DE102019133243A1 - Process for the production of spray-freeze-dried particles and correspondingly produced particles - Google Patents

Abstract

The invention relates to a method for producing spray-freeze-dried pharmaceutical particles, comprising the following steps: a) providing a solution comprising at least one pharmaceutical active ingredient and a solvent, b) spraying the solution into a cold environment, whereby solidified droplets are obtained, and c ) Removal of the solvent by atmospheric sublimation or vacuum freeze-drying, whereby spherical spray-freeze-dried particles are obtained, wherein in step a) the solvent is selected from tert-butanol, dimethyl sulfoxide, water and mixtures thereof and the solution has a solids content in the range of 1.5% to 60%, based on the total volume of the solution (m / V), and in step b) drops with a mean diameter in the range from 30 μm to 700 μm are generated and the drops in an environment with a temperature in the range of ≥ -100 ° C to ≤ 20 ° C µm.

Description

The present invention relates to a method for producing spray-freeze-dried particles.

The spray freeze drying process combines the advantageous properties of the spray drying and freeze drying drying processes established in the pharmaceutical industry. The combination of both processes, the processes with each other. Thermolabile substances are gently dried due to the low temperatures, while porous, spherical microparticles with good flow properties can be produced at the same time.

Various methods for spray-freeze drying of active pharmaceutical ingredients are known. Niwa et al., Chem Pharm Bull (Tokyo), 2012, 60 (7), 870-876 describe the spray freeze drying of cyclosporine. Here, solutions of the active ingredient in tert-butanol and the carrier mannitol in water are sprayed separately in liquid nitrogen, where they collide. The US 9,453,676 B2 describes a method of atmospheric spray-freeze drying, generally disclosing water, alcohols and mixtures thereof as solvents. The WO 2008/032327 A2 describes the spray drying of oil-in-water emulsions from organic solvents. The WO 2013 / 041542A1 describes the spray-freeze-drying of proteins, polypeptides, oligopeptides, peptides DNA, RNA using at least one cryoprotectant and at least one stabilizer from aqueous solution. Ali and Lamprecht also describe in the International Journal of Pharmaceutics 516, 170, 177, 2017, spray-freeze drying as an alternative technique for the lyophilization of polymeric and lipid-based nanoparticles.

The spray-freeze-drying of lipophilic and poorly soluble compounds, however, remains a challenge in the production of spray-freeze-dried pharmaceutical particles. In addition, lyophilizates are often obtained which do not have good flow properties. There is therefore still interest in improved methods for spray-freeze drying of active pharmaceutical ingredients.

The present invention was based on the object of providing a method which, in particular, allows the production of particles with improved flow properties.

1. a) Bereitstellen einer Lösung umfassend wenigstens einen pharmazeutischen Wirkstoff und ein Lösemittel,
2. b) Versprühen der Lösung in eine kalte Umgebung, wodurch erstarrte Tröpfchen erhalten werden, und
3. c) Entfernen des Lösemittels durch atmosphärische Sublimation oder Vakuum-Gefriertrocknung, wodurch sphärische sprüh-gefriergetrocknete Partikel erhalten werden, wobei in Schritt a) das Lösemittel ausgewählt ist aus tert.-Butanol, Dimethylsulfoxid, Wasser und deren Gemischen und die Lösung einen Feststoffgehalt im Bereich von ≥ 1,5 % bis ≤ 60 %, bezogen auf das Gesamtvolumen der Lösung (m/V) aufweist, und in Schritt b) Tropfen mit einem mittleren Durchmesser im Bereich von ≥ 30 µm bis ≤ 700 µm erzeugt werden und wobei die Tropfen in eine Umgebung mit einer Temperatur im Bereich von ≥ -100 °C bis ≤ 20 °C µm versprüht werden.

This object is achieved by a method for the production of spray-freeze-dried pharmaceutical particles, comprising the following steps,

1. a) providing a solution comprising at least one pharmaceutical active ingredient and a solvent,
2. b) spraying the solution in a cold environment, thereby obtaining solidified droplets, and
3. c) Removal of the solvent by atmospheric sublimation or vacuum freeze-drying, whereby spherical spray-freeze-dried particles are obtained, wherein in step a) the solvent is selected from tert-butanol, dimethyl sulfoxide, water and mixtures thereof and the solution has a solids content in the range from 1.5% to 60%, based on the total volume of the solution (m / V), and in step b) drops with a mean diameter in the range from 30 μm to 700 μm are generated and the drops be sprayed in an environment with a temperature in the range of ≥ -100 ° C to ≤ 20 ° C µm.

The method enables the production of porous, spherical, completely or partially amorphous particles. In particular, the spray-freeze-dried particles have a high sphericity and good flowability, which makes processing of the particles easier. In particular, by using tert-butanol as a solvent for producing the spray solution, lipophilic active ingredients and auxiliaries which are insoluble or poorly soluble in water or aqueous solution can be used and sprayed. Without wishing to be tied to a specific theory, it is assumed that the solids content of the sprayed solution and the droplet size have a significant influence on the resulting flowability of the spray-freeze-dried particles obtained. Another advantage is that the method offers the possibility of producing particles or amorphous solid dispersions for thermolabile active ingredients. This is not possible, for example, by melt extrusion due to the temperature and also only possible to a limited extent by spray drying.

The production of spray-freeze-dried particles or sphero-polyophilisates basically comprises the process steps of creating droplets, freezing the droplets and drying them. A solution containing an active ingredient and usually one or more auxiliaries is frozen by spraying in a very cold environment and then by means of sublimation in a vacuum or below Dried at atmospheric pressure. With a suitable spray head, for example a drop generator, a liquid jet is generated which, for example, experiences a uniform tear-off of the drops due to a piezoelectric pulse. The set jet of droplets can be directed into a spray tower, which is cooled from the outside, for example by a cold nitrogen flow. As a result, the drops freeze through very quickly. The particles frozen in this way are dried in a subsequent drying step. The particles frozen in this way can then be collected and lyophilized in the atmosphere or by means of vacuum freeze-drying. In atmospheric sublimation, the frozen droplets settle on a drying sieve due to the exit speed from the nozzle and the force of gravity, after which the drying process is initiated. The frozen droplets release the solvent into the gas flow by sublimation. After the solvent has been removed, a framework consisting of the solid components of the solution used remains.

