BIORELEVANT COMPOSITION

Abstract

A biorelevant precursor composition suitable, upon dispersing, dilution or suspension in an aqueous medium, for simulating fed-state gastric fluids of mammalian species, wherein said biorelevant precursor composition comprises a substantially solid/sol-id-like concentrate, a viscous gel-like concentrate, or a liquid fat dispersion/concentrate, comprising at least one primary component selected from each of the following groups of primary components comprising: i) Triglyceride and/or diglyceride and/or monoglyceride or any combinations thereof in an amount of from 1-70% by weight; ii) Lecithin and/or lysolecithin in an amount of from 1-45% by weight; iii) Carbohydrate in an amount of from 15-70% by weight; and iv) Water or other aqueous medium in an amount of from 1-70% by weight; wherein the weight ratio of total fats (one or more primary components from each of groups i) and ii) combined): total carbohydrates (one or more primary components from group iii) combined) is between 20:1 to 1:20; and the weight ratio of glyceride:lecithin and/or lysolecithin is between 45:1 and 1:45; and in addition at least one additional component selected from at least one of the following: (i) fatty acids (between 0.01-15% by weight); (ii) bile acid/salt (between 0.01-3% by weight); (iii) enzymes (between 0.01-2% by weight); (iv) cholesterol, sterols (between 0.01-5% by weight); (v) buffer agents (between 0.01-4% by weight); (vi) osmotic agents (between 0.01-10% by weight); 52 (vii) proteins (collagen, protein hydrolysates, amino acids) (between 0.01-30% by weight); (viii) mucin (between 0.1-5% by weight); (ix) viscosity modifier (between 0.1-5% by weight); and (x) preservatives, stabilizers (between 0.01-3% by weight), such as a) anti-oxidants, b) chelating agents, c) buffers (inorganic or organic), and d) antimicrobials; all percentages being by dry weight. A method of producing these compositions is also provided.

Claims

1. A biorelevant precursor composition suitable, upon dispersing, dilution or suspension in an aqueous medium, for simulating fed-state gastric fluids of mammalian species, wherein said biorelevant precursor composition comprises a substantially solid/solid-like concentrate, a viscous gel-like concentrate, or a liquid fat dispersion/concentrate, comprising at least one primary component selected from each of the following groups of primary components comprising: i) Triglyceride and/or diglyceride and/or monoglyceride or any combinations thereof in an amount of from 1-70% by weight; ii) Lecithin and/or lysolecithin in an amount of from 1-45% by weight; iii) Carbohydrate in an amount of from 15-70% by weight; and iv) Water or other aqueous medium in an amount of from 1-70% by weight; wherein the weight ratio of total fats (one or more primary components from each of groups i) and ii) combined):total carbohydrates (one or more primary components from group iii) combined) is between 20:1 to 1:20; and the weight ratio of glyceride:lecithin and/or lysolecithin is between 45:1 and 1:45; and in addition at least one additional component selected from at least one of the following: (i) fatty acids (between 0.01-15% by weight); (ii) bile acid/salt (between 0.01-3% by weight); (iii) enzymes (between 0.01-2% by weight); (iv) cholesterol, sterols (between 0.01-5% by weight); (v) buffer agents (between 0.01-4% by weight); (vi) osmotic agents (between 0.01-10% by weight); (vii) proteins (collagen, protein hydrolysates, amino acids) (between 0.01-30% by weight); (viii) mucin (between 0.1-5% by weight); (ix) viscosity modifier (between 0.1-5% by weight); and (x) preservatives, stabilizers (between 0.01-3% by weight), such as a) anti-oxidants, b) chelating agents, c) buffers (inorganic or organic), and d) antimicrobials; all percentages being by weight.

2. A composition according to claim 1, wherein the at least one triglyceride is selected from avocado oil, canola oil, coconut oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, rapeseed oil, safflower oil, sesame oil, soya oil, sunflower oil, and combinations thereof.

3. A composition according to claim 1, comprising at least one phospholipid and/or at least one lysophospholipid.

4. A composition according to claim 1, wherein the at least one carbohydrate comprises polysaccharide, oligosaccharide, disaccharide, monosaccharide and/or sugar alcohol.

5. A composition according to claim 4, wherein the sugar is selected from glucose, fructose and sucrose, and the polysaccharide is selected from starch, dextrin and cellulose.

6. A composition according to claim 1, which is in the form of a solid or solid-like concentrate containing between 1% and 10% by weight of water or aqueous medium.

7. A composition according to claim 1, which is in the form of a viscous gel-like aqueous concentrate containing between 10% and 25% by weight of water or aqueous medium.

8. A composition according to claim 1, which is in the form of a liquid emulsion concentrate containing between 25% and 70% by weight of water or aqueous medium.

9. A composition according to claim 1, wherein the biorelevant precursor concentrate has a water activity below 0.86, preferably below 0.70.

10. A method of producing a biorelevant precursor composition as claimed in claim 1, which comprises processing i) from 1-70% by weight of at least one triglyceride, and/or at least diglyceride and/or at least one monoglyceride; ii) from 1-45% by weight of at least one lecithin and/or lyso-lecithin; iii) from 15-70% by weight of at least one carbohydrate; and iv) from 1-70% of water or other aqueous medium; wherein the ratio of total fat (components i) and ii) combined):total carbohydrate is from 20:1 to 1:20, and the ratio of glyceride:lecithin and/or lyso-lecithin is from 45:1 to 1:45, and in addition at least one additional component selected from at least one of the following: (i) fatty acids (between 0.01-15% by weight); (ii) bile acid/salt (between 0.01-3% by weight); (iii) enzymes (between 0.01-2% by weight); (iv) cholesterol, sterols (between 0.01-5% by weight); (v) buffer agents (between 0.01-4% by weight); (vi) osmotic agents (between 0.01-10% by weight); (vii) proteins (collagen, protein hydrolysates, amino acids) (between 0.01-30% by weight); (viii) mucin (between 0.1-5% by weight); (ix) viscosity modifier (between 0.1-5% by weight); and (x) preservatives, stabilizers (between 0.01-3% by weight), such as a) anti-oxidants, b) chelating agents, c) buffers (inorganic or organic), and d) antimicrobials; by means of dispersing and/or homogenisation and/or control of water content by evaporation and/or addition or titration, to obtain a substantially solid/solid-like concentrate, a viscous gel-like concentrate, or a liquid fat dispersion/concentrate.

11. A method as claimed in claim 10, which comprises the use of controlled evaporation after addition of water containing at least one carbohydrate or directly controlling the addition of water containing at least one carbohydrate.

12. A method of producing a composition suitable for simulating fed-state gastric fluids of mammalian species, which method comprises dispersing, diluting or suspending in an aqueous medium a biorelevant precursor composition as claimed in claim 1.

13. A method as claimed in claim 12, which method comprises dispersing or diluting the biorelevant precursor concentrate composition in an aqueous medium or buffer concentrate that can be added/combined in any order for preparing the in vitro fed state gastric dissolution media at the required pH for in vitro dissolution testing.

14. A method as claimed in claim 12, wherein the aqueous medium for dispersing or diluting the biorelevant concentrate composition for preparing the in vitro fed state dissolution medium may comprise: (i) a buffer solution to reach the required pH, buffer capacity and osmolarity of the biorelevant dissolution media without further dilution; or (ii) a sufficient weighed/measured amount of the biorelevant concentrate, a sufficient weighed/measured amount of the buffer concentrate, and purified water to reach the required pH, buffer capacity and osmolarity, in any order of incorporation and/or dilution.

