Stable laquinimod preparations

[0001] This application reserves the benefits of US Provisional Patent Application No. 61 / 008,698 filed December 20, 2007.

Background Art [0002] Laquinimod is a compound that has been shown to be effective in an acute experimental autoimmune encephalomyelitis (aEAE) model (US Patent No. 6,077,851). Its chemical name is N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxamide and its number in the Chemical Register is 248281-84-7. The process of synthesis of laquinimod and the preparation of its sodium salt are disclosed in US Patent No. 6,077,851. An additional synthesis process for laquinimod is disclosed in US Patent No. 6,875,869.

[0003] Pharmaceutical compositions comprising laquinimod sodium are disclosed in PCT International Patent Application Publication Number WO 2005/074899.

[0004] US Application 2005/192315 discloses a method for testing degradation of laquinimod by measuring the disappearance of the 3-quinoline derivative of carboxamide or the formation of propyl ester.

SUMMARY OF THE INVENTION The disclosure provides a pharmaceutical composition comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a pharmaceutically acceptable salt thereof, an oxidation limiting agent and a pharmaceutically acceptable carrier.

[0006] The disclosure also provides a sealed package containing the pharmaceutical composition described herein or a pharmaceutically acceptable salt and oxygen absorbing agent thereof.

[0007] The disclosure also discloses a process for making a sealed package containing a pharmaceutical composition N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a pharmaceutically acceptable salt thereof preparing a pharmaceutical composition comprising a pharmaceutical composition of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a pharmaceutically acceptable salt thereof and packaging of said pharmaceutical composition in a package in an environment with reduced oxygen content compared to standard atmospheric conditions.

[0008] The disclosure also provides a pharmaceutical formulation in the form of a tablet characterized in that the tablet comprises a core comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier and a coating that prevents contact of oxygen with the core.

The present invention provides a process for validating a series of pharmaceutical product comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier for distribution.

VP / 2365 / AW

The present invention provides a process for validating a series of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or its salts for distribution and corresponding processes for the preparation of pharmaceutical products as defined in the claims.

The present invention also provides a process for preparing a pharmaceutical product comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier characterized in that the pharmaceutical product contains not more than the total amount of 0.5% m / m, based on N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3 -carboxamide, oxidative decomposition products: 2-chloro-6- (1-ethyl-W-methyl-2-oxoindoline-3-carboxamido) benzoic acid,

1H, 3H-spiro [5-chloro-1-methylquinoline-2,4-dion-3,3 '- [1] ethylindolin- [2] -one] and 5-chloro-W-ethyl-3-hydroxy-1- methyl-2,4-dioxo-W-phenyl-1,2,3,4-tetrahydro-quinoline-3-carboxamide as defined in claim 7.

[0012] The present invention also provides a process for testing whether a sample contains unwanted oxidative decomposition products of 2-chloro-6- (1-ethyl-W-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1H, 3H-spiro [5-chloro 1-methylquinoline-2,4-dion-3,3 '- [1] ethylindolin- [2] -one] or 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo In-phenyl-1,2,3,4-tetrahydro-kwinolino-3-carboxamide.

[0013] The present invention also provides an isolated compound having the structure:

<img file="PL2234485T3_D0001.tif" />

[0014] The present invention also provides an isolated compound having the structure:

VP / 2365 / AW

EP 2 234 485 B1

<img file="PL2234485T3_D0002.tif" />

Detailed Description of the Invention The disclosure provides a pharmaceutical composition comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a pharmaceutically acceptable salt thereof, a limiting agent oxidation and a pharmaceutically acceptable carrier.

[0016] In a preferred embodiment of the pharmaceutical composition, N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide is in the form of a pharmaceutically acceptable salt. [0017] In another preferred embodiment of the pharmaceutical composition, the pharmaceutically acceptable salt of Netyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide is its lithium salt, sodium salt or calcium salt.

[0017] In another preferred embodiment of the pharmaceutical composition, the pharmaceutically acceptable salt of Netyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide is N-ethyl-N-phenyl 1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide sodium.

[0019] In a preferred embodiment, the pharmaceutical composition is in solid form.

In another preferred embodiment, the pharmaceutical composition is characterized in that 1.0% or less of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3- carboxamide or its pharmaceutically acceptable salt degrades upon exposure to a 0.15% solution of H for 40 minutes₂ABOUT₂.

