Liposomal amphotericin b compositions and methods

Abstract

The present invention is a stable ready-to-use amphotericin B liposomal parenteral composition and methods of preparing and using the composition. The ready-to-use composition is prepared and filled into a flexible container, and stored frozen for at least one month or longer. After storage the frozen read-to-use composition is thawed and administered to a patient without the need for further diluting or addition of additional ingredients.

Description

[0001] LIPOSOMAL AMPHOTERICIN B COMPOSITIONS AND METHODS This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 587,077 filed on September 30, 2023, the contents of which are incorporated herein by reference. FIELD OF THE INVENTION The present invention relates to ready-to-use parenteral amphotericin B compositions and methods of using and preparing the compositions. BACKGROUND OF THE INVENTION Amphotericin B is a macrocyclic, polyene, antifungal antibiotic produced from a strain of Streptomyces nodosus. Amphotericin B is designated chemically as: [1R-1R*,3S*,5R*,6R*,9R*,11R*,15S*,16R*,17R*,18S*,19E,21E,23E,25E,27E,29E, 31E,33R*,35S*,36R*,37S*)]-33-[(3-Amino-3,6-dideoxy-β-D-mannopyranosyl)oxy]- 1,3,5,6,9,11,17,37-octahydroxy-15,16,18-trimethyl-13-oxo-14,39- dioxabicyclo[33.3.1]nonatriaconta-19,21,23,25,27,29,31-heptaene-36-carboxylic acid (CAS No. 1397-89-3). Amphotericin B has a molecular formula of C47H73NO17and a molecular weight of 924.09. The structure of amphotericin B is shown below: Currently, amphotericin B is marketed as lyophilized liposomes for injection which must be reconstituted first and further diluted in 5% Dextrose Solution prior to administration to patients. One of the commercially available amphotericin B liposome products that requires reconstitution and dilution is AMBISOME®available from Astellas Pharm. in 50 mg / vial. Amphotericin B is also commercially available as a lipid complex in a 5 mg / vial suspension product sold by Leadiant Biosciences, Inc. under the name as ABELCET®. The ABELCET product requires extracting the appropriate amount of the suspension from the vial into a syringe with an 18-gauge needle, replacing the needle on the syringe with a 5-micron filter needle and passing the contents of the syringe through the 5-micron filter needle and into a 5% dextrose solution. These diluted liposomal amphotericin B formulations lack sufficient storage stability. The diluted liposomal amphotericin B product must be used within 24 to 48 hours after reconstitution or preparation even when stored at refrigerator temperature (2-8°C) and within 6 hours after dilution in 5% dextrose and storage at room temperature. Because of this limited shelf life, diluted liposomal amphotericin B must be prepared at hospitals and doctor’s offices prior to administration to patients. However, this carry risks such as dilution errors and microbial contamination. SUMMARY OF THE INVENSION The present invention is a ready-to-use parenteral amphotericin B composition that is stable for at least 1 month, 3 months, 6 months, 9 months, 12 months or longer. The present invention further relates to a method for preparing the ready-to-use parenteral amphotericin B composition and methods of using the ready-to-use parenteral amphotericin B composition. In one aspect of the present invention, the ready-to-use composition is prepared by: (i) forming amphotericin B liposomes; (ii) mixing the amphotericin B liposomes with an aqueous solution, preferably an aqueous dextrose solution and most preferably a 5% aqueous dextrose solution, to obtain an amphotericin B composition with the desired concentration of amphotericin B for administration to a patient; (iii) filling the liposome solution of step (ii) into a flexible container such as a flexible infusion bag; and (iv) freezing the contents of the filled container of step (iii). In certain aspects of the present invention, the forming of the amphotericin B liposomes may comprise (a) mixing two or more of the liposome components and (b) hydrating the mixed components to form the amphotericin B liposomes. The components used in step (a) comprise amphotericin B, one or more phospholipids and optionally liposome stabilizing agents, antioxidants. The hydration step can employ water, preferably sterile water for injection. The mixing and / or hydration step may further comprise the addition of other excipients such as osmotic adjusting agents, cryoprotectants, pH buffering agents and combinations thereof. In certain aspects of the present invention, the method for preparing the ready-to-use composition may also comprise a sizing step wherein the size of the liposomes are reduced to a size of less than 250 nm, less than 200 nm, less than 150 nm, or less than 100 nm. The sizing may be conducted by any means known in the industry, such as filtration. The sizing step