15. A method of preparing a fed state gastric media as claimed in claim 12, which further includes adding enzymes, protein hydrolysates and/or other additional components as a separate step.

16. A method as claimed in claim 12, wherein the resulting dissolution media can be readily filtered using 0.22 to 10 μm pore size filters, the Z-average particle size using photon correlation spectroscopy is below 200 nm and typically 175 nm, and the size distribution reflected by polydispersity index is consistently below 0.2.

17. A kit for use in producing a composition suitable for simulating fed-state gastric fluids of mammalian species, which kit comprises an aqueous medium or a buffer concentrate in a first container together with a biorelevant precursor concentrate composition in a second container as claimed in claim 1.

18. A method of making a synthetic biorelevant in vitro fed state dissolution medium based on the amount of fat in high fat to low fat meals comprising adding an aqueous medium, buffered to from pH 1.5 to pH 7.5, or adding from ×3 times to ×60 times buffer concentrate to the biorelevant precursor concentrate composition of claim 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0076] The compositions of the invention are synthetic in vitro biorelevant concentrates, modelled after the amount of fat in meals with variable amounts of fat, and the resulting physicochemical properties of stomach fluids after consumption of the meal. Fats include triglycerides, diglycerides, monoglycerides, lecithin and/or lysolecithin. The term “biorelevant concentrate/composition” (also referred to as the “biorelevant precursor concentrate composition” herein) refers to the fact that the biorelevant concentrate composition does not itself necessarily mimic the physiological environment of the stomach. Rather, the readily water dispersible biorelevant concentrates are capable, upon dilution, dispersion or suspension in or with an aqueous medium, to prepare expediently reliable fed state gastric media with simple mixing (for example a magnetic stirrer) and without any high energy input. The resulting media comprise stable uniform fat dispersions readily filterable through a 0.45 micrometer filter. Primarily, the biorelevant media mimic the physiological and physicochemical functions of gastric fluids induced by consumption of the test meal, and for in vitro solubility and dissolution tests to ascertain food effects of drugs.

[0077] The substantially solid/solid-like concentrates typically contain between 1% and 10% by weight of water or aqueous medium.

[0078] The gel-like concentrates typically contain between 10% and 25% by weight of water or aqueous medium.

[0079] The fat dispersion/liquid concentrates typically contain between 25% and 70% by weight of water or aqueous medium.

[0080] The biorelevant precursor compositions of the invention are typically provided in a container. Typically, the container is a laminated pouch or sachet. This container can be (but is not limited to) a glass, suitable plastic bottle (HDPE, PE, PP, etc.), suitable metal bottle (aluminium, stainless steel). Typically, said sachet or pouch comprises from about 1 g to about 1500 g, for example from about 5 g to about 500 g, of said biorelevant concentrates. Containers up to, for example, 10 kg can also be used.

[0081] The biorelevant precursor composition of the invention can be provided in a kit together with inter alia compositions, for example solid dissolution compositions and/or concentrated buffer solution suitable, upon dispersion, dilution or suspension in an aqueous medium, for simulating, for example, simulated fed state gastric fluids of mammalian species (for example human, canine, rabbit, rodent, murine, simian, and porcine) at the desired physiological pH.

[0082] The kits may also contain filters to separate undissolved drug particles from the filtrate containing dissolved drug with pore diameters, for example between 0.2 to 1 micron and pre filters with pore diameters, for example between 1 to 10 micron selected from for example glass microfibre, PVDF, nylon or PES.

[0083] As described in more detail herein, the biorelevant concentrate compositions of the invention comprise uniformly dispersed fats comprising triglycerides and/or diglycerides and/or monoglycerides as well as mixtures of lecithin (diacyl phospholipids) and/or lysolecithin (monoacyl phospholipids) from diacylation, further comprising carbohydrates and/or sugar alcohols in the aqueous medium wherein the water content in said concentrate composition is between 1.0% and 70.0% by weight.

[0084] The compositions of the invention may also contain smaller amounts of bile salt components (<3.0%) to reflect the result of duodenal reflux.

[0085] The biorelevant precursor compositions are surprisingly stable and reproducible for preparing biorelevant fed state in vitro gastric media (FEDGAS). The unexpected and surprisingly robust physicochemical properties of the biorelevant precursor concentrates in on-going stability tests at 22° C. in excess of 9 months and at least 9 months at 40° C., point the way to making consistent in vitro fed state gastric media for reproducible dissolution testing of drugs and (other) industrial applications (See Case Study 2).

[0086] The media's predictive and user friendly properties rest chiefly with constant physicochemical parameters, for example particle size, fat components, buffer capacity, surface tension, osmolarity, wherein the weight ratio of weight of total fat and total carbohydrate contents in the medium is 20:1 to 1:20; alternatively or preferably 15:1 to 1:15, or 10:1 to 1:10, or 5:1 to 1:5, or 2:1 to 1:2.

[0087] The surface tension of the in vitro fed state gastric dissolution media is typically between 30 and 50 mN/m.

[0088] The in vitro fed state gastric media is readily filterable, with substantially uniform sub-micron particles consistently below 1000 nm, preferably below 500 nm, more preferably below 250 nm, still more preferably below 200 nm and typically below 175 nm, for example 150 nm, with narrow size distribution, and polydispersity index (pdi) consistently below 0.2. The consistent physicochemical properties (e.g. particle size, narrow distribution, surface tension, pH compatibility across the physiological pH of fed state gastric fluid between pH 1.5 and pH 7.5 and temperature stability around 37° C. for at least 6 hours) are important

[0089] Characteristically, the dissolution media can be readily filtered using 0.22 to 10 μm pore size filters, preferably 0.45 to 1.0 μm. At least 20 mL of the dissolution medium can be readily filtered manually using a 0.45 μm pore size GE Healthcare Whatman™ GD/X Glass Micro Fiber (GMF) Syringe Filters. Typically, the Z-average particle size using photon correlation spectroscopy) is below 200 nm and typically 175 nm. The size distribution reflected by polydispersity index is consistently below 0.2.

[0090] The biorelevant precursor composition of this invention is a substantially solid/solid-like concentrate, a viscous gel-like concentrate, or liquid fat dispersion concentrate, comprising at least one primary component selected from each of the following groups of primary components:

[0091] i) Triglyceride and/or diglyceride and/or monoglyceride or any combinations thereof (between 1-70% by weight, preferably 3-70% by weight, more preferably 5-70% by weight);

[0092] ii) Lecithin and/or lysolecithin (between 1-45% by weight, preferably 1-30% by weight, more preferably 1-15% by weight);

[0093] iii) Carbohydrate (between 15-70% by weight, preferably 20-60% by weight); and

[0094] iv) Water or other aqueous medium (between 1-70% by weight, preferably 1 to 66% by weight, preferably 1 to 60% by weight);

[0095] wherein the weight ratio of total fats (one or more primary components from each of groups i) and ii) combined):total carbohydrates (one or more primary components from group iii) combined) is between 20:1 to 1:20, alternatively or preferably 15:1 to 1:15, or 10:1 to 1:10, or 5:1 to 1:5, or 2:1 to 1:2;