[0021] In yet a further preferred embodiment, the pharmaceutical composition is free of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide oxidative decomposition products.

In yet another preferred embodiment, the pharmaceutical composition contains an undetectable amount of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxamide oxidative decomposition products.

[0021] In yet another preferred embodiment, the pharmaceutical composition contains less than 1% by mass of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxamide oxidative decomposition products. .

[0024] In yet another preferred embodiment of the invention, the pharmaceutical composition is free of 2-chloro-6- (1-ethyl-N-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1H, 3H-spiro [54

VP / 2365 / AW

Chloro-1-methylquinoline-2,4-dion-3,3 '- [1] ethylindolin- [2] -one] and 5-chloro-W-ethyl-3-hydroxy-1-methyl2 , 4-dioxo-W-phenyl-1,2,3,4-tetrahydro-kwinolino-3-carboxamide.

[0025] In yet another preferred embodiment of the invention, the pharmaceutical composition contains not more than 0.5% m / m, based on N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl- 2-oxoquinoline-3-carboxamide, 2-chloro-6- (1-ethyl-W-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1H, 3H-spiro [5-chloro-1-methylquinoline-2,4-dione- 3,3 '- [1] ethylindolin- [2] one] and 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo-W-phenyl-1,2,3,4 kwinolino-tetrahydro-3-carboxamide.

[0026] The disclosure also provides a sealed package containing the pharmaceutical composition described herein or a pharmaceutically acceptable salt and oxygen absorbing agent thereof.

[0027] In a preferred embodiment of the sealed package, the oxygen absorbing agent is iron. [0028] The disclosure also discloses a process for making a sealed package containing a pharmaceutical composition of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide, or a pharmaceutically acceptable salt thereof . comprising preparing a pharmaceutical composition comprising the N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide pharmaceutical composition or a pharmaceutically acceptable salt thereof, and packaging said pharmaceutical composition in a package in an environment with a reduced oxygen content compared to standard atmospheric conditions.

[0029] The disclosure also provides a pharmaceutical formulation in the form of a tablet characterized in that the tablet comprises a core comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier and a coating that prevents contact of oxygen with the core.

[0030] In one preferred embodiment of the invention, the coating comprises a cellulose polymer, a viscosity reducing substance and a dye. A viscosity reducing substance is a substance added to a surface dye to reduce its adhesion or viscosity and improve dye flow properties. Examples of viscosity reducing substances include lecithins, stearic acid, polysorbates, glycerol monostearate, sodium lauryl sulfate, poloxamers, monoglycerides, diglycerides and mixtures thereof. In a preferred embodiment of the invention, the shell is Opadry®fx ™, manufactured by Colorcon, West Point, PA, USA. Opadry®fx ™ is described in US Patent No. 6,902,609.

[0031] Opadry®fx ™ is a pearlescent film coating system for which excellent oxygen protective properties have been demonstrated compared to other film coating tablets. One study has shown that Opadry®fx ™ inhibits the oxidation of ibuprofen at various temperatures by acting as an oxygen barrier. It was shown that the oxidation rate of ibuprofen coated with Opadry®fx ™ was very low and difficult to quantify even at high temperatures (60 ° C). (Gulian et al., "Oxidative Protection of Ibuprofen Using Opadry®fx ™ Special Effects Film Coating System" American Academy of Pharmaceutical Scientists, November, 2004).

[0032] In addition, Opadry®fx ™ has been shown to provide protection against oxidation caused by light conditions. Gulian et al. compared degradation product profiles for uncoated ibuprofen tablets, hydroxypropyl methylcellulose (HPMC) / TiO2 coated tablets and Opadry®fx ™ coated tablets, exposed to UV light and visible light. The results showed

VP / 2365 / AW

It was found that Opadry®fx ™ coated tablets had the lowest content of degradation products. This study strongly suggests that the main pathways of photolytic degradation are inherently oxidizing. Because oxygen is an essential co-reactant during these photolytic degradation processes, the low permeability of Opadry®fx ™ to oxygen results in lower levels of degradation products. (Gulian et al.) [0033] The coating may also contain Opaglos®2 (manufactured by Colorcon, West Point, PA, USA), hydroxypropyl methylcellulose (HPMC) or titanium dioxide.

