SK184899A3 - Proliposome powders for inhalation stabilised by tocopherol - Google Patents

Abstract

There is described a proliposome powder, said powder comprising discrete particles each comprising in a single phase (1) a biologically active component, (2) a stabilising proportion of tocopherol, and (3) a lipid or mixture of lipids having a phase transition temperature of below 37 DEG C. Also described is a process for the preparation of, and the pharmaceutical use of, the powder.

Description

Proliposome powders stabilized with tocopherol for inhalation

Technical field

The invention relates to proliposome powders, in particular for inhalation, to a process for the production of proliposome powders, to compositions comprising proliposome powders and to a method for their use.

BACKGROUND OF THE INVENTION

Liposomes are membrane-shaped vesicles, consisting of a series of concentric lipid bilayers alternating with hydrophilic compartments. They can be formed from a variety of natural and synthetic lipids, such as natural or synthetic phosphoglycerolipids, sphingolipids, and digalactosylglycerolipids. One of the major uses for liposomes is the use as a carrier for different kinds of pharmaceutical active components to improve drug delivery and minimize the side effects of some treatments. Pharmaceutically active components can be incorporated into liposomes either by encapsulation into the hydrophilic compartments of the liposome (when the active component is water soluble) or by encapsulation into the lipid bilayers when the active component is lipophilic.

One of the major problems associated with pharmaceutical liposomal formulations is long-term stability. Aqueous liposome dispersions have limited stability due to aggregation, loss of the encapsulated active component to the external phase, chemical degradation of the active component or lipid material, etc.

These problems can be largely overcome if a solid formulation is used. Such a solid composition may comprise a liposome powder, i.e., a dried liposome dispersion or a proliposome powder.

WO 96/19199 discusses various literature on liposomes and pro2 liposomes and describes a proliposome powder. This powder contains discrete particles in a single phase which comprise a biologically active component and a lipid or lipid mixture having a phase transition temperature (Tc) of less than 37 ^e C.

It has been found that the stability of the proliposome powder of WO 96/19199 can be greatly increased.

SUMMARY OF THE INVENTION

The present invention provides a proliposome powder comprising discrete particles, each of which is made up in a single phase of (1) a biologically active component, (2) a tocopherol stabilizing moiety, and (3) a lipid or lipid mixture having a transition phase temperature below 37 ° C.

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

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The powder is particularly suitable for administration by inhalation.

Alternatively, the single phase powder may be described as comprising a homogeneous molecular mixture of a biologically active component, a lipid or a mixture of lipids having a transition phase temperature below 37 ° C and tocopherol.

It is clear from the terms single phase and homogeneous molecular mixture that there is no separate crystalline phase of the active component, lipid or tocopherol in the powder of the invention.

The single phase powder may be directly inhaled and form in situ, for example in the upper or lower airways, liposomes in which the active component is fully incorporated.

In general, any amphipathic lipid or mixture of lipids known to be suitable for the preparation of liposomes by known methods can be used according to the invention. The lipid or lipid mixture must have a phase transition temperature below body temperature (37 ° C) so that the proliposome powder product is capable of hydrating under physiological conditions (i.e., capable of forming liposomes in the respiratory tract). Phase transition temperatures for various lipid mixtures are readily determined using well known methods, such as differential scanning calorimetry (DSC) methods - see, for example, J. Suurkuusk et al., Biochemistry, Volume 15, no. 7, page 1393 (1976). In general, any natural or synthetic lipid or lipid mixture having a phase transition temperature of less than 37 ° C is useful in the present invention.

