Micronization process of indacaterol acetate

Abstract

The present invention provides a process for micronizing and conditioning crystalline indacaterol acetate which yields a micronized product containing low content of amorphous form. The invention also refers to crystalline micronized indacaterol acetate obtained by the process of the invention for use in pharmaceutical compositions for pulmonary inhalation for the treatment of asthma.

Description

[0001]MICRONIZATION PROCESS OF INDACATEROL ACETATE FIELD OF THE INVENTIONThe present invention provides a process for micronizing and conditioning crystallineindacaterol acetate which yields a micronized product containing low content ofamorphous form. The invention also refers to crystalline micronized indacaterol acetateobtained by the process of the invention for use in pharmaceutical compositions forpulmonary inhalation for the treatment of asthma.BACKGROUND ARTIndacaterol acetate, with chemical name (R)-5-(2-((5,6-diethyl-2,3-dihydro-1H-inden-2-yl)amino)-1-hydroxyethyl)-8-hydroxyquinolin-2(1H)-one acetate, compound (I), is a long-acting β2-agonist (LABA) approved in combination with mometasone furoate an inhaledcorticosteroid (ICS), under the brand name Atectura Breezhaler. Additionally, indacaterolacetate is approved in a triple combination with mometasone furoate and glycopyrroniumbromide, a long-acting muscarinic antagonist (LAMA), under the brand name EnerzairBreezhaler. Both medicaments are indicated for the maintenance treatment of asthma. Indacaterol acetate in crystalline form was first disclosed in WO2008 / 000839 A1,preparation example 15 and characterization example 16, among other pharmaceuticallyacceptable salts. Indacaterol acetate showed to be less prone than known maleate saltto cause post-inhalation cough in clinicals trials.According to the European Public Assessment Report (EPAR), indacaterol acetate is anon-solvated, slightly hygroscopic, crystalline micronized white to yellow or beigepowder. The commercial manufacturing process for the indacaterol acetate includes afinal micronisation and deamorphisation steps. However, said percentage of amorphouscontent in the finished dosage form is not disclosed.WO2011 / 131663 A1 discloses the co-micronization of carrier particles, such as lactosewith magnesium stearate, followed by a conditioning step by exposure co-micronizedparticles to a relative humidity of 50-75% at room temperature for a time comprisedbetween 6 and 60 hours, suitable for preparing dry powder formulations. The descriptionmentions indacaterol acetate among a large list of ingredients that could be formulatedwith the co-micronized particles but fails to provide any example with indacaterol acetate. There is the need to provide an efficient process for preparing micronized indacaterolacetate in high quality, i.e. with low content of non-crystalline or amorphous material,thereby avoiding a significant physical instability of the finished dosage form.SUMMARY OF THE INVENTION The present inventors have realized that micronizing crystalline indacaterol acetateunder standard conditions, i.e. by using jet milling with air and at room temperature,provided micronized indacaterol acetate having about 30% of amorphous content evenwhen the starting non-micronized indacaterol acetate is crystalline and contains not morethan 1% of amorphous material. This high quantity of amorphous content not only mayincrease the formation of impurities during storage due to the hygroscopicity of saidamorphous material, but also said amorphous material may recrystallize and change theparticle size distribution values, which in consequence may not comply with inhaledpharmaceutical compositions requirements.The exposure of micronized indacaterol acetate having about 30% of amorphous contentto humid conditions, for instance, at 90% HR for 9 days, reduced the percentage ofamorphous content to about 20% as measured by microcalorimetry, but with a significantloss of acetic acid.Surprisingly, the present inventors have developed an optimized micronization processallowing to obtain an indacaterol acetate with a particle size distribution (PSD)characterized by a D90 of equal to or below 10 µm, a reduced content of amorphousindacaterol acetate, preferably less than 15% w / w of amorphous form, as measured by microcalorimetry, more preferably less than 10% w / w, still more preferably less than 5%w / w. Advantageously, the crystalline indacaterol acetate obtained by said process hasan adequate acetic acid content, preferably higher than 10% w / w, as measured by HPLC method, preferably with an acetic acid content of 13.3%±1%, more preferably with an acetic acid content of 13.3%±0.5%, which makes the product suitable for pulmonaryinhalation. Additionally, the micronized indacaterol acetate may be subjected to aconditioning step in specific environments to reduce the amorphous material below to4%, 3%, 2%, or even 1% w / w.Therefore, in a first embodiment, the present invention relates to a process for treatingindacaterol acetate comprising the steps of:a) providing indacaterol acetate with a particle size distribution (PSD)characterized by a first D90of at least 25 μm and comprising not more than 20% w / w of amorphous indacaterol acetate, b) micronizing indacaterol acetate at a temperature lower than 10ºC to obtaina particle size distribution (PSD) characterized by a second D90 of equal toor below 10 µm, and c) optionally, maintaining the indacaterol acetate of step (b):i. for at least 48 hours in an open environment with a relative humidity(RH) comprised between 30% and 85% and a temperature comprised between 0°C to 30°C, or ii. for at least 6 hours in a closed environment having a relative humidity(RH) comprised between 0% and 90% and a temperature comprisedbetween 20°C and 60°C.The above-mentioned process is straightforward and allows obtaining an indacaterolacetate with a particle size distribution (PSD) characterized by a D90of equal to or below10 µm, a reduced content of amorphous product of not more than 20% w / w, preferablyless than 15% w / w of amorphous form, as measured by microcalorimetry, morepreferably less than 10% w / w, still more preferably less than 5% w / w. In addition, thehighly crystalline indacaterol acetate obtained by said process has a high acetic acidcontent, preferably higher than 10% w / w, preferably from 12.3 to 14.3%, more preferablyfrom 12.8% to 13.8%, as measured by HPLC method, which makes the product suitablefor pulmonary inhalation.In a further aspect, the present invention also relates to indacaterol acetate obtainableby the process according to first aspect. Particularly, the micronized indacaterol acetatethus obtained has an amorphous content below 10% by weight, preferably below 5%,more preferably below 1%, as measured by microcalorimetry. Further, indacaterolacetate thus obtained has a particle size distribution (PSD) characterized by a D10 of 0.1to 1.1 µm, a D50 of 1.2 to 2.5 µm and a D90 of 3.0 to 4.5 µm. DEFINITIONS When describing the compounds and methods of the invention, the following terms have the following meanings, unless otherwise indicated. The term “micronization” as used herein refers to the process of reducing the average diameter of particles for a solid material. Usually, the term micronization is used when the particles that are produced are only a few micrometres (typically less than 10 µm) in diameter. Traditional micronization techniques are based on the use of friction to reduce particle size. Such methods include milling and grinding. Reduction in particle size mayalso take place as a result of collision and impact of the particles to each other.The term “DX” as used herein means that x% of the particles in a composition (based on volume) have a diameter of equal to or below a specified D value. Thus, a D90of 10 µmmeans that 90% of the particles, by volume, have a diameter of or below 10 µm. As wellas using D90as a measuring reference to determine particle size, D50is sometimes used for such a purpose. Therefore, a D50of 5 µm means that 50% of the particle population,by volume, have a diameter of equal to or below 5 µm. The particle size distribution(PSD) may be determined using a HELOS / BR apparatus offered by SYMPATEC whichuses a parallel beam laser diffraction set-up, such as disclosed in the General Methods.The term “amorphous" as used herein described a disordered solid state, which may appear during manufacture of the drug substance such as in a crystallization step, drying, milling). The X-ray powder diffraction pattern of an amorphous solid exhibits no sharppeaks. The amount of amorphous material in a crystalline sample may be determined bysolution microcalorimetry such as disclosed in the General Methods.The term “room temperature” in the context of the present invention refers to a temperature from 15ºC to 30ºC, preferably from 20ºC to 25ºC. The term “Water vapor transmission rate” (WVTR), also moisture vapor transmission rate (MVTR), is a measure of the passage of water vapor through a substance. Varioustechniques are available to measure WVTR, ranging from gravimetric techniques that measure the gain or loss of moisture by mass, to highly sophisticated instrumental techniques that in some designs can measure extremely low transmission rates. Commercial instruments are available to determine WVTRs using either a pressure- modulated infrared detector or a mechanically modulated infrared detector. Numerous standard methods are described in e.g. ISO, ASTM, BS and DIN, like ASTM F1249 andDIN53122. The conditions under which the measurement is made have a considerableinfluence on the result. Both the temperature and the humidity gradient across thesample need to be measured, controlled and recorded with the result. The WVTR valueis a known parameter to express the passage of water vapor through the packagingmaterial in order to control the required quality and shelf life. The type pack material usedand its film thickness, determines the WVTR value.The term “closed environment” is used in the present description to define a confinedenvironment containing indacaterol acetate in a volume such that at least 40 g of indacaterol acetate are contained per liter of said environment.The term “open environment” is used in the present description to define an environmentcontaining indacaterol acetate in a volume such that less than 40 g of indacaterol acetate are contained per liter of said environment. Thus, when indacaterol acetate is contained in a confined but large volume (such that there are less than 40 g of indacaterol per liter of environment) it is considered in the context of the present invention to be in an open environment. BRIEF DESCRIPTION