may occur after the formation of the liposomes and before or during filling into the flexible container. In certain embodiments of this aspect of the invention, the liposomes are sized after formation and prior to the formation of the ready-to-use composition that is added to the flexible container. Once the ready-to-use composition is added to the flexible container and the container sealed, the contents of the container are frozen. The contents may be frozen under normal freezing conditions which include placing the filled and sealed flexible container in a freezer at a temperature of 0°C or less, preferably at least about -5°C, -10°C, -15°C, -20°C, or -25°C and allowing the contents of the filled and sealed container to freeze. In one embodiment the contents are quick frozen wherein the filled and sealed container are exposed to temperatures of -30°C or lower, -35°C or lower, -40°C or lower, -45°C or lower or -50°C or lower for about 5 minutes to about 5 hours, about 10 minutes to about 4 hours, about 20 minutes to about 3 hours, or about 30 minutes to about 2 hours to convert the liquid contents to a solid. Once the contents of the flexible container are frozen, the flexible container and frozen contents may be stored in a freezer (about -10°C to about -30°C) for 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 months or longer, preferably at least 6-24 months or longer and more preferably at least 12-24 months. After storage, the frozen ready-to-use composition may be removed from the freezer and thawed. Once the ready-to-use composition is thawed, can be administered to a patient in need of the amphotericin B treatment. The ready-to-use composition prior to freezing and after thawing should have a pH of about 4 to about 7, preferably a pH of about 4.5 to about 6.5 and more preferably a pH of about 5 to about 6. The ready-to-use composition prior to freezing and after thawing should have an osmolality of about 250-390 mOsmol / L. The ready-to-use composition after storage at about -10°C to about -30°C for at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 months should also retain at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of the initial amount of the amphotericin B and the size of the liposomes should not change from the initial size before freezing. For example, the D90 and / or D50 of the liposomes should not change by more than 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%. DETAILED DESCRIPTION Before the present invention is further described, it is to be understood that this invention is not limited to the particular embodiments described. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that as used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. The term "pharmaceutically acceptable" describes a material that is not biologically or otherwise undesirable, i.e. without causing an unacceptable level of undesirable biological effects or interacting in a deleterious manner. The term "therapeutically effective amount" means an amount effective to deliver a therapeutically effective amount of an active agent needed to delay the onset of, inhibit the progression of, or halt altogether the particular disease, disorder or condition being treated, or to otherwise provide the desired effect on the subject to be treated. As one of ordinary skill in the art would understand, a therapeutically effective amount varies with the patient's age, condition, and gender, as well as the nature and extent of the disease, disorder or condition in the patient and the dosage may be adjusted by the individual physician (or veterinarian). The terms "treating" and "treatment" refer to reversing, alleviating, inhibiting, or slowing the progress of the disease, disorder, or condition to which such terms apply, or one or more symptoms of such disease, disorder, or condition. The term “subject” or “patient” used herein refers to a human patient or a mammalian animal, such as cat, dog, cow, horse, monkey, or the like. As disclosed herein, a number of ranges of values are provided. It is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither, or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention. The term “about” generally refers to plus or minus 10% of the indicated number. For example, “about 10%” may indicate a range of 9% to 11%, and “about 20” may mean from 18 to 22. Other meanings of “about” may be apparent from the context, such as rounding off, so, for example “about 1” may also mean from 0.5 to 1.4. Similarly, “about 0.2” may encompass the value 0.22. The terms "comprising," "having," "including," and "containing," or the like, are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. As used herein, the term “ready-to-use" refers to a composition that may be administered directly to a patient without further diluting or addition of further components. The present invention