A continuously operating spray-freeze-drying process is preferred. The method of spray freeze drying is, unless otherwise described, preferably according to the teaching of WO 2013/041542 A1 and the device and process parameters described there. Further parameters used in detail in the context of the present invention are set out in the examples.

The properties of the spray-freeze-dried particles produced in this way can in particular be adjusted via the composition of the sprayed starting solution. In particular, the solids concentration of the starting solution can have an influence on the shape and porosity of the particles. The spray settings usually show a somewhat smaller influence on particle formation. The freezing temperature influences the particle morphology and a temperature in the range of ≥ -100 ° C to ≤ -50 ° C has proven to be advantageous for a quick and gentle freezing step in aqueous solutions. In the case of solvents such as tert-butanol, which solidify at higher temperatures, a correspondingly higher freezing temperature is possible and a range from - 100 ° C to -20 ° C is preferred. Preferably, the spray freeze drying method uses cold air for the freezing step. Such a temperature range can be set by external cooling with liquid nitrogen. In particular, the temperature can be in the range from -60 ° C or -50 ° C to -20 ° C. A preferred temperature in each case, low enough to ensure the stability of the active ingredient through rapid freezing, can be determined by the person skilled in the art by means of simple experiments, whereby, depending on the drop speed, he provides that the drops are frozen before they hit the collecting container.

The average diameter of the spray-freeze-dried particles can be adjusted in particular through the specifications of the spray nozzle. In embodiments, the mean diameter of the drops in step b) is in the range from 50 μm to 500 μm, preferably in the range from 150 μm to 400 μm, preferably in the range from 200 μm to 400 μm. With the method described here, droplet diameters in this range achieved particles with preferred particle diameters D ₅₀ (volumetric) in the range from 30 μm to 500 μm, preferably in the range from 50 μm to 300 μm. A person skilled in the art will adapt corresponding openings of the spray nozzles. Replacing the orifice of a drop jet nozzle with a double diameter model can double the diameter of the drop when the stimulation rate is changed to double, which can result in a drop size difference of about 10%.

The solution can in principle comprise customary auxiliaries for spray freeze drying, for example selected from the group comprising mannitol, sucrose, lactose, trehalose, hydroxypropylmethyl cellulose (HPMC), hydroxypropylmethyl cellulose acetate succinate (HPMC-AS), low-viscosity hydroxypropyl cellulose (PVPyrrol), (PVPyrrol) ), Maltodextrin, dextran, anionic copolymers of methacrylic acid and methyl methacrylate (e.g. Eudragit E), and / or surfactants such as polyethylene glycol and its copolymers (e.g. polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer, available under the brand Soluplus®), polyoxyethylene (20 ) sorbitan monooleate (polysorbate 80) or polyoxyethylene (20) sorbitan monolaurate (polysorbate 20).

Furthermore, the spraying of a solution, in contrast to the spraying of a suspension, has proven to be essential for achieving the advantageous properties of the particles. Overall, the interaction of the droplet size, the solids content of the sprayed solution and the freezing temperature have proven to be advantageous influencing variables for the flowability of the particles obtained. Without wishing to be tied to a specific theory, it is assumed that the solids content of the solution plays an essential role here. The solids content is in the range from 1.5% to 60%, based on the total volume of the solution (m / V). The solids content can relate to the active ingredient or for in the event that the solution comprises at least one excipient in addition to the active ingredient, to active ingredient and excipient. At higher solids contents, compact particles result which are no longer sufficiently compact. Lower solids contents lead to particles with insufficient mechanical stability.

Unless otherwise stated, in the context of this application, concentration data are given in the form of the mass fraction in the solvent with the percentage value% (m / V).

Tert-butanol, dimethyl sulfoxide, water and mixtures thereof are preferred as solvents for spray freeze drying. In particular, tert-butanol can advantageously be used. Dimethyl sulfoxide can also advantageously be used. These solvents can also be used to spray-freeze-dry lipophilic active ingredients and auxiliaries such as celecoxib, fenofibrate, chloramphenicol and clotrimazole that are insoluble or poorly soluble in water or aqueous solution. If tert-butanol is used, higher drying temperatures can also be used. In contrast, water is preferred as the solvent for the production of spray-freeze-dried particles containing an active protein such as lysozyme.

In preferred embodiments, the solution comprises at least one auxiliary, preferably a stabilizer. In preferred embodiments, in step a) the solids content, for example of active ingredient and excipient, of the solution is in the range from 1.5% to 50%, preferably in the range from 3% to 25%, based on the total volume of the solution (m / V). The solids content of the solution is preferably in the range from 3% or 5% to 10%, 15% or 25%, based on the total volume of the solution (m / V). Solids contents of 10% (m / V) resulted in particles with good flow behavior. In particular, in the range from 5% to 25% (m / V) solids content, good results were achieved with regard to the sphericity and the flow behavior of the resulting particles. For the production of respirable particles, the solids content can be 1% to 1.5% (m / V), for the production of particles for tableting in the range of 20% to 40% (m / V).

In addition to the active ingredient, the solution can have at least one stabilizer as an auxiliary. In addition to the stabilizer, the solution can also contain an anti-freeze agent. In preferred embodiments, the auxiliary used is a stabilizer, in particular polyvinylpyrrolidone (PVP), and optionally an anti-freeze agent. The antifreeze agent is preferably selected from the group comprising mannitol and sucrose.