OF THE FIGURES Examples of the invention are illustrated with the following drawings:Figure 1 illustrates the results of the solution microcalorimetry determination carried outon a sample of indacaterol acetate prepared as in Example 4.Figure 2 illustrates the results of the HPLC method for determination of acetic acidcontent carried out on a sample of indacaterol acetate prepared as in Example 4.Figure 3 illustrates the results of the solution microcalorimetry determination carried outon a sample of indacaterol acetate prepared as in Example 6 after micronization stepb).Figure 4 illustrates the results of the solution microcalorimetry determination carried outon a sample of indacaterol acetate prepared as in Example 6 after step c). DETAILED DESCRIPTION OF THE INVENTIONIn an embodiment, indacaterol acetate of step a) is in crystalline form as prepared as inExample 1 of WO 2008 / 000839 A1. In another embodiment, indacaterol acetate of stepa) is in crystalline form as prepared according to IN201841012935 A.The indacaterol acetate of step a) has a particle size distribution (PSD) characterized bya first D90 of at least 25 μm and comprises not more than 20% of amorphous indacaterolacetate.In an embodiment, indacaterol acetate of step a) comprises not more than 20%, not morethan 19%, not more than 18%, not more than 17%, not more than 16%, not more than15%, not more than 14%, not more than 13%, not more than 12%, not more than 11%,not more than 10%, not more than 9%, not more than 8%, not more than 7%, not morethan 6%, not more than 5%, not more than 4%, not more than 3%, not more than 2% ornot more than 1% of amorphous material measured by solution microcalorimetry. Inanother embodiment, indacaterol acetate of step a) comprises not more than 1% ofamorphous material measured by microcalorimetry. In a preferred embodiment,indacaterol acetate of step a) is fully crystalline, i.e. it does not comprise any amorphousmaterial measured by microcalorimetry. In an embodiment, indacaterol acetate of step a) has a particle size distribution (PSD) characterized by a first D90of at least 25 µm, at least 30 µm, at least 35 µm, at least 40µm, at least 45 µm, at least 50 µm, at least 60 µm, at least 70 µm, at least 80 µm, atleast 90 µm, at least 100 µm, at least 150 µm, at least 200 µm, at least 250 µm, at least300 µm or at least 500 µm, as measured by laser diffraction. In another embodiment,indacaterol acetate of step a) has a particle size distribution (PSD) characterized by afirst D90 of at least 30 µm, at least 35 µm, at least 40 µm, at least 45 µm, at least 50 µm,at least 60 µm, at least 70 µm, at least 80 µm, at least 90 µm, at least 100 µm, at least150 µm, at least 200 µm, or at least 250 µm, as measured by laser diffraction.In an embodiment, the indacaterol acetate is micronized in step b) to obtain a particlesize distribution (PSD) characterized by a second D90 of equal to or below 10 µm.In an embodiment, indacaterol acetate of step b) has a second D90 of equal to or below8 µm, measured by laser diffraction. In another embodiment, indacaterol acetate of stepb) has a second D90 equal to or below 6 µm, measured by laser diffraction.In an embodiment, indacaterol acetate of step b) has a D50 of equal to or below 6 µm, 5μm, 4 μm, 3 μm or 2 μm, measured by laser diffraction. In an embodiment, indacaterol acetate obtained after step b) has a particle size distribution (PSD) characterized by a D10 of 0.1 to 1.1 µm, a D50 of 1.2 to 2.5 µm and a D90 of 3.0 to 5.0 µm.In an embodiment of the process, the micronization of step (b) may be carried out at apressure of equal to or below 8 bar. In another embodiment of the process, themicronization of step (b) may be carried out at a pressure of equal to or below 6 bar. Inanother particular embodiment of the process, the micronization of step (b) may becarried out at a pressure of equal to or below 4 bar.In an embodiment of the process, the carrier gas used in the micronization process step b) may be air, dehumidified air, dry oil-free air, noble gases, nitrogen or mixtures thereof.In an embodiment of the process, the micronization of step (b) may be carried out at atemperature of from ^30°C to 10°C. In another embodiment of the process, themicronization of step (b) may be carried out at a temperature of from ^30°C to 0°C. Inanother particular embodiment of the process, the micronization of step (b) may carriedout at a temperature of from ^30°C to ^5°C. In a preferred embodiment of the process,the micronization of step (b) may be carried out at a temperature of from ^30°C to ^15°C.In a more preferred embodiment, the micronization of step (b) may be carried out at atemperature of from ^20°C to ^15°C.In an embodiment, indacaterol acetate before carrying out step (b) is cooled to atemperature below room temperature such as 10ºC, 5ºC, 0ºC, ^5ºC, ^10ºC, ^15ºC or^20ºC. In another embodiment, indacaterol acetate before carrying out step (b) may becooled to a temperature of from ^15ºC to ^20ºC.In an embodiment, the desired particle size distribution (PSD) is achieved after only onemicronization step b). In another embodiment, the desired particle size may also beachieved after more than one, such as two or three micronization steps.In an embodiment, the micronization of indacaterol acetate in step b) is carried out on itsown, i.e. in the absence of any excipient