is a ready-to-use parenteral amphotericin B composition that is stable for at least one month or longer preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 months or longer when stored at about -10°C to about -30°C. The present invention further relates to a method for preparing the ready-to-use parenteral amphotericin B composition and methods of using the ready-to-use parenteral amphotericin B composition. The ready to use composition comprises amphotericin B liposomes in an aqueous composition with one or more pharmaceutically acceptable excipients. The concentration of the amphotericin B in the ready-to-use composition may range from 0.05 mg / ml to 5 mg / mL, preferably 0.075 mg / mL to about 4 mg / mL, and more preferably about 0.1 mg / ml to about 3 mg / mL. The total volume of the ready-to-use compositions may range from 10 mL to about 1,000 ml and any volume between such as 25 mL, 50 mL, 100 mL, 150 mL, 200 mL, 250 mL, 300 mL, 350 mL, 400 mL, 450 mL, 500 mL, 550 mL, 600 mL, 650 mL, 700 mL, 750 mL, 800 mL, 850 mL and 900 mL. The liposomes use in the present invention can be prepared by any methods known in the art such as the methods described in U.S. Patent Nos. 4,663,167; 4,744,989; 4,766,046; 4,950,432; 4,978,654; and 5,180,718, which are incorporated herein by reference. The liposomes may also be made the method described in U.S. Patent No. 11,260,028, which is also incorporated herein by reference. The liposomes will comprise amphotericin B and at least one phospholipid. The liposomes may further optionally comprise a lipid stabilizing agent and an antioxidant. The phospholipid may be selected from the group consisting of dioleoylphosphatidylcholine (DOPC), dimyristoylphosphatidylcholine (DMPC), dilauroylphosphatidylcholine (DLPC), soy phosphatidylcholine (SPC), distearoylphophatidylglycerol (DSPG) and salts thereof such as the sodium salt, hydrogenated soy phosphatidylcholine (HSPC) and mixtures of two or more thereof. The ratio of phospholipid to amphotericin (wt %:wt %) in the liposome and the ready-to-use composition typically ranges from about 3:1 to about 12:1, about 4:1 to about 10:1, or about 5:1 to about 8:1. The lipid stabilizing agent may be cholesterol, or a derivative or analog thereof. The antioxidant, if present, is selected from the group consisting of tocopherol, ascorbic acid, propyl gallate, butylated hydroxyanisole, butylated hydroxytoulene, and tiary butyl hydroquinone, or the like. In certain embodiments the liposomes are free of antioxidant. In addition to the amphotericin B liposomes, the ready-to-use composition will further comprise, water, an osmotic agent, and optionally a cryoprotectant, a buffering agent and a pH- adjusting agent. The osmotic agent may be a pharmaceutically acceptable organic compound selected from the group consisting of dextrose, glycerol, sorbitol, xylitol, mannitol, glucose, trehalose, maltose, sucrose, raffinose, lactose, dextran, polyethylene glycol, and propylene glycol. Alternatively, the osmotic agent may be a pharmaceutically acceptable inorganic salt such as sodium chloride, mixtures of sodium chloride and one or more other pharmaceutically acceptable inorganic salts, or the like. The cryoprotectants are molecules, which protect liposomes during freezing, while frozen and the thawing process. These molecules are typically polyhydroxy compounds such as sugars (monosaccharides, disaccharides, or polysaccharides), polyalcohols, and their derivatives. Sucrose and trehalose are naturally occurring cryoprotectants. Sucrose is an example of preferred cryoprotectants for the present invention. In some embodiments the osmotic agent and the cryoprotectants may be the same compound(s). Stated another way an osmotic agent and a cryoprotectant may be the same compound and provide dual functions. In an alternative embodiment, the osmotic agent and cryoprotetant compounds are different compounds. In a certain aspect to the alternative embodiment, the osmotic agent may be dextrose, sodium chloride or a combination thereof to provide an osmolality of about 250-390 mOsmol / L to the composition and the cryoprotectant is a polyhydroxy sugar or polyalcohol other than dextrose such as sucrose or trehalose. The buffer or buffering agent may be selected from the group consisting of phosphate buffer, citrate buffer, Tris buffer, carbonate buffer, succinate buffer, maleate buffer, borate buffer, histadine, disodium succinate hexahydrate and combinations thereof. The pH adjusting agent may be selected from the group consisting of sodium hydroxide, potassium hydroxide, magnesium hydroxide, sodium carbonate, Tris, sodium linoleate, sodium oleate, potassium carbonate, potassium linoleate, potassium oleate, and mixtures of two or more thereof. The ready-to-use composition has a pH of about 4 to about 7, about 4.5 to about 6.5, or about 5 to about 6 prior to freezing