The present invention provides a process for validating a series of pharmaceutical product comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier for distribution covering

(a) subjecting the sample series to a stability test;

b) determining the total amount of oxidative decomposition products in the series sample after the stability test; and

c) batch validation for distribution only if the batch sample after stability tests contains not more than the total amount of 0.5% m / m with respect to N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1- methyl-2-oxo-quinoline-3-carboxamide, oxidative decomposition products of 2-chloro-6- (1-ethyl-W-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1H, 3H-spiro [5-chloro-1-methylquinoline-2,4-dion-3,3 '- [1] ethylindolin- [2] -one] and 5-chloro-W-ethyl-3-hydroxy-1-methyl -2,4-dioxo-W-phenyl-1,2,3,4-tetrahydro-kwinolino-3-carboxamide.

[0035] In a preferred embodiment of the process, the oxidative decomposition product is 2-chloro-6- (1-ethyl-W-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 5-chloro-W-ethyl-3-hydroxy-1-methyl -2,4-dioxo-W-phenyl-1,2,3,4-tetrahydro-quinoline-3-carboxamide or 1H, 3H-spiro [5-chloro-1-methyl-quinoline-2,4-dion-3,3 '- [1 ] -ethylindolin- [2] -one] or a mixture thereof.

[0036] In another preferred embodiment of the process during step (b), the amount is determined using mass measurements, UV light absorption, refractive index, ionization or voltamogram.

[0034] The present invention also provides a process for validating a series of N-ethyl-N-phenyl-1,2-dihydro4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxamide or its distribution salts

(a) subjecting the sample series to a stability test;

b) determining the total amount of oxidative decomposition products in the series sample after the stability test; and

c) batch validation for distribution only if the batch sample after stability tests contains not more than the total amount of 0.1% m / m with respect to N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1 -methyl-2-oxo-quinoline-3-carboxamide, oxidative decomposition products of 2-chloro-6- (1-ethyl-N-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1H, 3H-spiro [56

VP / 2365 / AW

Chloro-1-methylquinoline-2,4-dion-3,3 '- [1] ethylindolin- [2] -one] and 5-chloro-N-ethyl-3-hydroxy-1-methyl-2 , 4-dioxo-N-phenyl-1,2,3,4-tetrahydro-kwinolino-3-carboxamide.

[0038] In a preferred embodiment of the process, the oxidative decomposition product is 2-chloro-6- (1-ethyl-N-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 5-chloro-N-ethyl-3-hydroxy-1-methyl -2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-quinoline-3-carboxamide or 1H, 3H-spiro [5-chloro-1-methyl-quinoline-2,4-dion-3,3 '- [1 ] -ethylindolin- [2] -one] or a mixture thereof.

[0039] In another preferred embodiment of the process during step (b), the amount is determined using mass measurements, UV light absorption, refractive index, ionization or voltamogram.

The present invention also provides a process for preparing a pharmaceutical product comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier characterized in that the pharmaceutical product contains not more than the total amount of 0.5% m / m, based on N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3 carboxamide, oxidative decomposition products of 2-chloro-6- (1-ethyl-N-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1 W, 3H-spiro [5-chloro-1-methylquinoline-2,4-dione- 3,3 '- [1] ethylindolin- [2] -one] and 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo-W-phenyl-tetrahydro-quinoline-3-carboxamide, including

a) obtaining a series of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or its salts;

b) determination of the total amount of oxidative decomposition products of 2-chloro-6- (1-ethyl-N-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1H, 3H-spiro [5-chloro-1-methylquinoline-2,4-dione- 3,3 '- [1] ethylindolin- [2] -one] and 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo-W-phenyltetrahydro-quinoline-3-carboxamide present in series; and

c) preparation of a pharmaceutical product from the series only when it has been determined that the series does not cover more than 0.5% m / m, with respect to N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1- methyl-2-oxoquinoline-3-carboxamide, oxidative decomposition products: 2-chloro-6- (1-ethyl-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1H, 3H-spiro [5-chloro-1-methylquinoline-2,4-dione-3,3 '- [1] -ethylindolin- [2] -one] and 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo-W-phenyl 1,2,3,4-tetrahydroquinoline-3-carboxamide.