or other active ingredient. In anotherembodiment, the micronization of indacaterol acetate of step (b) may also be carried outin the presence of one or more other additional active ingredients, and / or one or more excipients, which are preferably pharmaceutically acceptable excipients.In an embodiment, additional active ingredients may be selected from β2-agonists,glucocorticoids, anticholinergic drugs and phosphodiesterase inhibitors or other drugs which may be administered in combination with indacaterol acetate. In anotherembodiment, additional active ingredients may be selected from the group consisting ofmometasone furoate and glycopyrronium bromide. In an embodiment, thepharmaceutically acceptable excipients may be magnesium stearate or lactose.In an embodiment, the micronized indacaterol acetate obtained in step (b) ischaracterized by having less than 30%, less than 25%, less than 20%, less than 19%,less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, less than 12%, less than 11%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2% or lessthan 1% w / w of amorphous content, as measured by microcalorimetry.In an embodiment, indacaterol acetate of step (b) is maintained in step c):i. for at least 48 hours in an open environment with a relative humidity (RH) comprisedbetween 30% and 85% and a temperature comprised between 0°C to 30°C, or ii. for at least 6 hours in a closed environment having a relative humidity (RH)comprised between 0% and 90% and a temperature comprised between 20°C and 60°C.In another embodiment, the pressure of the environment of the process step c) isatmospheric pressure.In an embodiment, step c) is carried out according to alternative i, i.e. by maintaining theindacaterol acetate of step (b) for at least 48 hours in an open environment with a relativehumidity (RH) comprised between 30% and 85% and a temperature comprised between0°C to 30°C. The relative humidity (RH) may take any value between 30% to 85%, suchas 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% and 85%, and a temperature comprised between 0°C to 30°C.In another embodiment, step c) is carried out according to alternative i.) in an openenvironment with a relative humidity (RH) comprised between 40% and 85% and atemperature comprised between 0°C to 30°C. In another particular embodiment, therelative humidity (RH) may be comprised between 50% and 85% and the temperaturecomprised between 0°C to 30°C.In an embodiment, step c) is carried out according to alternative i.) in an openenvironment consisting of opened capsules or trays and stored in a controlled chamberwhich is maintained between 0°C ± 2°C to 30°C ± 2°C with a relative humidity comprisedbetween 30% RH ± 5% RH to and 85% RH ± 5% RH for sufficient time to reduce theamorphous content.In an embodiment of the process, the micronized indacaterol acetate is maintained inthe conditioning step (c)(i.), i.e. in an open environment, for at least 48, 60, 72, 84, 96,108, 120 or 132 hours.In an embodiment of the process, the micronized indacaterol acetate is maintained inthe conditioning step (c)(ii.), i.e. in a closed environment, for at least 6, 7, 8, 9, 10, 11,12, 13, 14, 15, 16, 17, 18, 19, 20, 24, 48, or 72 hours.In an embodiment of the process, the micronized indacaterol acetate is maintained in aclosed environment having a relative humidity (RH) comprised between 0% and 90%and a temperature comprised between 20°C and 60°C. The relative humidity (RH) maytake any value between 0% to 90%, such as 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%,45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, and 90%, at a temperature of from20°C to 60°C, preferably at a temperature of from 30ºC to 55ºC. In an embodiment, the micronized indacaterol acetate obtained in step (c) is characterized by having equal or less than 15%, equal or less than 14%, equal or less than 13%, equal or less than 12%, equal or less than 11%, equal or less than 10%, equal or less than 9%, equal or less than 8%, equal or less than 7%, equal or less than 6%, equal or less than 5%, equal or less than 4%, equal or less than 3%, equal or less than2% or equal or less than 1% w / w of amorphous content, as measured bymicrocalorimetry. In an embodiment, indacaterol acetate obtained after step c) has a particle sizedistribution (PSD) characterized by a D90 equal to or below 10, equal to or below 9, equalto or below 8, equal to or below 7, equal to or below 6 or equal to or below 5 µm measuredby laser diffraction.In an embodiment, indacaterol acetate obtained after of step c) has a D50 of equal to orbelow 6, equal to or below 5, equal to or below 4 or equal to or below 3 µm, measuredby laser diffraction. In an embodiment, indacaterol acetate obtained after step c) has a particle size distribution (PSD) characterized by a D10of 0.1 to 1.1 µm, a D50of 1.2 to 2.5 µm and aD90 of 3.0 to 5.0 µm.In an embodiment, the closed environment may be obtained by confining the micronizedindacaterol acetate obtained in step b) in a closed space limited by a material characterized by having a moisture barrier with a Water Vapour Transmission Rate(WVTR) of equal or less than 1.5 g / m2 / day at 38ºC / 90% RH. In another embodiment, thematerial is characterized by having a moisture barrier with a Water Vapour Transmission Rate (WVTR) of equal or less than 1.5, equal or less than 