In the context of the present invention, the term “stabilizer” denotes a pharmaceutically acceptable excipient which gives the spray-freeze-dried particles or sphero-polyophilizates mechanical strength. The stabilizer can be selected from among hydroxypropylmethyl cellulose (HPMC), hydroxypropylmethyl cellulose acetate succinate (HPMC-AS), low-viscosity hydroxypropyl cellulose (HPC-SSL), polyvinylpyrrolidone (PVP), maltodextrin, dextran and / or anionic copolymers of methacrylic acid and / or methacrylic acid, for example ). A preferred stabilizer is polyvinylpyrrolidone (PVP). For example, an amount of stabilizer such as PVP in the solution, based on the total volume of the (m / V), from 0.75% up to 30%, for example from 0.75%, 1.5%, 5% or 7, 5%, resulting spray-dried particles with good mechanical properties. Under the electron microscope it was found that amorphous particles with a uniform surface and a low tendency towards holes, cracks and other imperfections can be obtained.

The term “anti-freeze” refers to pharmaceutically acceptable excipients, as they are commonly used in formulations that are subjected to freeze-drying in order to reduce the formation of ice crystals in the freezing droplet and to improve the subsequent reconstitution of the active ingredient solution. Such antifreeze agents can be, for example, alcohols, preferably polyalcohols such as mannitol, sorbitol and the like. The anti-freeze agent can also be a sugar, for example selected from sucrose and trehalose. A preferred alcohol as an anti-freeze agent is mannitol. A preferred sugar as an anti-freeze agent is sucrose. A particularly preferred anti-freeze agent is mannitol.

It may be preferred to use stabilizer and anti-freeze agent. The use of stabilizers and anti-freeze agents in a spray-freeze-drying process can enable the production of lyophilizate powders, the particles of which have good mechanical stability and good flow behavior. If the stabilizer and antifreeze agent are used, the stabilizer and antifreeze agents can be used in independent proportions. Spray-freeze-dried particles with very good sphericity and flowability were obtained using 0.75%, 5% and 7.5%, based on the total volume of the solution (m / V), of mannitol and polyvinylpyrrolidone. There can also be higher proportions to be used on antifreeze agents such as mannitol to stabilizers such as polyvinylpyrrolidone. It may be preferred to use higher proportions of polyvinylpyrrolidone than of mannitol if this has a positive effect on the solubility or the stability of the active ingredient.

In principle, many active pharmaceutical ingredients can be sprayed using the method described. Thus, the pharmaceutical active ingredient can be selected from the group comprising synthetic or natural compounds, in particular so-called small molecules, proteins, peptides, DNA, RNA, polysaccharides such as heparin, antibodies, insulin, or the like.

One advantage of using tert-butanol as a solvent is that, in particular, lipophilic active ingredients can also be spray-freeze-dried. Preferred active ingredients are selected from the group comprising celecoxib, fenofibrate, chloramphenicol and clotrimazole. For the production of spray-freeze-dried particles containing lipophilic active ingredients such as celecoxib, fenofibrate, chloramphenicol and clotrimazole, the particles are preferably dried by means of vacuum freeze-drying. To remove the solvent by means of vacuum freeze-drying, the frozen particles can be transferred to a customary freeze dryer and lyophilized using conventional drying times, for example from 24 to 48 hours and / or using a vacuum of 0.1 mbar to 1 mbar.

For the production of particles containing celecoxib, the proportion of active ingredient in the solution can be up to its maximum solubility in the solvent, in particular in the range from 2.5% to 10%, based on the total volume of the solution (m / V) . The proportion of stabilizer such as PVP in the solution can also be in the range from ≥ 2.5% to ≤ 10%, in particular in the range from ≥ 5% to ≤ 7.5%, based on the total volume of the solution (m / V) , lie.

Preferred protein active ingredients are selected from the group comprising lysozyme. Protein active ingredients are preferably sprayed using water as the solvent. Furthermore, protein active ingredients are preferably dried by means of atmospheric sublimation. Spraying from aqueous solution and atmospheric drying have proven to be advantageous for the spray-freeze-drying of protein active ingredients.

To remove the solvent by means of atmospheric sublimation, the frozen particles can be dried with a drying gas such as nitrogen or dry air, preferably in a temperature range from -20 to -5 ° C. Optionally, the drying step can be carried out continuously, for example by drying on a conveyor sieve or a sieve disk.

For the production of particles containing lysozyme, the proportion of active ingredient in the solution can be in the range from 0.5% to 5%, based on the total volume of the solution (m / V). The proportion of stabilizer such as mannitol in the solution can be in the range from ≥ 2.5% to ≤ 10%, in particular in the range from ≥ 5% to ≤ 7.5%, based on the total volume of the solution (m / V), lie.

Overall, the process allows the production of spray-freeze-dried particles with good sphericity, which can be referred to as sphero polyophilizates. Another subject matter of the invention relates to spray-freeze-dried particles, in particular produced by the method described above, the particles having a pharmaceutical active ingredient and at least one auxiliary, characterized in that the particles have a sphericity in the range from 0.75 to 1 and a powder sample of the particles has an angle of repose of ≤ 40 °.

The particles are preferably produced by means of spray freeze drying from a solution comprising tert-butanol, dimethyl sulfoxide, water or mixtures thereof, as described above. The particles show excellent flow properties, as a result of which a significant improvement in the handling of the lyophilizate powder can be provided during storage, such as in particular during administration. In the case of nasal, oral, buccal or sublingual administrations in particular, the particles are usually used in powder form for administration or reconstituted in solution immediately before administration, and good flow properties are essential for such administration. Flowable powders are also preferred for the production of lyophilizates to be administered parenterally, since their flowability simplifies their filling or storage as so-called “bulk” goods is possible.

