WO2009027337A1

WO2009027337A1 - Liposomal dispersion and dry powder formulations comprising oligonucleotides having improved downstream prossessing properties

Info

Publication number: WO2009027337A1
Application number: PCT/EP2008/061018
Authority: WO
Inventors: Fadi Eskandar
Original assignee: Novartis Ag
Priority date: 2007-08-24
Filing date: 2008-08-22
Publication date: 2009-03-05
Also published as: AR067997A1; TW200916126A; PE20090607A1; CL2008002479A1

Abstract

A pharmaceutical composition that comprises: (A) one or more drug substances; (B) a lipid; (C) a co-lipid; and (D) a flowability enhancer, wherein the co-lipid and the flowability enhancer together form a liposomal dispersion that comprises lipid vesicles that encapsulate the one or more drug substances. The pharmaceutical composition is optionally dried to form a dry powder formulation that is free-flowing and preferably suitable for inhalation or nasal administration. Processes for preparing the composition and the dry powder formulation are also described.

Description

LIPOSOMAL DISPERSION AND DRY POWDER FORMULATIONS COMPRISING OLIGONUCLEOTIDES HAVING IMPROVED DOWNSTREAM PROSSESSING PROPERTIES

1. Field of the Invention.

This invention relates to novel pharmaceutical compositions and dry powder formulations that contain one or more drug substances encapsulated within lipid vesicles. The present invention also concerns processes for the manufacture of such compositions and formulations and methods of treating diseases or disorders with such compositions and formulations. Other aspects, objects and advantages of the present invention will be apparent from the description below.

2. Background of the Invention

An active pharmaceutical ingredient [API] or a drug substance can only have a pharmacological effect in a patient if it reaches the therapeutic site in an adequate therapeutic effective amount. Sometimes drugs that are potentially therapeutically very active are not effective in vivo as they are unstable, they are taken up by non-target systems or they simply cannot enter the relevant cells.

It is known that one can improve the delivery of certain drugs to their therapeutic targets by encapsulating the drug in liposomes. In this way one can increase bioavailability and/or decrease side effects through the reduction of macrophagial phagocytosis. Unfortunately previous attempts to encapsulate drugs in liposomes have met with problems including low entrapment efficiency of the API, inability to encapsulate a sufficient quantity of API reproducibly, instability (especially in aqueous environment for extended periods of time), sensitivity toward mechanical stress, leakage of the API from the vesicle during storage, the use of toxico logically unsuitable lipids, time consuming processing and non-economic large scale manufactur ability .

Thus, there is a need for pharmaceutical compositions that deliver drug substances via liposomal encapsulation that overcome one or more of the aforementioned problems or at least provide a useful alternative to known compositions. There is also a need for a simple yet effective method of preparing pharmaceutical compositions that deliver drug substances via liposomal encapsulation. 3. Summary of the Invention

In a first aspect, the present invention provides a pharmaceutical composition that comprises: (A) one or more drug substances; (B) a lipid; (C) a co-lipid; and (D) a flowability enhancer; the pharmaceutical composition being characterised in that the lipid, the co-lipid and the flowability enhancer together form a liposomal dispersion that comprises lipid vesicles that encapsulate the one or more drug substances.

In a second aspect, the present invention provides a dry powder formulation, that comprises: (A) one or more drug substances; (B) a lipid; (C) a co-lipid; and (D) a flowability enhancer; the formulation being characterised in that the lipid, the co-lipid and the flowability enhancer together form a liposomal dispersion comprising lipid vesicles that encapsulate the one or more drug substances and dry to form a free-flowing dry powder formulation.

4. Brief Description of the Drawings.

Figure 1 : Lipoosomal dispersion particle size distribution of composition C measured using a M alvern Zetasizer.

Figure 2: Powder particle size distribution data of composition c measured using a Sympatech laser diffraction instrument.

Figure 3: Lipoosomal dispersion particle size distribution of composition D measured using a M alvern Zetasizer.

Figure 4: Powder particle size distribution data of composition D measured using a Sympatech laser diffraction instrument.

Figure 5 : Evaluation of the encapsulation efficiency of oligonucleotide A into the formulation composition E and F using capillary gel electrophoresis, which shows an encapsulation efficiency of more than 90% .

Figure 6: Powder particle size distribution data of composition E measured using a Sympatech laser diffraction instrument, which can target anterior deposition. into the nasal cavity. Figure 7: Powder particle size distribution data of composition F measured using a Sympatech laser diffraction instrument, which can target posterior deposition. into the nasal cavity.

Figure 8: X-ray Diffraction data combined with Scanning electron microscopical image for powder of composition G, which emphasize the present of flowability enhancer nanocrystals on the top of the powder particle, which emproves the powder flowing characteristics.

Figure 9: Aerodynamic particle size distribution of composition I measured using a Next Generation Impactor (NGI) at 60 L/min using a PennCentury DP4 inhalation device. Process 1 shows a higher deposition in the lower stages comparing with process 2.

Figure 10: Cummulative aerodynamic particle size distribution of composition I measured using a Next Generation Impactor (NGI) at 60 L/min using a PennCentury DP4 inhalation device. 50% of the particles produced using process 1 is below 1.1 μm comparing with 4.5 for process 2.

Figure 11 : Scanning Electron Microscopical (SEM) image of powder of composition I, which shows that each powder particle is an intact capsule.

Figure 12: Effect of encapsulating an inflamatory trigerring siRNA using the invnetion on the cytokine expression. While naked siRNA trigger INF? and TNFa, encapsulated siRNA into the liposomes of the present invention as well as placebo liposomes of the present invention powders does not trigger any cytokine mediated inflammation.

Figure 13: Scaling up manufacturing process diagram for theSuperSomes™ Technology.

Figure 14: Scanning Electron Microscopical data for composition I oppenly stored for two month at 40°C/75% R.H.

Figure 15: Metered Dose Uniformity data for composition E with the DirectHaler nasal device.

Figure 16: Comparison between the siRNA release profile through artificial lung surfactant for three different formulations: siRNA dissolved into buffer pH 7.0, siRNA encapsulated in liposomal dispersion composition I and siRNA encapsulated into powder of composition I. 5. Description of the Preferred Embodiments.

Preferably the average diameter of the lipid vesicles is between 70 and 550 nm, more preferably between 100 and 450 nm, and even more preferably between 100 and 250 nm.

Preferably the dry powder formulation is suitable for administration by inhalation. When the formulation is an inhalable powder the average aerodynamic particle size is preferably no greater than 10 microns, more preferably no greater than 5 microns, and even more preferably no greater than 3 microns.

Alternatively, the dry powder formulation is suitable for nasal administration as liquid after reconstituting or as a dry powder. When the formulation is a nasal powder the average aerodynamic particle size is preferably greater than 10 microns.

In a third aspect, the present invention provides a process for preparing a pharmaceutical composition, the process comprising the steps of:

(a) mixing a lipid and a co-lipid under high shear;

(b) admixing one or more drug substances; and

(c) admixing a flowability enhancer to form a liposomal dispersion that comprises lipid vesicles that encapsulate the one or more drug substances.

In a fourth aspect, the present invention provides a process for preparing a dry powder formulation, the process comprising the steps of: (a) mixing a lipid and a co-lipid under high shear; (b) admixing one or more drug substances;

(c) admixing a flowability enhancer to form a liposomal dispersion that comprises lipid vesicles that encapsulate the one or more drug substances;

(d) optionally, diluting the liposomal dispersion; and

(e) drying the liposomal dispersion to form the powder formulation.

Terms used in the specification have the following meanings:

"Carr's Index" as used herein is an indication of the flowability of a powder. It is calculated as follows: Carr's Index (% )= (Tapped Density- Bulk Density)* 100 / Tapped density "Co-lipid" as used herein is a substance that stabilises lipids, for example a lipid vesicle stabiliser.

"dsRNA" as used denotes means an oligoribonucleotide or polyribonucleotide, modified or unmodified, and fragments or portions thereof, of genomic or synthetic origin or derived from the expression of a vector, which may be partly or fully double -stranded and which may be blunt-ended or contain a 5 '- and/or 3 '- overhang, and also may be of a hairpin form comprising a single oligoribonucleotide which folds back up on itself to give a double-stranded region. dsRN A may also contain modified nucleotide residues.

"Emitted dose" or "ED" as used herein is the total mass of the drug substance emitted from the device following actuation. It does not include the material left inside or on the surfaces of the device. The ED is measured by collecting the total emitted mass from the device in an appropriate apparatus for instance a dose uniformity sampling apparatus (DUSA), and recovering this by a validated quantitative wet chemical assay.

"Encapsulation efficiency" as used herein is normally defined as the amount of drug substance entrapped into the liposomal structure and expressed in percent.