Examples of potentially useful lipids include natural and synthetic phosphoglycerolipids, sphingolipids and digalactosylglycerolipids. Natural lipids include sphingolipids (SL) such as sphingomyelin (SM), ceramide and cerebroside, galactosylglycerolipids such as digalactozyldiacylglycerol (DGalDG), phosphoglycerolipids such as egg yolk phosphatidylcholine (e-PC), and sosolecin phosphatidylsolines (s-lecins). egg yolk lecithin (e-lecithin) and soybean lecithin (s-lecithin). Amongst synthetic lipids may be mentioned dimyristoyl phosphatidylcholine (DMPC), dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC), dilauryl (DLPC), l-myristoyl-2-palmitoyl phosphatidylcholine (MPPC), l-palmitoyl-2-myristoyl phosphatidylcholine (PMPC), and dioleoyl ( DOPC). Lipid mixtures include the following: 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, DLC / DMPC / CH, DOPC / DSPC, DPSM / DMSM, e-lecithin / cholesterol, and s-lecithin / cholesterol. In addition to each of the foregoing, an ionic lipid such as dimyristoylphosphatidylglycerol (DMPG), diphospamitoylphosphatidylglycerol (DPPG), dimyristoylphosphatidic acid (DMPA), dipalmitoylphosphatidic acid (DPPA), or stearlamine (DPPA) may be added.

Particularly interesting lipids of the invention are DPPC and / or

DMPC. Mixtures of DPPC and DMPC containing at least 10% by weight of DMPC, for example 10 to 50% DMPC, are preferred. Particularly preferred is a mixture of DPPC and DMPC containing in addition at least one ionic lipid such as DMPG, DPPG, DMPA or SA, for example in an amount of up to 5% by weight. Other preferred mixtures include DPSM and DMSM, optionally containing at least one ionic lipid and cholesterol mixtures with either e-lecithin or s-lecithin, optionally containing at least one ionic lipid and having a T _{c of} less than 37 ° C. . Other mixtures can be readily selected by those skilled in the art with reference to, for example, Gregor Cevc, Phospholipids Handbook, Marcel Dekker, New York (1993), p. 427 to 435.

The tocopherol is preferably present in an amount of 0.05 to 1.0%, more preferably 0.1 to 0.6% by weight of the total single phase comprising the lipid (s) and the biologically active component.

Preferably, the active component has a molecular structure that can be incorporated into lipid bilayers to aid encapsulation into liposomes during hydration. An example of such a molecular structure is a fatty acid ester having a long hydrocarbon chain sufficient to act as a hydrophobic anchor.

Suitable active components may be identified by those skilled in the art and may include, for example, anti-inflammatory and bronchorelaxant drugs, antihistamines, cyclooxygenase inhibitors, leukotriene synthesis inhibitors, leukotriene antagonists, phospholipase-A2 (PLA2) inhibitors, platelet aggregation factor factor (PAF) antagonists. Antiarrhythmic drugs, tranquillizers, cardiac glucosides, hormones, antihypertensive drugs, antidiabetic, antiparasitic and anticancer drugs, sedatives, analgesics, antibiotics, anti-rheumatic drugs, immunotherapeutics, antifungal drugs, antihypertensive drugs, protein therapies, vaccines, vaccines, vaccines, vaccines, vaccines, vaccines, vaccines, vaccines interesting.

In particular, glucocorticosteroids such as budesonide, fluticasone propionate, ciclesonide, rofleponide, e.g. such as palmitate, mometasone, for example as its furoate, tipredane, RPR 106541, dexamethasone, betamethasone, fluocinolone, flumethasone, triamcinolone acetonide, flunizolide, beclomethasone and 16,17-acetals of pregnane derivatives and agonist-derived compounds 2, and S-2-agonists , salmeterol, salbutamol, formoterol, phenoterol, clenbuterol, prokaterol, bitolterol and broxaterol. The active component may also be a mixture of pharmaceutically active substances, for example a mixture of a glucocorticosteroid with a bronchodilator such as formoterol, salmeterol, terbutaline or salbutamol, and may be useful. For the avoidance of doubt as to the term active ingredient, it is to be understood that the term should also include pharmaceutically acceptable esters, salts and hydrates of the compounds.

When the active component is a steroid, it is preferably a steroid ester.