The sphericity or roundness, which represents a dimensionless parameter of the particles, can be determined using image analysis methods, for example using a particle size measuring device such as a Camsizer X2 (Retsch Technology, Haan). Here, images of individual particles are recorded and evaluated over the whole. The calculation of the sphericity is carried out using the following formula: sphericity = (4 * π * particle area) / (particle circumference) ² . For the ideal case of a perfectly round particle, the sphericity value is 1. In preferred embodiments, the spray-freeze-dried particles have a sphericity in the range from 0.8 to 0.99, preferably in the range from 0.9 to 0 .99 or in the range from ≥ 0.93 to ≤ 0.98.

Good flowability enables clean and uniform filling and dosing of the spray-freeze-dried particles. An empirical method to determine the flowability of bulk materials is the determination of the angle of repose or repose. Both terms are used synonymously here. The angle of repose, also known as the angle of repose, is determined by pouring the powder sample loosely into a cone of repose. In the context of the invention, the angle of repose was measured according to the specifications of the European Pharmacopoeia (PhEur 2.9.36) using a funnel whose opening was 1.0 cm wide. A smaller angle of repose corresponds to a better flowability of the particles in the powder sample. In preferred embodiments, a powder sample of the spray-freeze-dried particles has an angle of repose of 35 ° or 30 °. The angle of repose can be in the range from 30 ° to 35 °. Particles with such angles of repose show excellent flowability.

In preferred embodiments, the spray-freeze-dried particles have a particle diameter D ₅₀ (volumetric) in the range from 30 μm to 500 μm, preferably in the range from 50 μm to 300 μm. The particles can also advantageously have a particle _{diameter D 50} in the range of 150 μm, 200 μm or 250 to 300 μm, 350 μm or 400 μm. Particles with a particle diameter D ₅₀ in these areas had very good flow properties and are accordingly suitable for nasal, oral, sublingual and buccal administration.

In preferred embodiments, the spray-freeze-dried particles comprise an active ingredient selected from the group comprising celecoxib, fenofibrate, chloramphenicol and clotrimazole.

Another subject matter is a pharmaceutical preparation or a medicament comprising spray-freeze-dried particles according to the invention, in particular spray-freeze-dried particles produced by the method described above. For the description of the spray-freeze-dried particles and the method, reference is made to the description above.

Unless otherwise stated, the technical and scientific terms used have the meanings commonly understood by one of ordinary skill in the art to which this invention belongs.

Examples and figures which serve to illustrate the present invention are given below.

• 1 in den 1a), b), c), d) die röntgenpulverdiffraktometrischen Reflexe der Substanzen Fenofibrat (FENO), Chloramphenicol (CHLOR), Clotrimazol und Celecoxib in ihrer kristallinen Form, das amorphe Signal von PVP, sowie unten die Signale der sprüh-gefriergetrockneten Partikel.
• 2 das Freisetzungsprofil einer physikalischen Mischung aus Celecoxib und Polyvinylpyrrolidon sowie diese enthaltende sprüh-gefriergetrocknete Partikel.
• 3 in 3a), b) und c) rasterelektronenmikroskopische Aufnahmen sprüh-gefriergetrockneter Partikel in 200facher Vergrößerung.
• 4 in 4a) den Tropfendurchmesser sprüh-gefriergetrockneter Partikel für verschiedene Feststoffkonzentrationen und Düsendurchmessern, in 4b) die jeweiligen Böschungswinkel.
• 5 den Durchfluss sprüh-gefriergetrockneter Partikel aufgetragen gegen den Feststoffanteil ermittelt mit einer Trichteröffnung von 10 mm.
• 6 den Durchfluss sprüh-gefriergetrockneter Partikel aufgetragen gegen den Feststoffanteil ermittelt mit einer Trichteröffnung von 6 mm.
• 7 in den 8a), b), c) und d) rasterelektronenmikroskopische Aufnahmen sprüh-gefriergetrockneter Partikel in 200facher Vergrößerung.
• 8 in den 8a), b), c), d) und e) rasterelektronenmikroskopische Aufnahmen sprüh-gefriergetrockneter Partikel in 200facher Vergrößerung.
• 9 eine rasterelektronenmikroskopische Aufnahme eines sprühgefriergetrockneten Partikels in 200facher Vergrößerung.
• 10 eine rasterelektronenmikroskopische Aufnahme eines sprühgefriergetrockneten Partikels in 200facher Vergrößerung.
• 11 die Stabilität von Lysozym in sprüh-gefriertrockneten Lysozympartikeln für die Vakuum-Gefriertrocknung (SFD) und für die atmosphärische Sublimation (aSFD), wiedergegeben durch den Prozentsatz an nicht-aggregiertem Protein in der jeweiligen Formulierung.

The figures show:

• 1 in the 1a), b ), c), d) the X-ray powder diffractometric reflections of the substances fenofibrate (FENO), chloramphenicol (CHLORINE), clotrimazole and celecoxib in their crystalline form, the amorphous signal from PVP, and below the signals from the spray-freeze-dried particles.
• 2 the release profile of a physical mixture of celecoxib and polyvinylpyrrolidone as well as spray-freeze-dried particles containing them.
• 3rd in 3a), b ) and c) scanning electron microscope images of spray-freeze-dried particles magnified 200 times.
• 4th in 4a) the droplet diameter of spray-freeze-dried particles for various solids concentrations and nozzle diameters, in 4b) the respective slope angles.
• 5 the flow rate of spray-freeze-dried particles plotted against the solids content is determined with a funnel opening of 10 mm.
• 6th the flow rate of spray-freeze-dried particles plotted against the solids content is determined with a funnel opening of 6 mm.
• 7th in the 8a), b ), c) and d) scanning electron microscope images of spray-freeze-dried particles magnified 200 times.
• 8th in the 8a), b ), c), d) and e) scanning electron microscope images of spray-freeze-dried particles magnified 200 times.
• 9 a scanning electron micrograph of a spray-freeze-dried particle magnified 200 times.
• 10 a scanning electron micrograph of a spray-freeze-dried particle magnified 200 times.
• 11 the stability of lysozyme in spray-freeze-dried lysozyme particles for vacuum freeze-drying (SFD) and for atmospheric sublimation (aSFD), represented by the percentage of non-aggregated protein in the respective formulation.