[0041] A process for preparing a pharmaceutical product comprising N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or a salt thereof and a pharmaceutically acceptable carrier characterized in that no more than the total amount of 0.5% m / m is present in the product, in relation to N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide, a product of oxidative decomposition of 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo-W-phenyl-1,2,3,4-tetrahydro-quinoline-3-carboxamide, including

VP / 2365 / AW

EP 2 234 485 B1

a) obtaining a series of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide or its salts;

b) determining the total amount of 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo-W-phenyl-1,2,3,4-tetrahydro-quinoline-3-carboxamide present in the series; and

c) preparation of a pharmaceutical product from the series only when it has been determined that the series does not cover more than 0.5% m / m, with respect to N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1- 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo-N-phenyl-1,2,3,4-tetrahydro-quinoline-3-carboxamide methyl-2-oxoquinoline-3-carboxamide.

[0042] The present invention also provides a process for testing whether a sample contains unwanted oxidative decomposition products: 2-chloro-6- (1-ethyl-W-methyl-2-oxoindoline-3-carboxamido) benzoic acid, 1H, 3H-spiro [5-chloro -1-methylquinoline-2,4-dion-3,3 '- [1] ethylindoline- [2] -one] or 5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioxo -W-phenyl-1,2,3,4-tetrahydro-quinoline-3-carboxamide, which includes determining whether the sample contains a compound having the structure:

<img file="PL2234485T3_D0003.tif" />

[0043] The present invention also provides an isolated compound having the structure:

<img file="PL2234485T3_D0004.tif" />

VP / 2365 / AW

[0044] The present invention also provides an isolated compound having the structure:

<img file="PL2234485T3_D0005.tif" />

[0045] Any preferred embodiment of the invention or disclosure is considered applicable to any other preferred embodiment disclosed. For example, the disclosed pharmaceutical composition may be packaged in the disclosed sealed packages, and such a combination may be produced by the processes and methods disclosed.

[0046] Many previously known formulations of Laquinimod refer to formulations involving alkaline agents or meglumine.

[0047] Both of these excipients were found to be incompatible with certain coloring agents in the capsules, since discoloration of the capsules was observed for different capsules. This was related to the basic nature of the formulation. The advantage of the formulations presented here is their stability and compatibility with many types of dyes.

[0048] As used herein, "oxidation suppressing agent" refers to a group of chemical compounds that includes "antioxidants", "reducing agent", and "chelating agent".

[0049] As used herein, "antioxidant" refers to a compound selected from the group consisting of tocopherol, methionine, glutathione, tocotrienol, dimethylglycine, betaine, butylated hydroxyanisole, butylated hydroxytoluene, turmerine, vitamin E, ascorbyl palmitate, tocopherol, mesylate , ethylparaben, butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate, sodium or potassium metabisulfite, sodium or porous sulfite, alpha tocopherol or its derivatives, sodium ascorbate, disodium edetate, BHA (butylated hydroxyanisole), a pharmaceutically acceptable salt or ester of these compounds and mixtures thereof.

[0050] The term "antioxidant" as used herein also refers to flavonoids such as those selected from the group consisting of quercetin, moryna, narngenine and hespertin, taxifolin, afzelin, quercetin, myricistin, genistein, apigenin, biochanin A, flavivon, flavone isoflavonoids such as soy isoflavonoid, genistein, catechins such as tea catechin, epigallocatechin gallate, flavonol, epicatechin, hespertin, chrysin, diosmin, hesperidin, luteolin and routine.

[0051] As used herein, "reducing agent" refers to a compound selected from the group consisting of thiol, thioglycerol, mercaptoethanol, thioglycol, thiodiglycol, cysteine, thioglucose,

VP / 2365 / AW

Dithiothreitol (DTT), dithiobismaleimidoethane (DTME), 2,6-di-tert-butyl-4-methylphenol (BHT), sodium dithionite, sodium disulfate, sodium formamidine metabisulfite and ammonium disulfite.

[0052] As used herein, "chelating agent" refers to a compound selected from the group consisting of penicillamine, triethylenetetramine, N, N'-diethyldithiocarbamate (DDC), 2,3,2'-tetramino (2,3,2'-tet ), neocuproin, N, N, N ', N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), 1,10-phenanthroline (PHE), tetraethylenepentamine, triethylenetetramine and tri (2-carboxyethyl) phosphine (TCEP), ferrioxamine , CP94, EDTA, deferoxamine B (DFO) as the methanesulfate salt (also known as desferoxamine B mesylate (DFOM)), desferal from Novartis (formerly Ciba-Giegy) and apoferritin.

