HUP0003207A2 - Proliposome powders for inhalation stabilised by tocopherol, pharmaceutical compositions containing the same and the use of them - Google Patents

Abstract

The subject of the invention is proliposome powders, particularly suitable for inhalation purposes - the individual particles of which contain (1) a biologically active substance in a single phase; (2) tocopherol in the proportion necessary for stabilization; and (3) a lipid or a mixture of lipids with a phase transition temperature below 37 °C - a process for their preparation - which consists of dissolving components and lyophilizing the solution under controlled conditions - and forming pharmaceutical preparations containing them. HE

Description

S.B.G.&&. ·: 4^.*.3.á47’RAZ

International ······

Patent Office

H 1062 Budapest, Andrássy út H 3.

Phone: 34-24-950, Fax: 34-24-32^

Tocopherol-stabilized proliposome powders for inhalation \

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The invention relates to proliposome powders particularly suitable for inhalation purposes, a process for their preparation, pharmaceutical compositions containing proliposome powders and their use.

Liposomes are membrane-like vesicles composed of a series of concentric lipid bilayers with alternating hydrophilic interior spaces (compartments). Liposomes can be prepared from a wide variety of natural and artificial lipids, including phosphoglycerolipids, sphingolipids, and digalactosylglycerolipids. One of the main uses of liposomes is as a carrier for various pharmaceutical agents, with the aim of delivering the drug to its target site more efficiently and, in some treatments, minimizing side effects. The drug agents can be encapsulated in liposomes or hydrophilic compartments (this is the case for water-soluble drugs), or the lipid bilayer can encapsulate the drug, which in this case is lipophilic.

One of the major problems with liposomal formulations in pharmaceuticals is long-term stability. The stability of aqueous liposome dispersions is quite limited, which may be due to aggregation, loss of active substance from the shell to the external phase, chemical decomposition of the active substance or the fatty substance, etc. However, all these problems can be significantly overcome by using solid formulations. Such solid formulations may comprise liposome powders, i.e. dry liposome dispersions, or proliposome powders.

WO 96/19199 discusses the literature on liposomes and proliposomes in considerable detail and describes a proliposome powder. The powder consists of a single phase but discrete particles which, in addition to the biologically active component, contain a lipid or lipid mixture having a phase transition temperature (T 1 ) below 37 °C.

Recently, we have found that the stability of the proliposome powder disclosed in WO 96/19199 can be significantly increased.

The invention therefore provides a proliposome powder whose discrete particles contain in a single phase (1) a biologically active substance; (2) tocopherol in a proportion necessary for stabilization; and (3) a lipid or lipid mixture having a phase transition temperature below 37°C.

The tocopherol is preferably α-tocopherol, and more preferably racemic α-tocopherol.

The powder is particularly suitable for use in inhalation pharmaceutical compositions.

A single-phase powder can be described in other words as a homogeneous, molecular mixture of a biologically active component, a lipid or lipid mixture with a phase transition temperature below 37 °C, and tocopherol.

It is intended to be clear that the terms single phase and •5 7.364/RÁZ homogeneous molecular mixture are understood to mean that neither the active ingredient nor the lipid or tocopherol form a separate crystalline phase in the powder of the invention.

The single-phase powder can be inhaled directly, and liposomes are formed in situ, i.e. in the upper or lower respiratory tract, which include the biologically active component.

In general, any amphipathic lipid or lipid mixture that is suitable for the preparation of liposomes by known methods can be used for the compositions of the invention. However, it is an important requirement that the phase transition temperature of the lipid or lipid mixture be below body temperature, i.e. 37 °C, since this is a condition for the proliposome powder preparation to be able to hydrate under physiological conditions, i.e. liposomes to be formed in the respiratory tract. The phase transition temperature of different lipid mixtures can be easily determined by known methods — such as differential scanning calorimetry [see, for example, J. Suurkuusk et al.: Biochemistry 15(7), 1393 (1976)]. In general, it can be said that any natural or synthetic lipid — including mixtures thereof — if its phase transition temperature is below 37 °C can be used for the implementation of the invention.