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The active component is preferably a steroid, preferably a steroid which is esterified at the 21-position with a saturated or unsaturated fatty acid containing at least 8, for example at least 10 or at least 12 carbon atoms. The fatty acid may contain, for example, up to 24 carbon atoms, for example up to 20 carbon atoms or up to 18 carbon atoms. More preferably, the active component is steroid-21-palmitate, myristate, laurate, caprate, caprylate or stearate. The most preferred active component of the invention is (22R) -16α, 17α-butylidenedioxy-6α, 9α-difluoro-11S-hydroxy-21-palmitoyloxypregn-4-ene-3,20-dione, i.e. rofleponide palmitate.

When the active component is an ester, it must be hydrolyzable to the active base. The single-phase proliposome powder of the invention allows the unexpectedly needed hydrolysis in situ, while esters in the crystalline state will usually not be hydrolyzed.

Where desirable administration by inhalation, the greatest possible amount of proliposome powder should consist of particles with a diameter of less than 10 microns, for example 0.01 to 10 microns or 0.1 to 6 microns, for example 0.1 to 5 microns, or agglomerates of these particles. Preferably at least 50% of the powder consists of particles in the desired size range. For example, at least 60%, preferably less than 70%, more preferably at least 80% and most preferably at least 90% of the powder consists of either particles in the desired size range or agglomerates of said particles.

The proliposome powders of the invention need not contain any other ingredients. However, the pharmaceutical compositions containing the powders of the invention may also contain other pharmaceutically acceptable excipients such as pharmaceutically acceptable adjuvants, diluents and carriers. These may be added to the proliposome composition after optional micronizing or prior to optional micronizing, provided that the solvent is completely removed. The carrier is preferably a crystalline, hydrophilic substance. A preferred carrier is crystalline lactose monohydrate. Other suitable carriers include glucose, fructose, galactose, trehalose, sucrose, maltose, raffinose, maltitol, melezitose, stachyose, lactitol, palatinite, starch, xylitol, mannitol, myoinositol and the like, and their hydrates, and amino acids, and their amino acids, glycine and betaine.

The amount of ingredients present in the composition may vary within very wide ranges. In some cases, little or no additives may be needed, while it is often advantageous to dilute the powder with an additive to improve the properties of the powder for use in an inhaler. In this case, the composition may contain, for example, at least 50%, for example at least 70% or at least 80% of the ingredients, the remainder being a proliposome powder. The percentage of ingredients may also depend on the potency of the biologically active compound and on the optimum amount of powder for inhalation.

In the case where an additive, for example a carrier, is present, the entire composition may consist of particles having a size in the respirable particle size range. Alternatively, the carrier may comprise coarser particles, for example having a mean mass diameter greater than 20 microns, or may contain agglomerates of smaller particles, wherein the agglomerates have a mean mass diameter greater than 20 micrometers, so that an ordered mixture of proliposome and carrier is formed.

It is a further object of the invention to provide a process for producing a proliposome powder of the invention, that is, a process providing a proliposome powder in a single phase.

Accordingly, the present invention also provides a process for preparing a proliposome powder for inhalation, comprising dissolving a lipid or lipid mixture, tocopherol and a lipophilic biologically active component in a solvent, wherein said lipid or lipid mixture has a phase transition temperature of less than 37 ° C, thereby obtaining a crystalline solvent base and a single lipid phase in its glassy state by freezing the solution, said freezing being performed at a temperature below the lipid phase phase transition temperature, and the frozen solvent is evaporated at a temperature below the lipid phase phase transition temperature.

Freezing of the solution and evaporation of the solvent can be carried out by conventional methods, for example in a conventional lyophilizer. For example, it is possible to pour a solution of lipids and a biologically active component onto the lyophilizer shelves and lower the temperature to freeze the solution. The evaporation of the solvent can then be carried out, for example, by reducing the pressure in the lyophilization chamber. The resulting powder may be scraped off the shelves in the chamber and optionally sieved.

The lyophilized powder may optionally be subjected to further processing to obtain particles within the respirable particle size range. For example, the lyophilized powder can be micro-milled, for example using a jet mill, to obtain respirable particles.