Material:

Fenofibrate, chloramphenicol, clotrimazole and celecoxib were obtained in pharmaceutical grade. Polyvinylpyrollidone (PVP, Kollidon® 25) was obtained from BASF, Ludwigshafen, Germany. D (-) - mannitol [Ph. Eur.] Was obtained from VWR International, Amsterdam, Netherlands. Tert-butanol [Ph. Eur.] Was obtained from Sigma. Ultrapure water was made with a MilliQ, Millipore Corp., Billerica, MA, USA.

Methods:

Spray Freeze Drying (SFD)

The spray freeze drying process used involved three steps: droplet generation, freezing and freeze drying. To generate the drops, a monodisperse drop generator (MTG-01-02, FMP Technologies GmbH, Erlangen, Germany) with a nozzle diameter of 100 μm (unless otherwise stated) was used on the spray tower. The freezing process was carried out by spraying solutions in cold air (-60 ° C to -100 ° C) in a cooled stainless steel spray tower, which was surrounded by a jacket cooled with liquid nitrogen. The solutions of active ingredient and excipients) were sprayed into the spray tower by means of the nozzle mentioned above. The drops froze in flight through the cold air and were collected as frozen particles after settling in a cooled sieve with a mesh size that was at least 50% below the particle diameter.

To remove the solvent by atmospheric sublimation, the particles were then dried in the same tower. The drying gas used was nitrogen or dry air, preferably in a temperature range from -20 to -5 ° C. for aqueous solutions, the drying gas being passed through a loose pile of ice particles until the sphero polyophilizates were dry. The dryness was measured by means of the residual content in the exhaust air and the process was stopped at approx. 20 ppm. Optionally, this drying step can be carried out continuously, by drying on a conveyor sieve or a sieve disc.

To remove the solvent by means of vacuum freeze drying, the particles were alternatively collected in a vessel at the lower end of the spray tower for the subsequent freeze drying. The frozen particles were lyophilized for 48 hours in an Alpha 1-4 LSC Plus freeze dryer (Martin Christ, Germany) at a vacuum of 0.1 mbar and a condenser temperature of -52 ° C. In the following, both processes are referred to as freeze-drying.

Scanning electron microscopic analysis (SEM):

A Hitachi SU3500 SEM (Hitachi Ltd., Tokyo, Japan) was used to view the surface morphology of the spray-freeze dried samples. The samples were attached to an aluminum plate with double-sided adhesive tape and coated with gold using a Polaron SC7640 sputter coater (Quorum Technologies Ltd., Newhaven, UK) in an argon atmosphere.

Dynamic differential calorimetry (DSC):

A Mettier Toledo DSC2 (Columbus, OH, USA) was used for the thermal analyzes. The calibration was carried out with indium as the standard. Non-hermetically sealed aluminum crucibles were filled with 5-10 mg sample and analyzed. After an equilibration time of 2 minutes at 25 ° C., the samples were heated to 110 ° C. in the case of fenofibrate and 170 ° C. for celecoxib, chloramphenicol and clotrimazole at 5 K / min. After that there was a cooling step back to 25 ° C. The evaluation of the melting peaks was carried out in the first heating cycle. The STARcsw 13.0 program was used to evaluate the results.

X-ray powder diffractometry (XRPD):

The X-ray powder diffractometry was carried out using an X'Pert Philips (X'Pert Philips Analytical B.V., Almelo, Netherlands) device. The following configuration was used: Transmission-Reflection-Spinner, scanned angular range from 4 ° 28 to 45 ° 28, generator input 40 mA and 45 kV. The data were processed with the PANalytical X'Pert HighScore Plus program, version 2.2.c.

Example 1: Production of spray-freeze-dried pharmaceutical particles comprising fenofibrate, chloramphenicol, clotrimazole and celecoxib

The active ingredients fenofibrate, chloramphenicol, clotrimazole and celecoxib were each dissolved in tert-butanol at a concentration of 5% (w / v) and the solutions were mixed with a concentration of 5% polyvinylpyrrolidone (PVP, Kollidon® 25). The solutions were sprayed into the spray tower as described above using a nozzle diameter of 100 μm by means of a nozzle in cold air (−100 ° C.) and then freeze-dried.

It was found that the spray-freeze-drying process from tert-butanol was successful with all of the drugs investigated. Scanning electron micrographs confirmed that spherical particles of fenofibrate, chloramphenicol, clotrimazole and celecoxib with rough surfaces were obtained. All particles showed a porous structure inside.

The melting point of the spray-freeze-dried particles and the pure active ingredients fenofibrate, chloramphenicol, clotrimazole and celecoxib as well as PVP was determined by means of differential calorimetry (DSC). As expected, the pure active ingredients showed a sharp melting point, while PVP showed no detectable melting point. In the case of the spray-freeze-dried particles, the particles with chloramphenicol, clotrimazole and celecoxib showed no detectable melting point, which indicates the presence of amorphous particles. The particles containing fenofibrate showed a weak but significant melting point, which suggests a partially crystalline structure. The structure of the particles was further investigated by means of X-ray powder diffractometry.

The 1 shows in the 1a), b ), c) and d) the specific reflexes of the pure substances fenofibrate (FENO), chloramphenicol (CHLORINE), clotrimazole and celecoxib in their crystalline pure form, the amorphous signal from PVP, and below the signals from the spray-freeze-dried particles. The particles with chloramphenicol, clotrimazole and celecoxib only show signals which indicate the presence of amorphous particles, while the diffractogram of the particles containing fenofibrate shows reflections of a partially crystalline fenofibrate structure.

