# Patent

## Title
Depot formulations of a hydrophobic active ingredient and methods for preparation thereof

## Abstract

The invention provides extended release pro-liposomal, non-aqueous, pharmaceutical formulations of a hydrophobic active pharmaceutical ingredient (API) of low water solubility but readily dissolved in alcohols and methods for making same. The formulations can be administered by infiltration into an incision, or by injection.

## Background
This application is a national stage application under 35 U.S.C. §371 of International Application No. PCT/IL2013/050404 filed on May 9, 2013, which claims priority to U.S. Provisional Patent Application Nos. 61/645,066 filed on May 10, 2012, 61/649,400 filed on May 21, 2012, 61/781,625 filed on Mar. 14, 2013, and 61/781,595 filed on Mar. 14, 2013, the contents of all of which are hereby incorporated in their entirety by reference.


FIELD OF THE INVENTION
The present invention relates generally to a depot formulation that can be injected or infiltrated into a desired location and which can provide sustained release of a hydrophobic therapeutic agent. Specifically, the present invention relates to a non-aqueous pro-liposomal depot formulation essentially devoid of synthetic lipids, which advantageously may generate liposomes or other lipidic vesicular structures in situ upon contact with body fluids.
BACKGROUND OF THE INVENTION
Use of extended release formulation of therapeutic agents can improve patient compliance, reduce hospital stays and hospital costs and, therefore, result in costs savings to the patient and the healthcare system. The market for such extended release formulations are expected to exceed several billion dollars annually in the U.S. alone.
A useful method, by which long lasting therapy can be achieved, is by a single application of a depot formulation. The depot can be optimized for injection, infiltration into an incision, implantation or topical application. In a depot formulation, a therapeutic agent is formulated with carriers providing a gradual release of the therapeutic agent over a period of several hours to several days, or longer. Depot formulations are generally based upon a biodegradable matrix which gradually undergoes degradation or disperses thus releasing the therapeutic agent.
Hence, the advantage of depot formulations is that active therapeutic agents are released gradually over long periods without the need for repeated dosing. These formulations are thus highly suitable for situations where continuous therapeutic effect is desirable, where around-the-clock dosing via an injection pump-type dosing device that delivers medication into the veins (intravenously, the most common method), under the skin (subcutaneously), or between the dura mater and the backbone (epidurally).
Many depot formulations rely on particles incorporated into liposomes or microspheres for encapsulation of the therapeutic agent. Liposomal depot formulations, however, are difficult to manufacture, are extremely sensitive to surface active agents, have limited shelf-life or require special storage conditions and a sub-ambient temperature for storage. Due to their particle size and fragile nature which prevents the use of common sterilization methods such as filtration, irradiation or autoclaving, liposomal multivesicular depot formulations are usually made under aseptic conditions which make the manufacturing process cumbersome and costly. In addition, liposomal depot formulations generally provide extended release of the therapeutic agent for up to 12 hours only.
Various products are described with drugs incorporated into microspheres in oil based carriers.
For example U.S. Pat. No. 7,547,452 to Atkins et al. provides sustained-release microparticle compositions. The microparticle composition can be formulated to provide extended release over a period of from about 7 days to about 200 days. The microparticles may be formulated with a biodegradable and biocompatible polymer, and an active agent, such as risperidone, 9-hydroxy-risperidone, and pharmaceutically acceptable acidic salts of the foregoing.
U.S. Pat. No. 5,480,656 to Okada provides a microcapsule designed for zero order release of a physiologically active polypeptide over a period of at least two months, which is produced by preparing a water-in-oil emulsion comprising an inner aqueous layer containing about 20 to 70% (w/w) of said polypeptide and an oil layer containing a copolymer or homopolymer having a weight-average molecular weight of 7,000 to 30,000, wherein the composition ratio of lactic acid/glycolic acid in the copolymer or homopolymer is 80/10 to 100/0, and then subjecting said water-in oil emulsion to microencapsulation.
U.S. Pat. No. 5,654,010 to Johnson provides a composition, and methods of forming and using said composition, for the sustained release of biologically active, stabilized human growth hormone (hGH). The sustained release composition of this invention comprises a polymeric matrix of a biocompatible polymer and particles of biologically active, stabilized hGH, wherein said particles are dispersed within the biocompatible polymer. The method of the invention for producing a composition for the sustained release of biologically active hGH, includes dissolving a biocompatible polymer in a polymer solvent to form a polymer solution, dispersing particles of biologically active, stabilized hGH in the polymer solution, and then solidifying the polymer to form a polymeric matrix containing a dispersion of said hGH particles. The method for using a composition of the invention is a method for providing a therapeutically effective blood level of biologically active, non-aggregated hGH in a subject for a sustained period. In this method, a subject is administered an effective dose of the sustained release composition. The method of using the sustained release composition comprises providing a therapeutically effective blood level of biologically active, non-aggregated human growth hormone in a subject for a sustained period by administering to the subject a dose maximum allowed dosage since it may affect the CNS and is contraindicated to be used IV. As Naropin® Injection is often combined with per os taken opiates when administered to treat post-operative pain; it retains some of said sustained release composition.
U.S. Pat. No. 5,538,739 to Bodmer et al discloses microparticles comprising a polypeptide, preferably somatostatin or an analog or derivative thereof, more preferably octreotide, in a polymeric matrix, preferably poly(lactide-co-glycolide) glucose. The invention also discloses sustained release formulations containing said microparticles and the use of said formulations in treating acromegaly and breast cancer.
U.S. Pat. No. 6,132,766 to Sankaram et al. discloses a multivesicular liposome composition containing at least one acid other than a hydrohalic acid and at least one biologically active substance, the vesicles having defined size distribution, adjustable average size, internal chamber size and number, and provides a controlled release rate of the biologically active substance from the composition. The invention also discloses a process for making the composition which features addition of a non-hydrohalic acid effective to sustain and control the rate of release of an encapsulated biologically active substance from the vesicles at therapeutic levels in vivo.
U.S. Pat. No. 5,863,549 to Tarantino is directed to a method for making in vivo a lecithin gel which provides for the sustained release of a biologically active compound contained in the gel. This invention is also directed to a method for the sustained treatment of a human or of other mammals with a therapeutic amount of a biologically active compound using the gel for the sustained release of the biologically active compound. The biologically active compounds disclosed and exemplified are peptides and polypeptides.
US 2005/0287180 to Chen provides compositions that comprise a phospholipid component (that contains one or more phospholipids) and a pharmaceutically acceptable fluid carrier, where the phospholipid component is in the range from about 10% to about 90% of the total weight. The compositions may further comprise non-phospholipid filler materials, where the amount of the non-phospholipid filler materials is in the range from about 5% to about 50% of the total weight. In certain embodiments, the compositions may be injectable, non-liposomal, and/or in form of a gel or a paste. The compositions of the invention may be useful for repairing and augmenting soft and/or hard tissues or for sustained local drug delivery. One drug formulation exemplified is bupivacaine in a phospholipid paste with propylene glycol.
US 2012/0046220 to Chen et al. provides a clear depot comprising at least one hydrophilic water-soluble pharmaceutically active antibacterial agent selected from the group consisting of vancomycin, gentamicin, a pharmaceutically acceptable salt thereof and a mixture thereof, water, a phospholipid, an oil, optionally a pH adjusting agent, and a viscosity modifying agent selected from the group consisting of ethanol, isopropanol, and a mixture thereof, wherein the water present in the final depot formulation is no more than about 4 wt % relative to the total weight of the depot and the depot has a pH of between about 3 and about 6.
US 2012/0316108 to Chen et al. is directed to compositions and methods of preparation of phospholipid depots that are injectable through a fine needle.
Additional references describing phospholipid-based formulations include WO 89/00077, WO 02/32395, EP 0282405 and U.S. Pat. Nos. 4,252,793; 5,660,854; 5,693,337 and Wang et al., Lyophilization Of Water-In-Oil Emulsions To Prepare Phospholipid-based Anhydrous Reverse Micelles For Oral Peptide Delivery, 39 European Journal of Pharmaceutical Sciences, at 373-79 (2010).
The known phospholipid based depot formulations suffer from the drawback of high viscosity making them difficult to administer, and lack of long term stability at ambient temperatures. There is an unmet need for stable depot formulations of hydrophobic active ingredients with improved viscosity and particle size making them amenable to delivery to the required site of action.
SUMMARY OF THE INVENTION
The present invention provides a non-aqueous, pro-liposomal depot formulation of a hydrophobic active pharmaceutical ingredient (API) having low water solubility, which advantageously create liposomes or other lipidic vesicular structures in situ upon contact with body fluids. The present invention further provides a process for manufacturing the depot formulations of the invention wherein the composition is not exposed to an aqueous phase at any stage of the manufacturing process. The composition is not exposed to an aqueous phase at any stage of the manufacturing process. The composition is devoid of water except for residual moisture that may be present in the excipients used to make the composition.
Furthermore, the present invention provides a non-aqueous pro-liposomal depot formulation using only GRAS excipients and essentially devoid of synthetic phospholipids. The compositions of the invention thus provide improved stability, increased therapeutic duration of APIs and decreased potential adverse effects. Advantageously, the depot formulations of the invention provide therapeutically effective levels of the API contained therein over a period of days or even weeks. The therapeutic effects may advantageously be restricted to local effects at or near the site of administration of the depot.
The invention is based, in part, on the surprising discovery that an oily solution carrying an API is retained in the tissue longer and provides improved sustained release properties relative to a gel or a gel-like formulation carrying the same amount of the API. According to some embodiments, the solution of the invention forms liposomes or micelles or other types of lipid assemblies in vivo, following the natural introduction of physiological body fluids into the surgical site, thereby releasing the API over a sustained period of time. Accordingly, the pro-liposomal formulation is stable and can be stored at room temperature, which is advantageous with respect to transportation and storage of the formulations, as compared to liposomal formulations which require storage at 2-8° C. The formulation will retain its active ingredient and will not burst upon contact with surfactants, thus will not release the full amount of the API into the system as may be the case with liposomes when bursting.
In one aspect, the invention provides a pro-liposomal, non-aqueous pharmaceutical formulation comprising: a hydrophobic API; a natural non-synthetic phospholipid or pharmaceutically acceptable salt thereof; a non-aqueous pharmaceutically acceptable carrier; and a co-solvent as a viscosity regulator, wherein said composition is substantially devoid of water.
In another embodiment the non-aqueous pharmaceutical formulation consists essentially of: a hydrophobic API; a natural non-synthetic phospholipid or pharmaceutically acceptable salt thereof; a non-aqueous pharmaceutically acceptable carrier; and a co-solvent as a viscosity regulator, wherein said composition is substantially devoid of water.
In some embodiments, the non-aqueous pharmaceutical formulation consists of: a hydrophobic API; a natural non-synthetic phospholipid or pharmaceutically acceptable salt thereof; a non-aqueous pharmaceutically acceptable carrier; an anti-oxidant and a co-solvent as a viscosity regulator, wherein said composition is substantially devoid of water.
According to some embodiments, the composition is stable for at least 24 months at room temperature. According to some embodiments, the composition is stable for at least 12 months at room temperature. According to some embodiments, the composition is stable for at least 6 months at room temperature. According to some embodiments, the composition is stable for at least 1 month at room temperature.
According to some embodiments, the co-solvent is a non-aromatic co-solvent. According to some embodiments, the non-aromatic co-solvent is an alcohol. In some embodiments, the alcohol is ethanol. In some embodiments, ethanol is present in the amount of about 1% to about 15% by weight. In some embodiments, ethanol is present in the amount of about 2% to about 10% by weight. In some embodiments, ethanol is present in the amount of about 4% to about 6% by weight.
In some embodiments, the co-solvent serves as a viscosity regulator which renders the composition suitable for injection. In some embodiments, the viscosity of the formulation is below 2500 cP. In some embodiments, the viscosity of the formulation is below 2000 cP. In some embodiments, the viscosity of the formulation is in the range of 1000-2500 cP. In some embodiments, the viscosity of the formulation is in the range of 1000-2000 cP.
In some embodiments, the composition is devoid of particles above 100 nm in size. In some embodiments, the composition is devoid of particles above 50 nm in size. In some embodiments, the composition is devoid of particles above 20 nm in size. In some embodiments, the composition is devoid of particles above 10 nm in size. In some embodiments, the composition is an essentially particle-free oily solution. In some embodiments, the composition is a clear solution.