[0096] and the weight ratio of glyceride:lecithin and/or lysolecithin is between 45:1 and 1:45, alternatively or preferably 30:1 and 1:30, or 15:1 to 1:15, or 10:1 to 1:10, or 8:1 to 1:8, or 7:1 to 1:7, or 7:1 to 1:3;

[0097] and in addition at least one additional component selected from at least one member of the group comprising or consisting of: [0098] (i) fatty acids (between 0.01-15% by weight, preferably 0.1-10% by weight); [0099] (ii) bile acid/salt (between 0.01-3% by weight, preferably 0.1-1% by weight); [0100] (iii) enzymes (between 0.01-2% by weight, preferably 0.1-1.5% by weight); [0101] (iv) cholesterol, sterols (between 0.01-5% by weight, preferably 0.01 to 2.5% by weight); [0102] (v) buffer agents (between 0.01-4% by weight, preferably 0.1 to 2% by weight); [0103] (vi) osmotic agents (between 0.01-10% by weight, preferably 1 to 8% by weight); [0104] (vii) proteins (collagen, protein hydrolysates, amino acids) (between 0.01-30% by weight, preferably 0.1% to 25% by weight); [0105] (viii) mucin (between 0.1-5% by weight, preferably −2.5% by weight); [0106] (ix) viscosity modifier (between 0.1-5% by weight, preferably 0.1 to 2.5% by weight); and [0107] (x) preservatives, stabilizers (between 0.01-3% by weight, preferably 0.1 to 1.5% by weight), such as anti-oxidants, chelating agents, buffers (inorganic or organic), and antimicrobials.

[0108] Unless indicated to the contrary, all percentages by weight (referred to above and below) are by dry weight.

Glycerides

[0109] The biorelevant precursor compositions of the invention may comprise at least one triglyceride in an amount of from 1%-70% by weight, preferably 3%-70% by weight, preferably 5%-70% by weight. Any synthetic, semi-synthetic or natural triglyceride can be used, from any vegetable or animal source/origin. The triglyceride(s) can be liquid or solid at relevant temperatures, e.g. from 15° C. to 30° C., for example about 20° C. The triglyceride(s) can, for example, be selected from avocado oil, canola oil, coconut oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, rapeseed oil, safflower oil, sesame oil, soya oil (soybean oil), and sunflower oil. Preferable triglycerides include oils which are liquid at 20° C., such as soya oil (soybean oil), olive oil and rapeseed oil, and oils which are solid at 20° C., such as coconut oil and palm oil. Most preferably, the triglyceride comprises olive oil, avocado oil, palm oil. The triglyceride may be preferably a single oil from the same source or combining oils from different sources/origins. Natural or semi-synthetic or synthetic medium chain triglycerides (MCT) containing fatty acids with between six and 12 carbons are within the definition of triglycerides in this invention.

[0110] In preferred embodiments, the fatty acid profile of the biorelevant dissolution medium comprises at least 60% C18 but can be matched to the fatty acid profile of different type of meals. The biorelevant precursor compositions of the invention may comprise products of partial lipolysis of at least one triglyceride component as defined herein.

[0111] The biorelevant precursor compositions may further comprise at least one diglyceride. Any suitable diglyceride may be used in an amount of from 1%-70% by weight, preferably 3%-70% by weight, preferably 5%-70% by weight. Any diglyceride which is a product of lipolysis of any triglyceride defined herein may be used. Typically, the diglyceride when used is glyceryl di oleate.

[0112] The biorelevant precursor compositions of the invention may also comprise at least one monoglyceride in an amount of from 1%-70% by weight, preferably 3%-70% by weight, preferably 5%-70% by weight of the total glycerides. Further, the amount of monoglyceride when included would typically not be more than 50% of the total glycerides. Any suitable monoglyceride may be used; particularly any monoglyceride which is a product of lipolysis of any triglyceride or diglyceride as defined herein may be used. Typically, the mono glyceride is glyceryl mono oleate.

[0113] The biorelevant precursor compositions of the invention may also comprise at least one fatty acid at no more than 15% by weight. Any suitable fatty acid may be used; particularly any fatty acid which is a product of lipolysis of any triglyceride, diglyceride or monoglyceride as defined herein may be used. Typically, the fatty acid is oleic acid.

Lecithin and Lysolecithin

[0114] It is to be understood that the description of lecithin embraces phospholipid which is the main component group of lecithin, along with neutral lipids, for example, glycolipids, fatty acid, triglycerides amongst others. Phospholipids comprise chiefly phosphatidylcholine (PC). The purity of phospholipids/lecithin is conventionally linked to the amount of PC in the mixture; which mixture may also comprise phosphatides, such as phosphatidyl inositol, phosphatidyl serine, as examples.

[0115] Phospholipids (lecithin) can possess twin hydrocarbon tails and be identified as diacyl phospholipid. The molecule can also have only one hydrocarbon chain and be identified as mono acyl phospholipid. Monoacyl phospholipids are commonly known as lysolecithin. The hydrocarbon chain of the lecithin and lysolecithin can be saturated for example dimyristoylphosphatidylcholine and dimyristoylphosphatidylglycerol and/or unsaturated for example dioleoylphosphatidylcholine. The lecithin and lysolecithin further includes hydrogenated lecithin and lysolecithin for example hydrogenated soya lecithin. The lecithin and lysolecithin may be obtained synthetically, semi synthetically or from any vegetable or animal source, including but not limited to soy, egg, canola, rapeseed, sunflower or fish.

[0116] The biorelevant precursor concentrate compositions of the invention contain one or more phospholipid and/or one or more lysophospholipid as described. Any suitable lecithin (phospholipid) and/or lysophospholipid (lysolecithin) may be used from natural, semi-synthetic or synthetic sources. Charged phospholipids can improve stability of dispersed fat aggregates. Phospholipid (lecithin) comprises chiefly phosphatidylcholine (PC) along with smaller amounts of phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidic acid (PA), phosphatidylinositol (PI), phosphatidylglycerol (PG). Lysophospholipid (lysolecithin) comprises chiefly lysophoshatidylcholine along with smaller amounts of the monoacyl derivative of the other phosphatides.

[0117] Biorelevant precursor concentrate compositions have phospholipid content comprising lecithin and/or lysolecithin between 1-45% by weight, preferably 1-30% by weight, preferably 1-15% by weight.

[0118] Of this mixture, the PC may be broadly from 15% to 99% by weight. The LPC may be between 0.5% to 85.0% by weight. Phospholipids comprising 30.0% to 95.0% PC and between 2.0% and 70.0% LPC are preferred. In this invention, the terms lecithin and phospholipid are interchangeable and include: [0119] (i) both lecithin and lysolecithin or phospholipid and lysophospholipid in the mixture [0120] (ii) either lecithin (phospholipid) or lysolecithin (lysophospholipid) by themselves.
The amount of lecithin and lysolecithin together is between 30% and 98% by weight.

Carbohydrate

[0121] The biorelevant precursor concentrate compositions of the invention comprise at least one carbohydrate and/or sugar alcohol. Any suitable carbohydrate such as a saccharide (commonly known as a sugar) by itself, and/or a suitable sugar alcohol can also be used. For example, the saccharide/sugar may be selected from a list of monosaccharides, for example fructose, glucose, galactose, mannose, ribose and the like; a list of disaccharides, for example sucrose, lactose, maltose, trehalose and the like; or combinations of mono and disaccharides.