Example 2: Investigation of the dissolution of spray-freeze-dried celecoxib particles

The release determination was carried out using a custom-made release apparatus. The release vessels were completely filled with a volume of 20.0 ml of the celecoxib particles produced according to Example 1. A phosphate buffer with pH 6.8, which was stirred with a paddle stirrer at 75 rpm, was selected as the medium. The spray lyophilized samples were added directly to the medium. An Agilent Cary 8454 UV-Vis spectroscope (Agilent Technologies, Santa Clara, CA, USA) at a wavelength of 255 nm (Celecoxib) was used to quantify the sample. For comparison, a physical mixture of 50% by weight celecoxib and 50% by weight polyvinylpyrrolidone was investigated. At different times in the range from 5 to 360 minutes, a 1.0 ml sample was taken, replaced by 1.0 ml fresh phosphate buffer and the sample was examined UV-metrically for the active ingredient content.

The 2 shows the release profile of the physical mixture of celecoxib and polyvinylpyrrolidone and the spray-freeze-dried particles. How to get the 2 As can be seen, the spray-freeze-dried particles showed up to 450% greater release compared to the physical mixture. Without being tied to a specific theory, it is assumed that this is based on the one hand on the highly porous structure of the spray-freeze-dried particles and on the other hand on the amorphous structure of the sprayed celecoxib. The PVP stabilized the supersaturation of the solution only slightly; after reaching the maximum, the content of dissolved celecoxib fell due to precipitation.

Example 3: Investigation of different solids contents with varying nozzle size

Solutions with different solids concentrations of polyvinylpyrrolidone (PVP, Kollidon® 25) and mannitol were each prepared in water and as described above using nozzle diameters of 20 µm, 50 µm or 100 µm by means of a nozzle in cold air (-100 ° C) in sprayed the spray tower and then freeze-dried. 3.1 Determination of the angle of repose and the sphericity

The angle of repose or repose angle measurement was carried out according to the recommended procedure described in the European Pharmacopoeia (Ph. Eur. 2.9.36) for determining the angle of repose. The evaluation was carried out using a photograph of the sample after it had been trickled onto a flat surface through a funnel. The fixed funnel was filled slowly and from the upper edge of the funnel in order to minimize the impact of the particles on the top of the sample. The position of the camera was chosen so that the lens was always in a plane with the smooth surface. The evaluation was carried out using an image processing program. Lines were drawn along the slope of the hill to determine the height from their intersection, as well as the base to determine the diameter of the conical base.

The sphericity was determined using the Camsizer X2 particle size measuring device (Retsch Technology, Haan). Here, images of individual particles were recorded and evaluated over the whole. The sphericity was calculated using the following formula: sphericity = (4 * π * particle area) / (particle circumference) ² .

The mean droplet diameter and the width of the particle size distribution (SPAN) were also determined. The volumetric D50 value was determined from the sum of all individual particle measurements, and the span representing the polydispersity was determined using the standard calculation used in the Camsizer X2.

The following table 1 summarizes the compositions used, nozzle openings, as well as the specific slope angles, sphericity, droplet diameter and width of the particle size distribution (SPAN): Table 1: Parameters of the particles with different solids content: sample PVP [% (w / V)] Mannitol [% (w / V)] Nozzle opening [µm] Slope angle [°] D ₅₀ [µm] SPAN Sphericity 1 0.75 0.75 100 37.03 ± 0.55 210.44 0.625 0.908 2 1.5 1.5 100 36.46 ± 2.46 273.12 0.487 0.933 3rd 2.5 2.5 100 32.69 ± 8.72 300.77 0.498 0.935 4th 5 5 100 31.58 ± 0.42 302.21 0.458 0.955 5 7.5 7.5 100 28.37 ± 1.70 380.85 0.389 0.959 6th 0.75 0.75 50 45.72 ± 2.26 134.78 0.993 0.804 7th 1.5 1.5 50 46.86 ± 0.34 225.96 0.623 0.941 8th 2.5 2.5 50 44.55 ± 1.61 199.45 0.628 0.922 9 5 5 50 37.48 ± 0.11 183.27 0.669 0.934 10 7.5 7.5 50 32.78 ± 1.65 195.16 0.640 0.943 11 0.75 0.75 20th 51.62 ± 1.04 135.1 0.791 0.827 12th 1.5 1.5 20th 50.92 ± 4.47 133.21 0.834 0.762 13th 2.5 2.5 20th 45.84 ± 0.43 166.01 0.592 0.938 14th 5 5 20th 42.21 ± 1.08 157.72 0.582 0.920 15th 7.5 7.5 20th 37.10 ± 1.23 190.70 0.537 0.948 The 3a), b ) and c) show scanning electron microscope images of the particles from samples 4, 5 and 10 magnified 200 times. How to get the 3rd removed, the particles showed a spherical shape and good porosity.

The 4a) shows the drop diameter of Examples 1 to 15 for various solids concentrations and nozzle diameters, the 4b) the respective slope angles. How to get the 4th particularly, particles produced from solutions with a solids content of 5% to 15% (m / V) and an average droplet diameter of more than 150 μm showed a good angle of repose.

Determination of the flow behavior

The flowability of the 15 samples was measured on an ERWEKA granulate flow tester with a funnel opening of 10 mm. The samples were each weighed to 0.250 g on an analytical balance and measured. Samples that did not flow were marked with "#na". The measurement was carried out according to the specifications of the European Pharmacopoeia (PhEur 2.9.16) with a funnel with an opening 1.0 cm wide.

The 5a) and 5b) show the flow of the samples plotted against the solids content determined with a funnel opening of 10 mm. The results are reported in seconds per 0.250 g sample. How to get the 5 In particular, particles produced from solutions with a solids content of 5% (m / V) and more showed good flow behavior, even with small nozzle diameters or particle sizes. In addition, they had good mechanical stability.