In some embodiments, the API is present in the amount equivalent to about 0.2% to about 18% by weight. In some embodiments, the API is present in the amount equivalent to about 1% to about 12% by weight. In other embodiments, the API is present in the amount equivalent to about 2% to about 4% by weight. In some embodiments, the API is present in the amount equivalent to about 3% to about 6% by weight. In some embodiments, the API is a sole active pharmaceutical ingredient which is hydrophobic.
In some embodiments, the hydrophobic API is selected from the group consisting of: ropivacaine, diclofenac, dexamethasone, ketoprofen and combinations thereof. Each possibility is a separate embodiment of the invention.
In some embodiments, the hydrophobic API has an experimental Log P hydrophobicity value of at least 1.5. In some embodiments, the API has an experimental Log P hydrophobicity value of at least 1.6. In some embodiments, the API has an experimental Log P hydrophobicity value of at least 2.
In specific embodiments, the API of the composition has solubility in pure water of less than 10 mg/ml at a temperature of about 25° C. In some embodiments, the API of the composition has solubility in pure water of less than 1 mg/ml at a temperature of about 25° C.
In some embodiments, the phospholipid is a naturally occurring phospholipid. In some embodiments, the phospholipid is present in the amount of about 10% to about 80% by weight. In some embodiments, the phospholipid is present in the amount of about 40% to about 60% by weight. In some embodiments, the phospholipid is present in the amount of about 45% to about 55% by weight. In some embodiments, the phospholipid does not include any synthetic phospholipid. In some embodiments the phospholipid does not include 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) or a pharmaceutically acceptable salt thereof. In some embodiments, the natural non-synthetic phospholipid is phosphatidylcholine (PC) or a pharmaceutically acceptable salt thereof.
In some embodiments the formulation is essentially devoid of fillers, especially water insoluble or particulate fillers. In some embodiments, the formulations are devoid of inert particulate or suspended materials such as microspheres.
In some embodiments, the formulation is essentially devoid of water. In another embodiment, essentially devoid of water as used herein refers to less than 0.5% v/v or w/w of the formulation. In other embodiments, essentially devoid of water as used herein refers to 0.2% v/v or w/w of the formulation. In specific embodiments the composition is devoid of water except for residual moisture that may be present in the excipients used to make the composition. In specific embodiments the residual moisture is below 0.3%. In specific embodiments the residual moisture is below 0.15%.
In some embodiments, the non-aqueous pharmaceutically acceptable carrier comprises sesame oil, cottonseed oil, safflower oil, or one or more triglycerides. Each possibility is a separate embodiment of the invention. In some embodiments, the non-aqueous pharmaceutically acceptable carrier is castor oil.
In some embodiments, the non-aqueous pharmaceutically acceptable carrier is present in the amount of about 20% to about 50% by weight.
In specific embodiments, the ratio of the natural non-synthetic phospholipid and the non-aqueous pharmaceutically acceptable carrier is in the range of 2.2:1 to 1.2:1. In another embodiment, the ratio of the natural non-synthetic phospholipid and the non-aqueous pharmaceutically acceptable carrier is in the range of 2:1 to 1:1.
In some embodiments, the pharmaceutical formulation further comprises an anti-oxidant. In some embodiments, the anti-oxidant is cysteine or a pharmaceutically acceptable salt thereof.
In another aspect, the invention provides a pro-liposomal, non-aqueous, oleaginous pharmaceutical formulation comprising: an API in an amount equivalent to about 0.2% to about 10% by weight; about 40% to about 60% by weight of phosphatidylcholine (PC); about 35% to about 55% by weight of castor oil; and about 2% to about 10% by weight of ethanol, wherein the composition is substantially devoid of water.
In another aspect, the invention provides a pro-liposomal, non-aqueous, oleaginous pharmaceutical formulation comprising: ropivacaine in an amount equivalent to about 0.5% to about 5% by weight; about 40% to about 60% by weight of phosphatidylcholine (PC); about 35% to about 55% by weight of castor oil; and about 2% to about 10% by weight of ethanol.
In another aspect, the invention provides a pro-liposomal, non-aqueous, oleaginous pharmaceutical formulation comprising: ketoprofen in an amount equivalent to about 0.5% to about 5% by weight; about 40% to about 60% by weight of phosphatidylcholine (PC); about 35% to about 55% by weight of castor oil; and about 2% to about 10% by weight of ethanol.
In another aspect, the invention provides a pro-liposomal, non-aqueous, oleaginous pharmaceutical formulation comprising: diclofenac in an amount equivalent to about 0.5% to about 5% by weight; about 40% to about 60% by weight of phosphatidylcholine (PC); about 35% to about 55% by weight of castor oil; and about 2% to about 10% by weight of ethanol.
In another aspect, the invention provides a pro-liposomal, non-aqueous, oleaginous pharmaceutical formulation comprising: dexamethasone in an amount equivalent to about 0.5% to about 5% by weight; about 40% to about 60% by weight of phosphatidylcholine (PC); about 35% to about 55% by weight of castor oil; and about 2% to about 10% by weight of ethanol.
In some embodiments, the pharmaceutical formulation is administered as a depot formulation. In some embodiments, the pharmaceutical formulation is administered as a single dose. In some embodiments, the pharmaceutical formulation is administered by infiltration into an incision. In some embodiments, the pharmaceutical formulation is administered by injection into an incision. In some embodiments, the pharmaceutical formulation is administered by injection into an incision following the suturing of said incision.
In specific embodiments, the pharmaceutical composition is suitable for administration through a syringe with an 18-22 Gauge needle. In some embodiments, the pharmaceutical composition is suitable for administration through a syringe with a 21 Gauge needle.
In another aspect, the invention provides a method for making a pro-liposomal non-aqueous oleaginous pharmaceutical formulation, the method comprising: (a) mixing a non-aqueous pharmaceutically acceptable carrier with: (i) a hydrophobic API; (ii) a natural non-synthetic phospholipid or pharmaceutically acceptable salt thereof; and (iii) a co-solvent as a viscosity regulator, thereby providing a non-aqueous solution; (b) removing all or a portion of the co-solvent from the non-aqueous solution; (c) adding the same or a different co-solvent to the non-aqueous solution to a total amount of about 2% to about 12% by weight.
According to some embodiments, the pharmaceutical formulation prepared by the method is a clear solution, devoid of particles above 100 nm in size, stable at ambient temperature and substantially devoid of water.
According to some embodiments, the pharmaceutical formulation prepared by the method is a clear solution, devoid of particles above 50 nm in size, stable at ambient temperature and substantially devoid of water.
In some embodiments, removing all or a portion of the co-solvent from the non-aqueous solution results in an oleaginous solution.
According to the present invention, the process does not include exposure to an aqueous phase and does not involve emulsification steps.
In some embodiments, the non-aqueous pharmaceutically acceptable carrier comprises castor oil. In some embodiments, the methods further comprises mixing the non-aqueous pharmaceutically acceptable carrier with an anti-oxidant.
In some embodiments, the co-solvent is removed from the non-aqueous solution by evaporation and/or vacuum drying. In alternative embodiments, the process does not use excess co-solvent as a viscosity regulator and therefore there will be no need for evaporation or vacuum drying.
In some embodiments, the method further comprises autoclaving the resultant formulation.
In another aspect, the invention provides a kit comprising: a container containing the pharmaceutical formulation of any of the above embodiments; and instructions for use.
In another aspect, the invention provides a pre-filled syringe comprising the pharmaceutical formulation of any one of the above embodiments.
There is provided herein, according to another aspect of the invention, a pro-liposomal, non-aqueous stock formulation comprising all of the excipients of the depot formulation without the API, and a process for manufacturing same. In specific embodiments, the pro-liposomal, non-aqueous stock formulation comprises: a natural non-synthetic phospholipid; a non-aqueous pharmaceutically acceptable carrier; and a co-solvent as a viscosity regulator. According to some embodiments, the stock formulation is a-ready-to-use formulation to which a hydrophobic API can be added. According to another embodiment, the stock formulation is highly stable and may be stored for prolonged periods of time before the addition of a hydrophobic API.
In specific embodiments, the stock formulation is substantially devoid of water. In specific embodiments, the stock formulation is devoid of water except for residual moisture that may be present in the excipients used to make the depot. In specific embodiments, the residual moisture is below 0.3%. In specific embodiments, the residual moisture is below 0.15%.
In some embodiments, the viscosity of the stock formulation is in the range of 1000-2500 cP. In some embodiments, the viscosity of the stock formulation is in the range of 1000-2000 cP.
In some embodiments, the stock formulation is devoid of particles above 100 nm in size. In some embodiments, the stock formulation is devoid of particles above 50 nm in size. In some embodiments, the composition is devoid of particles above 20 nm in size. In some embodiments, the stock formulation is devoid of particles above 10 nm in size. In some embodiments, the stock formulation is an essentially particle-free oily solution. In some embodiments, the composition is a clear solution.
In another aspect, the invention provides a method for making a pro-liposomal, non-aqueous, stock formulation comprising all of the excipients of the depot formulation without the API. The method comprising: (a) equilibrating a non-aqueous pharmaceutically acceptable carrier; and (b) dissolving a natural non-synthetic phospholipid in said non-aqueous pharmaceutically acceptable carrier by heating and mixing. According to some embodiments the method further comprises adding a co-solvent at step (a). Alternatively, the method comprises adding a co-solvent at step (b) of the method. It is to be understood that the method can be a continuous process in which all ingredients are added and processed simultaneously.
According to some embodiments, the stock formulation prepared by the method is a clear solution, devoid of particles above 100 nm in size, stable at ambient temperature and substantially devoid of water.
According to some embodiments, the stock formulation prepared by the method is a clear solution, devoid of particles above 50 nm in size, stable at ambient temperature and substantially devoid of water.
It was surprisingly found that a combination of heat, torque and high shear mixing resulted in the in complete dissolving of the phospholipid in the pharmaceutically acceptable non-aqueous carrier. Accordingly, there is advantageously no need for adding excess ethanol and subsequent evaporation of the ethanol.
In specific embodiments, an anti-oxidant is added to the co-solvent prior to mixing the co-solvent into the stock formulation. Alternatively, the anti-oxidant is added separately at any of steps (a) or (b) of the method or simultaneously with the addition of all other ingredients.
In specific embodiments, equilibrating the non-aqueous pharmaceutically acceptable carrier (and optionally the co-solvent and anti-oxidant) comprises heating to at least about 50° C. In another embodiment, equilibrating the non-aqueous pharmaceutically acceptable carrier (and optionally the co-solvent and anti-oxidant) comprises heating to at least about 65° C. In another embodiment, equilibrating the non-aqueous pharmaceutically acceptable carrier comprises heating to at least about 85° C.
In specific embodiments, no stages of the method comprise exposure to an aqueous phase or emulsification.
In specific embodiments, no stages of the manufacturing process comprise excess ethanol. Hence, using this method, there is advantageously no need evaporation of ethanol in presence of the API thereby favorably avoiding any excessive waste of the API.
The invention is based, in part, on the surprising discovery that the stock formulation is a ready-to-use stock formulation into which a hydrophobic API is easily mixed without further processing of the formulation. As such, any hydrophobic API described herein can be added to the stock formulation forming a pro-liposomal, non-aqueous, pharmaceutical composition. Alternatively, the API is dissolved prior to being added to the stock formulation.
In specific another embodiments, the method further comprises autoclaving the resultant stock formulation.
There is provided herein, according to another aspect of the invention, a method for making a pro-liposomal, non-aqueous pharmaceutical composition comprising: (a) equilibrating a non-aqueous pharmaceutically acceptable carrier; and (b) dissolving a natural non-synthetic phospholipid in said non-aqueous pharmaceutically acceptable carrier by heating and mixing. The method further comprises adding a co-solvent at step (a) or (b). According to some embodiments, a hydrophobic API can be added at step (a) of the method. According to some embodiments, a hydrophobic API can be added at step (b) of the method. According to some embodiments, a hydrophobic API can be added at an additional step (c) of the method.
According to some embodiments, the pharmaceutical composition prepared by the method is a clear solution, devoid of particles above 100 nm in size, stable at ambient temperature and substantially devoid of water. According to some embodiments, the pharmaceutical composition prepared by the method is a clear solution, devoid of particles above 50 nm in size, stable at ambient temperature and substantially devoid of water.
According to some embodiments, the method enables adding the hydrophobic API to the pre-prepared stock formulation without further processing. Alternatively, the method is continuous meaning that all or at least a part of the ingredients are added and processed simultaneously.
According to another aspect of the invention, there is provided a kit comprising a container containing the stock formulation of any of the above embodiments. In specific embodiments, the kit further comprises a hydrophobic API.
According to another aspect of the invention, there is provided a pro-liposomal non aqueous stock formulation prepared by the method of any of any of the above embodiments.
In another aspect, the invention provides a method of administering a hydrophobic API to a subject comprising administering a pharmaceutical formulation of any of the above embodiments containing the hydrophobic active pharmaceutical ingredient.



BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described with reference to the following figures, which are presented for purposes of illustration only and which are not intending to be limiting to the invention.
FIG. 1 shows the results of a particle size distribution test obtained using a coulter LS230 particle size analyzer. FIG. 1A shows the results obtained for depot formulation A/saline (1:1), FIG. 1B shows the results obtained for depot formulation A/pig plasma (1:1).
FIG. 2 represents Cryo-TEM pictures of formulation A diluted with pig plasma at ratios of 1:1 and 1:2.
FIG. 3 is a graphical representation of a post-operative pain response study in 10 kg piglets administered with various ropivacaine formulations.
FIG. 4 is a graphical representation of pharmacokinetic response study in healthy volunteers administered with various ropivacaine formulations.



DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a non-aqueous, pro-liposomal depot formulation for a hydrophobic API and a process for manufacturing same in which no steps of emulsification are involved, and in which the composition is not exposed to an aqueous phase at any stage prior to entering the patient's body. Furthermore, the present invention provides a depot formulation essentially devoid of synthetic phospholipids, using only GRAS excipients.
The present invention also provides a pro-liposomal, non-aqueous stock formulation comprising all of the excipients of the depot formulation without an API, and a process for manufacturing same. The stock formulation is ready for the addition of a hydrophobic API and is substantially devoid of water.
Definitions and Abbreviations
A used herein an API of low water solubility is an API with a solubility in pure water of less than 10 mg/ml at room temperature, (i.e. at a temperature of about 25° C.), more preferably a solubility in pure water of less than 1 mg/ml. In one embodiment the API is hydrophobic, defined herein as having a Log P (wherein P is the octanol water partition coefficient) of at least 1.5.
As used herein solubility is defined according to the Pharmacopoeia (USP): a solubility in pure water of >1000 mg/ml at a temperature of about 25° C. refers to molecules which are “very soluble”, a solubility of 100-1000 mg/ml refers to molecules which are “freely soluble”, a solubility of 33-100 mg/ml refers to molecules which are “soluble”, a solubility of 10-33 mg/ml refers to molecules which are “sparingly soluble”, a solubility of 1-10 mg/ml refers to molecules which are “slightly soluble”, a solubility of 0.1-1 refers to molecules which are “very slightly soluble” and a solubility of <0.1 refers to molecules which are “practically insoluble”.
The term “hydrophobic active pharmaceutical ingredient” as used herein refers to compounds having a greater solubility in organic solvents of low polarity, such as long chain alcohols, than in aqueous solution. The formulations described by the present invention facilitate solubilization of hydrophobic compounds which readily dissolve in alcohols.
As used herein the term “hydrophobic” refers to an API with an experimental Log P hydrophobicity value of at least 1.5, more preferably at least 1.6, most preferably at least 2, wherein P is the octanol water partition coefficient.
As used herein, “solvate” refers to a molecular complex comprising a compound or a salt of the compound and one or more pharmaceutically acceptable solvent molecules, for example, one or more ethanol molecules.
As used herein, “hydrate” refers to a solvate in which the one or more solvent molecules are water molecules.
As used herein, “non-aqueous” is “essentially devoid of water” or “devoid of water”, and refers to a formulation in which the solvent does not comprise water. Hence, a “non-aqueous formulation” is a formulation which comprises less than 0.5%, 0.4%, 0.3%, or 0.2% w/w or v/v water. A “non-aqueous formulation,” however, can contain trace amounts of water (up to 0.5% w/w), such as water present in one of the solutes. Also, as used herein “non-aqueous formulation” refers to a formulation devoid of emulsion in any of its preparation stages. Dissolving the API may be obtained by sonication in a water bath sonicator heated to about 50° C. As used herein, “pro-liposomal formulation” refers to a formulation that is free of detectable amount of liposomes before use or under storage conditions. In another embodiment, liposomes are formed upon contact with living tissue fluids. In another embodiment, liposomes are formed in-vivo. In another embodiment, the non-liposomal formulation is a pro-liposomal formulation (liposomes are formed in-vivo upon contact with body fluids).
As used herein, “viscosity” refers to the resistance of the composition to gradual deformation by shear stress or tensile stress. According to some embodiments the composition has a viscosity in the range of 1000-3000 cP, 1250-2500 cP, 1400-2000 cP, 1500-1850 cP. Each possibility is a separate embodiment of the invention.
As used herein “injectable” refers to a formulation that can be injected or infiltrated into a wound using a needle ranging from 18-30 Gauge, 20-25 Gauge, 21-23 Gauge needle. Each possibility is a separate embodiment of the invention.
As used herein, “about” means within ±10% of the value that follows it. For example, “about 100” means between 90 and 110, including 90 and 110; “about 5%” means between 4.5% and 5.5%, including 4.5% and 5.5%.
As used herein, “phospholipid” refers to a molecule that comprises at least one phosphate head group and at least one non-polar tail group. As used herein, “phospholipid” is limited to natural non-synthetic phospholipid. As used herein, “phospholipid” is limited to a naturally occurring phospholipid.
As used herein, “oleaginous solution” refers to a solution with oil-like viscosity. An oleaginous solution has lower viscosity than a gel, a paste, a paste-like or a gel-like formulation. As used herein, “oleaginous liquid” refers to a liquid with oil-like viscosity. An oleaginous liquid has lower viscosity than a gel, a paste, a paste-like or a gel-like liquid.
As used herein, “co-solvent” refers to a substance that increases the solubility of the therapeutic agent within the formulation and/or reduces the formulation viscosity thereby rendering the formulation suitable for injection. According to some embodiments, the co-solvent is a non-aromatic co-solvent.
As used herein the term “stable composition” refers to compositions which do not form precipitates when stored at ambient temperature.
As used herein the term “ambient temperature” and “room temperature” interchangeably refer to a temperature in the range of 20-25° C.
As used herein the term “clear solution” refers to essentially transparent solutions devoid of particles above 100 nm. Alternatively, the term “clear solution” refers to essentially transparent solutions devoid of particles above 50 nm. Alternatively, the term “clear solution” refers to essentially transparent solutions devoid of particles above 20 nm.
As used herein the term “devoid of particles above 100 nm” refers to solutions containing less than 5% particles above 100 nm. As used herein the term “devoid of particles above 50 nm” refers to solutions containing less than 5% particles above 50 nm. As used herein the term “devoid of particles above 20 nm” refers to solutions containing less than 5% particles above 20 nm.
As used herein the terms “filler” and “non-phospholipid filler component” interchangeably refer to a biodegradable or non-biodegradable material such as but not-limited to poly lactide-co-glycolide (PLGA), hydroxyapatite, microspheres of polymethylmethacrylate (PMMA), which may be adapted for use as tissue fillers.
As used herein, unless specifically indicated otherwise, “by weight” refers to w/w. As used herein, the recitation of a numerical range for a variable is intended to convey that the invention may be practiced with the variable equal to any of the values within that range. Thus, for a variable which is inherently discrete, the variable can be equal to any integer value within the numerical range, including the end-points of the range. Similarly, for a variable which is inherently continuous, the variable can be equal to any real value within the numerical range, including the end-points of the range. As an example, and without limitation, a variable which is described as having values between 0 and 2 can take the values 0, 1 or 2 if the variable is inherently discrete, and can take the values 0.0, 0.1, 0.01, 0.001, or any other real values ≧0 and ≦2 if the variable is inherently continuous.
As used herein, unless specifically indicated otherwise, the word “or” is used in the inclusive sense of “and/or” and not the exclusive sense of “either/or”. In one embodiment, the term “comprising” includes “consisting”.
As used herein, the singular forms “a”, “an”, and “the” also include plural referents unless the context clearly indicates otherwise.
As used herein, “subject” refers to any animal, including but not limited to humans, non-human primates and other mammals, reptiles and birds.
The following abbreviations are used herein and have the indicated definitions: SC is subcutaneous, IM is intramuscular, IV is intravenous, PC is phosphatidylcholine, DMPG is 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol or a salt or a salt combination thereof, NAC is N-acetyl-L-cysteine, CTMC is 2-carboxy-2,5,7,8-tetrumethyl-G-chromanol, GP is Guinea pig, DS is domestic swine, NBF is neutral buffered formulation, RT is room temperature.
Extended Release Depot Formulations
Administration of a depot formulation is useful for the gradual release of an active therapeutic agent over prolonged period of treatment. In some embodiments, administration of a depot formulation that forms liposome-like structures in-vivo is useful for the gradual release of an active therapeutic agent. In some embodiments, an active therapeutic agent is formulated with carriers that provide a gradual release of the active therapeutic agent over a period lasting from few hours to a number of days. Depot formulations are often based upon a degrading matrix which gradually disperses in the body to release the active therapeutic agent. Depot formulations can be designed to either allow or prevent an initial burst release of the active agent. All components of depot formulations are biocompatible and biodegradable. In some embodiments, the terms “composition” and “formulation” are used interchangeably. In some embodiments, the terms: “depot formulation”, “depot composition”, “formulation of the invention”, “pro-liposomal formulation”, “oleaginous formulation”, and “non-aqueous formulation” are used interchangeably.
In this context, it is to be understood that the formulations of the invention are pro-liposomal, non-aqueous, RT stable uniform solutions from completion of production throughout storage and up to and including the time of application. In situ, after penetration into a subject, upon natural contact with bodily fluids, they spontaneously form liposomes or other vesicles or micelles.
Furthermore, the extended release depot formulations described herein minimize the burdens of patient compliance, reduce the frequency of clinic visits and the amount of clinical support needed and reduce the overall time and hospitalization and costs of treatment. In addition, depending on the active therapeutic agent it contains, the depot formulation described herein can reduce the risks of drug abuse by eliminating or reducing the need for take-home medication.
In some embodiments, the depot formulations described herein are non-liposomal. In another embodiment, the depot formulations described herein are non-liposomal and non-aqueous. In other embodiments, the depot formulations described herein are oleaginous but non-liposomal and non-aqueous. In some embodiments, the depot formulation forms liposomes upon in-vivo entry to a target tissue. In another embodiment, the depot formulation forms liposomes upon contact with a living tissue or bodily fluids.
Extended Release Depot Formulations
Hydrophobic API of Low Water Solubility
According to some embodiments, the API is hydrophobic. The API, in one embodiment, has an experimental Log P hydrophobicity value of at least 1.5. In another embodiment the API, has an experimental Log P hydrophobicity value of at least 1.6. In yet another embodiment the API has an experimental Log P hydrophobicity value of at least 2.
According to some embodiments the API is poorly soluble in water but readily soluble in non-aqueous polar solvents, in particular alcohols.
According to some embodiments the API has a solubility in pure water of less than 10 mg/ml at room temperature (i.e. at a temperature of about 25° C.). According to some embodiments the API has a solubility in pure water of less than 1 mg/ml.
According to some embodiments a combination of two or more hydrophobic APIs or their pharmaceutically acceptable salts can also be used.
Suitable hydrophobic active ingredients are not limited by therapeutic category, and can be, for example, analgesics, anti-inflammatory agents, antihelmimthics, anti-arrhythmic agents, anti-bacterial agents, anti-viral agents, anti-coagulants, anti-depressants, anti-diabetics, anti-epileptics, anti-fungal agents, anti-gout agents, anti-hypertensive agents, anti-malarial, anti-migraine agents, anti-muscarinic agents, anti-neoplastic agents, erectile dysfunction improvement agents, immunosuppressants, anti-protozoal agents, anti-thyroid agents, anxiolytic agents, sedatives, hypnotics, neuroleptics, beta.-Blockers, cardiac inotropic agents, corticosteroids, diuretics, anti-parkinson agents, gastro-intestinal agents, histamine receptor antagonists, keratolytics, lipid regulating agents, local anesthetics, anti-anginal agents, cox-2 inhibitors, leukotriene inhibitors, macrolides, muscle relaxants, nutritional agents, protease inhibitors, sex hormones, stimulants, muscle relaxants, anti-osteoporosis agents, anti-obesity agents, cognition enhancers, anti-urinary incontinence agents, nutritional oils, anti-benign prostate hypertrophy agents, essential fatty acids, non-essential fatty acids, and mixtures thereof. Each possibility is a separate embodiment of the invention.
Specific, non-limiting examples of suitable hydrophobic active ingredients are: acetretin, albendazole, albuterol, aminoglutethimide, amiodarone, amlodipine, amphetamine, amphotericin B, atorvastatin, atovaquone, azithromycin, baclofen, beclomethasone, benezepril, benzonatate, betamethasone, bicalutanide, budesonide, bupropion, busulfan, butenafine, calcifediol, calcipotriene, calcitriol, camptothecin, candesartan, capsaicin, carbamezepine, carotenes, celecoxib, cerivastatin, cetirizine, chlorpheniramine, cholecalciferol, cilostazol, cimetidine, cinnarizine, ciprofloxacin, cisapride, clarithromycin, clemastine, clomiphene, clomipramine, clopidogrel, codeine, coenzyme Q10, cyclobenzaprine, cyclosporin, danazol, dantrolene, dexamethasone, dexchlorpheniramine, diclofenac, dicoumarol, digoxin, dehydroepiandrosterone, dexamethasone, dihydroergotamine, dihydrotachysterol, dirithromycin, donezepil, efavirenz, eposartan, ergocalciferol, ergotamine, essential fatty acid sources, etodolac, etoposide, famotidine, fenofibrate, fentanyl, fexofenadine, finasteride, fluconazole, flurbiprofen, fluvastatin, fosphenytoin, frovatriptan, furazolidone, gabapentin, gemfibrozil, glibenclamide, glipizide, glyburide, glimepiride, griseofulvin, halofantrine, ibuprofen, irbesartan, irinotecan, isosorbide dinitrate, isotretinoin, itraconazole, ivermectin, ketoconazole, ketoprofen, ketorolac, lamotrigine, lansoprazole, leflunomide, lisinopril, loperamide, loratadine, lovastatin, L-thryroxine, lutein, lycopene, medroxyprogesterone, mifepristone, mefloquine, megestrol acetate, methadone, methoxsalen, metronidazole, miconazole, midazolam, miglitol, minoxidil, mitoxantrone, montelukast, nabumetone, nalbuphine, naratriptan, nelfinavir, nifedipine, nilsolidipine, nilutanide, nitrofurantoin, nizatidine, omeprazole, oprevelkin, oestradiol, oxaprozin, oxycodone, paclitaxel, paracalcitol, paroxetine, pentazocine, pioglitazone, pizofetin, pravastatin, prednisolone, probucol, progesterone, pseudoephedrine, pyridostigmine, rabeprazole, raloxifene, rofecoxib, ropivacaine repaglinide, rifabutine, rifapentine, rimexolone, ritanovir, rizatriptan, rosiglitazone, saquinavir, sertraline, sibutramine, sildenafil citrate, simvastatin, sirolimus, spironolactone, sumatriptan, tacrine, tacrolimus, tamoxifen, tamsulosin, targretin, tazarotene, telmisartan, teniposide, terbinafine, terazosin, tetrahydrocannabinol, tiagabine, ticlopidine, tirofibran, tizanidine, topiramate, topotecan, toremifene, tramadol, tretinoin, troglitazone, trovafloxacin, ubidecarenone, valsartan, venlafaxine, verteporfin, vigabatrin, vitamin A, vitamin D, vitamin E, vitamin K, zafirlukast, zileuton, zolmitriptan, zolpidem, and zopiclone. Each possibility is a separate embodiment of the invention. Of course, salts, isomers and derivatives of the above-listed hydrophobic active ingredients may also be used, as well as mixtures.