and after storage. The liposomes will have a particle size of less than 250 nm, less than 200 nm, less than 150 nm, or less than 100 nm. In one embodiment the liposomes in the ready-to-use composition before freezing and after storage will exhibit a weighted mean particle size in the range of about 50 nm to about 200 nm, or about 50 to about 250 nm, or about 50 nm to about 300 nm, as determined by dynamic light scattering (DLS). In one aspect of the present invention, the ready-to-use composition is prepared by: (i) forming amphotericin B liposomes; (ii) mixing the amphotericin B liposomes with an aqueous solution, preferably an aqueous dextrose solution and most preferably a 5% aqueous dextrose solution, to obtain an amphotericin B composition with the desired concentration of amphotericin B for administration to a patient; (iii) filling the liposome solution of step (ii) into a flexible container such as a flexible infusion bag; and (iv) freezing the contents of the filled container of step (iii). In one embodiment, the ready-to-use amphotericin B parenteral composition is prepared by passive liposome loading process which includes the steps of (1) preparing a dry powder of the liposome forming components, (2) hydrating the dry powder to form a bulk liposome composition, (3) sizing the liposomes created in step (2), e.g. liposome particle size reduction, (4) diluting of sized liposomes with an aqueous solution, preferably a 5% dextrose solution, (5) sterile filtrating the diluted solution and (6) filling and packaging / sealing the sterile solution into flexible infusion bags. The filled and packaged infusion bags are frozen, preferably fast-frozen at temperature ≤ -45°C for 1-2 hours prior to storage in a freezer at about -10°C to about -30°C for at least 1 month or longer period. The frozen product can be thawed and immediately administered to patients, i.e. within 6 hours or less after thawing, without further preparation. Examples Example 1 Amphotericin B, liposome Preparation, 2 mg / mL To prepare the amphotericin B liposomes, 138.4 mg DSPG Na is added to chloroform- methanol mixture, acidified to pH 1-3 with hydrochloric acid and warmed to 65°C to form a solution, 80 mg amphotericin B is mixed with the DSPG Na solution to dissolve amphotericin B at 56°C, 340.8 mg HSPC and 83.2 mg cholesterol are mixed with DSPG Na / amphotericin B solution at 56°C until a solution is formed. This resulting mixture was evaporated at 40°C in a Rotary Evaporator for 60 minutes. Next, 2880 mg sucrose and 76.8 mg disodium succinate hexahydrate are dissolved in 40 mL of purified water. The pH of the sucrose / disodium succinate hexahydrate buffer was adjusted with 1.0 M HCl or 1.0 M NaOH to 5.5. The sucrose / disodium succinate hexahydrate buffer was filtered through a 0.22 μm PES membrane filter. Twenty mL of sucrose / disodium succinate hexahydrate buffer was added to the dried Amphotericin B / DSPG Na / HSPC / Cholesterol mixture and mixed at 200 rpm at 40° C for 60 minutes to form a homogenous bulk liposome suspension. The bulk liposome suspension was extruded through double-stacked polycarbonate filters at 65°C using an Avestin™ Homogenizer / Extruder to reduce liposome particle size. The following filters were used: i) 200 nm sized filter ii) 100 nm sized filter iii) 80 nm sized filter The pH of the final sized liposome suspension was measured and if necessary adjusted to between 5-6 with 1.0 M NaOH or 1.0 M HCl. Next, 5 gm dextrose is dissolved in 100 mL purified water (5%dextrose). Next, 10 mL final sized amphotericin liposomes is mixed with 10 mL 5% dextrose to make the final amphotericin B liposomes. The liposome mixture is sterile filtered through a 0.22 μm PES membrane filter. The filtered liposome suspension is filled and packaged into flexible infusion bag. The packaged liposome is fast-frozen with liquid nitrogen or pre-chilled container to temperature of ≤ -45 for 10 – 60 min and then stored in the freezer at -10°C to -30°C for longer period. The details of the amphotericin liposome formulation composition are shown in Table 1 and the analytical results are summarized in Tables 2-4. The final liposome suspension was a translucent yellow suspension. The intensity-weighted mean particle size diameter measured by dynamic light scattering (DLS) (Malvern Particle Sizer) was 95 nm before freezing and remained essentially unchanged after freezing. The pH of the liposomes was 5.7 prior to freezing and unchanged after freeing. Assay, impurities and zeta potential also remained unchanged after freezing. This amphotericin B-containing liposome preparation can be injected to the patients as-is, without further dilution. TABLE 1 Composition of Amphotericin B liposomes, 2 mg / mL Ingredients Concentration (mg / mL) TABLE 2 Summary of Analytical Results Test Parameter Amphotericin B Amphotericin B Liposomes, Liposomes,

