure (3R)-enantiomer. The (3R)-enantiomer of compound 1 in the form of chloride salt is hereinafter referred to as compound 1′.
The compositions according to the present invention comprise the active ingredient in an amount such that, in case of administration by inhalation from inhalers, the daily therapeutically effective dose (hereinafter the daily dose) of compound 1 is advantageously comprised between about 0.1 μg and about 80 μg, preferably between about 0.5 μg and about 40 μg, even more preferably between about 1 and about 20 μg, even more preferably between 1 and about 10 μg and even more preferably between 1 and about 5 μg.
Said dose will depend on the kind and the severity of the disease and the conditions (weight, sex, age) of the patient and will be administered one or more times a day, preferably once a day.
In one embodiment, the daily dose may be reached by a single or double administration.
In another preferred embodiment, the daily dose may be reached by a single administration and delivered in one actuation of the inhaler.
In another preferred embodiment, the daily dose may be reached by a single administration and delivered in more actuations of the inhaler, preferably two.
In another preferred embodiment, the daily dose may be reached by a double administration and delivered in one actuation of the inhaler.
In another preferred embodiment, the daily dose may be reached by a double administration and delivered in more actuations of the inhaler, preferably two.
The daily dose may be delivered in one or two or more actuations (shots) of the inhaler wherein the pharmaceutical composition is contained. For example, a 10 μg daily dose may be administered in one shot of 10 μg or as two shots of 5 μg dose.
In one embodiment, the daily dose of a pharmaceutical composition comprising compound 1′ is comprised between 1 μg and 20 μg, preferably between 1 μg and 10 μg and more preferably between 1 μg and 5 μg.
The quantities of compound 1 in the compositions which are administered per single dose can be calculated analogously if instead of compound 1′, another salt is used.
In another aspect of the present invention, the pharmaceutical formulations may be in the form of suspension. Suspension aerosol formulations refer to formulations in which compound 1 is crystalline, is in particulate form, and is substantially insoluble in the formulation. The particles of compound 1 present in the formulations shall be in a micronized form so as to permit inhalation of the active ingredient into the lungs upon administration of the aerosol formulation. Advantageously, the particles of the active ingredient shall have a mass median diameter (MMD) of less than 10 microns, preferably in the range of 1 to 10 microns, more preferably between 1 and 6 microns. In certain embodiments, the propellant may consist of HFA 134a, while in other embodiments, the propellant may consist of HFA 227.
The suspension formulation may comprise additional excipients. Excipients suitable for MDI formulations are well known to the skilled person in the art.
In a particular embodiment, the suspension formulations may comprise a surfactant. Suitable surfactants are known in the art and include polysorbate 20, polysorbate 80, isopropyl myristate, oleic acid and sorbitan trioleate and lecithin. The amount of surfactant, which may be present in the formulation according to the present invention, is usually in the range of about 0.001 to 1.0% (w/w), preferably between 0.005 to 0.5% (w/w).
Optionally, a wetting agent may be present in the suspension formulations. The wetting agent may assist in the stability and in the manufacturing of the formulation, and is preferably present in a concentration range which does not lead to dissolution of the drug in the propellant formulation. For example, ethanol may be used in a concentration below 1% (w/w), preferably between 0.1% and 0.5% (w/w).
In other embodiments, the formulations according to the present invention may additionally comprise further excipients. Examples of excipients which may be mentioned in connection with the present invention are sugars such as lactose, amino acids such as alanine, betaine, cysteine, and/or antioxidants such as ascorbic acid, citric acid, sodium edetate, editic acid, tocopherols, butylhydroxytoluene, butylhydroxyanisol and ascorbyl palmitate. The weight ratio of the drug to the excipient is generally in the range of 1:0.1 to 1:100.
In another aspect, the pharmaceutical formulations of the invention may be in the form of solution.
Solution aerosol formulations refer to formulations in which compound 1 is fully dissolved in a mixture of a propellant and a co-solvent.
In said formulations, depending on volume of the metering valve to be used, compound 1 may be present in a concentration comprised between 0.002 and 0.2% (w/w), preferably from 0.01 and 0.08% (w/w). In certain embodiments, the concentration is comprised between 0.003 and 0.054% (w/w).
The co-solvent has a higher polarity than that of the propellant and may include one or more materials. Advantageously, the co-solvent is selected from the group of lower branched or linear alkyl (C1-C4) alcohols such as ethanol and isopropyl alcohol. Preferably the co-solvent is ethanol.
The concentration of the co-solvent will vary depending on the final concentration of the active ingredient in the formulation and on the type of propellant. For example, ethanol may be used in a concentration comprised between 5 and 25% (w/w), preferably between 8 and 22% (w/w), more preferably between 10 and 20% (w/w). In one of the preferred embodiments the concentration of ethanol is 15% (w/w).