"Fine particle dose" or "FPD" as used herein is the total mass of a drug substance which is emitted from the device following actuation which is present in an aerodynamic particle size smaller than a defined limit. This limit is generally taken to be 5 μm if not expressly stated to be an alternative limit, such as 1 μm or 3 μm, etc. The FPD is measured using an inertial impactor or impinger, such as a twin stage impinger (TSI), multi-stage liquid impinger (MSLI), Andersen Cascade Impactor (ACI) or a Next Generation Impactor (NGI). Each impactor or impinger has a pre -determined aerodynamic particle size collection cut-off point for each stage at a defined flow rate. The FPD value is obtained by interpretation of the stage -by-stage active agent recovery quantified by a validated quantitative wet chemical assay where either a simple stage cut is used to determine FPD or a more complex mathematical interpolation of the stage - by-stage deposition is used.

"Fine particle fraction" or "FPF" as used herein is normally defined as the FPD divided by the ED and expressed as a percentage. Herein, the FPF of ED is referred to as FPF(ED) and is calculated as FPF(ED) = (FPD/ED) x 100% . "Fine particle fraction" may also be defined as the FPD divided by the MD and expressed as a percentage. Herein, the FPF of MD is referred to as FPF(MD), and is calculated as FPF(MD) = (FPD/MD) x 100% . "Flowability enhancer" as used herein is a substance that enhances the flowability of a pharmaceutical composition.

"Geometrical Standard Deviation" or "GSD" as used herein is a measure for the aerosol polydispersity from laser diffraction particle size distribution data and is calculated as follows:

GSD = J™

V xio where X90 and XlO are the particle sizes at which 90% and 10% of the particle are below this size.

"Ion compensator" as used herein is a substance that neutralises a drug substance ion and allows the encapsulation into lipid.

"Lipid" as used herein means a pharmaceutically acceptable lipid, including, e.g. neutral lipids, pegylated lipids, cationic lipids, zwitterionic lipids (such as helper lipids) and anionic lipids.

"Liposomal dispersion" as used herein means a structure consisting of spherical vesicles composed of a bilayer membrane, which can be composed of natural or synthetic phospholipids or of pure surfactant components. These vesicles are dispersed in a suitable dispersion medium like water, organic solvent or oil based medium.

"Mass Median Aerodynamic Diameter" or "MMAD" as used herein means the median size of a spherical unit dense particle that has the same settling velocity as the particle in question.

"Mean particle size" is the average diameter of particles as measured by laser light diffraction. The x90 mean particle size is the mean particle size below which 90% of particles of a sample have a lower mean particle size. The x50 mean particle size is the mean particle size below which 50% of particles of a sample have a lower mean particle size. The xlO mean particle size is the mean particle size below which 10% of particles of a sample have a lower mean particle size.

"Metered dose" or "MD" of a dry powder formulation as used herein is the total mass of a drug substance present in the metered form presented by the inhaler device in question. For example, the MD might be the mass of a drug substance present in a capsule for a particular dry powder inhaler, or in a foil blister for use in a particular dry powder inhaler device. "Parenteral administration" as used herein means administration by injection intravenously, subcutaneously, intradermally, intramuscular, intraarticular, intraocular, intracranial, intrathecal by routes such as intravenous, subcutaneous, intradermal, intramuscular, intraarticular, intraocular, intracranial, intrathecal or to any other body part or tissue.

"Pharmaceutically acceptable" refers to those compounds, materials, compositions and/or dosage forms, which are, within the scope of sound medical judgment, suitable for contact with the tissues of mammals, especially humans, without excessive toxicity, irritation, allergic response and other problem complications commensurate with a reasonable benefit/risk ratio.

"RNA" as used herein means nucleic acid molecules, single or double stranded, that mediate ribonucleic acid interference which include, but are not limited to, double stranded nucleic acid ("dsNA"), double -stranded RNA ("dsRNA"), micro-RNA ("miRNA"), short hairpin RNA ("shRNA"), short interfering nucleic acid ("siNA") and short interfering ribonucleic acid

(" siRNA").

"siRNA" as used herein means short interfering RNAs and refers to short double stranded ribonucleic acids useful for RNA interference. Such siRNAs have lengths, for example, between 10 to 50 nucleotides, especially e.g., 15 to 25 nucleotides."

"Volume Mean Diameter" or "VMD" as used herein means the mean size of a spherical unit dense particle that has the same volume as the particle in question measured using a laser diffraction or any other suitable technique.

Throughout this specification and in the claims that follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The present invention, in broad terms, relates to a pharmaceutical composition. The composition comprises: (A) one or more drug substances; (B) a lipid; (C) a co-lipid; and (D) a flowability enhancer. The pharmaceutical composition is characterised in that the lipid, the co-lipid and the flowability enhancer together form a liposomal dispersion that comprises lipid vesicles that encapsulate the one or more drug substances. The composition can be dried to form a dry powder formulation which is free flowing and preferably suitable for inhalation and nasal administration.

The drug substance is entrapped into a double layer of lipid to form a liposomal vesicles. Several liposomal vesicles are further coated by a lipid layer to form a liposomal dry powder capsule. This capsule is further coated by a flowability enhancers which is preferably crystalline material to form a particle with the desired mean particle size. The final particle structure forms a free-flowing liposomal powder with low particle cohesion forces due to the small contact areas.

By encapsulating the drug substance(s) it is possible to increase local and systemic bioavailability, decrease the macrophagial phagocytosis of macromolecules and negatively charged molecules therefore decrease side effects (e.g. nasal irritation and damage to the epithelial layer of the nose), and decrease the hygroscopic characteristics of the drug substance thereby improving physical and chemical stability.

The one or more drug substances is or are any pharmaceutically active substance including small molecular weight compounds or macromolecules. Suitable small molecular weight compounds include but not limited to, for example, β2-adrenoceptor agonists, muscarinic antagonists, glucocorticosteroids, non-steroidal glucocorticoid receptor agonists, A2A agonists, A2B antagonists, antihistamines, caspase inhibitors, LTB4 antagonists, LTD4 antagonists, phosphodiesterase inhibitors (especially PDE4 inhibitors or PDE5 inhibitors), mucolytics, antibiotics, matrix metal loproteinase inhibitors (MMPi' s), leukotrienes receptor antagonists (LTRAs), IgE synthesis inhibitors, antibiotics, interferons, potassium channel inhibitors, immunomodulators, antineoplastic agents, elastase inhibitors, prostaglandin D2 (PGD2) antagonists active agents at the CRTH2 receptor and prostatin inhibitors. Suitable macromolecules include but not limited to peptides, proteins, oligonucleotides, RNA (including dsNA, dsRNA, miRNA, shRNA, siNA and siRNA), DNA, plasmids, insulin, interleukins, growth hormones, heparin, estradiols, GLP-I , antibiotics, anti-neoplastic agents and antibodies.

Each drug substance is present in a therapeutically effective amount or concentration. Such a therapeutically effective amount or concentration is known to one of ordinary skill in the art as the amount or concentration varies with the therapeutic agent being used and the indication which is being addressed. In certain preferred embodiments the drug substance is an oligonucleotide or RNA (especially siRNA).

In certain preferred embodiments the one or more drug substances is or are suitable for administration by inhalation or nasal application.

The lipid is a pharmaceutically acceptable lipid, including neutral lipids, cationic lipids, zwitterionic lipids and anionic lipids. Examples of neutral lipids are but not limited to, a phosphatidyl choline (which may or may not be hydrogenated or pegylated, natural or synthetic a phosphatidyl ethanolamine, a phosphatidylserine, a phosphatidylglycerol, a phosphatidyl inositol. In certain preferred embodiments the lipid is a phosphatidyl choline (e.g. di-marsetoil phosphatidyl choline (DMPC)), di-palmitoyl phosphatidyl choline (DPPC), a hydrogenated phosphatidyl choline (e.g. Lipoid S PC-3), or a soybean phospholipid (e.g. Lipoid S75 or soybean lecithin). Preferably the lipid is di-marsetoil phosphatidyl choline, di-palmitoyl phosphatidyl choline, soybean lecithin or a hydrogenated phosphatidyl choline.

Examples of cationic lipids include, but are not limited to l ,2-dioleoyl-3-trimethylammonium propane (DOTAP); N-[I -2(2, 3-dioleyloxy)propyl]-N,N,N -trimethyl-ammonium chloride (DOTMA); 2,3-dioleoyloxy-N-[2-(sperminecarboxamido)ethyl]-N,N -deimethyl-l- propanaminium (DOSPA); dioctadecyl amido glycil spermine (DOGS); and 3,[N -N¹JST- dimethylethylenediamine)-carbamoyl]-cholesterol (D-chol). Examples of zwitterionic lipids include, but are not limited to, l,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and cholesterol.

The co-lipid, which is a substance that stabilises lipids, particularly stabilises lipid vesicles, may be, but is not limited to cholesterol, a pegylated phosphatidyl choline, a phosphatidylglycerol, a polysorbate, a polyethylene glycol (PEGs), a polyvinylpyrrolidine (PVP) or cholesterol. In certain preferred embodiments the co-lipid is a pegylated phosphatidyl choline or cholesterol.