[0002] TABLE 3 Summary of Stability Results after storage in the Freezer (-20°C ± 10°C) for 12 months (Amphotericin B Liposomes, 2 mg / mL, After Normal Freezing) Test Parameter T0 1 month 3 month Appearance Yellow Yellow Yellow TABLE 3 (continued) Test Parameter 6 month 12 month Zeta Potential, mV -39.5 -39.0 Impurities 383 Imp-B (%) 1.72 2.18 TABLE 4 Summary of Stability Results after storage in the Freezer (-20°C ± 10°C) for 12 months (Amphotericin B Liposomes, 2 mg / mL, After Fast Freezing) Test Parameter T0 1 month 3 month nt Total Impurities (%) 7.8 8.2 8.0 Particle size Mean (nm) 98.7 100.9 104.0 TABLE 4 (continued) Test Parameter 6 month 12 month Appearance Yellow Yellow nt Example 2 Amphotericin B, Nanoliposome Preparation, 0.2 mg / mL To prepare the amphotericin B liposomes, 6.92 mg DSPG Na is added to chloroform- methanol mixture, acidified to pH 1-3 with hydrochloric acid and warmed to 65°C to form a solution, 4 mg amphotericin B is mixed with the DSPG Na solution to dissolve amphotericin B at 56°C, 17.04 mg HSPC and 4.16 mg cholesterol are mixed with DSPG Na / amphotericin B solution at 56°C until a solution is formed. This resulting mixture was evaporated at 40°C in a Rotary Evaporator for 60 minutes. Next, 144 mg sucrose, 3.84 mg disodium succinate hexahydrate and 1800 mg dextrose are dissolved in 40 mL of purified water. The pH of the sucrose / disodium succinate hexahydrate / dextrose buffer is adjusted with 1.0 M HCl or 1.0 M NaOH to 5.5. The sucrose / disodium succinate hexahydrate / dextrose buffer is filtered through a 0.22 μm PES membrane filter. Twenty mL of sucrose / disodium succinate hexahydrate / dextrose buffer is added to the dried Amphotericin B / DSPG Na / HSPC / Cholesterol mixture and mixed at 200 rpm at 40° C for 60 minutes to form a homogenous bulk liposome suspension. The bulk liposome suspension was extruded through double-stacked polycarbonate filters at 65°C using an Avestin™ Homogenizer / Extruder to reduce liposome particle size. The following filters were used: i) 200 nm sized filter ii) 100 nm sized filter iii) 80 nm sized filter The pH of the final sized liposome suspension was measured and if necessary adjusted to between 5-6 with 1.0 M NaOH or 1.0M HCl. The liposome mixture is sterile filtered through a 0.22 μm PES membrane filter. The filtered liposome suspension is filled and packaged into flexible infusion bag. The packaged liposome is fast-frozen with liquid nitrogen or pre- chilled container to temperature of ≤ -45 for 10 – 60 min and then stored in the freezer at -10°C to -30°C for longer period. The details of the amphotericin liposome formulation composition are shown in Table 5, and the analytical results are summarized in Tables 6-8. The final liposome suspension was a translucent yellow suspension. The intensity-weighted mean particle size diameter measured by dynamic light scattering (DLS) (Malvern Particle Sizer) was 104 nm and after freezing remained unchanged. The pH of the liposome was 5.7 and after freezing remained unchanged. Assay, impurities and zeta potential also remained unchanged after freezing. This amphotericin B-containing liposome preparation can be injected to the patients as- is, without further dilution. TABLE 5 Composition of Amphotericin B Liposomes, 0.2 mg / mL Ingredients Concentration (mg / mL) Amphotericin B 02 TABLE 6 Summary of Analytical Results Test Parameter Amphotericin B Amphotericin B 303 Imp-A <LOQ* <LOQ* nm Any individual unspecified N.D.** N.D. TABLE 7 Summary of Stability Results after storage in the Freezer (-20°C ± 10°C) for 12 months (Amphotericin B Liposomes, 0.2 mg / mL, After Normal Freezing) Test Parameter T0 1 month 3 month A Y ll Y ll Y ll nt D90 (nm) 176 180 188 *LOQ denotes limit of quantitation. **N.D. denotes not detectable. TABLE 7 (Continued) Test Parameter 6 month 12 month Appearance Yellow Yellow nt . . . . TABLE 8 Summary of Stability Results after storage in the Freezer (-20°C ± 10°C) for 12 months (Amphotericin B Liposomes, 0.2 mg / mL, After Fast Freezing) Test Parameter T0 1 month 3 month nt Assay (By HPLC), mg / mL 0.19 0.18 0.18 Zeta Potential, mV -45.5 -43.1 -46.6 TABLE 8 (continued) Test Parameter 6 month 12 month nt D90 (nm) 175 184 *LOQ denotes limit of quantitation. **N.D. denotes not detectable. All methods described herein can be performed in any suitable order unless expressly indicated otherwise or otherwise clearly in conflict with context. The invention described herein may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. Thus, for example, in each instance herein, any of the terms “comprising,” “consisting essentially of,” and “consisting of” may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the claims.