The pharmaceutical formulations of the present invention may optionally comprise a low volatility component in order to either increase the mass median aerodynamic diameter (MMAD) of the aerosol particles on actuation of the inhaler and/or improve the solubility of the active ingredient in the propellant/co-solvent mixture. For instance glycols such as propylene glycol, polyethylene glycol and glycerol are particularly suitable for both increasing the MMAD and improving the solubility. The amount of glycol may vary between 0.1 and 10% w/w, preferably between 0.5 and 5% (w/w), more preferably between 1 and 2% (w/w).
In another embodiment, an amount of water comprised between 0.005 and 0.5% (w/w) may be added to the formulations in order to favorably affect the solubility of the active ingredient without increasing the MMAD of the aerosol droplets upon actuation.
The pH of the aerosol solution formulation of the invention may be adjusted to an apparent value comprised between 2.5 and 5.5, preferably between 3.0 and 5.0. Strong concentrated mineral acids such as hydrochloric acid, nitric acid, sulphuric acid and phosphoric acid are preferably used to adjust the apparent pH. Phosphoric acid is particularly preferred. The amount of acid to be added to reach the desired apparent pH will depend on the concentration of the active ingredient and the amount of the co-solvent. In certain embodiments, the apparent pH may be adjusted by adding phosphoric acid at a concentration comprised between 60 and 85% (from about 10 M to about 15 M) in an amount comprised between 0.0004 and 0.040%, preferably comprised between 0.0008 and 0.020%, more preferably between 0.001 and 0.010% (w/w). In a particular embodiment, the apparent pH is adjusted by adding an amount of 85% phosphoric acid (15.2 M) comprised between 0.0013 and 0.0075% w/w, more preferably comprised between 0.002% and 0.0054% (w/w), even more preferably of 0.0027% (w/w). The control of pH may favor the chemical stability of the formulations. It has been found that the stability of the aerosol solution formulation of the invention may also depend on the type of metering valve used with the metered dose inhaler wherein the formulation is contained.
The formulation of the present invention may be filled into devices suitable for delivering pressurized pharmaceutical aerosol formulations, hereinafter referred to as pMDI devices. Such devices comprise a canister fitted with a metering valve. Actuation of the metering valve allows a small portion of the spray product to be released.
Part of all of the internal surfaces of the canister may be made of a metal, for example aluminum or stainless steel or anodized aluminum. Alternatively the canister may have part of all of the internal surfaces made of anodized aluminum, stainless steel or lined with an inert organic coating. Examples of preferred coatings are epoxy-phenol resins, perfluorinated polymers such as perfluoroalkoxyalkane, perfluoroalkoxyalkylene, perfluoroalkylenes such as poly-tetrafluoroethylene (Teflon), fluorinated-ethylene-propylene, polyether sulfone and a copolymer fluorinated-ethylene-propylene polyether sulfone. Other suitable coatings could be polyamide, polyimide, polyamideimide, polyphenylene sulfide or their combinations. In certain embodiments canisters having the internal surface lined with Teflon may preferably be used. In other particular embodiments canisters made of stainless steel may preferably be used.
The canister is closed with a metering valve for delivering a daily therapeutically effective dose of the active ingredient. Generally the metering valve assembly comprises a ferrule having an aperture formed therein, a body molding attached to the ferrule which houses the metering chamber, a stem constituted of a core and a core extension, an inner- and an outer seal around the metering chamber, a spring around the core, and a gasket to prevent leakage of propellant through the valve. The gasket may comprise any suitable elastomeric material such as, for example, low density polyethylene, chlorobutyl, black and white butadiene-acrylonitrile rubbers, butyl rubber, neoprene, EPDM (a polymer of ethylenepropylenediene monomer) and TPE (thermoplastic elastomer). EPDM rubbers are particularly preferred. Suitable valves are commercially available from manufacturers well known in the aerosol industry, for example, from Valois, France, Bespak, plc UK and 3M, Neotechnic Ltd UK. In general terms the valve seals, especially the gasket seal, as well as the seals shall preferably be manufactured of a material which is inert to and resists extraction into the contents of the formulation, especially when the contents include ethanol.
Advantageously, the material of the metering chamber is inert to and may resist distortion by contents of the formulation. Particularly suitable materials for use in manufacture of the metering chamber include polyesters e.g. polybutyleneterephthalate (PBT) and acetals, especially PBT. According to a preferred embodiment of the present invention, the material of all the internal surface of the canister as well as the material of the metering chamber, the core, the core extension, the spring and the body of the valve may be substantially or completely made of a metal, preferably of stainless steel. It has been indeed found that, although the formulations of the invention are chemically stable in devices wherein the metering valves are made of plastic materials such as polyesters or acetals, nevertheless compound 1, in particular when the device is stored inverted, might tend to adhere onto the surface of said plastic material, giving rise to a loss in the delivered dose, and hence to a potential variability of the therapeutic profile of the drug. Metering valves made of stainless steel are available under the registered name of Spraymiser™.