Example of lipid/ colipid combination include, but not limited to di-palmitoyl phosphatidyl choline [DPPCJ/N -(Carbonyl-methoxypolyethyleneglycol-2000)-l ,2-distearoyl-sn-glycerol-3- phosphoethanolamine, sodium salt [MPEG-2000-DSPE], di-palmitoyl phosphatidyl choline [DPPC]/N -(Carbonyl-methoxypolyethyfeneglycol-2000)-l,2-distearoyl-sn-glycerol-3- phosphoethanolamine, sodium salt [MPEG-2000-DSPE]/Cholesterol, di-palmitoyl phosphatidyl choline [DPPCJ/N -(Carbonyl-methoxypolyethyleneglycol-2000)-l ,2-distearoyl-sn-glycerol-3- phosphoethanolamine, sodium salt [M PEG -750 -D SPE], di-palmitoyl phosphatidyl choline [DPPC]/N -(Carbonyl-methoxypolyethyleneglycol-2000)-l,2-distearoyl-sn-glycerol-3- phosphoethanolamine, sodium salt [MPEG-750-DSPE]/cholesterol, di-palmitoyl phosphatidyl choline [DPPCJ/N -(Carbonyl-methoxypolyethyleneglycol-SOOO)-! ,2-dimyristoyl-sn-glycerol-3- phosphoethanolamine, sodium salt [MPEG-5000-DMPE], di-palmitoyl phosphatidyl choline [DPPCJ/N -(Carbonyl-methoxypolyethyleneglycol-5000)-! ,2-dimyristoyl-sn-glycerol-3- phosphoethanolamine, sodium salt [MPEG-5000-DMPE]/Cholesterol, di-palmitoyl phosphatidyl choline [DPPC]/N-(Carbonyl-methoxypolyethyleneglycol-2000)-l ,2-dimyristoyl- sn-glycerol-3-phosphoethanolamine, sodium salt [MPEG-2000-DMPE] and di-palmitoyl phosphatidyl choline [DPPC]/N-(Carbonyl-methoxypolyethyleneglycol-2000)-l ,2-dimyristoyl- sn-glycerol-3-phosphoethanolamine, sodium salt [MPEG-2000-DMPE]/cholesterol.

The flowability enhancer, which is a substance that enhances the flowability of a pharmaceutical composition, may be, but is not limited to, hydrophobic non-hygroscopic materials such as amino acids, mannitol, inulin, sucrose, lactose, L-leucine, D-leucine, isoleucine, serum albumin, dextrose, maltose, glycine, maltitol, calcium stearate, magnesium stearate, erythritol or a mixture thereof.

In certain preferred embodiments the flowability enhancer is crystalline. Crystalline flowability enhancers tend to crystallise on the exterior surface of the lipid vesicles in the liposomal dispersion.

In certain preferred embodiments the flowability enhancer is maltose, mannitol, inulin, sucrose, lactose, dextrose, maltitol, glycine, calcium stearate or magnesium stearate.

When the drug substance is ionic it is often desirable for the pharmaceutical composition to contain an ion compensator and/or a buffer system. The ion compensator, which is a substance that diminish the drug substance ion and allows the encapsulation into neutal lipid, may be, but is not limited to calcium stearate, calcium chloride, tribasic calcium phosphate, dibasic calcium phosphate, calcium sorbate, calcium propionate, magnesium chloride or magnesium stearate. In certain preferred embodiments the ion compensator is calcium chloride, tribasic calcium phosphate or calcium stearate. The buffer system adjusts the pH of the liposomal dispersion and adjusts the ionic charge on the drug substance(s). It may be, but is not limited to lactic acid, citric acid, acetate buffer, glycine, phosphate buffer or tris buffer. In certain preferred embodiment the buffer is lactic acid pH 4.0 and phosphate buffer pH 6.5. As mentioned above, the pharmaceutical composition of the present invention can be dried to form a dry powder formulation that is free flowing and preferably suitable for inhalation and/or nasal administration.

In accordance with the present invention there is provided a method of ameliorating drug substance induced inflammation in a human subject (e.g. patient) which method comprises providing a dry powder formulation as herein described. In preferred embodiments, the dry powder formulation comprises a liposomal dispersion comprising a neutral lipid such as DPCC. We therefore also provide a dry powder formulation comprising one or more drug substances for administration to a human patient wherein said formulation ameliorates inflammation induced by said drug substance upon administration to said human patient, said dry powder formulation comprises a neutral lipid such as DPCC, a co-lipid and a flowability enhancer (e.g. a crystalline flowability ehancer). Said dry powder formulation may be made by the process as described herein.

Drug delivery via the respiratory tract is an attractive route of drug administration for systemic and local action. Compared to the current conventional parenteral administration of APIs especially biological molecules their administration by via the respiratory tract reveals numerous advantages compared with the conventional oral, transdermal or parenteral route because the simpler self administration, the lungs provide a large mucosal surface for drug absorption, bypassing the first-pass effect in the liver, the reduced enzymatic and pH degradation of drugs compared with the oral route. Delivering drug substances by inhalation also enables local application into the lung thus reducing side effects and to improving the effectiveness of the drug at higher local concentration.

Dry powder formulations for inhalation in the treatment of respiratory diseases are generally formulated by mixing a micronised active pharmaceutical ingredient with coarse carrier particles to give to an ordered mixture. However, the ultrafine particles tend to have poor flowability and aerosolisation properties, leading to relatively low respirable fraction, i.e. the fraction of aerosol which deposited in the lung periphery. Another concern is particle -particle interaction forces such as hydrophobic binding, electrostatic and capillary water interaction, which can lead to the formation of aggregates and agglomerates. These can lead to a significant reduction in the efficiency of conventionally prepared dry powder systems. This can make it uneconomical to produce dry powders of expensive macromolecules and raise long-term stability concerns. In broad terms the intranasal route of administration has tended only to be employed to deliver conventional drugs for treating local discomforts such as nasal congestion and sinus infection. However more recently certain clinical trials have demonstrated that the intranasal route can also be useful when treating serious respiratory diseases such as asthma, allergy, cystic fibrosis, severe acute respiratory syndrome and infections caused by respiratory syncytial viruses and influenza virus - see Hussain A., Adv. Drug Del. Rev. (1998) 29: 39-49; Nyce & Metzger, Nature (1997) 385:721-725; Finotto et al., /. Exp. Med. (2001) 193: 1247-1260; Allakhverdi et al., Am. J. Respir. Crit. Care Med. (2002) 165: 1015-1021 , Aurora J., Drug Delivery Technology (2007) 85. Nasal administration can be an appealing approach for the systemic application of drugs as it permits a non-invasive application with prospects for improved patient compliance. The nasal cavity provides a large surface area for absorption, which is covered by a surface active lipoprotein that acts a surfactant and thus can assist in the intracellular uptake of drug substances including antiinflammatories, immunostimulatories, hormones, peptides, proteins, antibodies, oligonucleotides, vaccines, pDNA, RNAs, DNAs and antineoplastics.

Liquid nasal sprays and droplets are the most used drug formulations for intranasal administration. However dry powder formulations may be more suitable than liquid formulations where the drug substance is a macromolecule that has poor bioavailability due to hydrophilic characteristics, where the drug substance is not stable in an aqueous medium or where liquid fall off from the nasal cavity and/or swallowing nasally applied liquid leads to irreproducible dosing. Moreover, powder nasal delivery system can be designed to target a specific region in the nasal cavity and provide a sustain release action.

Moreover, a nasal delivery system can be designed to target a specific region in the nasal cavity as well as have a sustain release action. Dry powder formulations of the present invention where the mean particle size of the powder is greater than about 20 μm can target a drug deposition in the anterior portion of the nose, thus providing a longer residence time in the nose and therefore a local effect, and such dry powder formulations form an embodiment of the invention. Whereas dry powder formulations of the present invention where the mean particle size of the powder is between 10 and 20 μm can target a drug deposition in the posterior portion of the nose, where permeability is generally higher, thus providing shorter residence time in the nose and therefore systemic absorption., and such dry powders form an embodiment of the invention. While targeting a specific nasal region using a liquid nasal spray delivery system is challenging due to the wide distribution of the produced droplets as well as the dependency on the spray pattern, nasal dry powder formulations of the present invention can accurately and effectively deliver drugs to the region of interest in the nose.

Dry powder formulations of the present invention that are free flowing dry powders for nasal and/or lung administration offer various useful benefits. For example they tend to be more stable than traditional liposomal dispersion formulations, they can deliver the drug substance more efficiently and permit a reduced dose to be applied, they enable the drug substance to be targeted to a particular region of the nasal cavity, upper airways or alveolar deposition for local or systemic application and they do not require the use of preservatives.

Anti-adherent agents such as magnesium stearate have been used to address some of these problems in dry powder formulations that contain low molecular weight drug substances. However such agents are unsuitable when formulating macromolecules as peptides, proteins, oligonucleotides, RNA or DNA. Furthermore it does not help the targeting of the APIs into the cell or suspend the lung's natural clearance mechanism until the drug has been effectively delivered.

Lipid encapsulated dry particles normally have poor flowability and high stickiness, which creates problems in downstream processing, including filling and packaging. However, surprisingly, the dry powder formulations of the present invention are substantially free- flowing with low stickiness.