Claims

CLAIMS 1. A stable ready-to-use amphotericin B parenteral composition comprising 0.05 mg / mL to 5 mg / mL of amphotericin B in a phospholipid liposome, water, and an osmotic agent wherein the ready-to-use composition is prepared, packaged in a flexible container, frozen in the flexible container, stored frozen for at least one month and thawed prior to administration to a patient without the need for further diluting or addition of additional ingredients.

2. The stable ready-to-use composition of claim 1 wherein the volume of the ready-to-use composition in the flexible container is about 10 mL to about 900 mL.

3. The stable ready-to-use composition of claim 1 wherein the phospholipid used to prepare the liposome selected from the group consisting of dioleoylphosphatidylcholine (DOPC), dimyristoylphosphatidylcholine (DMPC), dilauroylphosphatidylcholine (DLPC), soy phosphatidylcholine (SPC), distearoylphophatidylglycerol (DSPG), salts thereof, and mixtures of two or more thereof.

4. The stable ready-to-use composition of claim 1 wherein the ratio of phospholipid to amphotericin in a wt%:wt% amount is about 3:1 to about 12:

1.

5. The stable ready-to-use composition of claim 4 wherein the ratio of phospholipid to amphotericin in a wt%:wt% amount is about 4:1 to about 10:

1.

6. The stable ready-to-use composition of claim 4 wherein the ratio of phospholipid to amphotericin in a wt%:wt% amount is about 5:1 to about 8:

1.

7. The stable ready-to-use composition of claim 1 wherein the composition further comprise a lipid stabilizing agent.

8. The stable ready-to-use composition of claim 7 wherein the lipid stabilizing agent comprises cholesterol.

9. The stable ready-to-use composition of claim 1 wherein the liposomes have a particle size of less than 250 nm.

10. The stable ready-to-use composition of claim 1 wherein the composition further comprises a cryoprotectant agent.

11. A method for preparing a stable ready-to-use composition comprising: (i) forming amphotericin B liposomes; (ii) mixing the amphotericin B liposomes with an aqueous solution to obtain an amphotericin B composition with a desired concentration of amphotericin B for administration to a patient; (iii) filling the liposome solution of step (ii) into a flexible container; and (iv) freezing the contents of the filled container of step (iii) wherein the frozen ready-to-use composition is stored frozen for at least one month and thawed prior to administration to a patient without the need for further diluting or addition of additional ingredients.

12. The method of claim 11 wherein the volume of the ready-to-use composition in the flexible container is about 10 mL to about 900 mL.

13. The method of claim 11 wherein the amphotericin B liposomes comprise a phospholipid selected from the group consisting of dioleoylphosphatidylcholine (DOPC), dimyristoylphosphatidylcholine (DMPC), dilauroylphosphatidylcholine (DLPC), soy phosphatidylcholine (SPC), distearoylphophatidylglycerol (DSPG), salts thereof, and mixtures of two or more thereof.

14. The method of claim 13 wherein the ratio of phospholipid to amphotericin in a wt%:wt% amount is about 3:1 to about 12:

1.

15. The method of claim 14 wherein the ratio of phospholipid to amphotericin in a wt%:wt% amount is about 4:1 to about 10:1.

16. The method of claim 14 wherein the ratio of phospholipid to amphotericin in a wt%:wt% amount is about 5:1 to about 8:

1.

17. The method of claim 11 wherein the ready-to-use composition further comprise a lipid stabilizing agent.

18. The method of claim 17 wherein the lipid stabilizing agent comprises cholesterol.

19. The method of claim 11 wherein the amphotericin B liposomes have a particle size of less than 250 nm.

20. The method of claim 11 wherein the ready-to-use composition further comprises a cryoprotectant agent.

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