The measurement of the flowability was repeated using a 0.6 cm funnel opening instead of a 1.0 cm funnel opening. The entire sample mass was measured in each case. A tared bowl was placed in the collection area of the flow tester so that the powder mass that had flowed could then be precisely weighed. The 6a) and 6b) show the flow rate of the samples plotted against the solids content determined with a funnel opening of 6 mm. The results are reported in seconds per 0.250 g sample. How to get the 6th removed, the measurement with a smaller funnel opening confirmed the good flow behavior of the particles produced from solutions with a solids content of 5% (m / V) and more.

Example 4: Determination of the maximum solids content

Solutions with different solids concentrations of polyvinylpyrrolidone (PVP, Kollidon® 25), mannitol, sucrose or mixtures thereof were each prepared in water and, as described above, using a nozzle diameter of 100 μm by means of a nozzle in cold air (-100 ° C) in the Spray tower sprayed and then freeze-dried.

The slope angle was determined as described in Example 3.1 using the method described in the European Pharmacopoeia (Ph. Eur. 2.9.36), and the sphericity was determined using the Camsizer X2 particle size measuring device (Retsch Technology, Haan). The mean droplet diameter and the width of the particle size distribution (SPAN) were also determined as described under Example 3.1.

The following table 2 summarizes the compositions used, as well as the determined slope angles, sphericity, droplet diameter and width of the particle size distribution (SPAN): Table 2: Parameters of the particles with a high solids content: sample PVP [% (w / V)] Mannitol [% (w / V)] Sucrose [% (w / v)] Slope angle [°] D ₅₀ [µm] SPAN Sphericity 16 - 23 - 29.97 ± 7.34 392.07 0.700 0.910 17th 30th - 30th 34.58 ± 3.30 444.56 0.960 0.840 18th 30th 20th - not definable 787.67 2.003 0.720 19th 20th 20th - 30.30 ± 0.07 489.00 0.921 0.863

The 7a), b ), c) and d) show scanning electron microscope images of the particles from samples 16, 17, 18 and 19 magnified 200 times. How to use Table 2 and the 7th removed, the particles Samples 16, 17 and 19 showed a good spherical shape. The particle of sample 17 with a solids content of 60% (w / v) showed good sphericity and an already quite compact surface. While the angle of repose of the sample with a higher proportion of stabilizer compared to antifreeze could not be determined, showed the sample with 20% (w / v) stabilizer and antifreeze agent each had a good angle of repose and moderately good sphericity.

Example 5: Determination of different concentrations of active ingredients and auxiliaries in tert-butanol

Solutions with different solids concentrations of polyvinylpyrrolidone (PVP, Kollidon® 25) and the active ingredient celecoxib were each prepared in tert-butanol and, as described above, using a nozzle diameter of 200 μm by means of a nozzle in cold air (-100 ° C) in the Spray tower sprayed and then freeze-dried. The determination of the angle of repose, the sphericity, the mean droplet diameter and the width of the particle size distribution (SPAN) were carried out as described under Example 3.1.

The following table 3 summarizes the compositions used, as well as the specific slope angles, sphericity, droplet diameter and width of the particle size distribution (SPAN): Table 3: Parameters of the particles with different concentrations of active ingredients and excipients: sample PVP [% (w / V)] Celecoxib [% (w / V)] Slope angle [°] D ₅₀ [µm] SPAN Sphericity 20th 5 2.5 35.60 ± 1.81 230.72 0.508 0.946 21 5 5 34.62 ± 5.39 337.75 0.690 0.883 22nd 5 7.5 30.39 ± 2.35 380.61 0.919 0.894 23 2.5 5 28.94 ± 2.39 350.16 0.546 0.956 24 7.5 5 32.42 ± 0.35 376.58 0.625 0.933

The 8a), b ), c), d) and e) each show scanning electron microscope images of the particles of samples 20, 21, 22, 23 and 24 magnified 200 times. How to use the Table 3 and the 8th removed, Samples 20 to 24 showed good sphericity, angle of repose, and good particle porosity.

Example 6: Use of hydroxypropyl cellulose as a stabilizer

A solution of 5% (w / V) low-viscosity hydroxypropyl cellulose (HPC-SSL) and 5% (w / V) Celecoxib was prepared in tert-butanol and, as described above, using a nozzle diameter of 200 μm by means of a nozzle in cold air (- 100 ° C) sprayed into the spray tower and then freeze-dried. Angle of repose, sphericity, mean droplet diameter and width of the particle size distribution (SPAN) were determined as described under Example 3.1.

The following table 4 summarizes the composition used, as well as the determined slope angle, sphericity, droplet diameter and width of the particle size distribution (SPAN): Table 4: Parameters of the particles using hydroxypropyl cellulose: sample HPC-SSL [% (w / V)] Celecoxib [% (w / V)] Slope angle [°] D ₅₀ [µm] SPAN Sphericity 25th 5 5 33.40 ± 0.65 676.27 1.502 0.804

The 9 shows the scanning electron micrograph of a spray-freeze-dried particle of sample 25 magnified 200 times. How to use the Table 4 and the 9 removed, the sample 25 showed a good angle of repose, sufficient sphericity and good particle porosity. This shows that hydroxypropyl cellulose can also be used as a stabilizer in tert-butanol with good results.

Example 7: Spray freeze drying with atmospheric sublimation

A solution of 5% (w / V) PVP and 5% (w / V) Celecoxib was prepared in tert-butanol and placed in cold air (- 100 ° C) as described above using a nozzle diameter of 200 µm. sprayed into the spray tower. After settling, the frozen particles were collected in a cooled vessel at the lower end of the spray tower on a sieve with a mesh size of 20 μm dried by means of atmospheric sublimation. The frozen particles were left in the same tower for 60 hours and ^{lyophilized with nitrogen at a gas flow of 60 1 min -1} and a temperature of 15 ° C. Angle of repose, sphericity, mean droplet diameter and width of the particle size distribution (SPAN) were determined as described under Example 3.1.