Examples of potentially suitable natural and synthetic lipids include natural and synthetic phosphoglycerolipids, sphingolipids and digalactosylglycerolipids. Natural lipids include sphingolipids such as sphingomyelin (SM), ceramide and cerebroside;

69.364/RÁZ galactosylglycerolipids, such as digalactosyldiacylglycerol (DGalDG); phosphoglycerolipids, such as egg yolk phosphatidylcholine (ePC) and soy phosphatidylcholine (sPC); and lecithins, such as egg yolk lecithin (e-lecithin) and soy lecithin (s-lecithin). Synthetic lipids include, for example, dimyristoylphosphatidylcholine (DMPC), dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC), dilaurylphosphatidylcholine (DLPC), l-myristoyl-2-palmitoylcholine (MPPC), l-palmitoyl-2-myristoylcholine (PMPC) and dioleoylphosphatidylcholine (DOPC). Among the lipid mixtures, the following can be mentioned: SM/PC, SM/cholesterol, ePC/cholesterol, sPC/cholesterol, PC/PS/cholesterol, DMPC/DPPC, DMPC/DPPC/CH,

DMPC/CH, DPPC/DOPC, DPPC/DOPC/CH, DLPC/DPPC, DLPC/DPPC/CH,

DLPC/DMPC, DLPC/DMPC/CH, DOPC/DSPC, DPSM/DMSM, e-lecithin/cholesterol and s-lecithin/cholesterol. In addition, any of the above may also contain charge-carrying lipids, which may be selected from, for example, dimyristoylphosphatidylglycerol (DMPG), dipalmitoylphosphatidylglycerol (DPPG), dimyristoylphosphatidic acid (DMPA), dipalmitoylphosphatidic acid (DPPA) or stearylamine (SA).

Lipids of particular interest for the purposes of the invention include, for example, DPPC and/or DMPC. Mixtures of DPPC and DMPC are also included, of which mixtures containing at least 10% by weight, for example 10-50% DMPC, are preferred. Particularly preferred mixtures of DPPC and DMPC are those which also contain at least one of the charge-carrying lipids, such as DMPG, DPPG, DMPA and SA, in a proportion not exceeding 5% by weight6' ^?í . 364/RÁZ ban. Preferred mixtures are also those which contain DPSM and DMSM and optionally at least one charge-carrying lipid, and mixtures of cholesterol with either e-lecithin or s-lecithin, optionally containing at least one charge-carrying lipid and having a T _c value below 37 °C. A skilled person can easily select mixtures other than these based on the data available in the literature [see, for example, Gregor Gevc: Phospholipids Handbook, Marcel Dekker, New York (1993), pp. 427-435].

The tocopherol is preferably present in an amount of between 0.05% and 1.0%, more preferably in an amount of between 0.1% and 0.6%, based on the total weight of the single-phase system comprising the lipid or lipids and the biologically active component.

The molecular structure of the active ingredient is preferably such that it allows the compound to be distributed in the lipid bilayer, as this facilitates the formation of liposomes encapsulating the active ingredient upon hydration. A suitable example of such a molecular structure is a fatty acid ester, the long hydrocarbon chain of which functions as a hydrophobic anchoring element.

The selection of the appropriate active ingredient is not a problem for those skilled in the art, and may include, for example, anti-inflammatories, bronchodilators, antihistamines, cyclooxygenase inhibitors, leukotriene synthesis inhibitors, leukotriene antagonists, phospholipase A2 (PLA2) inhibitors, platelet activating factor (PAF) antagonists and asthma prophylactics. In addition to the above, antiarrhythmics, tranquilizers, cardiac glycosides, hormones, antihypertensives, antidiabetic agents, antiparasitic and antitumor agents, sedatives, analgesics, antibiotics, antirheumatic agents, immunotherapeutic agents, antifungal agents, hypertensives, vaccines, antiviral agents, proteins, peptides and vitamins.

More specifically, the range of active ingredients that can be used in the form of the compositions according to the invention includes, for example, the following: glucocorticosteroids, such as budesonide, fluticasone propionate, ciclesonide, rofleponide, e.g. in the form of palmitate, mometasone, e.g. as its furoate, tipredane, RPR 106541, dexamethasone, betamethasone, fluocinolone, flumethasone, triamcinolone acetonide, flunisolide, beclomethasone, pregnane-16,17-acetal derivatives and compounds derived therefrom, and β-2 agonists, such as terbutaline, salmeterol, salbutamol, formoterol, fenoterol, clenbuterol, procaterol, bitolterol and broxaterol. The active ingredient component may also be a mixture of pharmaceutical active ingredients, for example a mixture of a glucocorticosteroid and a bronchodilator such as formoterol, salmeterol, terbutaline or salbutamol. For the avoidance of doubt, it is noted that when an active ingredient is mentioned herein, it is intended to include pharmaceutically acceptable esters, salts and hydrates of the compound in question.

In cases where the active ingredient is a steroid, an ester thereof is preferably used.