[0053] Each of the terms "antioxidant", "reducing agent" and "chelating agent" as used herein excludes meglumine.

[0054] As used herein, "oxygen absorbing agent" refers to a compound selected from the group consisting of a thiol containing compound, thioglycerol, mercaptoethanol, thioglycol, thiodiglycol, cysteine, thioglucose, dithiothreitol, dithiobismaleimidoethane (DTME), vitamin B, vitamin C, vitamin C, , 6-di-tert-butyl-4-methylphenol (BHT), sodium dithionite, sodium disulfate, tin ion, iron, copper, nickel, tin, zinc, tin salt such as tin chloride or tin tartrate, sulfur dioxide, sodium metabisulphate and ammonium disulphate.

Experimental details

Example 1: Laquinimod Sodium Capsules Containing Sodium Carbonate [0055] Capsules were prepared to correspond to 0.3 mg laquinimod acid (LA) per capsule and 0.6 mg laquinimod acid per capsule using excipients as shown in Table 1:

Table 1

<td>Ingredient</td><td>0.3 mg LA / capsule</td><td>0.6 mg LA / capsule</td>

<td>Laquinimod Sodium</td><td> 0.32</td><td> 0.64</td>

<td>USP Mannitol</td><td> 151.08</td><td> 302.16</td>

<td>Anhydrous sodium carbonate USP</td><td> 4.55</td><td> 9.10</td>

<td>NF sodium stearyl fumarate</td><td> 1.6</td><td> 3.2</td>

<td>Total mass</td><td> 157.55</td><td> 315.1</td>

[0056] Capsules were prepared using the following steps:

1. Mannitol and 99% of the total amount of anhydrous sodium carbonate required was placed in a high shear mixer and mixed for 30 seconds.

VP / 2365 / AW

EP 2 234 485 B1

2. A solution of Laquinimod sodium, 1% of the total required amount of anhydrous sodium carbonate and purified water was prepared in a mixer until dissolved.

3. The solution from step 2 was added to the contents of the high shear mixer from step 1 and mixed until the appropriate granulate was formed.

4. The granulate was dried in a fluid bed dryer with an inlet temperature of 50 ° C and an outlet temperature of 40 ° C.

5. The dry granulate was ground using a 0.8 mm sieve and mixed with sodium stearyl fumarate.

6. The mixture of step 5 was filled into hard gelatin capsules size 1 (0.5 mL volume) for a dose of 0.6 mg laquinimod acid and hard gelatin capsules size 3 (0.3 mL volume) for a 0.3 mg dose of laquinimod acid.

Example 2a: Laquinimod Sodium Capsules Containing Meglumine [0057] Capsules were prepared to correspond to 0.3 mg laquinimod acid (LA) per capsule and 0.6 mg laquinimod acid per capsule using excipients as shown in Table 2:

Table 2

<td>Ingredient</td><td>0.3 mg LA / capsule</td><td>0.6 mg LA / capsule</td>

<td>Laquinimod Sodium</td><td> 0.32</td><td> 0.64</td>

<td>USP Mannitol</td><td> 151.08</td><td> 302.16</td>

<td>USP meglumine</td><td> 5.0</td><td> 10.0</td>

<td>NF sodium stearyl fumarate</td><td> 1.6</td><td> 3.2</td>

<td>Total mass</td><td> 158</td><td> 316</td>

[0058] Capsules were prepared using the following steps:

1. Mannitol and 90% of the total amount of meglumine required were placed in a high shear mixer and mixed for 30 seconds.

2. A solution of Laquinimod sodium, 10% of the total required amount of meglumine and purified water was prepared in a mixer until dissolved.

3. The solution from step 2 was added to the contents of the high shear mixer from step 1 and mixed until the appropriate granulate was formed.

4. The granulate was dried in a fluid bed dryer with an inlet temperature of 50 ° C and an outlet temperature of 40 ° C.

VP / 2365 / AW

EP 2 234 485 B1

5. The dry granulate was ground using a 0.8 mm sieve and mixed with sodium stearyl fumarate.

6. The mixture of step 5 was filled into hard gelatin capsules size 1 (0.5 mL volume) for a dose of 0.6 mg laquinimod acid and hard gelatin capsules size 3 (0.3 mL volume) for a 0.3 mg dose of laquinimod acid.