The dry powder formulations of the present invention also show good physicochemical powder characteristics like the reduction of adhesion/cohesion forces due to the reduction in the particle/particle contact area and particle/packaging material contact area. This can ensure desirable powder aerosolisation characteristics and less powder retention in primary packaging or inhalation devices.

The dry powder formulations may also contain pharmaceutically acceptable excipients such as carriers, adjuvants, stabilizers, preservatives, dispersing agents, surfactants and other agents conventional in the art having regard to the type of formulation in question. Such materials are non-toxic to recipients at the dosages and concentrations employed; buffers such as phosphate, citrate, succinate, acetic acid, and other organic acids or their salts; antioxidants such as ascorbic acid; hydrophilic polymers such as polyvinylpyrrolidone; monosaccharides, disaccharides, and other carbohydrates including cellulose or its derivatives, glucose, manose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; counterions such as sodium; and/or nonionic surfactants such as polysorbates, poloxamers, or PEG. One of ordinary skill in the art may select one or more of the aforementioned excipients with respect to the particular desired properties of the parenteral dosage form by routine experimentation and without any undue burden. The amount of each excipient used may vary within ranges conventional in the art.

The pharmaceutical composition of the present invention is prepared, in broad terms, by the process comprising the steps of:

(a) mixing a lipid and a co-lipid under high shear;

(b) admixing one or more drug substances; and

In step (a) the lipid particles are formed by mixing a lipid and a co-lipid in a high shear mixer such as a Collette high shear mixer, Niro Pharmasystems, Denmark with or without ultrasonic assistance. The lipid particles are preferably conditioned at a constant temperature above the lipid transition temperature. The lipid and a co-lipid may be mixed together with a solvent system that comprises one or more solvents into which the lipid, co-lipid, the drug substance(s) dissolves. This is usually an organic solvent such as alcohol for example ethanol or isopropanol.

In step (b) the drug substance(s) may be admixed with the lipid using any art-known method that is suitable for the drug substance(s) used. However this is preferably conducted slowly with continuous mixing to encourage thorough and homogenous mixing and the entrapment of the drug substance into a liposomal vesicle but avoiding degradation or denaturation of the drug substance. In a preferred embodiment the drug substance is injected slowly into the lipid particle dispersion using a pumping system (flow rate 0.1 to 550 ml/min example for batch sizes between 10 ml and 100 L) with continuous mixing under controlled temperature.

When the drug substance is ionic it is often desirable for the pharmaceutical composition to contain an ion compensator and/or a buffer system. They can be admixed with the drug substance(s) in step (b).

In step (c) the flowability enhancer (with or without buffer salts) is mixed with the mixture of lipid particles and drug substance(s) using any art-known method that is suitable to form a liposomal dispersion of the one or more drug substances encapsulated into lipid vesicles. The average diameter of the vesicles is preferably between 70 and 550 nm, more preferably between 100 and 450 nm and even more preferably between 100 and 250 nm as determined by a dynamic light scattering technique carried out using a Master Zetasizer, Malvern Instruments Ltd, UK.

The pharmaceutical composition of the present invention can be processed further to prepare a dry powder formulation. The additional steps comprise: (d) optionally, diluting the liposomal dispersion; and (e) drying the liposomal dispersion to form the dry powder formulation.

In step (d), when dilution is required, the liposomal dispersion is preferably diluted to = 10% , preferably 2 to 5 % and most preferable = 2% , of the final concentration using water or buffered solution. However when preparing a dry powder formulation for nasal administration the liposomal dispersion is preferably diluted to 2 to 20 % , preferably 5 to 10 % of the final concentration using water or buffered solution.

In step (e) the liposomal dispersion dried, is dried using any art-known and suitable method, with a preferred method described in more detail below. Preferably the liposomal dispersion is spray dried. The resulting dry powder formulation is substantially free -flowing .

In accordance with the invention there is provided a process for the production of a dry powder formulation (e.g. having a mean particle size of greater than 20μm for delivery of the powder to the anterior portion of the nose or e.g. having a mean particle size of between lOμm to 20μm for delivery to the posterior portion of the nose) comprising a liposomal dispersion of lipid vesicles that encapsulates one or drug substances (e.g. siRNA and/or oligonucleotide) which process comprises

(a) mixing a lipid and a co-lipid under high (e.g. 50 rpm or greater) shear;

(b) admixing one or more drug substances; and (c) admixing a flowability enhancer to form a liposomal dispersion that comprises lipid vesicles that encapsulate the one or more drug substances;

(d) optionally, diluting the liposomal dispersion to between 5 to 10% of the final concentration using water or buffered solution;

(e) drying the liposomal dispersion (by e.g. spray drying at a temperature of about 130⁰C or greater) to form a powder formulation. In some embodiments, this process proceeds in the order (a) to (e) and the drying step is conducted at 130⁰C. The present invention extends to dry powder formulations produced by the processes of the present invention.

The drying process of step (e) maybe carried out using an optimized spray drying technique, in which the liposomal dispersion is atomized using a by-pass spraying nozzle operated using a pressurized gas like air or nitrogen to form droplet in the size of 5-50 μm. These droplets are suspended in a hot gas e.g, air or nitrogen to be dried. During this drying process the water evaporates with a diffusion rate based on the drying condition. Concurrently, all hydrophilic compositions of the formulation including the liposomal vesicles migrate toward the center of the droplet while the hydrophobic composition like the extra lipid hydrophobic tails migrate toward the gas/droplet interface. By adjusting this dynamic process through a tide controlling of the diffusion process, a liposomal dry powder particle maybe be produced, which efficiently encapsulate one or more drug substance. Moreover, the flowability enhancers precipitate on the surface of these powder capsule, allow a decrease particle particle contact area which significantly improve powder flowability and aerosolization performance.

In accordance therefore there is provided a process for the production of a dry powder formulation comprising a liposomal dispersion of lipid vesicles that encapsulates one or drug substances (e.g. siRNA and/or oligonucleotide) which process comprises

(a) mixing a lipid and a co-lipid under high (e.g. 50 rpm or greater) shear;

(b) admixing one or more drug substances; and

(c) admixing a flowability enhancer (e.g. in crystalline form) such as maltose, mannitol, inulin, sucrose, lactose, dextrose, maltitol, glycine, calcium stearate or magnesium sterate to form a liposomal dispersion that comprises lipid vesicles that encapsulate the one or more drug substances;

(d) optionally, diluting the liposomal dispersion;

(e) drying the liposomal dispersion to form a powder formulation in which the drying process comprises spray drying the liposomal dispersion to form droplets of the dispersion of between 5 and 50 μm suspended in a gaseous atmosphere (e.g. air, oxygen, nitrogen) at a temperature of (about) 130⁰C or greater.

In some embodiments, this process proceeds in the order (a) to (e). In certain preferred embodiments the dry powder formulation is inhalable with a Mass Median Aerodynamic Diameter (MMAD) no greater than 10 microns, but preferably no greater than 5 microns. For certain powder compositions the average MMAD is no greater than 1 to 3 microns, which can ensure deep lung deposition and a Volume Mean Diameter (VMD) no greater than 35 microns, but preferably no greater than 25 microns

In certain preferred embodiments the dry powder formulation is suitable for nasal application when the dry powder has a Mass Median Aerodynamic Diameter (MMAD) or the mean particle size is greater than 10 microns. As mentioned above, dry powder formulations of the present invention where the mean particle size of the powder is greater than about 20 μm can target a drug deposition in the anterior portion of the nose and give a local effect. Whereas dry powder formulations of the present invention where the mean particle size of the powder is between 10 and 20 μm can target a drug deposition in the posterior portion of the nose and provide systemic absorption.

The process can be adjusted to produce free flowing dry powder with a controlled particle size distribution which can target any desired region of the pulmonary tract.

Pharmaceutical compositions and dry powder formulations of the present invention can be used to treat a variety of diseases and disorders, which is dictated by the choice of drug substance(s). The composition may be administered by any appropriate route, e.g. orally, for example in the form of a tablet or capsule; parenterally, for example intravenously; topically to the skin, for example in the treatment of psoriasis; intranasally; or, preferably, by inhalation.

Oral dosage forms may include tablets and capsules. Formulations for topical administration may take the form of creams, ointments, gels or transdermal delivery systems, e.g. patches. Compositions for inhalation may comprise aerosol or other atomizable formulations or dry powder formulations. However in a preferred embodiment of the invention the pharmaceutical composition is in the form of a dry powder formulation that is suitable for administration by inhalation. In a preferred embodiment of the invention the pharmaceutical composition is liposomal dispersion that is suitable for administration by inhalation. In another preferred embodiment of the invention the pharmaceutical composition is in the form of a dry powder formulation that is suitable for nasal administration. In a preferred embodiment of the invention the pharmaceutical composition is liposomal dispersion that is suitable for nasal administration. Inhalable dry powder formulations of the invention can take various forms that are commonly used in the pharmaceutical industry. They can, for example, be packed into capsules, blisters or any other packaging system and applied as a dry powder to the respiratory tract or the nasal cavity using various inhalation/nasal devices. A suitable device for delivery of dry powder in encapsulated form is for example but not limited to the description in US 3,991 ,761 (including the AEROLIZER™ device) or WO 05/113042, while suitable DPI devices include those described in WO 97/20589 (including the CERTIH ALER™ device), WO 97/30743 (including the TWISTHALER™ device), WO 05/14089 (including the GEMINI™ device), WO 05/37353 (including the GYRO H ALER™ device) and WO 99/64095 (MicroDose^™).