Among the above-listed hydrophobic active ingredients, preferred active ingredients include: acetretin, albendazole, albuterol, aminoglutethimide, amiodarone, amlodipine, amphetamine, amphotericin B, atorvastatin, atovaquone, azithromycin, baclofen, benzonatate, bicalutanide, busulfan, butenafine, calcifediol, calcipotriene, calcitriol, camptothecin, capsaicin, carbamezepine, carotenes, celecoxib, cerivastatin, chlorpheniramine, cholecaliferol, cimetidine, cinnarizinc, ciprofloxacin, cisapride, citrizine, clarithromycin, clemastine, clomiphene, codeine, coenzyme Q10, cyclosporin, danazol, dantrolene, dexchlorpheniramine, diclofenac, digoxin, dehydroepiandrosterone, dexamethasone, dihydroergotamine, dihydrotachysterol, dirithromycin, donepezil, efavirenz, ergocalciferol, ergotamine, essential fatty acid sources, etodolac, etoposide, famotidine, fenofibrate, fentanyl, fexofenadine, finasteride, fluconazole, flurbiprofen, fluvastatin, fosphenytoin, frovatriptan, furazolidone, gabapentin, gemfibrozil, glibenclamide, glipizide, glyburide, glimepiride, griseofulvin, halofantrine, ibuprofen, irinotecan, isotretinoin, itraconazole, ivermectin, ketoconazole, ketoprofen, ketorolac, lamotriginc, lansoprazole, leflunomide, loperamnide, loratadine, lovastatin, L-thryroxine, lutein, lycopene, mifepristone, mefloquine, megestrol acetate, methdone, methoxsalen, metronidazole, miconazole, midazolam, miglitol, mitoxantrone, medroxyprogesterone, montelukast, nabumetone, nalbuphine, naratriptan, nelfinavir, nilutanide, nitrofurantoin, nizatidine, omeprazole, oestradiol, oxaprozin, oxycodone, paclitaxel, paracalcitol, pentazocine, pioglitazone, pizofetin, pravastatin, probucol, progesterone, pseudoephedrine, pyridostigmine, rabeprazole, raloxifene, rofecoxib, ropivacaine, repaglinide, rifabutine, rifapentine, rimexolone, ritanovir, rizatriptan, rosiglitazone, saquinavir, sibutramine, sildenafil citrate, simvastatin, sirolimus, spironolactone, sumatriptan, tacrine, tacrolimus, tamoxifen, tamsulosin, targretin, tazarotene, teniposide, terbinafine, tetrahydrocannabinol, tiagabine, tizanidine, topiramate, topotecan, toremifene, tramadol, tretinoin, troglitazone, trovafloxacin, verteporfin, vigabatrin, vitamin A, vitamin D, vitamin E, vitamin K, zafirlukast, zilcuton, zolmitriptan, zolpidem, zopiclone, pharmaceutically acceptable salts, isomers and derivatives thereof, and mixtures thereof. Each possibility is a separate embodiment of the invention.
More preferred hydrophobic active ingredients include: acetretin, albuterol, aminoglutethimide, amiodarone, amlodipine, amprenavir, atorvastatin, atovaquone, baclofen, benzonatate, bicalutanide, busulfan, calcifediol, calcipotriene, calcitriol, camptothecin, capsaicin, carbamezepine, carotenes, celecoxib, chlorpheniramine, cholecaliferol, cimetidine, cinnarizine, cisapride, cetirizine, clemastine, coenzyme Q10, cyclosporin, danazol, dantrolene, dexchlorpheniramine, dexamethasone, diclofenac, dehydroepiandrosterone, dihydroergotamine, dihydrotachysterol, efavirenz, ergocalciferol, ergotamine, essential fatty acid sources, etodolac, etoposide, famotidine, fenofibrate, fentanyl, fexofenadine, finasteride, fluconazole, flurbiprofen, fosphenytoin, frovatriptan, furazolidone, glibenclamide, glipizide, glyburide, glimepiride, ibuprofen, irinotecan, isotretinoin, itraconazole, ivermectin, ketoconazole, ketoprofen, ketorolac, lamotrigine, lansoprazole, leflunomide, loperamide, loratadine, lovastatin, L-thryroxine, lutein, lycopene, medroxyprogesterone, mifepristone, megestrol acetate, methoxsalen, metronidazole, miconazole, miglitol, mitoxantrone, montelukast, nabumetone, naratriptan, nelfinavir, nilutanide, nitrofurantoin, nizatidine, omeprazole, oestradiol, oxaprozin, oxycodone, paclitaxel, paracalcitol, pioglitazone, pizofetin, pranlukast, probucol, progesterone, pseudoephedrine, rabeprazole, raloxifene, rofecoxib, ropivacaine, repaglinide, rifabutine, rifapentine, rimexolone, ritanovir, rizatriptan, rosiglitazone, saquinavir, sildenafil citrate, simvastatin, sirolimus, tacrolimus, tamoxifen, tamsulosin, targretin, tazarotene, teniposide, terbenafine, tetrahydrocannabinol, tiagabine, tizanidine, topiramate, topotecan, toremifene, tramadol, tretinoin, troglitazone, trovafloxacin, ubidecarenone, vigabatrin, vitamin A, vitamin D, vitamin E, vitamin K, zafirlukast, zileuton, zolmitriptan, pharmaceutically acceptable salts, isomers and derivative thereof, and mixtures thereof. Each possibility is a separate embodiment of the invention.
In some embodiments, the hydrophobic API is selected from the group consisting of: ropivacaine, diclofenac, dexamethasone, ketoprofen and any combination thereof. Each possibility is a separate embodiment of the invention.
According to some embodiments, the API is present in the amount equivalent to about 0.2% to about 18% by weight. According to some embodiments, the API is present in the amount equivalent to about 0.5% to about 12% by weight. According to some embodiments, the API is present in the amount equivalent to about 1% to about 10% by weight. According to some embodiments, the API is present in the amount equivalent to about 3% to about 6% by weight.
Phospholipids
Phospholipids are useful components of the extended release depot formulations described herein. A phospholipid comprises at least one polar head group and at least one non-polar tail group, wherein at least one of the polar head groups is a phosphate group. The non-polar portions can be derived from the fatty acids. A phospholipid will typically contain two non-polar groups, although a single non-polar group is sufficient. Where more than one non-polar group is present these may be the same or different. Suitable phospholipid polar head groups include, but are not limited to, phosphatidylcholine (PC), phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol.
It was surprisingly found that the enhanced properties associated with the present formulation are linked to a naturally occurring phospholipid and not to a synthetic phospholipid such as but not limited to 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) or a pharmaceutically acceptable salt thereof. Therefore, the phospholipid, in some embodiments, is a naturally-occurring phospholipid. Suitable sources of phospholipids include egg, heart (e.g., bovine), brain, liver (e.g., bovine) and plant sources including soybeans. Naturally occurring phospholipids tend to cause lesser amounts of inflammation and reaction from the body of the subject. Not only is this more comfortable for the subject, but it may increase the residence time of the resulting depot formulation, especially for parenteral depot formulations, since less immune system activity is recruited to the administration site.
Phospholipids include lipid molecules derived from either glycerol (phosphoglycerides, glycerophospholipids) or sphingosine (sphingolipids). They include polar lipids, and certain phospholipids that are important in the structure and function of cell membranes, and are the most abundant of membrane lipids.
Some phospholipids are triglyceride derivatives in which one fatty acid has been replaced by a phosphorylated group and one of several nitrogen-containing molecules. The fatty acid chains are hydrophobic. However, the charges on the phosphorylated and amino groups make that portion of the molecule hydrophilic. The result is an amphiphilic molecule.
Amphiphilic phospholipids are major constituents of cell membranes. These molecules form a phospholipid bilayer with their hydrophilic (polar) heads facing their aqueous surroundings (e.g., the cytosol) and their hydrophobic tails facing each other. The most naturally abundant phospholipid is phosphatidylcholine (PC).
Phospholipids are available from naturally occurring sources or can be made by organic synthesis. Lecithin is a naturally occurring mixture of the diglycerides of stearic, palmitic, and oleic acids, linked to the choline ester of phosphoric acid, commonly called phosphatidylcholine. Hydrogenated lecithin is the product of controlled hydrogenation of lecithin.
Lecithin-Based Naturally-Occurring Phospholipids
According to the United State Pharmacopoeia (USP), lecithin is a non-proprietary name describing a complex mixture of acetone-insoluble phospholipids, which consists mainly of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (Ptd-L-Ser or PS), and phosphatidylinositol (PtdIns, or PI), combined with various amounts of other substances such as triglycerides, fatty acids, and carbohydrates. The composition of lecithin and hence its physical properties vary depending upon the source of the lecithin and the exact phospholipid composition, e.g., phosphatidylcholine content, etc. Commercially available lecithin products (lecithins) have two primary sources: egg yolk and soybeans. Lecithins include: lecithin (general), soybean lecithin or soy lecithin, and egg yolk lecithin or egg lecithin.
Lecithin is a component of cell membranes and is therefore consumed as a normal part of human diet. It is highly biocompatible and virtually nontoxic in acute oral studies, short-term oral studies, and sub-chronic dermal studies in animals. Lecithin and hydrogenated lecithin are generally nonirritating and non-sensitizing in animal and human skin cosmetics (See, Fiume Z, 2001 “Final report on the safety assessment of Lecithin and Hydrogenated Lecithin”, Int J Toxicol.; 20 Suppl 1:21-45).
Pharmaceutically, lecithins are mainly used as dispersing, emulsifying, and stabilizing agents and are included in intramuscular (IM) and intravenous (IV) injections, parenteral nutritional formulations and topical products. Lecithin is also listed in the FDA Inactive Ingredients Guide for use in inhalations, IM and IV injections, oral capsules, suspensions and tablets, rectal, topical, and vaginal preparations. Cosmetically, lecithin and hydrogenated lecithin are safe as used in rinse-off cosmetic products; they may be safely used in leave-on products at concentrations up to 15%, the highest concentration tested in clinical irritation and sensitization studies cosmetics.
One source of lecithin-based phospholipids suitable for the depot formulations described herein is soy lecithin of high purity, i.e., free from allergenic, inflammatory agents or agents that cause other deleterious biological reactions, which is qualified for use in injectable products. Such injectable forms of soy lecithin are commercially available in the brand names of Phospholipon® by Phospholipid GmbH (Cologne, Germany), Lipoid® S by Lipoid GmbH (Ludwigshafen, Germany), Epikuron® by Evonik Industries (Parsippany, N.J.—formerly Degussa). These refined soy lecithin products may contain different concentrations of phosphatidylcholine (PC) content ranging from 30% to 100%. By combining lecithin products of different PC contents, it is possible to vary the consistency of the implant and persistence in the tissue. A specific example of soy lecithins is Phospholipon® 90G, which is pure phosphatidylcholine stabilized with 0.1% ascorbyl palmitate.
Other Naturally-Occurring Phospholipids
Other examples of phospholipids from naturally-occurring sources that may be used on the depot formulations described herein include, but are not limited to, sphingolipids in the form of sphingosine and derivatives (from soybean, egg, brain or milk), phytosphingosine and derivatives (from yeast), phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol.
Total Phospholipid Content in the Depot Formulations
Optionally, the depot formulations described herein comprise more than one phospholipid. The combined amount (w/w) of all phospholipids in the depot formulation is referred to as total phospholipid content.
The total phospholipid content of the depot formulations described herein is generally in the range of about 10% to about 80% of the total weight of the depot formulation. In some embodiments, the minimum total phospholipid content (w/w) of in the depot formulation is about 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 75%, or 80% (including any value between 10% and 80%). In some embodiments, the maximum total phospholipid content (w/w) in the depot formulation is about 40%, 45%, 50%, 55, 60%, or 70% (including any value between 40% to 70%). Each possibility is a separate embodiment of the invention. In some embodiments, the total phospholipid content is between the value minimum phospholipid contents and the value of the maximum phospholipid content.
Non-Aqueous Pharmaceutically Acceptable Carriers
In one embodiment, the non-aqueous pharmaceutically acceptable carrier comprises sesame oil, cottonseed oil, safflower oil, or one or more triglycerides. In another embodiment, the non-aqueous pharmaceutically acceptable carrier is castor oil. In some embodiments, the non-aqueous pharmaceutically acceptable carrier is a surface-active agent. In some embodiments, the non-aqueous pharmaceutically acceptable carrier is present in the amount of about 20% to about 60% by weight. In yet another embodiment, the non-aqueous pharmaceutically acceptable carrier is present in the amount of about 30% to about 50% by weight.
In yet another embodiment, the ratio between the phospholipids and the non-aqueous carrier is in a range of 3:1-1:2, 2.5:1-1:5:, 2.2:1-1:1.2, 2:1-1:1. Each possibility is a separate embodiment of the invention.
Co-solvent
In one embodiment, the formulation further comprises a co-solvent. According to some embodiments, the co-solvent may be, but is not limited to: ethanol, propylene glycol, glycerol, dimethylacetamide, dimethyl isosorbide, dimethyl sulfoxide, N-methyl-2-pyrrolidinone, and the like. In some embodiments, the co-solvent is glycerol. In some embodiments, the co-solvent is ethanol. In some embodiments, the co-solvent is alcohol USP which contains between 94.9 and 96.0% v/v ethyl alcohol. In another embodiment, the co-solvent is present in the formulation in an amount of 1-15% by weight. In another embodiment, the co-solvent is present in the formulation in an amount of 0.5-10% by weight. In another embodiment, the co-solvent is present in the formulation in an amount of 4-8% by weight. In another embodiment, the co-solvent is present in the formulation in an amount of 5-7% by weight. In another embodiment, the co-solvent is present in the formulation in an amount of 5.5-6.5% by weight. It was surprisingly found that when using aromatic co-solvents, such as but not limited to benzyl alcohol, administration of the composition into to incision wound of a guinea pigs caused adverse reactions such as irritations of the skin at the site of application.
Viscosity Modifying Agents
In some embodiments the co-solvent serves as a viscosity regulator which renders the composition suitable for injection through 18-25 G injection needles. In another embodiment, the co-solvent serves as a viscosity regulator which renders the composition suitable for injection through a 21 G needle.
According to some embodiments, adding ethanol to the depot formulation does not negatively affect either the activity, nor the blood and wound concentration or the stability of the API of low water solubility, but enhances the flowability by reducing viscosity, thus enhancing injectability of the formulation and allows the use of much smaller diameter injection needles.
Moreover, as illustrated by the liposome formation assays, addition of the viscosity modifying agent ethanol to the depot formulation does not negatively influence the ability to form liposomes upon exposure to aqueous surroundings and subsequently to ensure the slow release of the hydrophobic API.
In some embodiments, the viscosity of the formulation is below 2500 cP. In some embodiments, the viscosity of the formulation is below 2000 cP. In another embodiment, the viscosity of the formulation is preferably in the range of 1000-3000 cP, 1000-2500 cP, 1000-2000 cP, 1250-2000 cP, 1500-2000 cP, 1500-1850 cP. Each possibility is a separate embodiment of the invention.
It was surprisingly found that in order to increase residence time and duration of activity, the composition should have a viscosity in the range of 1000-2000 cP despite the decreased injectability as a result thereof. For example, as shown in Example 5 below, a formulation according to the present invention showed maintenance of higher ropivacaine concentrations in the vicinity of the wound even four days after injection.
Anti-Oxidants