1.4, equal or less than 1.3,equal or less than 1.2, equal or less than 1.1, equal or less than 1.0, equal or less than0.9, equal or less than 0.8 or equal or less than 0.75 g / m2 / day at 38ºC / 90% RH. In apreferred embodiment, the material is characterized by having a moisture barrier with aWater Vapour Transmission Rate (WVTR) of equal or less than 0.75 g / m2 / day at 38ºC / 90% RH. In an embodiment, the closed space is created by confining the micronized indacaterolacetate obtained in step b) in a material with a Water Vapour Transmission Rate (WVTR)of equal or less than 0.75 g / m2 / day at 38ºC / 90% RH. In a preferred embodiment thematerial forms a packaging into which indacaterol acetate is packaged.In an embodiment, the packaging material comprises at least two bags, preferably a firstclosed inner bag and a second closed outer bag comprising at least an aluminium layer.In another embodiment, the pack material comprises at least two bags closed by a cabletie, preferably a first closed inner bag and a second closed outer bag comprising at leastan aluminium layer. In another embodiment, the outer bag comprises closing meansselected from the group of a clicky zipper and a heat induction seal.In an embodiment, the conditioning step c) according to the present invention may betypically conducted on trays maintained in a controlled chamber in which the environmentaccording to the invention, i.e. an open environment or a closed environment, ismaintained. In an embodiment, when the conditioning step is carried out in a closed environment,indacaterol acetate is enclosed in a confined space such that the amount of indacaterolis 40 g to 80 g, 50 g to 70 g or 60 g to 70 g per liter of volume of said confined space.The confined spaced may be created by placing indacaterol acetate in a packaging such as a bottle, a vial, a capsule, a sachet, a blister, a bag or an ampoule, preferably a bag. In another particular embodiment, indacaterol acetate in an amount of about 200 g ispackaged in a packaging having a volume of 3 liter.In an embodiment, 50 g of micronized indacaterol acetate prepared according to theprocess of the invention is packaged in 0,75 liter of a transparent bag such as LDPE,HDPE, plastic bags, which is tightly sealed (e.g. cable tie) inside an aluminium bagclosed with a clicky zipper.In an embodiment, indacaterol acetate thus obtained by the process of the invention maybe stored in a packaging system selected from a vacuum bag and an inflated bagproduced by introduction of an inert gas. The vacuum bag system requires a minimumof space as compared to inflated bags. The vacuum packaged systems are less prone to leakage and any leakage can be easily detected. It also forms part of the invention a pharmaceutical composition comprising themicronized indacaterol acetate obtainable by the process of the claims with one or morepharmaceutically acceptable carriers, or excipients. In the following, the present invention is further illustrated by examples. They should in no case be interpreted as a limitation of the scope of the invention as defined in the claims. Unless indicated otherwise, all indications of percentage are by weight and temperatures are in degrees Celsius. GENERAL METHODSDetermination of amorphous contentEquipment: Solution Microcalorimetry TAM IVSoftware: TAM Assistant Moisturizing solvent: 0.8 mL of Ethanol in both chambers. Bath temperature: 25ºCSample preparation: 50 mgAnalysis: Method Flow control: MC-IA-01General set conditions: Mixture: 10.0 %Gas Flow: Total mass flow: 200 mL / h Set wanted temperature: Absolute 40ºC Mixture profile: Phase Mixture % Duration Change Rate (% / h)0 Constant 10.000 5min1 Scanning Shortest Fastest1 Constant 90.000 3h 30min2 Scanning Shortest Fastest2 Constant 10.000 1h3 Scanning Shortest Fastest3 Constant 90.000 2h 30min4 Scanning Shortest Fastest4 Constant 10.000 5minBaselines:✓ Initial baseline: Baseline duration: 30 min✓ Collect baseline with sample(s) inserted✓ Automatically start baseline based on signal stability conditionsSignal stability conditions: AdvancedAbsolute value of slope is less than: 300 nW / hStandard dev. less than: 100 nWWindow length of linear fit: 20 minMaximum time to wait for signal stability: 3hUse baseline average as signal offsetResult (amorphous %):The subindex 90%RH of the above formula refers to the percentage of moisturizingethanol solvent used in both chambers for the determination.Determination of acetic contentEquipment: HPLC Agilent 1290 Quaternary DAD HPLC System.Solvents and reagents: Methanol (MeOH), tetrabutylammonium bisulfate, acetic acid,water Milli-Q.Sample preparation:Blank Solution: MethanolSample Solution: 4 mg / mL in MeOH100 mg of sample / 25 mL MeOHReference Standard Solution (System Suitability Test): 130 mg Acetic acid / 25 mLMeOH * 1 / 10 mL MeOH to obtain a concentration of 0.52 mg / mL (it corresponds to arelative concentration of 13%).Mobile phase:Mobile phase A: 1.5 g Tetrabutylammonium bisulfate into 1000 mL of Water Milli-Qand filter (0.45μm).Mobile phase B: MeOHChromatographic System:Mode: LCDetector: UV - 210 nm, Bandwidth 10 nmReference wavelength: 550 nm, Bandwidth 100 nmColumn: Atlantis dC18Size: 4.6 mm x 250 mmStationary phase: Octadecylsilane silica gel for chromatography (5 μm)Column temperature: 30ºCFlow rate: 1 mL / minInjection volume: 10 μLGradient elution:Time (min) Mobile Phase A Mobile Phase BComment (per cent V / V) (per cent V / V)0 – 5 80 20 Initial conditions5 – 6 80 → 25 20 → 75 Linear gradient6 – 12 25 75 Isocratic12 - 12.1 25 → 80 75 → 20 Return to initial conditionsSystem equilibration before injection: 8 minDetermination of Particle Size Distribution (PSD)Equipment: SYMPATEC model HELOS BR. Dry disperser: RODOS / M. Feeder:ASPIROS. Lent: R1 (< 35μm).Sample preparation: 30 mg in an Aspiros vial well closed.Measuring range:Density: 1.000 g / cm3Heywood shape factor: 1.000Calculation Mode: FREEForced stability: 0REMO: Not usedLimit curves: Not usedTrigger Conditions:Reference measurement: Duration 10 s Single / Time base 50.0 msNormal measurement start / stop trigger:Start: 0.000 s after opt. concentr. ≥ 1 %Valid: alwaysStop after: 2.000 s opt. concentr. ≤ 1 % or after 10.000 s real timeTrigger timeout: 60 sRepetition and seriesRepeat: 0 timesDisperser: RODOS / Type RODOS / MInjector: 4mmWith 0 cascade elementsPrimary pressure: 2.0 barFeeder: Type Aspiros / Aspiros speed 50 mm / sVacuum: Nilfisk / Delay 2 sDetermination of related substancesEquipment: HPLC Agilent 1290 Quaternary DAD HPLC System.Solvents and reagents: Methanol (MeOH), tetrabutylammonium bisulfate, acetic acid,water Milli-Q.Remark: Samples must be kept refrigerated at 5 º C. Solvents and Triethylamine (TEA), Methanol (MeOH), Phosphoric acid Reagents (H3PO4), Water Milli-Q (H2O) Sample preparation Blank Solution: MeOH Sample Solution: 1 mg / mL in MeOH 50 mg sample / 50 mL MeOH Reference Standard Solution (System Suitability Test): 1 mL Stock Sample Solution / 100 mL MeOH * 1 mL / 10 mL MeOH. to obtain a concentration of 1.0 μg / mL (it corresponds to a relative concentration of 0.1%). Reference Standard Solution spiked with impurities (Identification): 1 mg / mL in MeOH 5 mg Indacaterol Maleate Reference Standard spiked with impurities IND 05, IND 07 and IND 08 / 5 mL MeOH Mobile phase Mobile phase A: 3 mL TEA into 900 mL of Water Milli-Q,adjusted to pH=3.0 ± 0.1 with H3PO4:H2O (1:1). Raise up to 1000 mL and filter (0.45 μm).Mobile phase B: MeOHChromatographic System:Mode: LCDetector: UV - 260 nm, bandwidth 10 nmReference wavelength: 550 nm, bandwidth 100 nmColumn: Atlantis dC18Size: 4.6 mm x 15 mmStationary phase: Zorbax SB-phenyl; phenylsilyl silica gel for chromatography (3.5 μm)Column temperature: 25ºCFlow rate: 1 mL / minInjection volume: 10 μLGradient elution:Time (min) Mobile Phase A Mobile Phase BComment (per cent V / V) (per cent V / V)0 - 3 55 45 Initial conditions3 - 20 55 → 40 45 → 60 Linear gradient20 - 30 40 → 12 60 → 88 Linear gradient30 - 40 12 88 Isocratic40 – 40.1 12 → 55 88 → 45 Return to initial conditionsSystem equilibration before injection: 5 minIndacaterol Reference Standard spiked with below related impurities. Compound Relative Retention Relative ResponseTime (RRT) Factor (RRF)Indacaterol 1.00 1.00Impurity IND 05 1.59 1.00Impurity IND 07 1.98 0.74Impurity IND 08 0.97 0.34EXAMPLES The following non-limiting working examples further illustrate certain embodiments of the present invention. It will be understood that the micronization process of crystallineindacaterol acetate typically takes place with a partial retention of the product in themicronizer. Thus, the amount and yield of the product recovered from the micronizationprocess generally depends on the type of micronizer and has therefore not beenspecified in the following working examples.Comparative example 1. Preparation of micronized indacaterol acetate12 g of crystalline indacaterol acetate (D90: 100 µm) was micronized by jet milling atroom temperature (15-20 ºC) in a micro-macinazione “Jet Mill MC50 KX-BD 2” micronizerwith integrated GLOVE-BOX at a micronization pressure of 4 bar obtaining a particle sizedistribution D10: 0.5 µm, D50: 1.3 µm and D90: 3.6 µm.The micronized indacaterol acetate obtained was characterized by having 30% w / w ofamorphous content (measured by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”) and 11.4% w / w of acetic content (measured by HPLC).The micronized product was put placed in a laboratory porcelain opened capsule in aclimate chamber equipment “Climatic chamber BINDER KMF 115” at a temperature of25 ºC under humidity conditions of 90% HR for 9 days.After the conditioning step, the material was analyzed and more than 20% w / w ofamorphous content was present, as determined by Perfusion Microcalorimetry Perfusion“TAM IV Perfusion”. The acetic content in the sample, determined by HPLC assay“Agilent 1290 Quaternay DAD HPLC System”, was 9.2% w / w.Example 2. Preparation of micronized indacaterol acetate12 g of crystalline indacaterol acetate (D90: 100 µm) was micronized by jet milling at^15ºC / ^20ºC in a micro-macinazione “Jet Mill MC50 KX-BD 2” micronizer with integratedGLOVE-BOX at a micronization pressure of 4 bar obtaining a particle size distributionD10: 0.6 µm, D50: 1.6 µm and D90: 4.6 µm.The micronized indacaterol acetate obtained was characterized by having 19% w / w ofamorphous content (measured by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”) and 12.5% w / w of acetic content (measured by HPLC).The micronized product was put placed in a laboratory porcelain opened capsule in aclimate chamber “Climatic chamber BINDER KMF 115” at a temperature of 25 ºC underhumidity conditions of 90% HR for 4 days.After the conditioning step, the