Example 2b: Laquinimod Sodium Tablets Containing Meglumine [0059] Laquinimod sodium tablets were prepared using the same excipients as listed in Table 2 using the procedure described in steps 1-5 of Example 2a. After step 5, the mixture was transferred to a tablet press and pressed. The tablets were analyzed for average weight, weight of individual tablets, density, hardness, friability and disintegration properties.

Example 3: Forced Degradation of Laquinimod Sodium Capsules [0060] Laquinimod sodium capsules prepared according to Examples 1 and 2 were exposed to 0.15% solution H₂ABOUT₂ for 40 minutes.

[0061] The amount of laquinimod sodium in each exposed capsule was measured by chromatographic analysis and the percent loss is listed below:

Example 1 formulation: 28.5% loss.

Example 2 formulation: 0.7% loss.

Results [0062] The use of meglumine as a diluent for laquinimod sodium prevented degradation associated with the oxidation of laquinimod sodium under forced conditions.

Example 4: Laquinimod Sodium Formulations Containing Antioxidants and Chelating Agents [0063] Laquinimod Sodium formulations are prepared using the process described in Example 2 using antioxidants instead of meglumine or with the addition of meglumine, using the following proportions:

VP / 2365 / AW

EP 2 234 485 B1

Table 3

<td>Limiting factor oxidation</td><td>% in the formulation</td>

<td>Ascorbyl palmitate</td><td> 0.01-1</td>

<td>Sodium or potassium metabolite</td><td> 0.01-1</td>

<td>Sodium or Potassium Sulfite</td><td> 0.01-1</td>

<td>Alpha tocopherol or its derivatives</td><td> 0.001-0.05</td>

<td>Sodium ascorbate</td><td> 0.01-1</td>

<td>Disodium edetate</td><td> 0.005-1</td>

<td>BHA (butylated hydroxyanisole)</td><td> 0.001-0.1</td>

<td>BHT (butylated hydroxytoluene)</td><td> 0.001-0.1</td>

<td>Propyl gallate</td><td> 0.002-0.1</td>

Example 5: Laquinimod Sodium Formulations Packaged in Oxygen Absorbing Containers [0064] The oxygen absorbing agent is material that removes oxygen from a sealed container by chemical reaction with oxygen, resulting in its binding.

[0065] A preferred example of an oxygen absorbing agent is iron, preferably in the form of a powder. In a sealed container, the oxygen absorbing agent maintains the oxygen content of the air in the tank space preferably below 10%, most preferably below 1%.

[0066] Other metals that can be used are nickel, tin, copper and zinc.

[0067] Examples of oxygen absorbers are disclosed in US Application Publication Number US 2007/0163917.

[0068] Laquinimod sodium formulations are packaged in closed containers containing oxygen absorbent and in closed containers not containing oxygen absorbent. After a month, the amount of laquinimod in the formulations in both containers is determined.

[0069] Oxygen absorbents may be useful in reducing the intensity of oxygen-induced degradation in laquinimod formulations.

Example 6: Laquinimod Sodium Formulations Packaged in Oxygen Impermeable Containers [0070] Laquinimod Sodium formulations are packaged in containers sealed in an oxygen-free environment or with a limited amount of oxygen. The formulations are stored for a month. The content of Laquinimod in the formulations is compared to similar formulations that are packaged in a standard environment with unlimited oxygen.

[0071] Oxygen absorbents may be useful in reducing the intensity of oxygen-induced degradation in laquinimod formulations.

VP / 2365 / AW

EP 2 234 485 B1

Example 7: Coating of Laquinimod Tablets with an Oxygen Resistant Coating [0072] The tablets are coated with an enveloping film that prevents contact with the atmosphere. The film does not significantly change the solubility profile of the tablet, but prevents contact of oxygen from the air within the packaging with laquinimod in the tablet.

[0073] The shell may be a wax or shell such as Opadry®fx ™ manufactured by Colorcon, West Point, PA, USA.

[0074] The coatings can be used on laquinimod tablets with meglumine, without meglumine, with or without antioxidants.