In one embodiment, the extended release depot formulations comprise one or more anti-oxidants. Anti-oxidants can be used to prevent or reduce oxidation of the phospholipids in the depot formulations described herein. Any non-toxic biocompatible anti-oxidant can be used for this purpose. Exemplary anti-oxidants include, but are not limited to, ascorbic acid (vitamin C), cysteine (L-cysteine), N-acetyl-L-cysteine (NAC), L-carnitine, acetyl-L-carnithine, alpha lipoic acid, glutathione, alpha tocopherol (vitamin E), 2-carboxy-2,5,7,8-tetramethyl-6-chromanol (CTMC), ascorbyl palmitate and uric acid. Pharmaceutically acceptable salts of these or other anti-oxidants are also considered “anti-oxidants” and can be used in the depot formulations described herein. These exemplary anti-oxidants mentioned above are commercially available from a variety of sources.
Excipients
Various excipients can be included in the depot formulations of hydrophobic APIs of low water solubility.
Examples of suitable pharmaceutical excipients are described in Remington's Pharmaceutical Sciences 1447-1676 (Alfonso R. Gennaro eds., 19th ed. 1995) and in Strickley R., “Solubilizing Excipients in Oral and Injectable Formulations,” Pharmaceutical Research, Vol. 21, No. 2, February 2004, pp. 201-230, both of which are incorporated herein by reference in their entirety.
Where necessary, the depot formulations of a hydrophobic API of low water solubility can also include a solubilizing agent. Generally, the ingredients are supplied either separately or mixed together in unit dosage form, for example, as a dry lyophilized powder or water-free concentrate in a hermetically sealed container such as an ampule or sachet indicating the quantity of active agent.
Pro-Liposomal, Non-Aqueous Depot Formulations
In one embodiment, the extended release depot formulations are non-aqueous, oleaginous, or any combination thereof. The formulations can comprise (a) a hydrophobic API of low water solubility; (b) a first phospholipid or a pharmaceutically acceptable salt thereof; (c) optionally, a second phospholipid or a pharmaceutically acceptable salt thereof; (d) a non-aqueous pharmaceutically acceptable carrier such as but not limited to an oil; and (e) a co-solvent such as but not limited to an alcohol. In some embodiments the depot is pro-liposomal and forms liposomes in situ.
In some embodiments, the composition is devoid of particles above 100 nm. In some embodiments, the composition is devoid of particles above 50 nm in size. In some embodiments, the composition is devoid of particles above 20 nm in size. In some embodiments, the composition is devoid of particles above 10 nm in size. In some embodiments, the composition is an essentially particle-free oily solution. In some embodiments, the composition is a clear solution.
Prior art formulations (see US 2012/0316108) prepared according to a method of preparation involving forming a nanodispersion which is subsequently lyophilized to obtain an anhydrous gel, fail to form clear solutions and contain particles. In other words these are nanodispersions rather than clear solutions.
In some embodiments, an API is present in the amount equivalent to about 0.2% to about 18% by weight. In another embodiment, an API is present in the amount equivalent to about 1% to about 12% by weight. In yet another embodiment, an API is present in the amount equivalent to about 2% to about 10% by weight. In yet another embodiment, an API is present in the amount equivalent to about 3% to about 6% by weight.
Though the API may be uploaded in high doses, the amount of the API in the depot formulation will depend on: which API is used, the current maximal onetime amount allowed, the medical indication, the patient, etc.
In some embodiment, the natural non-synthetic phospholipid can be any of the phospholipids described above. In some embodiments, the natural non-synthetic phospholipid is present in the formulation in the amount of about 10% to about 80% by weight. In some embodiments, the phospholipid is not a synthetic lipid such as 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) or a pharmaceutically acceptable salt thereof. In another embodiment, the formulation of the invention is devoid of 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) or a pharmaceutically acceptable salt thereof. In other embodiments, the compositions of the invention are substantially devoid of DMPG. In this context devoid of DMPG refers to a concentration below 0.5%, preferably below 0.1%.
In some embodiments, the non-synthetic phospholipid is present in the formulation in the amount of about 40% to about 60% by weight. In some embodiments, the phospholipid is phosphatidylcholine (PC) or a pharmaceutically acceptable salt thereof.
In some embodiments, the non-aqueous pharmaceutically acceptable carrier is present in the formulation in the amount of about 20% to about 50% by weight. In some embodiments, the non-aqueous pharmaceutically acceptable carrier is castor oil, sesame oil, cottonseed oil, safflower oil, or one or more triglycerides.
In some embodiments, the co-solvent is a non-aromatic co-solvent. In some embodiments, the co-solvent is an alcohol. In some embodiments, the alcohol is ethanol. Ethanol can be present in the formulations in the amount of about 1% to about 15% by weight. In some embodiments the co-solvent serves as a viscosity regulator which renders the composition suitable for injection. In some embodiments, the viscosity of the formulation is below 2500 cP. In some embodiments, the viscosity of the formulation is below 2000 cP. In some embodiments, the viscosity of the formulation is in the range of 1000-2500 cP. In some embodiments, the viscosity of the formulation is in the range of 1000-2000 cP. The non-aqueous pro-liposomal depot formulations optionally comprise an anti-oxidant. Suitable anti-oxidants have been described above.
The non-aqueous non-liposomal depot formulations can optionally comprise additional ingredients, such as various excipients, pH modifying agents, metal chelators such as EDTA or edetic acid, salts, coloring agents and the like.
According to some embodiments the formulation is devoid of sugars, such as but not limited to, sucrose, dextrose, lactose, glucose, trehalose, maltose, mannitol, sorbitol, glycerol, amylose, starch, amylopectin, or a mixture thereof.
While the pro-liposomal non-aqueous depot formulation described herein are termed non-aqueous (or essentially devoid of water), residual or trace water molecules, e.g., from ingredients used to make the formulation, may remain present. Such depot formulation is still deemed to be non-aqueous. In some embodiments, water trigger the formation of liposomes and therefore the depot formulation must be devoid of water or at least have minute amount of water as described herein. In specific embodiments, the residual moisture was below 0.3% as determined using the Karl Fischer method. In specific embodiments, the residual moisture was below 0.15% as determined using the Karl Fischer method. Thus, in some embodiments, liposomes are formed within the depot formulation upon contact with aqueous body fluids (such as contact with a living a tissue which comprises water). In some embodiments, the formulation of the present invention is prepared and stored in dry conditions which ensure that the compositions are essentially “waterless” and that the liposomes can form only after administration to the bodily fluids in situ.
Methods for Making Non-Liposomal Non-Aqueous Formulations
In some embodiments, pro-liposomal non-aqueous depot formulations of the invention are prepared as follows:
1. An API (e.g., diclofenac), a natural non-synthetic phospholipid (e.g., Phospholipon® 90G), a pharmaceutically acceptable non-aqueous carrier (e.g., castor oil), and optionally, an anti-oxidant (e.g., cysteine HCl) are dissolved in a co-solvent (such as an alcohol e.g., ethanol) by warming and/or sonication, and/or any other means for dispersing and/or mixing the ingredients.
2. The excess alcohol is removed or partially removed, e.g., by evaporation, and/or vacuum pump drying. Other processes can also be used for the removal of the alcohol, or the formulation is produced with the exact amount of ethanol in the final formulation.
3. Optionally, the amount of residual alcohol in the end product of step 2 is predetermined.
4. If required, additional amounts of the same or a different co-solvent may be added and mixed with the product of step 2 to a final alcohol concentration of about 4-8% (w/w). The final alcohol concentration of 6% (w/w) has been determined to work well.
5. Optionally, the product of step 4 is transferred to vials and/or sterilized (e.g., by autoclaving).
Various modifications to this procedure are also contemplated. However, water is not added as a processing aid or as an excipient in the manufacturing process of the pro-liposomal non-aqueous depot formulations. As no water is added during the preparation process, no lyophilization step is required. In effect, the preparation of the composition does not require the addition of sugars, often required to avoid aggregation of phospholipid particles or droplets during the water removal processes.
As no emulsion or dispersion is formed in the method disclosed, the resultant formulation is substantially devoid of particles and is a true solution. In case particles are present, such particles will have an average particle size below 50 nm, alternatively below 20 nm, alternatively below 10 nm and can be termed an essentially particle free oily solution. This process is advantageous in contrast to other methods known in the art, which comprise a step of emulsification and/or dispersion. Known methods involving emulsification or dispersion result in the formation of particle containing compositions as exemplified below.
It was surprisingly found that the formulation of the present invention can be subject to sterilization such as but not limited to autoclaving without damaging the activity or the consistency of the formulation. This is in contrast to prior art formulations generated through a method of preparation involving emulsification or nanodispersion, which is subsequently lyophilized to obtain an anhydrous gel. Autoclaving the prior art formulations will destroy the nanoparticles present in the gel and in effect the activity and consistency of the formulation.
Pro-Liposomal, Non-Aqueous Stock Formulations
The invention is based, in part, on the surprising discovery that a ready-to-use stock formulation, into which a hydrophobic API is easily mixed, can be formed. The stock formulation comprises a natural non-synthetic phospholipid; a non-aqueous pharmaceutically acceptable carrier; and a co-solvent as a viscosity regulator. According to some embodiments, the stock formulation is devoid of water except for residual moisture that may be present in the excipients used to make the composition. In specific embodiments the residual moisture was below 0.3% as determined using the Karl Fischer method for automatically determination of water content. In specific embodiments the residual moisture was below 0.15% as determined using the Karl Fischer method for automatically determination of water content.
Upon preparation of the stock formulation, the hydrophobic API can readily be added without further processing of the formulation apart from mixing. Alternatively, the API is pre-dissolved prior to being added to the stock formulation. According to some embodiments, the API is dissolved in the same or a different pharmaceutically acceptable non-aqueous carrier prior to being added to the stock formulation. Alternatively, the API can be added followed by heating and mixing of the final composition.
In some embodiments, the stock formulation is devoid of particles above 100 nm. In some embodiments, the stock formulation is devoid of particles above 50 nm in size. In some embodiments, the stock formulation is devoid of particles above 20 nm in size. In some embodiments, the stock formulation is devoid of particles above 10 nm in size. In some embodiments, the stock formulation is an essentially particle-free oily solution. In some embodiments, the stock formulation is a clear solution.
Prior art formulations disclosed as anhydrous one phase gels (US 2012/0316108) appear as translucent suspensions of nanoparticles, but are not in fact true solutions. Prior art formulations prepared by a) mixing the components to form a primary dispersion comprising one or more phospholipid(s), and excessive water; b) homogenizing the primary dispersion to form a nanodispersion with an average particle size of less than about 200 nm in diameter c) passing the nanodispersion through a 0.2- or 0.45-micron filter; and d) removing water to less than 5%, preferably less than 3% and more preferably less than 1% by wt fail to form clear solutions and contain particles. In other words these are nanodispersions rather than clear solutions.
According to some embodiments the formulation is devoid of sugars such as but not limited to sucrose, dextrose, lactose, glucose, trehalose, maltose, mannitol, sorbitol, glycerol, amylose, starch, amylopectin, or a mixture thereof.
In one embodiment, the natural non-synthetic phospholipid can be any of the phospholipids described above. In another embodiment, the natural non-synthetic phospholipid is present in the formulation in the amount of about 10% to about 80% by weight. In yet another embodiment, the phospholipid is not a synthetic lipid such as 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) or a pharmaceutically acceptable salt thereof. In yet another embodiment, the formulation of the invention is devoid of 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) or a pharmaceutically acceptable salt thereof. In yet another embodiment, the compositions of the invention are substantially devoid of DMPG. In this context devoid of DMPG refers to a concentration below 0.5%, preferably below 0.1%.
In one embodiment, the first phospholipid is present in the formulation in the amount of about 40% to about 60% by weight. In another embodiment, the phospholipid is phosphatidylcholine (PC) or a pharmaceutically acceptable salt thereof.
In one embodiment, the non-aqueous pharmaceutically acceptable carrier is present in the formulation in the amount of about 20% to about 50% by weight. In another embodiment, the non-aqueous pharmaceutically acceptable carrier is castor oil, sesame oil, cottonseed oil, safflower oil, or one or more triglycerides. In yet another embodiment, the ratio between the phospholipids and the non-aqueous carrier is in a range of 3:1-1:2, 2.5:1-1:5:, 2.2:1-1:1.2, 2:1-1:1. Each possibility is a separate embodiment of the invention.
In one embodiment, the co-solvent is an alcohol. In another embodiment, the alcohol is ethanol. Ethanol can be present in the formulations in the amount of about 1% to about 15% by weight. As explained above, the co-solvent can serve as a viscosity regulator. In some embodiments, the viscosity of the stock formulation is below 2500 cP. In some embodiments, the viscosity of the stock formulation is below 2000 cP. In some embodiments, the viscosity of the stock formulation is in the range of 1000-2500 cP. In some embodiments, the viscosity of the stock formulation is in the range of 1000-2000 cP.
The non-aqueous, pro-liposomal depot formulations optionally comprise an anti-oxidant. Suitable anti-oxidants have been described above.
The non-aqueous, non-liposomal depot formulations can optionally comprise additional ingredients, such as various excipients, pH modifying agents, metal chelators such as EDTA or edetic acid, salts, coloring agents and the like.
While the pro-liposomal, non-aqueous depot formulation described herein are termed non-aqueous (or essentially devoid of water), residual or trace water molecules, e.g., from ingredients used to make the formulation, may remain present. Such depot formulation is still deemed to be non-aqueous. In specific embodiments the residual moisture was below 0.3% as determined by the Karl-Fischer method for automatically determination of water content. In specific embodiments the residual moisture was below 0.15% as determined by the Karl-Fischer method for automatically determination of water content.
Methods for Making Non-Liposomal Non-Aqueous Stock Formulations
According to some embodiments, the pro-liposomal, non-aqueous pharmaceutical compositions of the invention were prepared by adding a hydrophobic API to a pre-prepared stock formulation. Using this method there is advantageously no need for adding excess ethanol and subsequent evaporation of the ethanol in presence of the API.
It was surprisingly found that a combination of heat, torque and high shear mixing resulted in the complete dissolving of the phospholipid in the pharmaceutically acceptable non-aqueous carrier.
The stock formulation was prepared as follows:

    
    
        1. A pharmaceutically acceptable, non-aqueous carrier (e.g., castor oil), and optionally a co-solvent (such as an alcohol e.g., ethanol) optionally containing an anti-oxidant (e.g., cysteine HCl) is equilibrated at 65° C.
        2. A natural non-synthetic phospholipid (lecithin e.g., Phospholipon® 90G) is added and high torque and shear mixed at 65° C.
        3. Upon complete dissolving of the non-synthetic phospholipid, the mixture is cooled to room temperature.
        4. Optionally, the product of step 3 is transferred to vials and/or sterilized (e.g., by autoclaving).
    
    


A hydrophobic API (e.g., ketoprofen), can now be added to the pre-prepared stock formulation. Alternatively, the hydrophobic API can be added at step 1 of the method, at step 2 of the method, at step 3 of the method or at step 4 of the method. Each possibility is a separate embodiment of the invention.
As understood by the skilled in the art, the improved process of preparation eliminates the need for adding excess ethanol in the dissolution process. As a result, the subsequent removal of excess ethanol from the formulation by evaporation in presence of the API is avoided.
It was surprisingly found that the formulation of the present invention can be subject to sterilization, such as but not limited to autoclaving, without damaging the activity or the consistency of the formulation. This is in contrast to similar formulations generated through a method of preparation involving generating a nanodispersion which is subsequently lyophilized to obtain an anhydrous gel. Autoclaving the latter will destroy the nanoparticles present in the gel an in effect the activity and consistency of the formulation.
Administration of Pro-Liposomal Non-Aqueous Depot Formulations
The compositions described herein are useful for carrying a hydrophobic API and releasing it slowly (extended release).
The depot formulations described herein can be used for a variety of therapeutic purposes that require a slow release formulation.
In some embodiments, the pharmaceutical formulation is administered as a depot formulation. In some embodiments, the depot formulations can be administered parentally. In some embodiments, the depot formulation is administered by injection into an incision. In some embodiments, the formulations are administered by subcutaneous (intra-dermal) injection. In some embodiments, the pharmaceutical formulation is administered by infiltration into an incision, or the depot formulation is administered by multiple small dose intradermal injections along affected nerve routes or endings. Furthermore, the depot formulation can be administered by implantation, topically, or in the form of transdermal skin patches well known to those of ordinary skill in that art. To be administered in the form of a transdermal delivery system, the dosage administration can be continuous rather than intermittent throughout the dosage regimen. Other illustrative topical preparations include creams, ointments, lotions, aerosol sprays and gels, wherein the concentration of the API ranges from about 0.1% to about 10%, (w/w) or (w/v).
In some embodiments, the depot formulation is administered using a drug delivery device suitable for parenteral delivery, such as a syringe.
In some embodiments, the pharmaceutical formulation upon administration is therapeutically active for at least about 24 hours. In some embodiments, the formulation is therapeutically active between 24 and 48 hours. In some embodiments, the pharmaceutical formulation is therapeutically active for at least about 48 hours. In some embodiments, the pharmaceutical formulation is therapeutically active between 48 and 72 hours. In some embodiments, the pharmaceutical formulation is therapeutically active for at least about 72 hours.
This extended period of drug delivery of the invention is made possible by a one-time injection with relatively high load of the API present in the depot formulations described herein or in repeated successive small doses, without the hazard of bursting effect as may be the case in liposomal injections, a sudden increase of dose to toxic levels or levels which may adversely affect the internal body systems. In one embodiment, an API is delivered to the subject without the need for re-accessing the syringe and/or without the need for re-filling the syringe or repeated dosing after a period of time.
In one embodiment substantially continuous delivery of an API (e.g., by infusion, diffusion, etc.) can be accomplished using, for example, a drug delivery device in the form of an external or implantable pump. Routes of delivery contemplated by the invention include, but are not necessarily limited to, implants, parenteral routes (e.g., subcutaneous injection infiltration or instillation, intravenous, intramuscular, intraspinal, infiltration and the like) as well as topical application. Parenteral delivery into an open wound or next to it (e.g., infiltration into a surgical incision) is a delivery route of particular interest.
If a longer period of drug delivery is desired, the administration of the depot formulation can be repeated. Typically, administration of the depot formulation can be repeated two, three or more times within a period ranging from about 1 week to about 12 months or more.
The actual dose of drug delivered can be readily calculated by one of skill in the art and will vary with a variety of factors such as the potency and other properties of the selected drug used (e.g., hydrophobicity).
The amount of the API that is effective for treatment or prevention can be determined by standard clinical techniques. In addition, in vitro or in vivo assays can optionally be employed to help identify optimal dosage ranges. The precise dose to be employed can also depend on the route of administration, and the seriousness of the condition being treated and can be decided according to the judgment of the practitioner and each subject's circumstances in view of, e.g., published clinical studies. Suitable effective dosage amounts, however, range from about 0.1% to about 10% API by weight of the depot formulation. In one embodiment the effective dosage is about 0.2%, 0.5%, about 1%, about 1.5%, about 2%, about 2.5%, about 3%, about 3.5% mg, about 4%, about 4.5%, about 5%, about 6% mg, about 7%, about 8%, about 9%, or about 10%.
Equivalent dosages can be administered over various time periods including, but not limited to, about every 12 hours, about every 24 hours, about every 36 hours, about every 48 hours, about every 72 hours, about every week, about every two weeks, about every three weeks, about every month, and about every two months. The effective dosage amounts described herein refer to total amounts administered; that is, if more than one API is administered, the effective dosage amounts correspond to the total amount administered.
The dosage regimen utilizing the depot formulations of APIs described herein can be selected in accordance with a variety of factors including type, age, weight, sex and medical condition of the subject; the severity of the condition to be treated; the route of administration; the renal or hepatic function of the subject; and the particular API employed.
The depot formulations of a hydrophobic API can be administered in a single daily dose, or the total daily dosage can be administered in divided doses of two, three or four intervals daily.
The depot formulations can be assayed in vitro or in vivo for the desired therapeutic or prophylactic activity prior to use in humans. Animal model systems can be used to demonstrate safety and efficacy of the depot formulations described herein.
The present invention can further comprise administering a prophylactic or therapeutic agent to the subject being administered the API. In one embodiment the other prophylactic or therapeutic agent is administered in an effective amount.
In one embodiment, the other prophylactic or therapeutic agent is an agent useful for reducing any potential side effect of the API. Such potential side effects include, but are not limited to, nausea, vomiting, headache, low white blood cell count, low red blood cell count, low platelet count, headache, fever, lethargy, a muscle ache, general pain, diarrhea, neuropathy, pruritus, a mouth sore, alopecia, anxiety or depression.
In one embodiment, the depot formulation of an API can be administered prior to, concurrently with, or after the other prophylactic or therapeutic agent, or on the same day, or within 1 hour, 2 hours, 12 hours, 24 hours, 48 hours or 72 hours of each other.
Effective amounts of the other prophylactic or therapeutic agents are well known to those skilled in the art. However, it is well within the skilled artisan's purview to determine the other prophylactic or therapeutic agent's optimal effective amount range. In one embodiment of the invention, where another prophylactic or therapeutic agent is administered to a subject, the effective amount of the API in the depot formulation is less than its effective amount would be where the other prophylactic or therapeutic agent is not administered. In this case, without being bound by theory, it is believed that the API and the other prophylactic or therapeutic agent act synergistically.
Pharmaceutical compositions of the invention for parenteral administration comprise the product according to the invention in combination with one or more pharmaceutically acceptable sterile non-aqueous solutions, dispersions, suspensions or emulsions, or sterile powders which may be reconstituted into sterile injectable solutions or dispersions just prior to use, which may contain antioxidants, buffers, bacteriostats, solutes which render the formulation isotonic with the blood of the intended recipient or suspending or thickening agents.
Products Containing Depot Formulations Described Herein
Kits
The invention provides kits that can simplify the administration of a depot formulation of a hydrophobic API to a subject.
A typical kit comprises a unit dosage form of a depot formulation of the hydrophobic API.
In one embodiment the unit dosage form is a container, which can be sterile, containing an effective amount of a depot formulation of the API. The kit can further comprise a label or printed instructions instructing the use of the depot formulation of an API.
A kit can also comprise a container containing the stock formulation of any of the above embodiments. The kit may further comprise a hydrophobic API.
The kit can also further comprise a unit dosage form of another prophylactic or therapeutic agent, for example, a container containing an effective amount of the other prophylactic or therapeutic agent. In some embodiments the kit comprises a container containing a depot formulation of more than one API. Examples of potential APIs are listed above.
Pre-Filled Syringes
According to certain embodiments, the invention provides a pre-filled syringe filled with a depot formulation described herein. The depot formulation includes a hydrophobic API. The pre-filled syringe can also comprise a needle suitable for injection of the depot formulations or other means of deploying the formulation. In one embodiment, the needle is an 18-25 G needle. In another embodiment, the needle is a 21 G needle.
This invention is further illustrated by the following examples, which should not be construed as limiting. Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific substances and procedures described herein. Such equivalents are intended to be encompassed in the scope of the claims that follow the examples below. A number of references have been cited, the entire disclosures of which are incorporated herein by reference in their entirety.
EXAMPLES
Example 1
Preparation of Pro-Liposomal—Non-Aqueous Oleaginous Depot Formulation
A pro-liposomal, non-aqueous oleaginous depot formulation of ropivacaine was prepared as follows. The required amount of ropivacaine HCl monohydrate was placed into a pre weight (tare) round bottom flask and the required amount of cysteine HCl is added. The required amount of lecithin (PL90G, phosphatidylcholine) was added into the flask followed by the required amount of castor oil (the order of ingredients is unimportant). Absolute ethanol, in an amount equal to or exceeding the required final amount, was added to the flask. The flask was closed tightly and weighed. The flask with ingredients was placed into a water bath sonicator and heated to about 50° C. When all ingredients were dissolved and absolute ethanol amount exceeded the required final amount, the flask was connected to a suitable evaporating apparatus (e.g., Rotavapor) and the water bath was maintained at a heat of about 50° C. Vacuum was adjusted to 200 mbar and the flask was rotated at about 60 rpm. The vacuum was gradually decreased in increments of 10 mbar until it reached 40 mbar. The evaporation was continued until the weight of the flask indicated to be containing the required final amount of 6% or less (w/w) of absolute ethanol, as calculated by weighing the flask and contents or the amount of evaporated and cooled down alcohol trapped outside the evaporator. The flask and its contents were allowed to cool to room temperature. If necessary, absolute ethanol was added to reach 6% (w/w). If the solution was determined to contain less than 6% (w/w) of absolute ethanol, ethanol was added to make up the desired percentage % (w/w). The flask may be stored refrigerated or at room temperature until the vial or syringe filling is planned. The flask was re-heated and rotated in a sonicator bath heated to 50° C. for about 1 hour before dispensing to final containers. The flask and its contents were allowed to cool to room temperature. Using a suitable filling apparatus, the resultant solution was filled into glass vials or other containers.
As can be seen from the process described above, no water was added during this entire process.
Example 2
Pro-Liposomal—Non-Aqueous Oleaginous Formulations of Ropivacaine
The non-aqueous pre-liposomal oleaginous ropivacaine formulation was prepared in accordance with the process described in Example 1. Table 1A provides the components of the formulation (formulation A).










TABLE 1A







FORMULATION A
% [w/w]









Ropivacaine HCl monohydrate
 4.78% 




(equivalent to 4% 




ropivacaine base)



Phospholipon (PL90G) (Lipoid (GMbH))
53.91%



(Pure phosphatidylcholine stabilized with 0.1% 




ascorbyl palmitate)




Castor oil
35.21%



Cysteine HCl
 0.1%



Ethanol*
 6.0%







*Quantity reflects the final concentration in the formulation, but used in larger quantities during the production process






Table 1B provides the components of inferior formulations comprising synthetic phospholipids used for comparison with formulation A.