[0122] The sugar alcohol may be selected from mannitol, lactitol, sorbitol and xylitol, and the like. The term sugar alcohol herein includes polyols such as glycerol.

[0123] Preferred concentrates comprise sugar by itself, and/or sugar alcohol selected from glucose, fructose, sucrose, lactose, erythritol, maltitol, isomaltol, mannitol or xylitol. Combinations of sugar(s) and/or sugar alcohol(s) can also be used.

[0124] Primary component group of carbohydrate components comprising saccharide (sugar), sugar alcohol, and combinations thereof in suitable proportions may be combinations of, for example, glucose (monosaccharide), fructose (sugar alcohol), sucrose (disaccharide), dextrin or starch (polysaccharides) providing the biorelevant precursor concentrate of this invention with a water activity below 0.86, preferably below 0.70, thereby inhibiting microbial growth and providing excellent long term storage of the precursor concentrates with a CFU below 10 (Table 2). For the solid/solid like concentrates the water activity is also below 0.7. Water activity is a parameter for industrial applicability and benefits offered by this invention in the field of biorelevant in vitro dissolution testing and simulation of fed state gastric fluids.

TABLE-US-00002 TABLE 2 Physicochemical properties of the biorelevant gel-like precursor concentrate. Microbiology (CFU/g)  <10 Water activity (aw) 0.5-0.8 Average particle size (nm) <200

[0125] If the water activity is greater than 0.86 or the CFU count is above for example >10 CFU/g, the microbial burden of the precursor concentrate composition may be reduced by, for example but not limited to, pasteurization, UHT, aseptic filtration, steam sterilization.

[0126] The biorelevant precursor concentrates of the invention may further comprise a viscosity modifier, including but not limited to an oligosaccharide and/or polysaccharide which may be digestible or non-digestible. For example, the polysaccharide can be starch, modified starch, dextrin, celluloses, polydextrose, pectin, galactomannans, alginates and the like, and/or semi synthetic versions such as methylcellulose, carboxymethylcellulose, hydroxypropyl methylcellulose, chitosan, and the like.

[0127] The precursor concentrates of the invention contain total fat:carbohydrate ratios within the range 20:1 to 1:20, preferably 15:1 to 1:15, preferably 10:1 to 1:10, preferably 5:1 to 1:5, preferably 2:1 to 1:2.

[0128] When the readily water dispersible precursor concentrates are diluted or dispersed in aqueous medium, the ratios in the resultant in vitro biorelevant fed state gastric dissolution media are maintained.

Fatty Acids

[0129] The biorelevant precursor concentrates of the invention may comprise additional components further comprising free fatty acid, for example oleic acid, lauric acid, linoleic acid, stearic acid and palmitic acid and their salts.

Bile Salts

[0130] The biorelevant precursor concentrates of the invention may comprise additional components, for example, a bile salt. Any suitable bile salt can be used. Suitable bile salts include sodium cholate, sodium taurocholate, sodium glycocholate, sodium deoxycholate, sodium taurodeoxycholate, sodium glycodeoxycholate, sodium ursodeoxycholate, sodium chenodeoxycholate, sodium taurochenodeoxycholate, sodium glyco chenodeoxycholate, sodium cholylsarcosinate, sodium N-methyl taurocholate and their free acids, and combinations thereof. Preferably, the bile salt is selected from sodium cholate, sodium taurocholate, and sodium glycocholate. More preferably, the bile salt is sodium taurocholate.

Buffers

[0131] The biorelevant precursor concentrate of the invention may comprise buffer agents and osmotic agents. However, the buffer agents, preferably buffer concentrates or solutions, are incorporated/added to the biorelevant concentrate composition or the in vitro biorelevant fed state simulated dissolution media. More preferably, the buffer agents are added using dilutable concentrates that require from ×3 to ×60, preferably from ×5 to ×40, more preferably from ×15 to ×30 dilution.

[0132] The buffer concentrates may be incorporated into the biorelevant concentrate composition; or alternatively the said biorelevant concentrate composition may be incorporated into the buffer concentrate in reverse order to provide in vitro fed state dissolution medium at the required pH (pH 1.5 to pH 7.5), buffer capacity (5 to 100, preferably between 10 and 30, between 15 and 30 mM/ΔpH).

[0133] Further, purified water may be added to the mixture containing the biorelevant concentrate and dilutable buffer concentrate to prepare in vitro fed state dissolution media of the invention at the required target pH between pH 1.5 to pH 7.5 for dissolution testing. The biorelevant precursor concentrate composition, (ii) buffer concentrate and (iii) purified water can be added/combined in any order for preparing the in vitro fed state gastric dissolution media at the required pH for in vitro dissolution testing.

Buffer Concentrate

[0134] A dilutable ×25 buffer concentrate containing the appropriate amounts of sodium chloride, citric acid and sodium citrate (amounts from Table 6) was prepared by dissolving the buffers and osmotic agent (sodium chloride) in purified water.

900 mL of the in vitro test media was prepared by
1) Weighing 36.8 g of ×25 buffer concentrate (pH3) into a suitable container
2) Adding 732.6 g of purified water

3) Adding 153.0 g of FEDGAS gel

[0135] 4) Stirring until the dispersion is thoroughly homogeneous
The resulting in vitro test media has a pH of 3.0 and a buffer capacity of typically 22 mM/ΔpH.

[0136] The buffer concentrates and the biorelevant precursor concentrate compositions are in separate containers and combined in the manner described for preparing the in vitro fed state gastric media.

[0137] The two separate containers may be included in a kit along with, inter alia, filters for carrying out in vitro solubility and dissolution testing.

[0138] Any suitable buffer agent can be used. Suitable buffer agents include at least one inorganic buffer agent selected from monobasic sodium phosphate; acetic acid; hydrochloric acid; maleic acid; citric acid; lactic acid; potassium phosphate monobasic; trisodium citrate; sodium acetate trihydrate; imidazole; sodium carbonate; sodium hydrogen carbonate; sodium cacodylate; sodium barbital; phosphate salts such as Na.sub.2HPO.sub.4, NaH.sub.2PO.sub.4, K.sub.2HPO.sub.4 and KH.sub.2PO.sub.4; and sodium hydroxide, and/or at least one organic buffer agent selected from 2-(N-morpholino)ethanesulfonic acid (MES); Bis-tris methane (Bis Tris); 2-[(2-amino-2-oxoethyl)-(carboxymethyl)amino]acetic acid (ADA); N-(2-Acetamido)-2-aminoethanesulfonic acid (ACES); Bis-tris propane 1,3-bis(tris(hydroxymethyl)methylamino)propane; piperazine-N,N′-bis(2-ethanesulfonic acid) (PIPES); 2-(carbamoylmethylamino)ethanesulfonic acid (ACES); 2-Hydroxy-3-morpholinopropanesulfonic acid (MOPSO); Cholamine chloride; Cholamine chloride hydrochloride; 3-Morpholinopropane-1-sulfonic acid (MOPS); N N-bis 2-hydroxyethyl-2-aminoethanesulfonic acid (BES); 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid (TES); 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid (HEPES); [3-Bis(2-hydroxyethyl) amino-2-hydroxypropane-1-sulfonic acid] (DIPSO); [3-Bis(2-hydroxyethyl) amino-2-hydroxypropane-1-sulfonic acid] MOBS; acetamidoglycine; 3-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl] amino]-2-hydroxypropane-1-sulfonic acid (TAPSO); 2,2′,2″-Nitrilotri(ethan-1-ol) (TEA); Piperazine-N,N′-bis(2-hydroxypropanesulfonic acid) (POPSO); 4-(2-Hydroxyethyl)piperazine-1-(2-hydroxypropanesulfonic acid) (HEPPSO); 4-(2-Hydroxyethyl)-1-piperazinepropanesulfonic acid (HEPPS); N-[Tris(hydroxymethyl)methyl]glycine (Tricine); tris(hydroxymethyl)aminomethane (Tris); glycinamide; glycine; glycylglycine; histidine; N-(2-Hydroxyethyl)piperazine-N′-(4-butanesulfonic acid) (HEPB S); 2-(Bis(2-hydroxyethyl)amino)acetic acid (Bicine); [tris(hydroxymethyl)methylamino]propanesulfonic acid (TAPS); 2-Amino-2-Methyl-1-Propanol (AMPB); 2-(Cyclohexylamino)ethanesulfonic acid (CHES); β-Aminoisobutyl alcohol (AMP); N-(1,1-Dimethyl-2-hydroxyethyl)-3-amino-2-hydroxypropane sulfonic acid (AMP SO); 3-(Cyclohexylamino)-2-hydroxy-1-propanesulfonic acid, CAPSO Free Acid (CAPSO); 3-(Cyclohexylamino)-1-propanesulfonic acid (CAPS); and 4-(Cyclohexylamino)-1-butanesulfonic acid (CABS).