Suitable unit dose devices for delivery of dry powder to the nasal cavity include those described in WO 96/22802 (including the DIRECTH ALER™ device), US 6626379 (including the Pfeiffer dry powder nasal applicator. Suitable multidose DPI devices for nasal administration include those described in WO 04/33009 (including the POWERJET™ device), WO 06/90149 (including the OPTINOSE™ dry powder nasal applicator), and WO 90/13328 and WO 96/16687 (including the TURBOH ALER™ device).

The liposomal dispersion and the inhalable dry powder formulations of the present invention can also be reconstituted in a vehicle directly before application and aerosolized using a nebulizer, aqueous droplet inhaler or nasal applicator. Suitable nebulizers include traditional nebulizers such as jet nebulizers e .g. the PARI LC series (PARI GmbH ) as well as vibrating membrane nebulizer such as OMRON Micro A-I-R, (OMRON), Aeroneb^® (Nektar Therapeutics Inc.), PARI eFlow^® (PARI GmbH), PARIeFlow^® rapid, iNeb inhaler (Respironics) as well as a soft mist or soft spray inhalers such as the AERx^® (Aradigm Corp., US), Mystic (Ventaira Pharmaceuticals Inc.), Aria (Chrysalis Technologies Inc.) or Respimat^® (Boehringer Ingelheim).

Inhalable dry powder formulations of the present invention can also be dispensed in a suitable propellant system such as but not limited to hydrofluoroalkanes (HFAs) such as HFAl 34a or d HFA227 with or without further excipients and aerosolized using a suitable pressurized metered dose inhaler (pMDI).

In accordance therefore with the present invention there is provided a pharmaceutical composition for inhaled and/or nasal delivery of one or more drug substances (such as a oligonucleotide and/or siRNA) which composition comprises a liposomal dispersion comprising lipid vesicles that encapsulate one or more drug substances. In accordance with another aspect of the invention there is provided a dry powder formulation for inhaled and/or nasal devlivery of one or more drug substances (such as an oligonucleotide and/or siRNA) which composition comprises a liposomal dispersion comprising lipid vesicles with an average diameter of between 70 and 550 nm (preferably between 100 and 250nm) that encapsulate the one or more drug substances.

In accordance therefore with the present invention there is provided a pharmaceutical composition for inhaled and/or nasal delivery of one or more drug substances (such as a oligonucleotide and/or siRNA) which composition comprises a liposomal dispersion comprising lipid vesicles that encapsulate one or more drug substances wherein the dispersion is formed by a process that comprises the steps of;

(a) mixing a lipid and a co-lipid (such as pegylated phosphatidyl choline or cholesterol) under high shear; (b) admixing one or more drug substances; and

In accordance with another aspect of the invention there is provided a dry powder formulation for inhaled and/or nasal delivery of one or more drug substances (such as an oligonucleotide and/or siRNA) which composition comprises a liposomal dispersion comprising lipid vesicles that encapsulate the one or more drug substances wherein the formulation is formed by a process that comprises the steps of; (a) mixing a lipid and a co-lipid under high shear; (b) admixing one or more drug substances;

(d) optionally, diluting the liposomal dispersion; and

(e) drying the liposomal dispersion to form the powder formulation.

In accordance with a further aspect of the present invention there is provided a free-flowing dry powder formulation for intranasal administration via the anterior portion of the nose of one or more drug substances (such as an oligonucleotide and/or siRNA) which formulation comprises a liposomal dispersion comprising lipid vesicles that encapsulate the one or more drug substances wherein the average vesicle size distribution, as measured by laser diffraction, is

(a) 10% below the xlO value

(b) 50% below the x50 value

(c) 90% below the x90 value.

In another aspect of the invention, there is provided a pharmaceutical composition comprising one or more drug substances (such as an oligonucleotide and/or siRNA)) substantially as described in any one of compositions A,B,C or D.

In accordance with a further aspect of the present invention there is provided a method of treating a human patient (afflicted with e.g. asthma, allergic rhinitis, COPD, lung fibrosis, pulmonary hypertension and/or cystic fibrosis) with one or more inhaled or nasally delivered drug substances which method comprises providing a pharmaceutical composition or dry formulation as hereinbefore described.

In a further aspect there is provided a pharmaceutical composition or dry powder formulation as hereinbefore described for use in a medical treatment of a human patient.

The invention also provides a pharmaceutic al product comprising a pharmaceutical composition as hereinbefore described in association with one or more delivery devices. In a further aspect, the invention provides a delivery device, or a pack of two or more delivery devices, containing a pharmaceutical composition as hereinbefore described.

6. Exemplfication

The invention is illustrated by the following Examples.

EXAMPLES

Example 1 Preparation of pharmaceutical compositions of the invention Pharmaceutical compositions A, B, C and D are prepared from the following:

Composition A

Composition B

Composition C

Composition D

Oligonucleotide A is an immunomodulatory oligonucleotide or "immunomer" with TLR9- agonist activity that is useful in the treatment of allergic inflammatory diseases including allergic rhinitis. Its structure can be represented as follows:

5'-TCR2AACR2TTCR2-Y-TCTTR1 CTGTCT-5' (SEQ.I.D.NO:1 ) where C is cytosine, T is thymine, G is guanine, Y is a propanediol linker and R1/R2 are synthetic guanosine derivatives as shown below:

Rl=Arabinoguanosine

R2=2 '-deoxy -7 -deazagu ano sine

Oligonucleotide A and a method of its preparation is described in international patent application WO 2006/002038 (see SEQ ID NO 22 therein). Immunomers, generally, and methods for making them are also described in international patent applications WO 2003/035836 and WO 2003/057822. The contents of all three documents are incorporated herein by way of reference.

Oligonucleotide A is water soluble so it is dissolved in 0.1 % lactic acid solution pH 4 to neutralize the negative charge on the molecule.

siRN A A is siRN A for Flu. It is chemically synthesised RNA that silences the Flu-mRNA in the treatment of pandemic influenza. The SiRNA in use is a short double stranded oligos (MW: 14 kDa) comprising 21 nucleotides per strand. Its structure can be represented as follows: Sense strand sequence: 5 '-GAGCCUAUGUGGAUGGAU UTST-S ' (SEQ.I.D.NO:2)

Antisense strand sequence: 5 '-AAUCCAUCCACAUAGGCUCTST-S ' (SEQ.I.D.NO:3)

Where single letter nucleotide codes are: A is adenosine, C is cytidine, G is guanosine, U is uridine, sT is thymidine and the hyphen represents a 3 '-5' phosphodiester linkage. This drug substance is also negatively charged and water soluble so it is dissolved in 0.1% lactic acid solution pH 4 to diminish the negative charge on the molecule.

In each case the lipid, co-lipid and solvent system are poured into a high shear mixer (Collette Micro Gral high shear mixer, Niro Pharmasystems, Denmark) and mixed for about 20 minutes at 40-60⁰C at impeller speed of 50-150 rpm and chopper speed of 200-600 rpm until lipid particles are formed. The drug substance, diluent, lactic acid pH 4.0 and ion compensator are injected into the lipid particles using a pumping system ISMATEC peristaltic pump, ISMATECH SA, Switzerland providing a flow rate of 0.5-10 ml/min. The flowability enhancer and buffer pH 6.5 areadded to form a liposomal dispersion of the one or more drug substances encapsulated into lipid vesicles. This is evident by the turbidity of the liposomal dispersion with no obvious sedimentation for more than two hours. The lipid vesicles within the liposomal dispersion have an average diameter of between 70 and 550 nm as determined by a dynamic light scattering technique carried out using a Master Zetasizer, Malvern Instruments Ltd, UK.

Example 2

Preparation of dry powder formulations of the invention

The pharmaceutical compositions A, B, C and D prepared in Example 1 are further processed to prepare dry powder formulations of the invention.

In Case A & B the nanosuspension formed in Example 1 is diluted down to have 2% solid content weight per volume while in case C & D in Example 1 is diluted down to have 0.5% solid content weight per volume to give a liposomal dispersion with low viscosity which can easily be atomized in the spray drier and form small inhalable free flowing powders particles < 10 μm. Each diluted liposomal dispersion is then spray dried using Bϋchi 191 spray dryer, Bϋch labor Technick AG, Switzerland in which the dispersion is atomized in hot air of 90°-150°C to give a free-flowing dry powder composition. The average geometrical particle size of the dry powder is about 4-13μm as measured by HELOS laser diffraction instrument, Sympatech GmbH, Germany.