TABLE 1B






Formulation 
Formulation 


COMPONENTS
3
4







Ropivacaine HCl monohydrate
 4.78% 
 4.78%



(equivalent to 
(equivalent to 



4% ropivacaine 
4% ropivacaine 



base)
base)


DMPG (1,2, Dimyristoyl-sn-glycero-3-
 5.02%
 5.02%


phosphoglycerol NH4/Na salt 




(Avanti Polar Lipids)




Phospholipon (PL90G) (Lipoid (GMbH))
48.89%
50.89%


(Pure phosphatidylcholine stabilized 




with 0.1% ascorbyl palmitate)




Castor oil
35.21%
35.21%


Cysteine HCl
 0.1%
 0.1%


Ethanol*
 6.0%
 4.0%





*Quantity reflects the concentration in the final formulation, but used in larger quantities during the production process.






Stability testing of the samples in clear vials was performed for samples stored in stability chambers at room temperature (RT) and accelerated stability conditions at 40° C. over a period of several weeks to several months by visual observation of the samples for any precipitation, change in color, and change in clarity followed by chemical dosage confirmation. It was found that Formulations 3 and 4 precipitated at RT, which rendered the formulations into virtually opaque gels. These precipitations could not be re-dispersed, even with vigorous shaking. In contrast the preferred depot formulation A was physically and chemically stable for over 24 months under these conditions. It was further noted, that formulation A was clear and transparent, with no visible particles. Thus, it was concluded that the formulations containing synthetic phospholipids are unsuitable for further commercial development.
Example 3
Preparation of a Pro-Liposomal—Non-Aqueous Stock Depot Formulation
It was advantageously found that a pro-liposomal non-aqueous ready to use depot formulation, which does not require evaporation of the ethanol in presence of the API, can be prepared. The combination of heat, torque and high shear mixing enabled preparing a ready-to-use stock formulation that is stable, does not contain excess ethanol and facilitates adding the hydrophobic API required.
The stock formulation was prepared as follows:
The required amounts of castor oil, ethanol and cysteine (pre-dissolved in the ethanol) were added to a container and equilibrated at 65° C. The lecithin was then added followed by high torque and shear mixing at 125 rpm and 3577 rpm respectively for approximately half an hour. Following complete dissolving of the lecithin the mixture was discharged into flasks and stored over-night yielding a transparent oil As understood from the process described, no water was added during this entire process.
It is understood by the skilled in the art that the stock formulation of the invention facilitates the addition of various hydrophobic APIs.
It is further understood that the improved process of preparation eliminates the need for adding excess ethanol in the dissolution process. As a result, the subsequent removal of excess ethanol from the formulation by evaporation in presence of the API is avoided. Table 2 provides the components of the stock formulation.








TABLE 2






% 


STOCK FORMULATION
[w/w]
















Phospholipon (PL90G) (Lipoid (GMbH))
56.62


(Pure phosphatidylcholine stabilized with 0.1% ascorbyl palmitate)



Castor oil
36.98


Cysteine HCl
0.10


Ethanol*
6.30


TOTAL
100









Example 4
Pro-Liposomal—Non-Aqueous Oleaginous Formulations of Ropivacaine
A non-aqueous pro-liposomal oleaginous stock formulation was prepared in accordance with the process described in Example 3. Ropivacaine was added to the ready-to-use stock formulation. Table 3 provides the constituents of compositions with various amounts of ropivacaine.







TABLE 3





ROPIVACAINE FORMULATION (% w/w)




















Ropivacaine
1.20
2.40
4.78



PL90G
55.94
55.26
53.91



Castor oil 
36.54
36.09
35.21



Cysteine HCl
0.10
0.10
0.10



EtOH
6.22
6.15
6.00



TOTAL
100.0
100.0
100.0










The final formulation was clear and transparent, with no visible particles. The final formulation was stable for at least one month under accelerated stability testing. Preferably the formulation is stable for over 2 months, over 4 months, over 6 months or longer.
Example 5
Pro-Liposomal—Non-Aqueous Oleaginous Compositions of Diclofenac
A non-aqueous, pro-liposomal, oleaginous stock formulation was prepared in accordance with the process described in Example 3. Diclofenac was subsequently added to the ready-to-use stock formulation. Table 4 provides formulations with various amount of diclofenac.







TABLE 4





DICLOFENAC FORMULATION (% w/w)




















Diclofenac
1.25
2.49
4.99



PL90G
55.91
55.21
53.79



Castor oil
36.52
36.06
35.13



Cysteine HCl
0.10
0.10
0.10



EtOH
6.22
6.14
5.99



TOTAL
100.0
100.0
100.0










The final formulation was clear and transparent, with no visible particles. The final formulation was stable for at least one month under accelerated stability testing. Preferably the formulation is stable for over 2 months, over 4 months, over 6 months or longer.
Example 6
Pro-Liposomal—Non-Aqueous Compositions of Dexamethasone
A non-aqueous non-liposomal oleaginous stock formulation was prepared in accordance with the process described in Example 3. Dexamethasone was added to the ready-to-use stock formulation. Table 5 provides compositions with various amounts of dexamethasone.







TABLE 5





DEXAMETHASONE FORMULATION (% w/w)


















Dexamethasone
1.00
2.00
4.00


PL90G
56.05
55.48
54.35


Castor oil
36.61
36.24
35.50


Cysteine HCl
0.10
0.10
0.10


EtOH
6.24
6.17
6.05


TOTAL
100.0
100.0
100.0









The final formulation was clear and transparent, with no visible particles. The final formulation was stable for at least one month under accelerated stability testing. Preferably the formulation is stable for over 2 months, over 4 months, over 6 months or longer.
Example 7
Pro-Liposomal—Non-Aqueous Compositions of Ketoprofen
A non-aqueous non-liposomal oleaginous stock formulation was prepared in accordance with the process described in Example 3. Ketoprofen was subsequently added to the ready-to-use stock formulation. Table 6 provides compositions with various amounts of ketoprofen.







TABLE 6





KETOPROFEN FORMULATION (% w/w)




















Ketoprofen
1.00
2.00
4.00



PL90G
56.05
55.48
54.35



Castor oil
36.61
36.24
35.50



Cysteine HCl
0.10
0.10
0.10



EtOH
6.24
6.17
6.05



TOTAL
100.0
100.0
100.0










The final formulation was clear and transparent, with no visible particles. The final formulation was stable for at least one month under accelerated stability testing. Preferably the formulation is stable for over 2 months, over 4 months, over 6 months or longer.
Example 8
Pro-Liposomal—Non-Aqueous Oleaginous Formulations of Oxycodone
A non-aqueous pre-liposomal, oleaginous oxycodone formulation is prepared in accordance with the process described in Example 1. Table 7 provides the components of the formulation.










TABLE 7







OXYCODONE FORMULATION
% [w/w]









Oxycodone
1-5%



Phospholipon (PL90G) (Lipoid (GMbH))
45-60%



(Pure phosphatidylcholine stabilized with 0.1% 




ascorbyl palmitate)




Castor oil
30-40%



Cysteine HCl
0.1%



Ethanol*
6.0%







*Quantity reflects the final concentration in the formulation, but used in larger quantities during the production process.






Example 9
Pro-Liposomal—Non-Aqueous Oleaginous Formulations of Fentanyl
A non-aqueous, pre-liposomal, oleaginous fentanyl formulation is prepared in accordance with the process described in Example 1. Table 8 provides the components of the formulation.










TABLE 8







FENTANYL FORMULATION
% [w/w]









Fentanyl
1-5%



Phospholipon (PL90G) (Lipoid GMbH)
45-60%



USP(Pure phosphatidylcholine stabilized with 




0.1% ascorbyl palmitate)




Castor oil
30-40%



Cysteine HCl
0.1%



Ethanol*
6.0%







*Quantity reflects the final concentration in the formulation, but used in larger quantities during the production process






Example 10
Viscosity Measurements of the Ropivacaine Depot Compositions
The viscosity of depot ropivacaine formulation A as well as ropivacaine formulations 3 and 4 was measured by the spindle method using viscometer (Brookfield model DV-II) equipped with spindle 5; bath temperature of 30° C., speed of 30, 60 and 100 RPM.
Ropivacaine formulation A had a lower viscosity (1720 cP) than formulations 3 and 4 which contain DMPG (3031 cP). This difference was made explicit by the increased flow characteristics of depot formulation A as well as an eased overall handling (syringability and injectability) which makes ropivacaine formulation A more suitable for parenteral administration. Formulations devoid of ethanol had higher viscosity and are unsuitable for parental administration.
Example 11
Viscosity Measurements of Ropivacaine Compositions with Different Concentrations of Co-solvent
The viscosity of depot ropivacaine formulations with various amount of ethanol was measured by the spindle method using viscometer (Brookfield model DV-II) equipped with spindle 5; bath temperature of 30° C., speed of 30, 60 and 100 RPM. As seen from table 9, the viscosity testing demonstrated a decreased viscosity with increased ethanol concentrations.










TABLE 9









Formulation
Speed (rpm)












description
50
60
100
















2%Ropi/4%EtOH
3791
3779
3863



2%Ropi/4%EtOH
3479
3439
3395



2%Ropi/5%EtOH
2184
2280
2280



2%Ropi/6%EtOH
1512
1620
1692



2%Ropi/6%EtOH
1824
1760
1704










Example 12
Syringability Testing Measurements of Ropivacaine Depot Formulations with Different Concentrations of Co-solvent
The injectability of depot ropivacaine compositions with various amount of ethanol was measured by extrusion from a 21 G syringe of a predetermined amount of the composition onto a pre-weighed dish.
As seen from table 10, the injectability rate increased with increased ethanol concentrations.










TABLE 10







Formulation description
Injectability rate (mg/sec)









2%Ropi/4%EtOH
1.46



2%Ropi/4.5%EtOH
1.76



2%Ropi/5%EtOH
2.18



2%Ropi/5.5%EtOH
2.38










Example 13
Liposome Like Structures Formation Upon Exposure to Saline or Pig Plasma
Ropivacaine depot formulation A was kept in scintillation vials and 0.9% NaCl solution or pig plasma were slowly injected into the formulation up to a quantity of 50% (w/w) of the total formulation weight reaching a formulation/saline ratio of 1:1. The resulting mixtures were then agitated at 200 rpm using a water bath shaker at 37° C.
The physical characteristics of depot formulation A containing saline or pig plasma, at a ratio of 1:1, were evaluated using the following methods:

    1. Particle size distribution: Particle size distribution was analyzed using the Coulter LS230 Particle Size Analyzer.
    2. Cryo-TEM morphological evaluation: Morphological evaluation was performed by means of TEM (FEI Technai 12 G2 120 kV with a Gatan cryo-holder maintained at −180° C. and images were recorded on a slow scan cooled charge-coupled device CCD camera Gatan manufacturer).


The particle size distribution (FIGS. 1A and B) results indicate the formation of multi lamellar liposomal vesicles (MLV) in both mixtures. A determined mean/median particle size of about 1.4 μm was obtained with the formulation A/saline dilution, suggesting more multilamellar particles than micelle particles or oil-in-water emulsion droplets which are in the nanosize range. The determined mean/median particle size of the depot formulation A/pig plasma (1:1) was about 20 μm which is significantly larger than in the case of depot formulation A/saline (1:1), indicating MLV formation upon exposure to bodily fluids in vivo.
For the Cryo-TEM morphological evaluation, formulation A was diluted with pig plasma to reach 1:1 and 1:2 dilutions. Samples were then subjected to Cryo-TEM. Blank pig plasma was used as control.
As seen in FIG. 2, multilamellar vesicles and similar lipid assemblies were easily detected following 1:1 and 1:2 dilution of formulation A with pig plasma. This was in sharp contrast to the absence of such structures in the blank pig plasma sample.
It is concluded that depot formulation A creates MLVs upon exposure to pig plasma and that the addition of the viscosity agent ethanol surprisingly does not interfere with the formation of these liposomal vesicles upon exposure to aqueous solutions. Moreover, these results indicate that the slow release and extended duration of pain relief obtained when administering formulation A of the present invention are most likely due to the formation of liposomes or other lipidic vesicular structures and do not require a gel or a gel-like consistency as generally presumed.
Example 14
In vivo Efficacy of Pro-Liposomal—Non-Aqueous Formulations of Ropivacaine
In this study, ropivacaine formulations were evaluated in the juvenile pig model for post-operative pain using Von Frey methodology. The Von Frey hair filaments are made from a nylon filament of varying diameters. The filaments are to be pressed against the skin with enough force so that the hair buckles and forms a U-shape. The gram force required for each filament to buckle is constant, i.e. these hairs can be used to apply a very accurate and repeatable force to test specific, predetermined areas on the skin, thus making the Von Frey hair a diagnostic, research and screening tool. It is readily used to study skin areas with normal responsiveness as well as hyper- or hyposensitive areas.
The various ropivacaine formulations administered to pigs are shown in Table 11. The term 4% ropivacaine refers to 4% ropivacaine base.







TABLE 11







Study design













Total dose of






ropivacaine (mg)




Group
Formulation
per animal
Volume 
Route





1M
Positive Control Ropivacaine
 25 mg
5 ml
SC



injectable solution 0.5%






(Naropin 1% diluted 2X) 





2M
Formulation 4 placebo 4%






ethanol

5 ml
SC


3M
Formulation 3 6% EtOH
200 mg
5 ml
SC


4M
Formulation A 6% ethanol
200 mg
5 ml
SC





* SC is meant as being instilled into the surgical wound following suturing






Table 12 lists the experimental groups in the study. The term 4% ropivacaine refers to 4% ropivacaine base.







TABLE 12







Experimental groups













No. of






Group
Animals
Treatment
Solution
Dosing
Von Frey Tests





1M
6
Positive
commercial
One SC
Group 1M




Control
product
administration
Pain assessment by Von




(Naropin ®)

immediately
Frey was performed prior






post incision
to surgery and at 1.5 h,






closure
3 h, 6 h, 8 h and 12 h post-







surgery


2M
6
Formulation-
6% EtOH

Groups 2M and 3M: Pain




Placebo


assessment by Von Frey


3M
6
Formulation
4%

was performed prior to




3
Ropivacaine

surgery and at 3 h, 6 h, 8 h,





6% EtOH

24 h, 30 h, 36 h. Animals







that demonstrated drug







efficacy at 36 h, were







tested again at the







following time points 42







hours and 48 hours


4M
6
Formulation
4%

Group 4M:




A
Ropivacaine

Pain assessment by Von





6% EtOH

Grey was performed







prior to surgery and at







1.5 h, 3 h, 6 h, 8 h, 24 h, 30 h







and 36 h. Additional tests







were performed for







groups showing







analgesia after 36 hours.