The following table 5 summarizes the composition used, as well as the determined slope angle, sphericity, droplet diameter and width of the particle size distribution (SPAN): Table 5: Parameters of the particles using atmospheric sublimation: sample PVP [% (w / V)] Celecoxib [% (w / V)] Slope angle [°] D ₅₀ [µm] SPAN Sphericity 26th 5 5 36.20 ± 1.41 380.33 0.63 0.87

The 10 shows the scanning electron micrograph of a particle of sample 26 dried by atmospheric sublimation, magnified 200 times. How to use the Table 5 and the 10 removed, the sample 26 showed a good angle of repose, sufficient sphericity and good particle porosity. This shows that good results were also achieved with atmospheric sublimation, which are comparable to sublimation using vacuum.

Example 8: Spray-freeze-drying of a protein by means of atmospheric sublimation and vacuum-freeze-drying

A solution of 5% (w / v) mannitol, 2.5% (w / v) Kollidon® 12 PF and 1% (w / v) lysozyme was prepared in water and as described above using a nozzle diameter of 200 μm by means a nozzle in cold air (- 100 ° C) in the spray tower. After settling, the frozen particles were collected in a cooled vessel at the lower end of the spray tower on a sieve with a mesh size of 20 μm and dried by means of atmospheric sublimation. The frozen particles were left in the tower for 24 hours and ^{lyophilized with nitrogen at a gas flow of 60 L min -1} and a temperature of -10 ° C.

In a parallel experiment, the solution was sprayed under identical conditions and to remove the solvent by means of vacuum freeze drying, the frozen particles were collected in a vessel at the lower end of the spray tower and transferred to an Alpha 1-4 LSC Plus freeze dryer (Martin Christ, Germany) and lyophilized for 24 hours at a vacuum of 0.1 mbar.

It was then determined how much aggregate or how much remaining monomer of the protein can be obtained from the formulation after reconstitution with water. This was determined by size exclusion chromatography (or gel permeation chromatography) using an AdvanceBio SEC 300Å 7.8 x300 mm column, in a Waters 2996 photodiode array (UV-Vis) detector at 280 nm, at a flow rate of 0.5 ml / min using a 200 mM phosphate buffer, pH 7.0.

The 11 shows the yield of spray-freeze-dried lysozyme particles for vacuum freeze-drying (SFD) and for atmospheric sublimation (aSFD). How to get the 11 taken, a significantly higher stability of the protein active ingredient was achieved with the freeze-spray drying of the protein active ingredient lysozyme using atmospheric sublimation.

Overall, the results show that spray-freeze-dried pharmaceutical particles from a solution in tert-butanol or water with a solids content of active ingredient and excipient in the range from 1.5% to 60% (m / V) an average diameter of 30 μm to 500 µm can be produced with good sphericity and flowability.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 9453676 B2 [0003]
• WO 2008/032327 A2 [0003]
• WO 2013/041542 A1 [0003, 0009]

Non-patent literature cited

• Niwa et al., Chem Pharm Bull (Tokyo), 2012, 60 (7), 870-876 [0003]

Claims (10)

A method for producing spray-freeze-dried pharmaceutical particles, comprising the following steps, a) providing a solution comprising at least one pharmaceutical active ingredient and a solvent, b) spraying the solution into a cold environment, whereby solidified droplets are obtained, and c) removing the solvent by atmospheric sublimation or vacuum freeze-drying, whereby spherical spray-freeze-dried particles are obtained, characterized in that in step a) the solvent is selected from tert-butanol, dimethyl sulfoxide, water and mixtures thereof and the solution has a solids content in the range of ≥ 1.5% to 60%, based on the total volume of the solution (m / V), and in step b) drops with a mean diameter in the range from 30 μm to 700 μm are generated and the drops in a Environment with a temperature in the range of ≥ -100 ° C to ≤ 20 ° C µm. Procedure according to Claim 1 , characterized in that in step a) the solids content of the solution is in the range from 1.5% to 50%, preferably in the range from 3% to 25%, based on the total volume of the solution (m / V) . Procedure according to Claim 1 or 2 , characterized in that the mean diameter of the droplets in step b) is in the range from µm 50 µm to 500 µm, preferably in the range from 150 µm to 400 µm, preferably in the range from 200 µm to 400 µm . Method according to one of the preceding claims, characterized in that the solution comprises at least one auxiliary substance, preferably a stabilizer, in particular polyvinylpyrrolidone (PVP), and optionally an anti-freeze agent, preferably selected from the group comprising mannitol and sucrose. Spray-freeze-dried particles, in particular produced by a method according to one of the Claims 1 to 4th , the particles having a pharmaceutical active ingredient and at least one excipient, characterized in that the particles have a sphericity in the range from ≥ 0.75 to 1 and a powder sample of the particles has an angle of repose of 40 °. Spray-freeze-dried particles after Claim 5 , characterized in that the particles have a sphericity in the range from ≥ 0.9 to ≤ 0.99 or in the range from ≥ 0.93 to ≤ 0.98. Spray-freeze-dried particles after Claim 5 or 6th , characterized in that a powder sample of the particles has an angle of repose of ≤ 35 ° or ≤ 30 °. Spray-freeze-dried particles according to one of the Claims 5 to 7th , characterized in that the particles have a particle _{diameter D 50} (volumetric) in the range from 30 µm to 500 µm, preferably in the range from 50 µm to 300 µm. Spray-freeze-dried particles according to one of the Claims 5 to 7th , characterized in that the particles comprise an active ingredient selected from celecoxib, fenofibrate, chloramphenicol and clotrimazole. A pharmaceutical preparation comprising spray-freeze-dried particles according to one of the Claims 5 to 9 .

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