Example 3

Flowability of dry powder formulations of the invention

The dry powder formulations prepared in Example 2 are tested using a STAV II densitymeter, J Engelsmann AG, Germany. In each case 10 g of the dry powder formulation is placed in a volumetric cylinder. The powder volume is measured and the bulk density or "BD" is calculated in g/cm3 as follows:

BD [g/cm3]= powder weight (g)/powder bed volume (ml or cm³)

The dry powder is tapped 1250 times and the powder volume bed is measured. The tapped density or "TBD" is calculated as follows:

TBD [g/cm3]= powder weight (g)/powder bed volume tapping (ml or cm³)

The Carr's Index is calculated as follows:

Carr's Index [% ]= (Tapped Density- Bulk Density)* 100 / Tapped density

The Carr's index for the four dry powder formulations are given in Table 1 below:

Table 1

These results indicates the dry powder formulations powders are free-flowing. Example 4

Particle size characteristics of the dry powder formulations of the invention

The particle size characteristics of the dry powder formulations prepared in Example 2 is determined by a HELOS laser diffraction instrument [Sympatech GmbH, Germany

The results are given in Table 2 below (n = 3):

Table 2

In that table VMD is the Volume Mean Diameter and GSD is the Geometrical Standard Deviation. These particle size characteristics indicate the dry powder formulations should target the desired region of the pulmonary tract.

Example 5

Further analysis of the dry powder formulation prepared from pharmaceutical composition C

The dry powder formulation prepared from pharmaceutical composition C in Example 2 is further analysed. The characteristics of this powder are summarised in Table 3 below:

Table 3

In this table 10% of the particles have an average particle size that is below the XlO value measurement, 50% of the particles have an average particle size that is below the X50 value measurement, and 90% of the particles have an average particle size that is below the X90 value measurement. The Osmolarity, as measured by Micro Osmometer (Advanced Inst. Inc, US), indicates the siRNA is efficiently encapsulated. VMD is the Volume Mean Diameter and GSD is the Geometrical Standard Deviation.

The mass median aerodynamic diameter [MMAD or d_aer] can be calculated from the volume diameter [dv] by the formula: daer = ^dv V P where p is the powder density in g/cm³

The low density of this powder can ensure a low MMAD, which leads to a high Fine Particle Fraction [FPF<5μm].

The liposomal dispersion particle size distribution measured by laser diffraction is shown in Figure 1 of the accompanying drawings. The powder particle size distribution measured by laser diffraction is shown in Figure 2.

The average particle size of the liposomal dispersion is 517.5 nm. The liposomal dispersion has a poly dispersity index of 0.47.

These results show the dry powder formulation composed of monodisperse particles which are is suitable for administration by inhalation and substantially free-flowing.

Example 6

Further analysis of the dry powder formulation prepared from pharmaceutical composition D

The dry powder formulation prepared from pharmaceutical composition D in Example 2 is further analysed. The characteristics of this powder are summarised in Table 4 below:

Table 4

In this table 10% of the particles have an average particle size that is below the XlO value measurement, 50% of the particles have an average particle size that is below theX50 value measurement, and 90% of the particles have an average particle size that is below the X90 value measurement.

The Osmolarity, as measured by Micro Osmometer (Advanced Inst. Inc, US), indicates the siRNA is efficiently encapsulated. VMD is the Volume Mean Diameter and GSD is the Geometrical Standard Deviation. The mass median aerodynamic diameter (MMAD or d_aer) can be calculated from the volume diameter [dv] by the formula: d_aer = d_vjp where p is the powder density in g/cm³

The low density of this powder can ensure a low MMAD, which leads to a high Fine Particle Fraction (FPF < 5μm).

The liposomal dispersion particle size distribution measured by laser diffraction is shown in Figure 3 of the accompanying drawings. The powder particle size distribution measured by laser diffraction (Malvern Zetasizer, UK) is shown in Figure 4.

The average particle size of the liposomal dispersion is 229.5 nm. The liposomal dispersion has a poly dispersity index of 0.261.

These results show the dry powder formulation is suitable for administration by inhalation and substantially free-flowing.

Example 7 Preparation of further pharmaceutical compositions of the invention

Pharmaceutical compositions E, F, G and H are prepared from the following:

Composition E

Composition F

Composition G

Composition H

These compositions, which are liposomal dispersions, are prepared as described in Example 1, where Oligonucleotide A is the same immunomodulatory oligonucleotide with TLR9-agonist activity, however the oligonucleotide is negatively charged with a Zeta potential of -45 mV (measured using Master Zetasizer, Malvern Instruments Ltd, UK) and after encapsulation the Zeta potential is increased toward the neutral value with (0 to -6 mV). Reducing the negative charge on the oligonucleotide in this way avoids irritation in the nasal mucosa and allows the drug substance to be present in an unionized form that is suitable for absorption. siRNA B is siRNA designed against Luciferase. It is chemically synthesised RNA that silences the firefly protein hydro lyzing luciferine, producing light. The SiRNA in use is a short double stranded oligos (MW: 13486 Da) comprising 21 nucleotides per strand. Its structure can be represented as follows:

Sense strand sequence:

5'- CUUACGCUGAGUACUUCGAdTsdT -3' (SEQ.I.D.NO:4)

Antisense strand sequence:

5'- UCGAAGUACUCAGCGUAAGdTsdT -S' (SEQ.I.D.NO:5)

Where single letter nucleotide codes are: A is adenosine, C is cytidine, G is guanosine, U is uridine, sT is thymidine and the hyphen represents a 3 '-5' phosphodiester linkage. This drug substance is also negatively charged and water soluble so it is dissolved in 0.1 % lactic acid solution pH 4 to diminish the negative charge on the molecule.

The solid concentration of the composition in the liposomal dispersion was set to 5% w/w.

Example 8

Preparation of dry powder formulations of the invention for intranasal administration

The pharmaceutical compositions E, F, G and H prepared in Example 7 are spray dried to give dry powder formulations of the invention that are suitable for intranasal administration.

The spraying drying is carried out using a Biichi 191 spray dryer, Biich labor Technick AG, Switzerland to give free-flowing dry powder.

A 2 mm spray nozzle is used to prepare a dry powder formulation for nasal application that has a mean particle size greater than 20 μm for targeted anterior nasal deposition. A 0.7 mm spray nozzle is used to prepare a dry powder formulation for nasal application that has a mean particle size between 10 and 20 μm for targeted posterior nasal deposition.

Example 9 Characterisation of dry powder formulations of the invention for intranasal administration

The mean vesicular size of each of the compositions E, F, G and H of Example 7 is determined by a dynamic light scattering technique using a Master Zetasizer, Malvern Instruments Ltd, UK. The Polydispersity Index (PDI) of each composition is determined accordingly. It is an indication of width of the particle distribution as a low PDI can indicate a narrow distribution. The results are shown in Table 5 below:

Table 5

Example 10

Encapsulation efficiency of dry powder formulations for intranasal administration

The encapsulation efficiency of each of the formulations E, F, G and H is determined by high performance liquid chromatography (HPLC), by gel electrophoresis and by capillary gel electrophoresis (CGE). In the HPLC method each dry powder formulation is resuspended in phosphate buffered saline (PBS), briefly mixed, the non-encapsulated oligonucleotide is extracted by centrifugation, and the supernatant is analysed for the present of free oligonucleotide. Using this method the encapsulation efficiency of Oligonucleotide A and siRNA A is calculated to be > 95% . In the gel electrophoresis method, each of pharmaceutical compositions E, F, G and H is loaded on a 4% agarose E-gel (Invitrogen™), on which the free, negatively-charged oligonucleotide migrates toward a positively -charged cathode. Qualitative detection of the oligonucleotide is determined using a UV transilluminator.

In Capillary gel electrophoresis the liposome samples are injected in a coated capillary containing a replaceable gel for sieving. A BECKMAN PA800 capillary electrophoresis instrument equipped with a fixed wavelength detector has been used. An example is presented in Figure 5 for compositions E and F. All methods show consistent results for the encapsulation efficiency in the liposome as well as in the powder .

Example 11

Particle size of dry powder formulations for intranasal administration

The particle size of each of dry powder formulations E, F, G and H is measured using a HELOS Laser diffraction with wet dispersion from Sympatech GmbH, Germany. The results are shown in Table 6 below:

Table 6

In each case the volume mean diameter (VMD) is found to be optimal for nasal deposition. The mass median aerodynamic diameter (MMAD or d_aer) can be calculated from the volume diameter [dv] by the formula:

where p is the powder density in g/cm³

The choice of particle size can be used to target a specific region in the nasal cavity. For example, dry powder formulation E has the particle size distribution shown in Figure 6 measured by laser diffraction and summarized in Table 7 to target a drug deposition in the anterior portion of the nose, where permeability is generally lower than elsewhere in the nose:

Table 7

Where 10% of the particles have an average particle size that is below the XlO value measurement, 50% of the particles have an average particle size that is below the X50 value measurement, and 90% of the particles have an average particle size that is below the X90 value measurement, in each case determined by H ELO S Laser diffraction with wet dispersion from Sympatech GmbH, Germany and GSD is the Geometrical Standard Deviation of the previously measured particle size. The particle size distribution shown in Figure 6 and Table 7 provides a longer than usual residence time in the nose due to the deposition into the anterior third of the nose which is lined by skin-like epithelium, which limits the absorption and is thus especially suitable for providing a local therapeutic effect.