Osmotic Agents

[0139] Osmotic agents are included to adjust the osmolarity of the dissolution media to simulate the osmolarity of the fed state gastric fluids after a meal for example an FDA meal. Osmotic agents include but are not limited to typically sodium chloride, potassium chloride, calcium chloride, magnesium chloride, hydrochloric acid and sodium hydroxide, including combinations thereof. Carbohydrates and buffers may also contribute to the overall osmolarity of the in vitro dissolution media. The osmotic agents may be incorporated in the biorelevant precursor concentrate composition or preferably in the buffer concentrate. The osmolarity range of the fed state dissolution media is between 200 to 800 mOsm/L, typically 300 to 600 mOsm/L. After a meal, the osmolarity of the high-fat meal gastric fluids in the stomach is usually higher than after a low-fat meal. Furthermore, the osmolarity can be affected by the food contents and residence time in the fed stomach. The osmolarity of the in vivo fed state gastric fluids that can be simulated in the in vitro fed state gastric media of this invention are typically between 400 and 550 mOsm/L.

Enzymes

[0140] If desired, additional components, for example enzymes such as gastric lipase and/or pepsin may be added to the actual dissolution media rather than in the concentrates.

Preservatives and Stabilizers

[0141] Examples of anti-oxidants include but are not limited to ascorbic acid, ascorbyl palmitate, vitamin E and esters, carotenoids, vitamin A. Chelating agents include but are not limited to dimercaprol, disodium EDTA, desferrioxamine, citrate. Buffers (inorganic or organic) are as listed in the buffer section. Antimicrobials include but are not limited to thiomersal, sodium azide, butylated hydroxytoluene, butylated hydroxyanisol, sorbic acid.

[0142] In one preferred biorelevant precursor concentrate composition: [0143] i) the at least one triglyceride is selected from soybean oil, olive oil, rapeseed oil, coconut oil, avocado oil and palm oil; [0144] ii) the at least one diglyceride is selected from glycerol dioleate, glycerol distearate, glycerol dilaurate and linoleic diglyceride; [0145] iii) the at least one monoglyceride is selected from glycerol monooleate, glyceryl mono stearate, glycerol monolaurate and linoleic monoglyceride; [0146] iv) the at least one component selected from lecithin and/or lysolecithins comprises at least 40% phospholipid and/or at least 40% by weight lysophospholipid [0147] vi) the at least one sugar and/or sugar alcohol comprises glucose and fructose and/or sorbitol [0148] vii) the at least one polysaccharide comprises a starch, modified starch and/or dextrin,
wherein the total fat:total carbohydrate ratio is 20:1 to 1:20, preferably 15:1 to 1:15, preferably 10:1 to 1:10, preferably 5:1 to 1:5, preferably 2:1 to 1:2; and, furthermore, the ratio of glyceride:lecithin and/or lysolecithin is between 45:1 and 1:45, preferably 30:1 and 1:30, preferably 15:1 to 1:15, preferably 10:1 to 1:10, preferably 8:1 to 1:8, preferably 7:1 to 1:7, preferably 7:1 to 1:3.

[0149] In particularly preferred biorelevant precursor compositions: [0150] i) the at least one triglyceride comprises olive oil; [0151] ii) the at least one diglyceride comprises glycerol dioleate; [0152] iii) the at least one monoglyceride comprises glycerol monooleate; [0153] iv) the at least one component selected from lecithin and/or lysolecithin comprises at least 15% by weight phosphatidylcholine (PC) and/or at least 0.5% lysophosphatidylcholine (LPC); [0154] vi) the at least one sugar comprises glucose and fructose and sucrose; [0155] vii) the at least one polysaccharide comprises a dextrin,

[0156] wherein the total amounts of fat:carbohydrate is 20:1 to 1:20, preferably 15:1 to 1:15, preferably 10:1 to 1:10, preferably 5:1 to 1:5 preferably 2:1 to 1:2; and, furthermore, the ratio of glyceride:lecithin and/or lysolecithin is between 45:1 and 1:45, preferably 30:1 and 1:30, preferably 15:1 to 1:15, preferably 10:1 to 1:10, preferably 8:1 to 1:8, preferably 7:1 to 1:7, preferably 7:1 to 1:3.

[0157] Variations in the biorelevant precursor composition of the invention can be made to meet desired physicochemical and in particular fat content of compositions which may be variants of for example the standard FDA high-fat meal.

[0158] It is within the scope of this invention to adjust and select total fat and carbohydrate contents in the concentrates for preparing dissolution media simulating fed state gastric media modelled-after meals with target fat values.

[0159] Typically, the water content of the composition is controlled between 1.0% and 25.0% to form either substantially solid/solid-like and gel-like liquid concentrates. Water removal by evaporation may be for example vacuum assisted or by freeze drying, for example lyophilisation.

[0160] The content of bile salt(s) in the composition of the invention is based on the amount of intestinal fluid regurgitated from the duodenum. When present, the amount of bile salts in the composition of the invention is below 3.0%, typically below 1.0% by weight.

[0161] By way of example and not by way of limitation, the following are typical examples illustrating the invention. A typical example of a concentrate composition is shown in Table 3 along with the range of typical components. The compositions may comprise lecithin and/or lysolecithins with different PC content (purity) in the mixtures.

[0162] Freeze fracture of the biorelevant concentrate viscous gel-like precursor is shown in FIG. 10.

[0163] An example of the actual dissolution medium is shown in Table 8.

TABLE-US-00003 TABLE 3 Typical Composition of Precursor Composition/Concentrate Component Concentration % (wt/wt) Glycerides   35 (between 1.0% and 70%) Lecithin*    4 (between 1.0% and 45%) Carbohydrates   39 (between 15.0% and 70%) Bile salts  0.2 (between 0.01% and 3%) Stabilizers**  0.9 (between 0.01% and 3%) Water 17.0 (between 1.0% and 70%) *(Lecithin and/or lysolecithin) **Optional

[0164] Preparation and composition of in vitro dissolution medium prepared from the biorelevant concentrate composition shown in Table 3.