[0075] Oxygen-resistant coatings may be useful in reducing the intensity of oxygen-induced degradation in laquinimod formulations.

Example 8: Oxidative Pollutants in Pharmaceutical Compositions

Laquinimod [0076] The table below lists compounds that, due to oxidation of laquinimod, may be present in small amounts in pharmaceutical compositions containing laquinimod.

Table 4

<td rowspan="2">2-chloro-6- (1-ethyl-W-methyl-2-oxoindoline-3-carboxamido) benzoic acid (Compound I)</td><td colspan="2">about</td>

<td>ABOUT</td><td>rn</td>

<td>1 H, 3H-spiro [5-chloro-1-metylokwinolino-2,4-dione</td><td></td><td>_ about</td>

<td>3,3 '- [1] -ethylindolin- [2] -one] (Compound II)</td><td></td><td></td>

<td></td><td></td><td>* A.</td>

<td></td><td rowspan="2">about</td><td></td>

<td></td><td>V—— Z</td>

<td></td><td></td><td>N 1</td>

<td>5-chloro-W-ethyl-3-hydroxy-1-methyl-2,4-dioksoW-phenyl-tetrahydro-kwinolino-3-carboxamide</td><td></td><td>Ιϊχ JO</td>

<td></td><td rowspan="2">ά</td><td></td>

<td></td><td></td>

<td></td><td></td><td>l</td>

VP / 2365 / AW

[0077] These oxidation products may be formed in the presence of laquinimod and oxygen. Factors that may enhance the formation of these products include water and / or transition metal ions that are in direct contact with laquinimod, e.g. which are present in the formulation.

Discussion [0078] The use of meglumine reduces the degradation of laquinimod sodium in the formulation. More specifically, when treated with 0.15% H solution₂ABOUT₂ for 40 minutes, the formulation with meglumine of Example 2 showed less than 2.5% degradation of laquinimod sodium, compared to an analogous formulation without meglumine, under the same conditions. Meglumine appears to be limiting oxidation of laquinimod. Thus, other methods for preventing or reducing oxidation such as the methods described herein can be used to reduce oxidation of laquinimod and to prevent or inhibit the formation of oxidative degradation products. Such methods include formulating laquinimod with antioxidants, chelating agents and / or reducing agents as well as packaging methods, encapsulation methods and / or processing methods designed to reduce oxidation.

[0079] To determine whether a given method of preventing or limiting oxidation is effective, known techniques for identifying whether a laquinimod composition comprises any of Compounds I, II or III or a mixture thereof may be used.

Example 9: Preparation of Compound II [0080]

<img file="PL2234485T3_D0006.tif" />

[0081] Laquinimod (14.01 mmol, 5.00 g), CAN (28.02 mmol, 15.4 g), ethanol (99.5%, 50 ml), and acetic acid (5.0 ml) were stirred at ambient temperature for 1 hour, and then water ( 30 ml). After stirring for 10 min by filtration, the precipitate was collected, washed with water and then washed with cold ethanol (99.5%) and dried to give spiro Compound II (4.73 g, 95%).

VP / 2365 / AW

EP 2 234 485 B1

Example 10: Preparation of Compound I [0082] ci

<img file="PL2234485T3_D0007.tif" />

[0083] Compound II of Example 9 (5.15 mmol, 1.83 g) was mixed with a mixture of 1M NaOH (10.0 mmol, 10.0 mL) and 1,4-dioxane (4 mL) at room temperature for 2 h and then diluted with water (30 mL). The mixture was acidified with 5M HCl to pH 1, stirred 15 min and the precipitate was collected, washed in water and dried to obtain Compound I (1.73 g, 90% yield). When Compound I is heated in ethanol, the molecule decomposes into 2-methylamino-6-chlorobenzoic acid ethyl ester and 1-ethyl-2-oxo-2,3-dihydro-1H-indole-3-carboxylic acid. Compound I is purified by dissolving in a mixture of ethanol and aqueous 1M NaOH and precipitation induced by the addition of HCl, carried out at room temperature.