Whereas dry powder formulation F has the particle size distribution shown in Figure 7 measured by laser diffraction and summarized in Table 8 to target a drug deposition in the posterior portion of the nose beneath the nasal valve, which is covered by a thin layer of Mucosa and dense network of blood vessel, where permeability is generally higher than elsewhere in the nose:

Table 8

Where XlO, X50, X90 and GSD have the same meanings as before and theparticle size distribution shown in Figure 7 and Table 8 provides a shorter than usual residence time in the nose due to the dense network of blood vessel in this region and is thus especially suitable for providing systemic absorption.

Example 12 pH of dry powder formulations for intranasal administration

The pH of each dry powder formulation is acidic i.e. between about pH 4.5 and pH 6.5 so that the pH of the nasal cavity into which each formulation is administered is sufficiently acidic to avoid inactivating lysozymes that are present in the nose and serve to combat any bacterial invasion into the nose. For example, the dry powder formulations E, F, G and H have a pH of

5.3, 5.5, 6.8 and 5.5 respectively. Example 13

Flowability of dry powder formulations of the invention for intranasal administration

The flowability of the dry powder formulations E, F, G and H is determined with reference to measurements of bulk density (BD), tapped density (TBD) and especially Carr's Index using a STAVII densitymeter, J Engelmann AG, Germany.

In each case 1 g of the dry powder formulation is placed in a volumetric cylinder. The powder volume is measured and the bulk density or "BD" is calculated in g/cm3 as follows:

BD [g/cm3]= powder weight (g)/powder bed volume (ml or cm³)

TBD [g/cm3]= powder weight (g)/powder bed volume tapping (ml or cm³)

The Carr's Index is calculated as follows:

Carr's Index [% ]= (Tapped Density- Bulk Density)* 100 / Tapped density

The results are mean of three measurements and shown in Table 9 below:

Table 9

These powders have good flowability according to the European Pharmacopeaia guidelines (Ph. Eur. 5.8, 2007,<2.936>). While not wanting to be bound by theory, this good flowability could be attributed to the formation of flowability enhancer nanocrystals on the top of the powder particle as detected by scanning electron microscopy (Philips XL 20, Phillips B. V., The Netherlands) and X-ray powder diffraction analysis (Stoe & Cie GmbH, Germany), e.g. dry powder formulation G (see Figure 8).

Example 14 Optimisation of spray drying for dry powder formulations for intranasal administration

The yield of the spray drying process is optimized through the setting of the cuttpoint of the cyclone of the spray dryer to be able to choose the particle size fraction required. The yield could be increase by further coating of the cyclone with an anti-electrostatic coating (e.g. coating with titanium oxide, silica derivatives, Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) or an amphiphilic surface active agent). For example, pharmaceutical compositions E, F, G and H , which are liposomal dispersions, are spray dried in a Biichi 191 spray dryer, Bϋchi AG, Switzerland. A high performance glass cyclone with internal diameter of 6.3 cm was coated by an antistatic surfactant such as but not limited to hydroxy propyl methyl cellulose. The cyclone internal diameter was set to 6.3 cm to improve the separation of smaller particles, which may lead to product losses on the back filter. The yield of each dry powder formulation made by spray drying each of the aforementioned pharmaceutical compositions is given in Table 10 below.

Table 10

Each yield is above 60% at laboratory scale, which indicates a higher yield on further scaling up steps.

Example 15: In this example one formulation composition was used. By tailoring the preparation method, a free flowing liposomal powder with two different particle size can be prepared. The free flowing dry powder particles generated using process 1 , is small enough to target alveolar deposition. The particles prepared using process 2 were larger to target upper airway deposition. Both powders have a narrow particle size distribution which ensures an efficient local deposition in the targeted site into the lung.

Composition example I

Component Amount [g/L] function

SiRNA B 0.300 drug substance

Di-Palmitoyl Phosphatidyl Choline 3.500 Lipid material for the encapsulation

(DPPC)

PEG-Phosphatidyl choline 0.200 Co-lipid (lipid vesicle stabilizer)

Cholesterol 0.500 Co-lipid (lipid vesicle stabilizer)

Ca CI2.2H2O 0.250 Negative ions compensation

Lactic acid pH 4.5 0.006 Buffer

Na₂HPO₄-H₂O pH 6.5 0.017 Buffer

Glycine 0 227 Flowability enhancer/particle surface modifier

As described before, the preparation method is composed of 2 steps. Step I, was kept constant, while step II, which is the spray drying process was tailored to target a specific dry powder particle size distribution. Step I (solvent injection technique under high shear mixing):

• Preparation A (DPPC, PEG- PC and Cholesterol) is dissolved in 100 ml ethanol and placed in a high shear mixer and conditioned at a temperature of 45 ± 5⁰C.

• Preparation B (siRNA B, CaC12.2H2O) is dissolved into 800 ml lactate buffer pH 4.5 and injected slowly using a pumping system into the preparation A at flow rate of 3 ml/min , while continuous mixing is performed.

• Preparation C (Glycine dissolved into 100 ml phosphate buffer pH 6.5) is to be mixed with preparation A+B at flow rate of 10 ml/min.

• The formed liposomal dispersion has a solid content Of 0.5% w/w. Step II (Spray Drying):

• The prepared liposomal dispersion is spray-dried using a Bϋchi B- 191 lab scale spray dryer (Bϋchi AG, Flawil, Switzerland) to form free flowing particles for pulmonary application with an aerodynamic diameter tailored to target either alveolar region (process 1) or upper airways (process 2). A full description of the setting parameters for both processes are presented in Table 11 : Table 11

* Main factors affecting particle size.

Following findings can be derived from this experiment:

• As the formulation composition and step I are the same for both batches, a liposomal dispersion with the same characteristics is prepared with vesicular size and zeta potential, which are determined using a Master Zetasizer, Malvern Instruments Ltd, UK [Table 12].

• The encapsulation efficiency of the siRNA into the liposomal dispersion is measured by the previously described Capillary Gel Electrophoresis method. Data are presented in Table 12.

Table 12

• The powder volume based particle size is measured using a HELOS Laser diffraction with wet dispersion, Sympatech GmbH, Germany [Table 13] :

Table 13

* VMD = Volume Mean Diameter ** GSD = Geometrical Standard Deviation • The aerodynamic particle size distribution is measured using a Next Generation

Cascade Impactor [NGI] (Copley Scientific Inc., UK) at 60 L/min. 5 mg powder was aerosolized in the impactor using a DP4 PennCentury Dry powder inhaler, PennCenury Inc., USA (n = 2) [Table 14, Figure 9, Figure 10].

Table 14

* MMAD = Mass Median Aerodynamic Diameter ** GSD = Geometrical Standard Deviation ***LC = Labelle Claim = 300 μg siRNA While process 1 generate particles with a MMAD of 1.5 μm, which ensure an efficient alveolar deposition, process 2 generate particles with a MMAD of 7.7 μm, which is mainly deposited in the upper airways.

Process 1 produce particles which have a fine particle fraction (FPF) < 5 μm of

71%, which is an indication for ca. 71% deep lung deposition. This high deposition efficiency could be attributed to the good flowing and aerodynamic characteristics of this powder. According to this high efficiency a decrease of the applied therapeutic dose could be achieved, which is desired in the case of expensive macromolecules.

In contrast, using process 2 a FPF with 66% particles > 5 μm can be generated, which ensures upper airway deposition. The Particle Size Distributions [PSD] presented in Figure 9 and 10 emphasizes that both processes generates particles with a mono- modal distribution. Process 1 generates smaller particles than Process 2, nevertheless it generates more agglomerates than process 2 as well, which can be concluded from the higher throat deposition. This could be attributed to the higher surface area that a 1-2 μm particles have comparing with 7-8 μm particles. Process 1 generates particles with a high deposition in stage 4 and 5, which has a cut off diameter of 2.82 μm and 1.66 μm at 60 L/min, respectively. Opposing that, process 2 generates particles with a high deposition in stage 1 and 2, which has a cut off diameter of > 8.06 μm and 8.06 μm at 60 L/min, respectively.

Example 16

Composition example I (example 15) was used to encapsulate a double stranded siRNA which stimulate IF? and TNFa.

The liposomal formulation was characterized by measuring the particle size distribution and the Zeta potential using a Malvern Zetasizer, Malvern Instruments Ltd., UK or using a Helos Sympatech particle sizer, Sympatech GmbH, Germany. The encapsulation efficiency of siRNA into the liposome and powders were measured using capillary gel electrophoresis method, which is described before. The water uptake of the drug substance powder and the free flowing liposomal powder were measured using a dynamic vapor sorption apparatus, SMS Inc., UK

Table 15

• It can be concluded from the data presented in table 15, that the formulation can effectively encapsulate siRNA, as a reduction of the zeta potential from -45 mV to 0 mV can be observed. Moreover the powder has much higher encapsulation efficiency compared with the liposomal formulation, which can emphasize that each powder particle is an intact capsule, which encapsulate liposomal vesicles and free siRNA into it. This can be confirmed by the SEM data [Figure H].