The freezing of the solution of the biologically active component, the tocopherol and the lipids is carried out in a manner that provides a single lipid phase in a frozen solvent base. The preparation of a single lipid phase is regulated by the final temperature and freezing rate of the solution. The optimum freezing rate of any particulate solution will be somewhere within the time required to crystallize the respective solvent and the time required to crystallize the lipid (s), the tocopherol and the active component, and can be readily determined by one of skill in the art by trial and error. The optimum final temperature should be 10-20 ° C below the glass transition temperature of the lipid phase. For example, an X-ray method can be used to monitor crystallinity, and a differential scanning calorimeter can be used to monitor the degree of incorporation of a biologically active component into liposomes after hydration.

The solvent must have the ability to completely dissolve the lipids, tocopherol and the biologically active component, since it is important that all components are in solution before freezing, thereby preventing precipitation or phase separation, resulting in powder formation with more than one phase. In addition, the solvent should be toxicologically acceptable, have an appropriate pour point and preferably have a high vapor pressure. The solvent may be, for example, an organic solvent, for example an alcohol, or a mixture of aqueous and organic solvents. A preferred solvent for use in the present invention is tertiary butanol.

The powder may optionally be agglomerated into small spheres to regulate the cohesion of the powder. Preferably, the beads should not be larger than 1 mm in diameter. Balls larger than 1 mm in diameter should be removed by sieving. All agglomerates should be crumbled to easily deagglomerate in, for example, a powder inhaler.

The pro-liposome powder of the invention is useful for the topical or systemic treatment of diseases and can be administered, for example, through the upper and lower respiratory tract, including the nasal route. The present invention also provides said proliposome powder for use in therapy, the use of proliposome powder in the manufacture of a medicament for treating diseases via the respiratory tract, and a method of treating a patient in need of treatment by administering to said patient a therapeutically effective amount of proliposome powder.

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For example, the pro-liposome powder of the invention can be used to treat inflammatory diseases of the respiratory tract, for example, asthma, rhinitis, alveolitis, bronchiolitis and bronchitis.

Administration to the respiratory tract can be accomplished, for example, using a dry powder inhaler or a pressurized aerosol inhaler.

Suitable powder inhalers are metered-dose inhalers, for example single dose inhalers known under the trademark Monohaler ^R and multi-dose inhalers, for example multi-dose, breath actuated dry powder inhalers known under the trademark Turbuhaler ^R.

Although the proliposome powder of the invention is particularly intended for administration by inhalation, it may also be included in formulations intended for other forms of administration. For example, oral, topical and injectable compositions may be prepared for use in the treatment of inflammatory diseases of the joints, for example arthritis, skin and intestinal diseases.

The following examples are intended to illustrate but not limit the scope of the invention. The parts are weight parts.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Rofleponide palmitate (10 parts), (24 parts), NaDPPG (3 parts) and (0.1 parts) were dissolved at 80 ° C

DPPC (63 parts), DMPC racemic α-tocopherol in tertiary butanol (1300 parts). The solution was poured onto lyophilizer shelves tuned to -35 ° C. The solution reached this temperature in about 30 minutes. The freeze-dryer was depressurized to induce sublimation of the solution. While the sublimation rate could be adjusted by reducing the pressure and increasing the temperature, the temperature was not allowed to rise above -10 ° C during the process. In lyophilization

F ¹ , continued until the solvent was removed. The resulting powder was scraped off the lyophilizer shelves and sieved.

This powder was micro-ground in a jet mill to powder particles of less than 5 gm. The micronized powder was mixed with lactose monohydrate (20 parts powder: 80 parts lactose monohydrate) by sieving, and the mixture was then further homogenized at low pressure by micronising in a jet mill.

The powder mixture was agglomerated to beads no larger than 1 mm using standard methods. Larger beads were removed by sieving. The agglomerated powder was filled into a Turbuhaler® dry powder inhaler.

In the individual experiments, the amount of α-tocopherol in the above formulation was changed to 0.06 parts and 0.6 parts, respectively.

The proliposome formulations of Example 1 were found to be more stable than equivalent formulations containing other antioxidants.

Powder analysis

The X-ray diffractogram of the powder mixture of Example 1 showed that no crystalline state was present in the powder.