The formulation shall be actuated by a metering valve able of delivering a volume of between 50 μl and 100 μl, e.g. 50 μl or 63 μl. 100 μl is also suitable.
Advantageously the MDI device filled with the formulation may be equipped with a dose counter. For instance, said types of devices are described in the pending application nos. EP 1758631 and EP 1787668, which are incorporated herein by reference in their entireties.
Conventional bulk manufacturing methods and machinery well known to those skilled in the art of pharmaceutical aerosol manufacture may be employed for the preparation of large scale batches for the commercial production of filled canisters.
For example, the aerosol suspension formulations according to the invention may be prepared by adding the active ingredient to a chilled propellant or optionally a pre-mixed blend of propellant and optionally further excipients and, then dispersing the resulting suspension using a suitable mixer. After homogenization, the suspension can be filled into the MDI canister which is closed by crimping a metering valve on the canister. Alternatively the active ingredient and optionally further excipients can be added to a vessel. The liquefied propellant is then introduced into the vessel under pressure and the active ingredient is dispersed and homogenized using a suitable mixer and homogenizer. After homogenization, the bulk formulation can be transferred into the individual MDI canisters by using valve to valve transfer methods known to the skilled person.
In the case of the aerosol solution formulations of the present invention, the active ingredient is added to a charge vessel and a mixture of ethanol, liquefied propellant, and optionally the low volatility component and the pH-adjusting acid are filled under pressure through the charge vessel into a manufacturing vessel. An aliquot of the formulation is then filled through the metering valve into the canister.
In an alternative process, an aliquot of the liquefied formulation is added to an open canister under conditions which are sufficiently cold that the formulation does not vaporize, and then a metering valve crimped onto the canister.
In an alternative process, an aliquot of the active ingredient dissolved in co-solvent, optionally in the presence of the low volatility component and the pH-adjusting acid is dispensed into an empty canister, a metering valve is crimped on, and then the propellant is filled into the canister through the valve.
Preferably, the processes are carried out an in inert atmosphere, for instance by insufflating nitrogen, in order to avoid the uptake of humidity from the air.
Each filled canister is conveniently fitted into a suitable channeling device prior to use to form a metered dose inhaler for administration of the medicament into the lungs of a patient. Suitable channeling devices comprise, for example a valve actuator and a cylindrical or cone-like passage through which medicament may be delivered from the filled canister via the metering valve to the mouth of a patient e.g. a mouthpiece actuator.
In a typical arrangement, the valve stem is seated in a nozzle block which has an orifice leading to an expansion chamber. The expansion chamber has an exit orifice which extends into the mouthpiece. Actuator (exit) orifice having a diameter in the range 0.15-0.45 mm and a length from 0.30 to 1.7 mm are generally suitable. Preferably an orifice having a diameter from 0.2 to 0.44 mm may be used, e.g. 0.22 0.25, 0.30, 0.33 or 0.42 mm.
In certain embodiments of the present invention, it may be useful to utilize laser-drilled actuator orifices having a diameter ranging from 0.10 to 0.22 mm, in particular from 0.12 to 0.18 mm as those described in WO 03/053501, which is incorporated herein by reference in its entirety.
The use of said fine orifices may also increase the duration of the cloud generation and hence, may facilitate the coordination of the cloud generation with the slow inspiration of the patient.
In the case when the ingress of water into the formulation is to be avoided, it may be desired to overwrap the MDI product in a flexible package capable of resisting water ingress. It may also be desired to incorporate a material within the packaging which is able to adsorb any propellant and co-solvent which may leak from the canister (e.g. a molecular sieve).
Optionally, the MDI device filled with the formulation of the invention may be utilized together with suitable auxiliary devices favoring the correct use of the inhaler. Said auxiliary devices are commercially available and, depending on their shape and size, are known as “spacers”, “reservoirs”, or “expansion chambers”. Volumatic™ is, for instance, one of the most known and used reservoirs, while Aerochamber™ is one of the most used and known spacers. A suitable expansion chamber is reported for example in WO 01/49350, which is incorporated herein by reference in its entirety.
The formulation of the present invention may also be used with common pressurized breath-activated inhalers such as those known with the registered names of Easi-Breathe™ and Autohaler™.
The formulations of the present invention may further comprise other therapeutic agents currently used in the treatment of respiratory disorders, e.g. corticosteroids such as budesonide and its epimers, beclometasone dipropionate, triamcinolone acetonide, fluticasone propionate, flunisolide, mometasone furoate, rofleponide and ciclesonide, anticholinergic or antimuscarinic agents such as ipratropium bromide, oxytropium bromide, tiotropium bromide, glycopyrrolate bromide, and the group of phosphodiesterase-4 (PDE-4) inhibitors such as roflumilast, and their combinations.