• Moreover, the free flowing powder generate particles which encapsulate the siRNA into it and consequently decrease its hygroscopic characteristics and so allows better stability.

• As shown by SEM in Figure 10, this capsule is not porous, nevertheless it has empty spaces inside it like a pollen grain particle, this could be emphasized by differences in the Volume mean diameter of these particles and the aerodynamic mass median diameter. These particles has a VMD of 3.73 μm, while a MMAD of 1.5 μm, this means that the volume of the particle is more than twice its aerodynamic size, which indicates that the half of the space in these capsules are empty. Moreover, the real density of these particles can be calculated as followed

Where ? is the real density in g/Cm³, d_aer is the aerodynamic particle size in μm and dy is the volume diameter in μm. The density can be calculated as followed: ? = (1.5/3.7)² The density of this particles = 0.16 g/cm3

The empty space in the particle can be calculated as followed:

% empty space into the capsule= [1- (Tapped density/particle density)] X 100 = [1-

(0.25/0.16)] XlOO] = 56 %

• Encapsulation of this siRNA into neutral lipid as DPPC, which is a natural composition of the lung biological fluids, neutralize the siRNA charge and decrease possible side effects such as inflammatory response generated by the stimulation of IF? and TNFa [Figure 12].

• Moreover, the formulation was well tolerated in vivo as no side effect could be observed after dosing 80 rats with two doses each at a dose of lmg/kg siRNA using a PennCentury DP4 intratracheal inhalation device, PennCentury Inc, USA. Example 17 - Scale up trial

• Composition example I (see example 15) was used for the scaling up trial.

• The process has been scaled up from 1 L batch size to 10 L batch size using an UltimaGral High Shear Mixer, GEA process Engineering, Denmark. The process parameter was the same for both batches. The only exception is the solvent feed rate which is set at 3ml/min for the IL batch and 30ml/min for the 1OL batch.

• The spray drying process was scaled up from 5 g to 100 g using a Niro Mobile Minor spray dryer, GEA process Engineering, Denmark. Process parameters are stated in Table 16:

Table 16

A full discribtion of the scaling up process is presented in Figure 12.

A pilot scaling up of the process was successfully done as the data obtained from the pilot scale batches are comparable to the data obtained using the lab scale batches [Table 17].

Table 17

* VMD = Volume Mean Diameter

** GSD = Geometrical Standard Deviation

Example 18 - Accelerated Stability data

Composition example I (see example 15) is stored in white glass vials closed using untied rubber stopper (open storage stability) for two month at three different conditions, 5⁰C, 25°C/60% R.H. and 40°C/75% R.H. The powder was dispensed in 5 mg per powder, which is contributed to 300 μg siRNA B per vial.

The data shown in table 18 indicates the long term stability of siRNA according to the invention. The only exception is the decrease of encapsulation efficiency and the increase in particle size distribution observed after storage for two months at 4O⁰C and 75% R.H.. This could be attributed to the recrystalization of CaCb out of the formulation at high relative humidity of 75% RH after 2 months, which was expected as the packaging system used here was untied. This was confirmed by the SEM data [see Figure.14].

Through extrapolating these data, a minimum of 8 month stability at 5⁰C. and two months at 25°C/60% R.H.. Moreover, by packaging the powder in a tide packaging system like AIu/ AIu blisters to reduce the water vapour diffusion into the powder, a significant improve in long-term stability at 40°C/70% R.H. can be aimed.

Table 18

* LOD = Limit of ditection

**VMD = Volume Mean Diameter

*** GSD = Geometrical Standard Deviation ****Measured using Thermal Gravimetric analyzer, Perkin Elmer, UK

Example 19

« 5 mg powder of composition I, which contains 300 μg siRNA B was filled in 20 DIRECTHALER™ inhalation devices, DirectHaler A/S, Denmark. Emitted dose uniformity of the free flowing powder from these devices was tested at 12 L/min, powder was collected on a glass fiber filter.

• The mean emitted dose was equal 4.14 ± 0.35 mg (n = 20) and the residual amount of powder into the device was 17.5%. All individual values as well as the mean were within the EU Pharmacopeias specification. See Figure 14.

Example 20

• The siRNA diffusion release profile through biological fluids was tested using a specific release model, which simulates the biological condition into the lung.

• A 20 μm thickness Artificial Lung Surfactant (ALS) layer was set in 6 trans-well plate on the top of a PET filter with 40 nm pore diameter. As receptor medium a phosphate buffer pH 7.0 with 0.05% (w/w) DPPC was used.

• 5 mg powder (contain 300 μg siRNA B)or 0.5 ml liposome (contain 300 μg siRNA B) of composition example I (see example 15), is dispensed on the top of the ALS layer and the amount of siRNA diffused through the ALS and the PET membrane filter at 37⁰C to the receptor medium was determined over 24 hrs using RP-HPLC. • As control 0.5 ml of 600 μg/ml siRNA B solution into phosphate buffer pH 7.0 is dispensed on the top of the ALS layer and the test is run as mentioned before.

The powder shows a quicker release profile of siRNA comparing with the siRNA solution and the liposomal dispersion as ca. 66% of the siRNA was released from the powder after 2 hrs comparing with 53% and 32% for the siRNA solution and the liposomal dispersion, respectively (see figure 15).

Claims

1. A pharmaceutical composition that comprises: (A) one or more drug substances; (B) a lipid;

(C) a co-lipid; and

(D) a flowability enhancer; the pharmaceutical composition being characterised in that the lipid, the co-lipid and the flowability enhancer together form a liposomal dispersion that comprises lipid vesicles that encapsulate the one or more drug substances.

2. A composition according claim 1 wherein the average diameter of the lipid vesicles is between 70 and 550 nm.

3. A composition according claim 1 or 2 wherein the or each drug substance is a 62- adrenoceptor agonist, a muscarinic antagonist, a glucocorticosteroid, a non-steroidal glucocorticoid receptor agonist, an A2A agonist, an A2B antagonist, an antihistamine, a caspase inhibitor, a LTB4 antagonist, a LTD4 antagonist, a phosphodiesterase inhibitor, a mucolytic, a matrix metal loproteinase inhibitor, a leukotriene receptor antagonist, a growth hormone, heparin, estradiol, a prostaglandin D2 antagonist, a CRTH 2 receptor antagonist, sodium cromoglycate, an IgE synthesis inhibitor, an antibiotic, an interferon, a potassium channel inhibitor, an immunomodulator, a cytostatic agent, an elastase inhibitor, an anti-neoplastic, a prostatin inhibitor, a peptide, an oligonucleotide, RNA (such as siRNA), DNA, a plasmid, insulin, an interleukin, GLp-I, an anti-neoplastic agent or an antibody.

4. A composition according to any preceding claim wherein the lipid is di-marsetoil phosphatidyl choline, di-palmitoyl phosphatidyl choline, soybean lecithin or a hydrogenated phosphatidyl choline.

5. A composition according to any preceding claim wherein the co-lipid is a pegylated phosphatidyl choline or cholesterol.

6. A composition according to any preceding claim wherein the flowability enhancer is maltose, mannitol, inulin, sucrose, lactose, dextrose, maltitol, glycine, serum albumin, L- leucine, D-leucine, isoleucine, calcium stearate, magnesium stearate, erythritol or a mixture thereof.

7. A composition according to any preceding claim that further comprises an ion compensator and/or a buffer system.

8. A composition according to any preceding claim in the form of a dry powder formulation.

9. A dry powder formulation, that comprises: (A) one or more drug substances; (B) a lipid; (C) a co-lipid; and (D) a flowability enhancer; the formulation being characterised in that the lipid, the co-lipid and the flowability enhancer together form a liposomal dispersion comprising lipid vesicles that encapsulate the one or more drug substances and dry to form a free-flowing dry powder formulation.

10. A dry powder formulation according claim 9 wherein the mean particle size of the powder is no greater than about 10 microns for inhalation.

11. A dry powder formulation according claim 9 wherein the mean particle size of the powder is greater than 10 microns for nasal administration.

12. A dry powder formulation according to claim 11 wherein the mean particle size is between 10 and 20 μm to target a drug deposition in the posterior portion of the nose.

13. A dry powder formulation according to claim 11 wherein the mean particle size is greater than 20 μm to target a drug deposition in the anterior portion of the nose.

14. A process for preparing a pharmaceutical composition, the process comprising the steps of:

(a) mixing a lipid and a co-lipid under high shear;

(b) admixing one or more drug substances; and

15. A process for preparing a dry powder formulation, the process comprising the steps of:

(a) mixing a lipid and a co-lipid under high shear;

(b) admixing one or more drug substances;

(d) optionally, diluting the liposomal dispersion; and (e) drying the liposomal dispersion to form the dry powder formulation.