[0165] The amount of total fat in the biorelevant precursor concentrate of the invention is typically such that the fat concentration between 0.5% and 20% w/v is obtained when the precursor is dispersed, diluted or suspended in an aqueous medium to give a biorelevant medium.

[0166] More typically, the amount of fat in the biorelevant precursor concentrate is such that a fat concentration of from 4.0% w/v to 20.0% w/v, preferably 5% to 15% w/v, preferably 6% to 10% w/v, is obtained when the precursor composition is dispersed, diluted or suspended in an aqueous medium to give a biorelevant medium modelled on variants of FDA recommended standard meal with high-fat and low-fat amounts. Furthermore the amount of fat and amount used may be adjusted and selected in order to take into account other variants, namely medium-fat, low-fat variations, extremely high-fat contents up to 15% and extremely low-fat contents down to 0.1% are not outside the scope of this invention.

[0167] Table 3 sets out the primary components in a typical concentrate composition according to this invention. The variable fat contents of the desired in vitro test media may be obtained by selecting the components and adjusting amounts from said Table 3 thereby providing concentrated compositions for dilution and preparation of the test media for in vitro dissolution, solubility and stability tests of drugs and drug products. The tests in the in vitro dissolution media also evaluate the potential food effects on the drug and drug products due to the fat content at the physiological pH of the stomach or from beverages/drinks containing fat, for example tea with full-fat or reduced-fat milk.

Typical Manufacturing Method of Precursor Compositions

Step 1

[0168] The following components are weighed into a suitable reactor or processing vessel: [0169] Purified water 66 kg [0170] **Stabilizers 0.8 kg

**Optional

[0171] Suitable reactors include but are not limited to evaporator, thin film evaporator, microwave, optionally vacuum assisted. The solution is stirred between 50 to 10000 RPM, preferably between 50 to 2000 RPM, preferably between 50 to 500 RPM, and maintained between 15-80° C., preferably between 30-80° C., more preferably between 40-70° C.

Step 2

[0172] When the solution from step 1 is homogeneous, the following components are added:

TABLE-US-00004 ***Lecithin 4.50 kg Bile salts 0.16 kg ***Lecithin and/or lysolecithin.
The suspension from step 2 is stirred between 50 to 30000 RPM, preferably between 100 to 10000 RPM, preferably between 200 to 5000 RPM at temperatures between 15-80° C., preferably between 40-70° C. A light vacuum is maintained until all the components are fully hydrated.

Step 3

[0173] When the suspension from step 2 is homogeneous, the following component is added:

TABLE-US-00005 ****Glycerides 28 kg ****triglyceride.

Step 4

[0174] The suspension from step 3 is stirred between 50 to 30000 RPM, preferably between 100 to 10000 RPM, preferably between 200 to 5000 RPM at temperatures between 15-80° C., preferably between 30-80° C., preferably between 40-70° C. A light vacuum is maintained until all the components are fully mixed. A homogeneous fat dispersion with particle size of about 0.5 to 5 microns is obtained.

Step 5

[0175] The fat dispersion from step 4 may be further processed using homogenizer selected from high shear mixers, high pressure, microfluidizer, ultrasonic or any other appropriate high energy homogenizer.
99.5 kg (yield) of the homogenised fat dispersion from step 5 and components shown in Table 4 is obtained with 1000 nm Z-average diameter, typically below about 500 nm.
The homogenised fat dispersion is transferred to a suitable holding tank or container.

TABLE-US-00006 TABLE 4 Typical Example of the components in homogenized fat dispersion at the end of step 5. Components Concentration % (w/w) Water 66 Glycerides 28 Lecithin*** 4.5 Bile salts 0.16 Stabilizers** 0.8 **Optional ***Lecithin and/or lysolecithin

Step 6

[0176] The components below are added to the reactor in step 1:

TABLE-US-00007 Carbohydrate*** 22.10 kg Dextrin  1.16 kg ***Invert sugar
The solution is stirred and heated between 20-80° C., typically between 50-70° C. A vacuum is applied to start evaporation, typically between 10 to 1000, preferably between 50 to 200 mbar. The water content at this stage is between 1 and 70%, typically between 15 and 30% by weight.

Step 7

[0177] The homogenized fat dispersion, previously stored in the holding tank, is added continuously to the reactor. The fat dispersion is added at a controlled flow rate between 0.1 to 10 l/min, for example between 0.1 to 5 l/min, in keeping with the rate of evaporation under vacuum between 10 to 1000 mbar. During the continuous addition of the homogenized fat dispersion, the water content of the mixture inside the suitable reactor is between 5% and 70%, preferably maintained between 10 and 40%.
At the end of step 7, the concentrate composition is in the form of a substantially solid/solid-like concentrate, substantially gel-like concentrate or liquid fat dispersion/concentrate depending on the targeted water content generally between 1 and 70% by weight, between 10% and 25% for a viscous gel-like concentrate illustrated in Table 5, For a solid/solid-like concentrate the water content is typically between 1.0% and 10.0%, for a fat dispersion/liquid concentrate the water content is between 25% and 70%.

TABLE-US-00008 TABLE 5 Typical Example of precursor gel-like composition at the end of step 7 Components Concentration % (w/w) Water 17 Glycerides 35.2 Lecithin*** 5.8 Bile salts 0.2 Stabilizers** 0.9 Carbohydrates 41.1 **Optional ***Lecithin and/or lysolecithin

Packaging of the Precursor Composition

[0178] The gel-like concentrate/composition obtained in step 7 is filled into a suitable container. This container can be (but is not limited to) a sachet, a pouch, a suitable plastic bottle (HDPE, PE, PP, etc.), suitable metal bottle (aluminium, stainless steel, etc).
The composition is preferably packed under vacuum or sealed under an inert gas blanket, e.g. nitrogen.
The gel-like concentrate can be filled and/or packed in a single dose or a multi dose container, for example suitable containers of up to 10 kg capacity.

Biorelevant Media Preparation

[0179] A synthetic aqueous biorelevant medium is obtained by adding an aqueous medium to the biorelevant gel-like composition/concentrate in Table 5 as described under the manufacturing method. The aqueous medium comprises, for example, but is not limited to, purified water, aqueous medium comprising buffers, osmotic components. Citrate buffers illustrated in the examples can be substituted by other combinations, for example acetic buffer for pH 5 and phosphate buffer for pH 3. Additional components, for example enzymes such as gastric lipase, may also be present, along with osmotic agents and buffers in the dissolution compositions of the invention.

[0180] Typically, the biorelevant dissolution medium is prepared as follows from the concentrate in Table 5 to make, for example, 900 ml of medium for a high-fat FDA meal: [0181] 1—Add approx. 600 g of water and suitable buffer components for the desired pH into a container. [0182] 2—Add 152.3 g of concentrate shown in Table 5 into the container. [0183] 3—Make up to volume by adding the rest of the purified water (763.62 g of total water). [0184] 4—Add magnetic stirrer and leave to stir until all the components have been thoroughly mixed. [0185] 5—Check pH 4.5.
The following typical examples in Table 6, Table 7 and Table 8 can be obtained using the preparation method above.