material was analysed and 13% w / w of amorphouscontent was present, as determined by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”. The acetic content in the sample, determined by HPLC assay “Agilent 1290Quaternay DAD HPLC System”, was 11% w / w.Example 3. Preparation of micronized indacaterol acetate12 g of crystalline indacaterol acetate (D90: 100 µm) was micronized by jet milling at^15ºC / ^20ºC in a micro-macinazione “Jet Mill MC50 KX-BD 2” micronizer with integratedGLOVE-BOX at a micronization pressure of 4 bar obtaining a particle size distributionD10: 0.6 µm, D50: 1.6 µm and D90: 4.6 µm.The micronized indacaterol acetate obtained was characterized by having 19% w / w ofamorphous content (measured by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”) and 12.5% w / w of acetic content (measured by HPLC).The micronized product was put placed in a laboratory porcelain opened capsule in aclimate chamber “Climatic chamber BINDER KMF 115” at a temperature of 25 ºC underhumidity conditions of 90% HR for 21 days.After the conditioning step, the material was analysed and 4.3% w / w of amorphouscontent was present, as determined by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”. The acetic content in the sample, determined by HPLC assay “Agilent 1290Quaternay DAD HPLC System”, was 10.5% w / w. In the Particle size distribution (PSD)determined by SYMPATEC “Particle size distribution with laser diffraction HELOS / BR”,a small increase was observed, with values of D50: 2.2 µm and D90: 4.9 µm.Example 4. Preparation of micronized indacaterol acetate10 g of crystalline indacaterol acetate (D90: 100 µm) was micronized by jet milling at^15ºC / ^20ºC temperature in a micro-macinazione “Jet Mill MC50 KX-BD 2” micronizerwith integrated GLOVE-BOX at a micronization pressure of 4 bar obtaining a particle sizedistribution D10: 0.6 µm, D50: 1.6 µm and D90: 4.2 µm.The micronized indacaterol acetate obtained was characterized by having 18.6% w / w ofamorphous content (measured by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”) and 13.2% w / w of acetic content (measured by HPLC).The micronized product was packaged in a transparent bag inside a closed aluminumbag,and placed in a climate chamber “Climatic chamber BINDER KMF 115” at atemperature of 50ºC under humidity conditions of 80% HR for 24 hours.After the conditioning step, the material was analysed and 1.6% w / w of amorphouscontent was present, as determined by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”. The acetic content in the sample, determined by HPLC assay “Agilent 1290Quaternay DAD HPLC System”, was 13.6% w / w. In the Particle size distribution (PSD)determined by SYMPATEC “Particle size distribution with laser diffraction HELOS / BR”,a small increase was observed, with values of D50: 1.6 µm and D90: 4.2 µm.Example 5. Preparation of micronized indacaterol acetate10 g of crystalline indacaterol acetate (D90: 68 µm) was micronized by jet milling at -^15ºC / ^20ºC temperature in a micro-macinazione “Jet Mill MC50 KX-BD 2” micronizerwith integrated GLOVE-BOX at a micronization pressure of 5 bar obtaining a particle sizedistribution D10: 0.5 µm, D50: 1.4 µm and D90: 3.6 µm.The micronized indacaterol acetate obtained was characterized by having 18.7% w / w ofamorphous content (measured by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”) and 13.2% w / w of acetic content (measured by HPLC).The micronized product was packaged in a transparent bag inside a closed aluminumbag, and placed in an air oven at a temperature of 60 ºC for 72 hours.After the conditioning step, the material was analysed and 1.1% w / w of amorphouscontent was present, as determined by Perfusion Microcalorimetry Perfusion “TAM IVPerfusion”. The acetic content in the sample, determined by HPLC assay “Agilent 1290Quaternay DAD HPLC System”, was 13.4% w / w. In the Particle size distribution (PSD)determined by SYMPATEC “Particle size distribution with laser diffraction HELOS / BR”,a small increase was observed, with values of D50: 1.7 µm and D90: 3.9 µm.Example 6. Preparation of micronized indacaterol acetate240 g of crystalline indacaterol acetate (D90: 40 µm) was micronized by jet milling at^15ºC / ^20ºC temperature in a HOSOKAWA ALPINE “Jet Mill 100 AS” micronizer withintegrated GLOVE-BOX at a micronization pressure of 3.6 bar obtaining a particle sizedistribution D10: 0.6 µm, D50: 1.7 µm and D90: 3.5 µm. The micronized indacaterol acetate obtained was characterized by having 3.9% w / w of amorphous content (measured by Perfusion Microcalorimetry Perfusio “TAM IVPerfusion”) and 13.2% w / w of acetic content (measured by HPLC).The micronized product was packaged in a transparent bag inside a closed aluminumbag, and placed in a climate chamber “Climatic chamber BINDER KMF 115” at atemperature of 50ºC under humidity conditions of 80% HR for 48 hours. After the conditioning step, the material was analysed and 0.4% w / w of amorphous content was present, as determined by Perfusion Microcalorimetry Perfusion “TAM IV Perfusion”. The acetic content in the sample, determined by HPLC assay “Agilent 1290Quaternay DAD HPLC System” was 13.1% w / w. In the Particle size distribution (PSD)determined by SYMPATEC “Particle size distribution with laser diffraction HELOS / BR”, a small increase was observed, with values of D50: 2.0 µm and D90: 4.0 µm.