Example 11: Preparation of Compound III [0084]

III [0085] 5-Chloro-N-ethyl-1,2-dihydro-4-hydroxy-1-methyl-2-oxo-N-phenyl-3-quinolinecarboxamide sodium salt (1.00 g, 2.64 mmol) was added to the anhydrous disodium hydrogen phosphate mixture (1.15g, 6.4 mmol), Oxane (2KHSO &lt;KHSO4K_;SO4, 1.97g, 3.20 mmol), and water (20 ml) and stirred for 30 minutes. The resulting precipitate was collected, washed in a 2: 8 ethanol / water solution and dried to obtain Compound III (939 mg, 95%). K. Jansson et al. "Synthesis and Reactivity of Laquinimod, a Quinoline-3-carboxamide: Intramolecular Transfer of the Enol Proton to a Nitrogen Atom as a Plausible Mechanism for Ketene Formation", J. Org. Chem. 2006, 71, p1667.

VP / 2365 / AW

EP 2 234 485 B1

Example 12a: Experiments with Laquinimod Sodium with Antioxidants [0086] Two wet granulations were prepared with Laquinimod Sodium, mannitol, lactose and water (Series 1 and 2). One series (Series 1) did not contain the antioxidants: Butylated Hydroxytoluene (BHT) and Butylated Hydroxyanisole (BHA). For the second series (Series 2), antioxidants (BHT and BHA) were dissolved in EtOH and added to the granulate.

[0087] The granules were dried and milled. 10% Crospovidone was added to both batches and mixed for 15 minutes, then Pruv® was added and mixed for 5 minutes. Final mixtures were tested for the presence of non-polar IDD (3-HLAQ) (Compound III). Series 1 and 2 compositions and percentage 3-HLAQ impurity (Compound III) obtained relative to Laquinimod are shown in Table 5. Impurities were detected prior to storage under accelerating conditions.

Table 5

<td rowspan="2"></td><td> 1</td><td> 2</td>

<td colspan="2">Quantity (mg)</td>

<td>Laquinimod sodium</td><td> 0.64</td><td> 0.64</td>

<td>mannitol</td><td> 70.00</td><td> 70.00</td>

<td>Lactose M.</td><td> 70.00</td><td> 70.00</td>

<td>BHT</td><td> -</td><td> 0.028</td>

<td>BHA</td><td> -</td><td> 0.028</td>

<td>Pruv®</td><td> 1.50</td><td> 1.50</td>

<td>crospovidone</td><td> 10%</td><td> 10%</td>

<td>3-HLAQ (%)</td><td> 0.34</td><td> 0.15</td>

Example 12b: Experiments with Laquinimod Sodium with Antioxidants [0088] Two wet granulations were prepared with Laquinimod Sodium, mannitol, lactose, Povidone K30 and water.

[0089] In one series (Series 3), the granules were dried and milled. Then 0.1% Pruv® was added and mixed for 5 minutes. The final mixture was tested for the presence of non-polar IDD (3-HLAQ) (Compound III).

[0090] For another series (Series 4), antioxidants (BHT, BHA and propyl gallate) were dissolved in EtOH and added to the granulate. The granules were dried and ground. The mixture was tested for the presence of non-polar IDD (3-HLAQ) (Compound III). Impurities were detected prior to storage under accelerating conditions.

[0091] The compositions for each lot and the final percentage of 3-HLAQ impurity (Compound III) relative to Laquinimod are shown in Table 6.

VP / 2365 / AW

EP 2 234 485 B1

Table 6

<td rowspan="2"></td><td> 1</td><td> 2</td>

<td colspan="2">Quantity (mg)</td>

<td>Laquinimod sodium</td><td> 0.64</td><td> 0.64</td>

<td>mannitol</td><td> 70.00</td><td> 70.00</td>

<td>Lactose M.</td><td> 70.00</td><td> 70.00</td>

<td>Povidone K-30 (10%)</td><td> 14.00</td><td> 14.00</td>

<td>BHT</td><td> -</td><td> 0.028</td>

<td>BHA</td><td> -</td><td> 0.028</td>

<td>Propyl gallate</td><td> -</td><td> 0.185</td>

<td>Pruv®</td><td> 1.50</td><td> -</td>

<td>3-HLAQ (%)</td><td> 1.39</td><td> 0.77</td>

Discussion [0092] Experiments 12a and 12b show that antioxidants reduce the formation of impurities and limit the percentage of degradation product 3-HLAQ (Compound III) relative to Laquinimod.

VP / 2365 / AW

EP 2 234 485 B1