Preferably, the active ingredient component is a steroid, particularly preferably a steroid which has a saturated group of at least 8, but for example at least 10 or at least 12 carbon atoms in the 21-position.

69.364/RAZ

or is esterified with an unsaturated fatty acid. The number of carbon atoms in the fatty acid in question may be up to 24, or may be, for example, 20 or 18 carbon atoms. More preferably, the active ingredient is a steroid 21-palmitate, myristate, laurate, decanoate, octanoate or stearate. The most preferred active ingredient according to the invention is (22R)-16α,17α-(butylidenedioxy)-6α,9α-difluoro-lip-hydroxy-21-(palmitoyloxy)-pregn-4-ene-3,20-dione, also known as rofleponide palmitate.

In the case where the active ingredient is an ester, it is necessary that it be hydrolysable to the actual active ingredient. Surprisingly, we have found that the single phase proliposome powder of the invention facilitates the necessary hydrolysis to occur in situ, whereas esters in the crystalline state are usually not hydrolysable in this manner.

In the case where it is intended to be used for inhalation purposes, the proliposome powder according to the invention should, as far as possible, consist of particles or agglomerates of such particles with a diameter of less than 10 μm, for example 0.01-10 μm, or between 0.1 and 6 μm, for example 0.1-5 μm. Preferably, at least 50% of the powder composition consists of particles with a particle size within the specified range. Thus, for example, preferably at least 60%, more preferably 70%, but particularly preferably 80%, and very particularly preferably at least 90% of the powder composition consists of particles or agglomerates thereof whose size is within the desired range.

It is not necessary for the proliposome powder of the invention to contain other ingredients, however, the proliposome powder of the invention

Pharmaceutical preparations prepared using 69.364/RAZ powders may contain other pharmaceutically acceptable additives, such as enhancers, diluents or carriers. These can be added to the proliposome preparation after micronization or before micronization, provided that the solvent has been completely removed beforehand. The other carriers are preferably crystalline, hydrophilic materials. A preferred carrier is, for example, crystalline lactose monohydrate. Other suitable carriers include, but are not limited to, glucose, fructose, galactose, trehalose, sucrose, maltose, raffinose, maltitol, melezitose, stachyose, lactitol, palatinite, starch, xylitol, mannitol, myoinositol or the like, hydrates thereof, and amino acids, for example, alanine and betaine.

The amount of additives present in the composition may vary widely, since under certain circumstances very little, if any, additive is required to improve the properties of the powder composition for inhalation use, but it may often be advantageous to dilute the powder. In the latter case, additives may constitute at least 50%, for example at least 70% or at least 80% of the composition, with the remainder being proliposome powder. The proportion of additives may also depend on the potency of the biologically active component and the amount of powder composition considered optimal for inhalation use.

In cases where an additive, such as a carrier, is also present in the pharmaceutical composition, it either consists entirely of particles of only respirable particle size, or the carrier has a coarser particle size, for example the particles have a center of gravity of

364/RAZ, their diameter is greater than 20 μπι, or the smaller particles of the carrier may form agglomerates, the particles of which agglomerate have a diameter greater than 20 μπι, measured at the center of mass, for example, and thus in any case the proliposome and the carrier form a so-called ordered mixture.

A further object of the invention is to provide a process for producing the proliposome powder of the invention, i.e. a process resulting in a single-phase proliposome powder.

Consequently, in addition to the above, the invention relates to a method for preparing a proliposome powder for inhalation purposes, which comprises dissolving a lipid or a mixture of different lipids with a phase transition temperature below 37°C, tocopherol and a lipophilic biologically active component in a solvent; freezing the solution to form a glassy mass consisting of a single lipid phase embedded in a crystalline solvent, the freezing being carried out at a temperature below the phase transition temperature of the lipid phase; and evaporating the frozen solvent at a temperature below the phase transition temperature of the lipid phase.

Freezing the solution and evaporating the solvent can be carried out by conventional methods, for example in a conventional lyophilization apparatus. For example, the procedure can be followed by loading the solution containing the lipid(s), tocopherol and biologically active component into the compartments of the lyophilization apparatus, lowering the temperature until the solution freezes, and then reducing the pressure in the lyophilization chamber to remove the solvent.

69.364/RÁZ evaporate, and finally the resulting powder can be scraped off the wall of the lyophilization chamber and, if necessary, passed through a sieve.

The lyophilized powder may, if necessary, be subjected to further processing operations to obtain particles of respirable particle size, for example, micronization in a gas jet mill, thereby producing a respirable particle size powder formulation.