Claims

CLAIMS1. A process for treating indacaterol acetate, comprising the steps of:a) providing indacaterol acetate with a particle size distribution (PSD)characterized by a first D90 of at least 25 μm and comprising not more than20% w / w of amorphous indacaterol acetate,b) micronizing indacaterol acetate at a temperature lower than 10 ºC to obtaina particle size distribution (PSD) characterized by a second D90 of equal toor below 10 µm andc) optionally, maintaining the indacaterol acetate of step (b):i. for at least 48 hours in an open environment with a relative humidity(RH) comprised between 30% and 85% and a temperature comprisedbetween 0°C to 30°C, or ii. for at least 6 hours in a closed environment having a relative humidity(RH) comprised between 0% and 90% and a temperature comprisedbetween 20°C and 60°C.

2. The process according to claim 1, wherein the second D90 is equal to or below 8µm, preferably the second D90 is equal to or below 6 µm.

3. The process according to anyone of claims 1 to 2, indacaterol acetate obtainedin step b) has a D50of equal to or below 6 µm, preferably a D50of equal to or below 5 µm.

4. The process according to any one of claims 1 to 3, wherein the micronization ofstep (b) is carried out at a pressure of equal to or below 8 bar, preferably at apressure of equal to or below 6 bar.

5. The process according to any one of claims 1 to 4, wherein the micronization ofstep (b) is carried out at a temperature of from ^30°C to 10°C.

6. The process according to any one of claims 1 to 5, wherein the micronization ofstep (b) is carried out at a temperature of from ^30°C to 0°C.

7. The process according to any one of claims 1 to 6, wherein the micronization ofstep (b) is carried out at a temperature of from ^30°C to ^5°C, preferably at atemperature of from ^30°C to ^15°C, most preferably of from -20ºC to -15ºC.

8. The process according to any one of claims 1 to 7, wherein micronizedindacaterol acetate is maintained in the conditioning step (c) for at least 96 hoursin an open environment.

9. The process according to any one of claims 1 to 7, wherein micronizedindacaterol acetate is maintained in the conditioning step (c) for at least 24 hoursin a closed environment.

10. The process according to any one of claims 1 to 9, wherein the first D90 is at least25 µm, at least 100 µm, preferably at least 200, more preferably at least 250 µm.

11. The process according to any one of claims 1 to 10, wherein the micronizedindacaterol acetate obtained in step (c) is characterized by having less than 15% w / w of amorphous content, preferably equal or less than 10% w / w of amorphous content, more preferably equal or less than 5% w / w of amorphous content, measured by microcalorimetry.

12. The process according to any one of claims 1 to 11, wherein the closedenvironment is obtained by confining the micronized indacaterol acetate obtained in step b) in a closed space limited by a material characterized by having amoisture barrier with a Water Vapour Transmission Rate (WVTR) of equal or lessthan 1.5 g / m2 / day at 38ºC / 90% RH, preferably of equal or less than 0.75 g / m2 / dayat 38ºC / 90% RH.

13. The process according to claim 12, wherein the closed space is created byconfining the micronized indacaterol acetate obtained in step b) in a material witha Water Vapour Transmission Rate (WVTR) of equal or less than 0.75 g / m2 / dayat 38ºC / 90% RH.

14. The process according to claim 13, wherein the material confining indacaterolacetate forms a packaging into which indacaterol acetated is packaged.

15. The process according to any one of claims 13 or 14, wherein the pack materialcomprises at least two bags, preferably a first closed inner bag and a secondclosed outer bag comprising at least an aluminium layer.

16. The process according to claim 15, wherein the outer bag is closed with closingmeans selected from the group of a clicky zipper and a heat induction seal.

17. The process according to any one of claims 1 to 16, wherein the micronizationstep (b) is carried out in the presence of one or more additional active ingredientsand / or excipients.

18. Indacaterol acetate obtainable by the process according to any one of claims 1to 17.

19. Indacaterol acetate according to claim 18, characterized in that it has anamorphous content below 10% by weight, preferably below 5%, more preferablybelow 1%, as measured by microcalorimetry.

20. Indacaterol acetate according to claim 19, having a particle size distribution(PSD) characterized by a D10 of 0.1 to 1.1 µm, a D50 of 1.2 to 2.5 µm and a D90of 3.0 to 5.0 µm.

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