TABLE-US-00009 TABLE 6 Typical example of a pH 3 biorelevant dissolution medium produced from the biorelevant concentrate and an aqueous buffer solution. Individual Component Component Component group Component Component Component group group (g) % (w/w) (g) % (w/w) Biorelevant — — — 152.30 13.56 concentrate in Table 5 Buffer/salts Sodium citrate 0.54 0.06 7.16 0.62 dihydrate Citric acid 4.45 0.48 Sodium chloride 0.77 0.08 Water (in buffer) Water 763.62 82.85 763.62 82.85 TOTAL 921.67 100.00 921.67 100

TABLE-US-00010 TABLE 7 Typical example of a pH 4.5 biorelevant dissolution medium produced from the biorelevant concentrate and an aqueous buffer solution. Individual Component Component Component Component % group group Component group Component (g) (w/w) (g) % (w/w) Biorelevant — — — 152.30 16.50 concentrate in Table 5 Table 5 - Typical Example of precursor gel-like composition at the end of step 7 Buffer/salts Sodium citrate 4.46 0.48 8.00 0.87 dihydrate Citric acid 3.55 0.38 Water (in buffer) Water 762.62 82.63 762.62 82.63 TOTAL 922.92 100 922.92 100

TABLE-US-00011 TABLE 8 Typical example of a pH 6 biorelevant dissolution medium produced from the biorelevant concentrate and an aqueous buffer solution. Individual Component Component Component Component Component group group group Component (g) % (w/w) (g) % (w/w) Biorelevant — — — 152.30 16.53 concentrate in Table 5 Buffer/salts Sodium citrate 6.74 0.73 7.68 0.83 dihydrate Citric acid 0.943 0.10 Water (in buffer) Water 787.51 85.45 787.51 82.64 TOTAL 921.60 100.00 921.60 100.00
The dissolution medium can also be prepared from individual components by weighing them out separately into a buffer solution and then homogenising, as shown in Table 9a.

TABLE-US-00012 TABLE 9a Typical dissolution medium comprising individual components in an aqueous buffer solution at pH 4.5 Component Component (g) Component % (w/w) Individual Glycerides 53.61 5.81 components Lecithin 8.83 0.96 Bile salts 0.30 0.03 Stabilizers** 1.37 0.15 Carbohydrates 62.60 6.78 Buffer/salts Sodium citrate 4.46 0.48 dihydrate Citric acid 3.55 0.38 Water Water 788.20 85.40 TOTAL 922.92 100 **Optional
The biorelevant dissolution medium shown in Table 9b is prepared as follows to make, for example, 900 ml of medium of a low-fat FDA meal: [0186] 1—Add approx. 600 g of water and suitable buffer components for the desired pH into a container. [0187] 2—Add 76.15 g of concentrate from Table 5 into the container. [0188] 3—Make up to volume by adding the rest of the purified water (889 g of water needs to be added in total). [0189] 4—Add magnetic stirrer and leave to stir until all the components have been thoroughly mixed. [0190] 5—Check pH 4.5.

TABLE-US-00013 TABLE 9b Typical example of a pH 4.5 biorelevant dissolution medium simulating a low-fat FDA meal produced from the biorelevant concentrate and an aqueous buffer solution. % (w/w) individual Component % (w/w) Component Component (g) Component group (g) Component group Biorelevant — — — 76.15 8.25 concentrate in Table 5 Buffer/salts Sodium citrate 4.46 0.48 8.00 0.87 dihydrate Sodium chloride 3.55 0.38 Water (in buffer) Water 838.77 90.88 838.77 90.88 TOTAL 922.92 100.00 922.92 100
The biorelevant dissolution medium shown in Table 10 is prepared as follows to make, for example, 900 ml of medium of a double high-fat FDA meal: [0191] 1—Add approx. 500 g of water and suitable buffer components for the desired pH into a container. [0192] 2—Add 304.59 g of concentrate from Table 5 into the container. [0193] 3—Make up to volume by adding the rest of the purified water (610.33 g of water needs to be added in total). [0194] 4—Add magnetic stirrer and leave to stir until all the components have been thoroughly mixed. [0195] 5—Check pH 4.5.
The following typical example in Table 10 is obtained using the preparation method above.

TABLE-US-00014 TABLE 10 Typical example of a pH 4.5 biorelevant dissolution medium simulating a double high-fat FDA meal produced from the biorelevant concentrate and an aqueous buffer solution. % (w/w) % (w/w) Component individual Component Component Component (g) Component group (g) group Biorelevant — — — 304.59 33.05 concentrate in Table 5 Buffer/salts Sodium citrate 4.46 0.48 8.00 0.87 dihydrate Citric acid 3.55 0.38 Water (in buffer) Water 610.33 66.13 610.33 66.13 TOTAL 922.92 100.00 922.92 100
Table 11 shows the typical physicochemical properties of the media prepared previously.

TABLE-US-00015 TABLE 11 Physicochemical properties of the typical media prepared as shown for preparing the dissolution media shown in Table 9 and Table 10 Average Surface Buffer capacity particle Polydispersity tension Osmolarity (mmol/(l.ΔpH) size (nm) index (mN/m) (mOsm/L) pH 3 22 160 0.14 40.6 435 pH 5 27 160 0.11 41.3 451 pH 6 30 160 0.14 39.3 479

Biorelevant Dissolution Media for Simulating Fed State Gastric Fluid

[0196] The biorelevant dissolution medium can also be made from scratch by combining all the components in Table 5 with a predetermined amount of water to obtain the target content of the biorelevant dissolution medium. The fat content of this medium can vary from 20 to 100 grams in 500 ml of media (USP Dissolution Apparatus 2) depending on the amount of concentrate used in Table 5 and the dose of the drug in the dissolution test. Buffer salts and additional components can be added before or after the lipophilic components are dissolved or suspended in the aqueous medium.

[0197] However, dissolution media made from scratch do not have the stability and storage properties of concentrates. Thus, media prepared from scratch must be used within 24 hrs since they are prone to microbiological, physical and chemical spoilage, thereby making them less suitable and fit for purpose as dissolution media in terms of reliability, consistency and reproducibility.

Case Studies

[0198] The case studies reported below demonstrate the usefulness of the present invention in evaluating food effects in the stomach on drug products.

[0199] In the case studies from 1 to 4, FEDGAS media at pH 6, pH 5 and pH 3 were prepared by adding the appropriate amount of purified water in a suitable container, adding the corresponding buffer concentrate and adding the appropriate amount of biorelevant precursor concentrate and mixing with a magnetic stirrer until homogeneous.

Case Study 1—Dissolution of Exemestane (25 mg) Tablets (Brand Name: Aromasin, a Poorly Soluble Neutral Compound Immediate Release Formulation)

[0200] Three biorelevant fed state gastric media at pH 6, pH 5 and pH 3 using the composition in Table 5 were produced.
The media at these three pHs were characterised by measuring pH, buffer capacity, particle size (Z-average and polydispersity using Nanosizer) and surface tension (Kruss surface tension K6).
The media were stable at time zero and physically stable after 24 hours. Similarly, the key physicochemical properties were unchanged after 24 hours.
The dissolution of exemestane (4 tablet×25 mg tablets) in the media was carried out using USP 2 Dissolution Apparatus at 75 rpm (n=6 vessels). Samples of the three biorelevant media were taken from the dissolution vessels and filtered through a 0.45 micrometer nylon filter with prefilter at 5 mins, 10 mins, 15 mins, 20 mins, 25 mins, 30 mins, 45 mins, 60 mins, 90 mins and 120 mins and analysed for exemestane content by HPLC.
The results of these dissolution studies are provided in FIG. 1.
In line with the neutral chemical structure of exemestane, as can be seen exemestane was not sensitive to different pHs and the three dissolution profiles were very similar. Within 30 minutes more than 80% of the drug was dissolved across the three media.