The solution containing the biologically active component, tocopherol and lipid(s) is frozen in such a way that a lipid mass consisting of a single phase is formed when embedded in the frozen solvent. The formation of a single phase mass can be controlled by the final temperature and the rate of freezing of the solution, the optimum freezing rate for any solution being somewhere between the time required for crystallization of the solvent in question and the time required for crystallization of the lipid(s), tocopherol and the biologically active component, and should not present any difficulty to the skilled person to determine this simply by trial and error. The optimum final temperature corresponds to a value about 10-20 °C lower than the glass transition temperature of the lipid phase. A suitable method for monitoring crystallinity is, for example, the X-ray powder diffraction method, while the proportion of the biologically active component found inside the liposomes after hydration can be determined in a differential scanning calorimeter.

The lipid(s), tocopherol and biologically active component must be completely dissolved in the solvent, as the

In order to avoid precipitation or phase separation from the 364/PAZ solution, it is essential that all components are in solution prior to freezing, otherwise the resulting powder formulation will have more than one phase. The solvent, in addition to having a suitable freezing point and preferably a high tension, must also be toxicologically acceptable. The solvent may be, for example, an organic solvent, such as an alcohol, or a mixture of water and organic solvents. In the course of carrying out the invention, tert-butyl alcohol has been found to be particularly advantageous as a solvent.

The powder can optionally be agglomerated into tiny globules to control its cohesiveness. The size of the globules should not exceed 1 mm, larger particles should be removed, for example, by sieving. The agglomerates should have a loose, pulverizing structure so that they can easily disintegrate, for example, in the air flow generated in the inhaler.

The proliposome powder composition according to the invention can be used for local or systemic treatment of diseases and can be delivered to the body, for example, via the upper or lower respiratory tract and via the nose. The invention therefore further relates to the use of said proliposome powder composition for therapeutic use and to the use of said proliposome powder for the preparation of pharmaceutical compositions for the treatment of diseases via the respiratory tract. The invention also relates to a method for treating a patient in need of such therapeutic treatment, which comprises administering to the patient a therapeutically effective amount of the proliposome powder composition according to the invention.

69.364/RAZ

The proliposome powder preparation of the invention can be used for the treatment of inflammatory diseases of the respiratory tract, such as asthma, rhinitis, periodontitis, inflammation of the pulmonary bronchioles and bronchitis.

Administration via the respiratory tract can be done using a dry powder inhaler or a pressurised aerosol inhaler.

Suitable inhalers include, for example, the single dose inhaler known as Monohaler® for dry powder inhalation and devices for multiple doses, such as powder inhalers which are actuated by inspired air, such as the ^Turbuhaler® .

Although the proliposome powder composition of the invention is particularly suitable for inhalation, it can also be used for other forms of administration. For example, such powders can be used to prepare oral, topical or injectable pharmaceutical compositions, for example for the treatment of inflammatory joint diseases such as arthritis, for the treatment of skin diseases and for the treatment of intestinal diseases.

The following example is intended to illustrate the invention and is in no way intended to be limiting of the claims. The amounts are by weight.

Example 1:

parts rofleponide palmitate, 63 parts DPPC, 24 parts DMPC, 3 parts NaDPPG and 0.1 part racemic a-tocopherol at 80 C

69.364/RAZ is dissolved in 1300 parts of tert-butyl alcohol. The solution is charged into the compartments of a lyophilizer cooled to -35 °C, and when this temperature is reached, after about 30 minutes, the pressure is reduced to start the sublimation of the solvent. The rate of sublimation can be controlled by reducing the pressure and increasing the temperature, but the temperature is not allowed to exceed -10 °C during the entire operation. Lyophilization is continued until all the solvent has been removed. The resulting powder is then scraped from the walls of the compartments and passed through a sieve.

The powder is micronized in a gas jet mill to a particle size of less than 5 pm, then 80 parts of lactose monohydrate are added to 20 parts of the micronized powder. The mixing is combined with a sieving operation, and finally the powder mixture is micronized once more in a jet mill at low pressure and further homogenized.

The powder mixture is agglomerated into globules smaller than 1 mm in size following the usual procedure and the larger globules are then removed by sieving. The agglomerated powder preparation is then filled into a dry powder inhaler known as the Turbuhaler’.

In another experiment, during the preparation of the above preparation, we changed the amount of α-tocopherol and added 0.6 parts to the powder instead of 0.06 parts.

Surprisingly, we found that the proliposome powder formulation prepared as described in Example 1 is more stable than the same formulations containing other antioxidants.