Administration of the formulations of the present invention may be indicated for the prevention and/or treatment of mild, moderate or severe acute or chronic symptoms or for prophylactic treatment of respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). Other respiratory disorders characterized by obstruction of the peripheral airways as a result of inflammation and presence of mucus such as chronic obstructive bronchiolitis and chronic bronchitis may also benefit by this kind of formulation.
Other features of the invention will become apparent in the course of the following descriptions of exemplary embodiments which are given for illustration of the invention and are not intended to be limiting thereof.
To prepare the suspension formulations according to the present invention crystalline (3R)-3-[[[(3-fluorophenyl)[(3,4,5-trifluoro phenyl)methyl]amino]carbonyl]oxy]-1-[2-oxo-2-(2-thienyl)ethyl]-1-azoniabicyclo[2.2.2]octane chloride (compound 1′), obtained as reported in the co-pending patent application no. PCT/EP2007/057585 (incorporated herein by reference in its entirety), is micronized by methods known per se in the art, to prepare the active substance in the form of particles having a typical particle size suitable for inhalation. Examples of formulations are reported in Tables 1-3.
To prepare aerosol solution formulations according to the invention, compound 1′ is dissolved in the propellant in the presence of ethanol and optionally phosphoric acid and water according to the methods reported in the description. Examples of formulations are reported in Tables 4-9.
The formulations (f), (h), and (i) of Example 2 are filled in Teflon coated standard aluminum canisters under pressure and fitted with a metering valve having a 63 μl metering chamber. An actuator with an orifice diameter of 0.22 mm is used. The aerodynamic particle size distribution of each tested formulation is characterized using a Multistage Cascade Impactor according to the procedure described in European Pharmacopoeia 2nd edition, 1995, part V.5.9.1, pages 15-17. In this specific case, an Andersen Cascade Impactor (ACI) is utilized. The following parameters are determined:
i) delivered dose which is calculated from the cumulative deposition in the ACI;
ii) respirable dose (fine particle dose) which is obtained from the deposition on Stages 3 (S3) to filter (AF) corresponding to particles ≦4.7 microns, divided by the number of actuation per experiment; and
iii) respirable fraction (fine particle fraction) which is the ratio between the respirable dose and the delivered dose.
Deposition of the drug on each ACI plate is determined by high pressure liquid chromatography (HPLC). The delivery characteristics of said formulations are reported in Table 10.
Airway reactivity is measured using barometric plethysmography (Buxco, USA). Male guinea pigs (500-600 g) are individually placed in plexiglass chambers. After an acclimatisation period, animals are exposed to nebulised saline for 1 minute to obtain airway baseline reading. This is followed by a 1 minute challenge with nebulised acetylcholine (Ach)-2.5 mg/mL. After 60 minutes, 5 minute nebulisation of vehicle or the compound 1′ in the range 2.5-250 μM are applied and Ach challenge is then repeated after 2, 5, 24, 48 and 72 hours (h). Recording of pressure fluctuations in the chambers are taken for 5 minutes after each nebulisation and analysed to calculate Enhanced Pause (Penh). Airway reactivity is expressed as percentage increase in Penh compared with Penh values from the nebulisation of vehicle. Two hours after the end of nebulisation with compound 1′, the Ach-induced increase in Penh is dose-dependently inhibited by the compound, with a maximal effect of 99.6±0.4 at 50 μM. As for the time-course of the effect, compound 1′ shows increasing duration of action with increasing dose. After inhalation of 250 mM of compound 1′, effect persists unchanged up to 48 hours (83.0±16.1%), while at 72 hours a residual activity of 34.8±20.9% is present. Twenty-four hours after 25 and 50 μM compound 1′ inhalation, a significant bronchoprotective effect was observed (63.7±15.1% and 87.1±8.7%, respectively). At 50 μM, a significant inhibition persists up to 48 h (49.2±23.2%). Inhalation of lower concentrations results in an effect that did not exceed the 5 h observation point.
The estimation of lung levels of compound 1′ achieved after nebulisation endowed with a submaximal bronchodilator activity at 2 hours after treatment reveals that the its retained dose in the target organ is about 50 μg/kg. If an extrapolation of these results from guinea pig to human is made, it can be predicted that in patients the daily therapeutically effective dose might be comprised between 1 and 20 μg, preferably between 1 and 10 μg and more preferably between 1 and 5 μg.
Where a numerical limit or range is stated herein, the endpoints are included. Also, all values and subranges within a numerical limit or range are specifically included as if explicitly written out.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
All patents and other references mentioned above are incorporated in full herein by this reference, the same as if set forth at length.
| Number | Date | Country | Kind |
|---|---|---|---|
| 08000602.6 | Jan 2008 | EP | regional |