Case Study 2—Fed State Simulated Gastric Concentrate Stored for 9 Months at 40° C.

[0201] The biorelevant concentrate was stored at 22° C. and 40° C. for nine months and the study in Case Study 1 was repeated with media prepared from stored precursor concentrate. The ease of dispersibility in aqueous media of the fresh and stored precursor concentrate were very similar.
Unexpectedly, the dissolution profiles in the test media across the three pHs were found to be the same as when the media were prepared from freshly made precursor concentrate.

Case Study 3—Dissolution of Cinnarizine (Basic Drug)

[0202] The dissolution of Sturgeron (15 mg cinnarizine immediate release tablets) was tested in a fasted gastric media (control experiment) and compared with fed gastric media at pH 6, pH 5 and pH 3 using the same dissolution set up as described previously.
The dissolution profiles in fasted state gastric media are provided in FIG. 2.
The dissolution profile of this drug product in the fasted gastric media indicates this basic drug cinnarizine dissolves rapidly in the fasted stomach. This control experiment shows that within 30 minutes close to 90% of the drug is dissolved.
In contrast, as seen in FIG. 3, this basic drug exhibits slower drug dissolution in all fed state gastric media (across the pH range from pH 6 down to pH 3). There is also a trend for the cinnarizine dissolution to be faster at lower pH (i.e. at a longer residence time of the drug in simulated fed state media, the dissolution rate increases). Reflecting the pH of the gastric fluids towards the end of gastric emptying.
These in vitro dissolution profiles can further be used with modelling software to better simulate how drugs behave in the stomach and how the drug (dissolved or suspended) is presented to the small intestine as the stomach empties. In combination with dissolution profiling in small intestinal fluids (fed and fasted), these inputs can lead to more accurate prediction in vitro in vivo correlations leading to more efficient development of a drug product.

Case Study 4—Dissolution of Mefenamic Acid (Acidic Drug)

[0203] The dissolution of mefenamic acid hard gelatine capsules was carried out in fasted state gastric media (control) and compared with biorelevant fed state gastric media at pH 6, pH 5 and pH 3 as described using the set up and method in the Case Study 1.
Referring to FIG. 4, the dissolution in fasted state gastric media is negligible even after 2 hours of dissolution. Less than 0.1% of the drug dose is dissolved even after 2 hours of dissolution.
In sharp contrast to fasted state gastric media, in biorelevant fed state gastric media mefenamic acid dissolution proceeds considerably more rapidly (see FIG. 5). Dissolution reaches about 45%, 25% and 10% of the dosage form within 30 minutes in fed state gastric media at pH 6 (simulating fed conditions immediately after ingestion FDA high-fat meal), pH 5 (simulating fed conditions approximately 1 to 3 hours after ingestion of FDA high-fat meal) and pH 3 (simulating fed conditions approximately 4 to 5 hours after ingestion of FDA high-fat meal) respectively.

Case Study 5—Dissolution of Danazol Capsules Acid (Neutral Drug)

[0204] The dissolution of danazol (100 mg) hard gelatine capsules was carried out in fasted state gastric media (control) and compared with biorelevant fed state gastric media at pH 6, pH 4.5 and pH 3 as described using the set up and method in the Case Study 1.
Referring to FIG. 6, the dissolution in fasted gastric media is negligible even after 2 hours of dissolution. Less than 0.2% of the drug dose is dissolved even after 2 hours of dissolution.
In sharp contrast to fasted state gastric media, in the biorelevant fed state gastric media danazol dissolution proceeds considerably more rapidly (see FIG. 7). Dissolution reaches about 55% of the dosage form within 60 minutes in fed state gastric media at pH 6, pH4.5 and pH 3 respectively.
Case Study 6—Examining Physicochemical Properties of FEDGAS Dissolution Media Stored for 72 Hrs at Room Temperature with Dissolution of Megesterol Acetate Capsules
FEDGAS media at pH 6, pH 4.5 and pH 3 were prepared by adding the appropriate amount of water in a suitable container, adding the corresponding buffer concentrate and adding the appropriate amount of readily water dispersible biorelevant precursor concentrate and mixing with a magnetic stirrer until homogeneous. The three media were stored at room temperature for up to 72 hours. Dissolution in each of the media at t=0, t=24 hours, t=48 hours and t=72 hours after media preparation was carried out using megesterol acetate capsules (160 mg) in 900 mL of medium in the vessels. The results of the dissolution tests are provided in FIG. 8. The pH, buffer capacity, surface tension and particle size (Z-average) of the FEDGAS pH 6 and FEDGAS pH 3 were measured at t=0 and at t=72 hours. The results are provided in Table 12.
The results indicate that the dissolution profiles of megesterol acetate hard gelatin capsules for all three media at the four time points were identical. This study indicates that the 3 media did not age after three days of storage. The pH, buffer capacity, surface tension and particle size at t=72 hours were close to the values at t=0 hours.

TABLE-US-00016 TABLE 12 Biorelevant media properties after preparation according to the examples. Media was stored for 72 h at room temperature. Surface Buffer capacity tension Particle size Biorelevant pH (mmol/(ΔpH .Math. L)) (mN/m) (nm) media 0 h 72 h 0 h 72 h 0 h 72 h 0 h 72 h Early 5.99 6.00 25.0 25.5 41 43 151.8 151.2 FEDGAS pH 6 Late 2.99 3.01 22.8 22.7 41 43 151.1 153.1 FEDGAS pH 3

[0205] The invention provides biorelevant dissolution compositions and methods of obtaining simulated media from precursor concentrates for in vitro dissolution and solubility studies. The simulated gastric media are modelled after stomach contents following consumption of high and low-fat meals and alternatives, containing even higher fat (up to 200 g of fat) and even lower fat amounts (1 g of fat). The invention fills a practical need for fed-state biorelevant testing alongside fasted state media, permitting more precise in vitro assessments after meal intake such as food effect on drugs after a FDA standard meal. Food effects also include in vitro dissolution testing of a drug product in simulated gastric fluids (FEDGAS) containing for example 1 g of fat that is in for example in a cup of milk tea supporting improved in vitro-in vivo correlations. Use of said biorelevant media rather than prior art media is compelling and advantageous; in particular, for the characterisation of pharmacologically active/relevant substances such as drug compounds, oral dosage forms, and the like. Furthermore, examining food effects in the stomach fills a practical need for characterisation of drugs, for example in lead optimisation as well as generic formulation development thereby leading to cost and time savings.

[0206] The invention provides unexpectedly stable, readily water dispersible biorelevant concentrate compositions. The biorelevant concentrate and buffer concentrate compositions can be used to produce a readily filterable and surprisingly stable biorelevant test media which simulate fed state stomach fluids after consumption of for example high-fat to low-fat FDA meals. The invention is thereby clearly advantageous and has industrial applicability. The proposed fed state simulated gastric fluids can be used in biorelevant dissolution and solubility studies for profiling drugs and drug products.