’.364/RAZ

Dust analysis:

The powder composition prepared as described in Example 1 was subjected to X-ray powder diffraction analysis, which showed that the powder did not contain any crystalline parts.

The ratio of the active ingredient within the liposome:

The proliposome powder preparation prepared according to Example 1 was subjected to differential scanning calorimetry analysis after hydration to determine the extent to which the active ingredient is located within the liposomes. The DSC analysis showed that the entire amount of the active ingredient is located within the liposomes.

69.364/RAZ

Claims (27)

Patent claims 1. A proliposome powder, the discrete particles of which comprise in a single phase (1) a biologically active substance; (2) tocopherol in a proportion necessary for stabilization; and (3) a lipid or mixture of lipids having a phase transition temperature below 37°C. 2. The powder of claim 1, wherein the tocopherol is α-tocopherol. 3. The powder of claim 2, wherein the tocopherol is racemic α-tocopherol. 4. A powder according to any one of claims 1-3, wherein the tocopherol present constitutes between 0.05 and 1.0% by weight of the single phase. 5. Powder according to claim 4, wherein tocopherol is present in a proportion of between 0.1 and 0.6 by weight. 6. Powder according to any one of claims 1-5, comprising one or more lipids selected from natural and synthetic phosphoglycerolipids, sphingolipids and digalactosylglycerolipids. 7. The powder according to any one of claims 1-6, comprising one of the following lipid mixtures: SM/PC, SM/cholesterol, ePC/cholesterol, sPC/cholesterol, -PC/PS/cholesterol, DMPC/DPPC, DMPC/DPPC/CH, DMPC/CH, DPPC/DOPC, DPPC/DOPC/CH, DLPC/DPPC, DLPC/DPPC/CH, DLPC/DMPC, DLPC/DMPC/CH, DOPC/DSPC, DPSM/DMSM, e-lecithin/cholesterol and s-lecithin/cholesterol. 8. A powder according to any one of claims 1-7, comprising: 69.364/RAZ €*»♦ It uses the lipids DPPC and DMPC or a mixture of DPPC and DMPC. 9. The powder of claim 8, comprising at least 10% DMPC. 10. The powder of any one of claims 1-9, further comprising a charge-carrying lipid. 11. The powder of claim 10, wherein the charge-carrying lipid is selected from the group consisting of dimyristoylphosphatidylglycerol (DMPG), dipalmitoylphosphatidylglycerol (DPPG), dimyristoylphosphatidic acid (DMPA), dipalmitoylphosphatidic acid (DPPA), and stearylamine (SA). 12. A powder according to any one of claims 1-11, wherein the active ingredient component is a glucocorticosteroid. 13. The powder of claim 12, wherein the active ingredient component is a glucocorticosteroid esterified at the 21-position with a fatty acid having at least 8 carbon atoms. 14. The powder of claim 13, wherein the active ingredient component is a glucocorticosteroid esterified at the 21-position with a fatty acid having at least 10 carbon atoms. 15. The powder according to claim 14, wherein the active ingredient is -component is a glucocorticosteroid-21-palmitate. 16. The powder according to claim 15, wherein the active ingredient is -component rofleponide palmitate. 17. The powder of any one of claims 1-16, wherein at least 50% of the powder consists of particles with a diameter of less than 10 μιπ. 18. The powder of claim 17, wherein at least 50% of the powder consists of particles with a diameter of 0.01-10 μm. 19. The powder of claim 18, wherein at least 50% of 69.364/SHOCK It consists of particles with a diameter of 0.1-6 μιυ. 20. The powder according to any one of claims 17-19, which consists of agglomerated particles. 21. A pharmaceutical composition comprising a powder according to any one of claims 1-19 and a pharmaceutically acceptable carrier. 22. A pharmaceutical composition according to claim 21, comprising crystalline lactose monohydrate as a carrier. 23. A pharmaceutical composition according to any one of claims 21 or 22, wherein the carrier consists of particles or agglomerates thereof having a diameter of less than 10 μm measured at the center of mass. 24. An inhaler for inhaling a dry powder, comprising a proliposome powder formulation according to any one of claims 1-23. 25. A dry powder inhaler according to claim 24, adapted for single dose administration. 26. A method for treating a patient in need of treatment with a biologically active compound, comprising administering to said patient an effective amount of a powder according to any one of claims 1-20 or a pharmaceutical composition according to any one of claims 21-23. 27. Use of a powder according to any one of claims 1-20 for the preparation of a composition for therapeutic use. Member of the Patent Office H-1062 Budapest, Andrássy út 113. Telephone: 34-24-950, Fax: 34-24-323