Incorporation of the active component into liposomes

The proliposome powders of Example 1 were hydrated and the degree of incorporation of the active component was measured using Differential Scanning Calorimetry (DSC) methods. DSC has shown that the active component is fully incorporated into the liposomes.

Claims (24)

PATENT CLAIMS Proliposome powder, characterized in that it comprises discrete particles, each containing in one phase (1) a biologically active component, (2) a tocopherol stabilizing fraction, and (3) a lipid or lipid mixture having a phase transition temperature less than 37 ° C. Powder according to claim 1, characterized in that the tocopherol is α-tocopherol. Powder according to claim 2, characterized in that the tocopherol is racemic α-tocopherol. Powder according to claims 1 to 3, characterized in that the tocopherol is present in an amount of 0.05 to 1.0% by weight of a single phase. Powder according to claim 4, characterized in that the tocopherol is present in an amount of 0.1 to 0.6% by weight. Powder according to claims 1 to 5, characterized in that it contains one or more lipids selected from the group consisting of natural and synthetic phosphoglycerolipids, sphingolipids and digalactosylglycerolipids. Powder according to claims 1 to 5, characterized in that it comprises a mixture of lipids selected from the group consisting of SM / PC, SM / cholesterol, ePC / cholesterol, sPC / cholesterol, PC / PS / cholesterol, DMPC / DPPC, DMPC / DPPC / CH, DMPC / CH, DPPC / DOPC, DLPC / DPPC, DLPC / DMPC, DLPC / DMPC / CH, DPSC / DSPC, DPSM / DMSM, e-lecithin / cholesterol and s-lecithin / cholesterol. Powder according to claims 1 to 7, characterized in that it comprises DPPC, DMPC or a mixture of DPPC and DMPC. Proliposome powder according to claim 8, characterized in that the mixture contains at least 10% DMPC. Powder according to claims 1 to 9, characterized in that it additionally contains an ionic lipid. Powder according to claim 10, characterized in that the ionic lipid is selected from the group consisting of dimyristoylphosphatidylglycerol (DMPG), diphosphpalmitoylphosphatidylglycerol (DPPG), dimyristoylphosphatidic acid (DPPA) and stearylamine (SA). Powder according to claims 1 to 11, characterized in that the active component is a glucocorticosteroid. Powder according to claim 12, characterized in that the active component is a glucosteroid which is esterified at the 21-position with a fatty acid containing at least 8 carbon atoms. ' Powder according to claim 13, characterized in that the active component is a glucosteroid which is esterified at the 21-position with a fatty acid containing at least 10 carbon atoms. Powder according to claim 14, characterized in that the active component is glucosteroid-21-palmitate. and by Powder according to claim 15, characterized by: at j ú c and sa t ý m, that the active component is roflenid palmitate. Powder according to claims 1 to 16, characterized by: from n and no at j ú c i s a in that at least 50% of the powder consists of particles having a diameter of less than 10 microns. Powder according to claim 17, characterized in that at least 50% of the powder consists of particles having a diameter of 0.01 to 10 microns. Powder according to claim 18, characterized in that at least 50% of the powder consists of particles having a diameter of 0.1 to 6 microns. Powder according to claims 17 to 19, characterized in that it contains agglomerated particles. A pharmaceutical composition comprising the powder of claims 1 to 20 and a pharmaceutically acceptable carrier. 22. The pharmaceutical composition of claim 21, wherein the carrier is crystalline lactose monohydrate. Pharmaceutical composition according to claims 21 or 22, characterized in that the carrier comprises particles with a mean mass diameter of less than 10 microns or agglomerates of these particles. 24. A dry powder inhalation device, comprising a proliposome powder according to claims 1 to 23. The dry powder inhalation device of claim 24, wherein the inhaler is a single dose inhaler. 26. A method of treating a patient in need of treatment with said biologically active compound, comprising administering to said patient a therapeutically effective amount of a powder of claims 1 to 20 or a composition of claims 21 to 23. Use of a powder according to claims 1 to 20 for the preparation of a composition for use in therapy.