5M
Sham (Negative Control) no 

Group 5M:



injection made

Pain assessment by Von





Grey was performed





prior to surgery and at





1.5 h, 3 h, 6 h, 8 h, , 24 h,





30 h and 36 h. Additional





tests were performed for





groups showing





analgesia after 36 hours









During surgery the piglets were anesthetized by an isoflurane/oxygen mixture delivered through a facemask. A 6-7 cm long skin and fascia incision was made in the left flank, keeping the muscle intact. The skin incision was closed using a sterile suture. The TI treatments, Placebo, gel test formulation (formulation 3), oily test formulation (formulation A) or positive control were carefully administered into the surgical made pocket as two 2.5 ml injections (5 ml/animal). Each injection was performed using a fresh 3.5 ml luerlock syringe through an 18 G needle. Each treatment was applied in the same direction (cranial to caudal). Each incision was performed using an autoclaved sterile set of surgery tools. Following the incision the pigs optionally received 2 types of antibiotics. The animals were kept under anesthesia for the duration of the surgery and dosing (about 20 minutes).
The test formulations were administered only once on study day 0 as subcutaneous injection under the suture. The animals' baseline response to Von Frey was taken on study day −1. The data considered to serve as baseline was the data recorded on study day −1. Animals were included in the study if the flack withdrawal force at baseline was ≦26 g. Preferably, the flank withdrawal force at baseline was 60 g at both flanks. Pain is considered as flank withdrawal at a force of ≦10 g.
Von Frey filaments (Ugo Basile) were applied at approximately  ̃0.5 cm proximal to the incision line to the surface of the flank skin. As the gram number of filaments increased, the force on the flanks' skin increased. The maximum force was 60 g. Filaments were applied until the animal withdrew from the stimuli. Each filament was applied 3-5 times.
As seen in FIG. 3, formulation A, which is an oleaginous solution, unexpectedly provided a longer pain relief compared to all other formulations tested in the experiment, including the formulations having identical ethanol and ropivacaine concentrations. This is evident from the force value shown in FIG. 3 at 18 hrs post-dosing. This result is surprising because the oleaginous solution is less viscous than the gel like formulation containing DMPG. Depot formulations are commonly solid implants or gel-like substances and do not disperse or spread when injected into tissue. Accordingly, it is generally believed that more viscous formulations are retained in the tissue longer than less viscous formulations, as a more viscous material disperses more slowly if at all.
It was found that when the viscosity of the formulation is in the range of 1000-2000 cP, residence time and duration of activity is optimal, despite the decreased injectability of the formulation.
The finding that a depot formulation in the form of an oleaginous solution (formulation A) provided a favorable sustained release profile was unexpected and surprising and suggested that indeed the addition of the viscosity reducing agent ethanol did not have a negative effect neither on the efficacy of ropivacaine nor on the duration of the pain relief.
In order to evaluate the distribution of ropivacaine between wound tissue and blood, wound tissue and blood samples were taken 4 days after administration of either Naropin® or formulation A, and Ropivacaine concentrations were determined by using HPLC/MS/MS.
As can be seen from the results presented in Table 13, a significantly higher concentration of ropivacaine in the wound was obtained when using depot formulation A as compared to that of the Naropin® injection.







TABLE 13







Plasma and wound concentration of ropivacaine









Ropivacaine concentration (ng/mL)










Wound
Plasma












Formulation A*
3798.5
31.4


Naropin ®**
15.4
2.1





*results shown are the mean values obtained in 6 independent measurements.


**results shown are the mean values obtained in 3 independent measurements.






These results indicate that depot formulation A enables the maintenance of higher ropivacaine concentrations in the vicinity of the wound even four days after injection.
Based on all the above results, it was concluded that the depot formulation A is superior to the Naropin® commercial formulation as well as the gel formulations and therefore this formulation was selected for further development.
Example 15
Phase I—Clinical Efficacy Study in Healthy Human Volunteers
The purpose of this study was to evaluate the onset and duration of analgesia of 2.5 ml each of depot formulation A, ropivacaine solution (Naropin®) and placebo gel formulation administered by subcutaneous (SC) injection in a human experimental pain model.
Part 1 of the study included fifteen (15) male subjects who were evaluated for 72 hours post injection. Each subject acted as his own control and received all treatments simultaneously as 2.5 mL subcutaneous injections. Table 14 describes the treatments which each patient received.







TABLE 14







Study design










Treatment
Volume







Formulation A
2.5 mL



Formulation w.o. ropivacaine placebo
2.5 mL



Ripovacaine solution 0.5% (Naropin ®)
2.5 mL










Four circumscribed areas were marked on each volunteer's back and each of the three treatments was injected into one randomly assigned area while a fourth, randomly selected area, was used as a non-injected control. The effect of local analgesia induced by the study medication and controls were evaluated using Tactile Threshold (von Frey hair), Pinprick Test (PPT), Cold Sensation, and Heat Pain Tolerance. The tests showed that the duration of the pain relief was longer when formulation A was administered compared to the Naropin® solution. In accordance the percentage of subjects who achieved analgesia for ≧24 hours was greater following administration of formulation A, as can be seen in table 15.







TABLE 15







Duration of pain relief















Placebo formulation



Response
Formulation A
Naropin ® 
without ropivacaine







Yes (%)
53.8
30.8
7.7










Part 2 of the study was a pharmacokinetic analysis to which nine subjects were enrolled. Each subject received a 2.5 mL subcutaneous single injection on his back of either oligoneous depot formulation A (6 subjects) or Ropivacaine Injectable commercial Solution 0.5% (Naropin®) (3 subjects). Venous blood samples (9 ml samples), for the measurement of plasma concentration of ropivacaine, were drawn immediately before the drug administration (time 0) and at 0.5, 1, 1.5, 2, 3, 6, 9, 12, 18, 24, 30, 36, 48, and 72 hours after drug administration.
As seen in FIG. 4, the concentration of ropivacaine in the blood was significantly higher when formulation A was administered, compared to Naropin®, already 3 hours after injection. The duration of the effects for formulation A lasted for over 48 hours and was significantly longer than the ropivacaine solution (Naropin®) which lasted only for up to 12 hours. Table 16 summarizes the main pharmacokinetic parameters. As seen in the table, the Cmax value of formulation A resembles that of the Naropin® injection and is distinguishably below the Cmax of approximately 0.87 mg/mL obtained for lysosomal formulations of ropivacaine as well as distinguishably below the toxic threshold of 0.6 mg/mL, indicating that an initial burst of ropivacaine is avoided. This facilitates administration of high ropivacaine concentration in a single injection.







TABLE 16







pharmacokinetics











Naropin ®
Formulation A 
P 


Parameter
N = 3
N = 6
value*





Cmax 
100.02 ± 41.34 
164.35 ± 42.95 
0.1934


(ng/mL)





Tmax (hr)
0.83 ± 0.29
15.25 ± 10.83
0.0586


AUClast 
596.69 ± 147.78
4669.04 ± 1242.98
0.0595


(ng•hr/mL)





AUCinf 
614.00 ± 138.33
5032.393 ± 1502.73 
0.0595


(ng•hr/mL)





Lambda-z 
0.12 ± 0.08
0.05 ± 0.02



(1/hr)





Number of 
6.67 ± 5.51
4.67 ± 1.63



points for 





Lambda-z





T1/2 (hr)
9.55 ± 8.86
15.43 ± 7.33 
0.3926


Volume (mL)
297379.07 ± 277334.00
449449.02 ± 163865.10



Clearance 
21029.41 ± 4498.87 
21417.55 ± 6326.11 



(mL/hr)









The conclusion of this study was that formulation A has a favorable prolonged release profile compared to the commercially available 0.5% ropivacaine solution, and that the safety of formulation A was not compromised.
Example 16
Particle Size Distribution of Depot Formulations
The particle size distribution of the depot formulation devoid of the hydrophobic API (prepared as described in example 3 is measured by dynamic light scattering using a Malvern Zetasizer, Coulter N4plus or Nicomp 300 particle size analyzer able to measure particle size in the submicron range (test range ≧0.5 nm≦1 μm).
Similarly, the particle size of a prior art formulation, designated herein formulation 5 (see US 2012/0316108) is also measured for comparative purposes. The comparative formulation 5 is prepared according to a method of preparation comprising the steps of a) mixing the components to form a primary dispersion comprising one or more phospholipid(s), and excessive water; b) homogenizing the primary dispersion to form a nanodispersion with an average particle size of less than about 200 nm in diameter c) passing the nanodispersion through a 0.2- or 0.45-micron filter; and d) removing water to less than 5%, preferably less than 3% and more preferably less than 1% by wt. Table 17 provides the components of prior art formulation 5.







TABLE 17







Formulation 5 Composition (% wt)










Component
%wt














Soy lecithin
45



Sesame oil
44



EDTA disodium dehydrate
0.10



Potassium monobasic phosphate
0.14



Benzyl alcohol
1.0



Ethanol
4.0



1N KOH
pH to 7.0










Prior art formulation 5 is prepared as follows:

    
    
        1. Weigh out sesame oil, soy lecithin and benzyl alcohol into a glass flask.
        2. Add ethanol USP 200 proof and rotate the flask to dissolve all.
        3. Vacuum dry to remove ethanol to less than 1% by weight.
        4. Add KH2PO4, EDTA and DI-water.
        5. Homogenize to form a nanodispersion.
        6. Adjust pH to 7.0+/−0.2 using NaOH/HCl.
        7. Sterile filter the nanodispersion through a 0.2 micrometer pore filter.
        8. Lyophilize the nanodispersion to remove water to less than 2%.
        9. Add ethanol.
        10. Mix to obtain an anhydrous gel.
    
    


Example 17
In vivo Efficacy of Pro-Liposomal—Non-Aqueous Oleaginous Formulations of Ropivacaine as Compared to Prior Art Formulations
The distribution of ropivacaine between wound tissue and blood is compared for different formulations. Naropin®, formulation A, or formulation 5 containing ropivacaine prepared according to the method described in Example 16 are instilled into a surgical wound only once on day 0. Wound tissue or exudate and blood samples are taken daily for up to 4 days after administration. The concentrations are determined by using HPLC/MS/MS as described in Example 13.

## Claims

1. A pro liposomal non aqueous pharmaceutical depot composition consisting essentially of:
a hydrophobic active pharmaceutical ingredient having a Log P hydrophobicity value of at least 1.5;
about 40% to about 70% by weight of a natural phospholipid;
about 20% to about 60% by weight of an oil as a non-aqueous pharmaceutically acceptable carrier; and
about 0.5% to about 12% by weight of an alcohol as a viscosity regulator,
wherein said composition is in the form of a clear oleaginous liquid solution, stable at
ambient temperature, devoid of water, and has viscosity below 2500 cP.

2. The composition of claim 1, wherein the composition is stable for at least six months at room temperature.

3. The composition of claim 1, wherein the viscosity regulator is ethanol.

4. The composition of claim 1, having a viscosity in the range of 1000-2000 cP.

5. The composition of claim 1, wherein said composition forms liposomes in vivo upon exposure to bodily fluids.

6. The composition of claim 1, wherein said hydrophobic active pharmaceutical ingredient is present in the amount equivalent to about 0.5% to about 10% by weight.

7. The composition of claim 1, wherein said hydrophobic active pharmaceutical ingredient has a solubility in water of less than 10 mg/ml at a temperature of about 25° C.

8. The composition of claim 7, wherein said hydrophobic active pharmaceutical ingredient has a solubility in water of less than lmg/ml at a temperature of about 25° C.

9. The composition of claim 1, wherein said hydrophobic active pharmaceutical ingredient is selected from the group consisting of: ropivacaine, ketoprofen, diclofenac and dexamethasone.

10. The composition of claim 3, wherein ethanol is present in the amount of about 0.5% to about 10% by weight.

11. The composition of claim 1, wherein the natural phospholipid is present in the amount of about 40% to about 60% by weight.

12. The composition of claim 1, wherein the oil is castor oil.

13. The composition of claim 1, wherein the non-aqueous pharmaceutically acceptable carrier is present in the amount of about 30% to about 50% by weight.

14. The composition of claim 1, further comprising an anti-oxidant.

15. The composition of claim 14, wherein the anti-oxidant is cysteine or a pharmaceutically acceptable salt thereof.

16. The composition of claim 1, wherein the composition is substantially devoid of fillers.

17. A method for making a depot composition comprising:
(a) mixing an oil as a non-aqueous pharmaceutically acceptable carrier with:
(i) a hydrophobic active pharmaceutical ingredient (API);
(ii) a natural phospholipid or pharmaceutically acceptable salt thereof; and
(iii) alcohol as a viscosity regulator;

to form a non-aqueous oleaginous liquid solution;
(b) removing all or a portion of the viscosity regulator from the non-aqueous solution; and
(c) adding the alcohol viscosity regulator to the non-aqueous solution to a total amount of about 2% to about 12% by weight,
wherein the depot composition consists essentially of about 40% to about 70% by weight of the natural phospholipid and about 20% to about 60% by weight of the oil.

18. The composition of claim 1, comprising about 0.5% to about 10% by weight of the viscosity regulator.

19. The composition of claim 1, containing a pharmaceutically acceptable excipient.

20. The composition of claim 19, wherein the excipient is selected from the group consisting of pH modifying agents, metal chelators, salts, and coloring agents.