IMATINIB COMPOSITIONS

The invention relates to a pharmaceutical composition, preferably a tablet, containing about 23-29% w/w imatinib and processes for its preparation.

Skip to: Description  ·  Claims  · Patent History  ·  Patent History
Description
CROSS REFERENCE TO RELATED APPLICATIONS

The present invention claims the benefit of the following U.S. Provisional Patent Application No. 60/995,321, filed Sep. 25, 2007; and 60/995,651, filed Sep. 26, 2007. The contents of these applications are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to formulations containing imatinib or a pharmaceutical acceptable salt thereof, preferably imatinib mesylate in an amount of about 23-29% w/w of the total formulation.

BACKGROUND OF THE INVENTION

Imatinib mesylate, 4-(4-methylpiperazin-1-ylmethyl)-N-[4-methyl-3-[(4-pyrinin-3-yl)pyrimidin-2-yloamino]phenyl]benzamide mesylate, a compound having the chemical structure,

Imatinib is a protein-tyrosine kinase inhibitor, especially useful in the treatment of various types of cancer and can also be used for the treatment of atherosclerosis, thrombosis, restenosis, or fibrosis. Thus imatinib can also be used for the treatment of non-malignant diseases. Imatinib is usually administered orally in the form of a suitable salt, e.g., in the form of imatinib mesylate.

International Patent Application Nos. WO 99/03854, WO 2005/077933, WO 2005/095379, WO 2004/106326, WO 2006/054314, WO 2006/024863, WO 2006/048890, US 2006/0030568, WO 07/023,182 and U.S. Pat. No. 6,894,051 apparently describe crystalline forms of imatinib mesylate designated Forms H1, α, α2, β, δ, ε, I, II, and amorphous. International Patent Application No. WO 2007/136510 describes additional crystalline forms of imatinib mesylate including forms V and X.

PCT application no. WO 03/090720 relates to formulations containing imatinib containing 30-80% w/w which were prepared using wet granulation. These tablets are described as being of a small size and hence convenient to swallow despite the high dosage level of the active ingredient. However, these tablets express high friability and poor abrasion resistance, as well as limited flexibility in the amount of excipients usable due to the high drug load. In addition, the process to manufacture such tablets is also difficult due to poor flow of the final mixture and poor compressibility properties of such final mixture. Further, PCT application No. WO 01/47507 describes a pharmaceutical composition/tablet containing about 22% w/w imatinib mesylate. Also, US 2006/0275372 and WO 2007/119601 describe nanoparticulate compositions of imatinib mesylate.

In view of the nature of this active ingredient, the high dosage administered to patients and the problems reported regarding the difficulties in tableting, it is an objective of the present invention to further optimize tablets containing imatinib.

SUMMARY OF THE INVENTION

In one embodiment the present invention provides a pharmaceutical composition, preferably a tablet containing imatinib or a pharmaceutical acceptable salt thereof, preferably imatinib mesylate, in an amount of about 23-29% w/w of the total composition.

In another embodiment the present invention provides processes for preparing a pharmaceutical composition, preferably a tablet, containing imatinib or a pharmaceutical acceptable salt thereof, preferably imatinib mesylate, in an amount of about 23-29% w/w of the total composition of by a process such as by dry granulation, or direct compression.

DETAILED DESCRIPTION

As used herein, the term “core” refers to an uncoated tablet.

As used herein, the term “% w/w” refers a weight of a substance expressed as a percentage of the total weight of the formulation. In the case of a tablet containing imatinib mesylate: this is the weight of imatinib mesylate expressed as a percentage of the total tablet weight, wherein the total weight is the weight of imatinib mesylate together with excipients.

The present invention provides a pharmaceutical composition, preferably a tablet containing imatinib or a pharmaceutical acceptable salt thereof, preferably imatinib mesylate, in an amount of about 23-29% w/w, preferably of about 25-29% w/w, more preferably of about 28-29% w/w, that possess improved properties compared to prior art pharmaceutical compositions such as tablets with respect to hardness, friability, uniformity, homogeneous dispersibility, compressibility and flowability. Preferably, the tablet of the present invention has a hardness of at least about 10 scu, more preferably at least about 15 scu, most preferably of about 15 scu to about 30 scu. The hardness of a tablet is measured by the force in kp (kilopond) or SCU (1 SCU=1.4 kp) required to break the tablet. Preferably, the tablet of the present invention has a friability of less than 1%, more preferably less than 0.5%, most preferably less than 0.1%. Friability can be defined as a measure describing whether a tablet can stay intact and withhold its form from any outside force of pressure:


% friability=100×(Wo−Wf)/Wo

where Wo is the original weight of the tablets, and Wf is the final weight of the tablets after the collection is put through the friability tester.

Imatinib in the pharmaceutical composition, preferably tablet, of the present invention may be either in the form of a base or a pharmaceutical acceptable salt, preferably, a mesylate salt. Most preferably, the imatinib mesylate is in a polymorphic form V or form X. Forms V and X are described in detail in co-pending U.S. application Ser. No. 11/796,573, published as US 2008-0090833 (or as international patent application WO 2007/136510), which is incorporated herein by reference.

Form V is characterized by data selected from the group consisting of: a powder XRD pattern with peaks at about 9.9, 11.7, 13.3, 16.6, and 22.1±0.2 degrees two-theta; a powder XRD pattern with peaks at about 9.9, 11.7, 13.3, and 16.6±0.2 degrees two-theta; a PXRD pattern having peaks at about: 5.6, 9.9, 11.7, 13.3, 16.6, and 18.5±0.2 degrees two-theta; a PXRD pattern having at least five peaks selected from the list consisting of peaks at about: 5.6, 9.9, 11.7, 13.3, 16.6, 18.5, 22.1, 24.0, 26.2, 26.9±0.2 degrees two-theta; a solid-state 13C NMR spectrum with signals at about 162.8, 161.5, 158.5±0.2 ppm; a solid-state 13C NMR spectrum having chemical shifts differences between the signal exhibiting the lowest chemical shift and another in the chemical shift range of 100 to 180 ppm of about 53.9, 52.6 and 49.6±0.1 ppm.

Form X is characterized by data selected from the group consisting of: a powder XRD pattern with peaks at about 6.0, 8.6, 11.4, 14.2, 18.3±0.2 degrees two-theta; a powder XRD pattern having peaks at about: 6.0, 8.6, 10.2, 11.4, 14.2, 18.3±0.2 degrees two-theta; a powder XRD pattern having at least five peaks selected from the list consisting of peaks at about: 6.0, 8.6, 10.2, 11.4, 14.2, 17.8, 18.3, 21.6, 22.4, 23.6, 24.8±0.2 degrees two-theta; a solid-state 13C NMR spectrum with signals at about 159.9, 158.2 and 153.4±0.2 ppm; a solid-state 13C NMR spectrum having chemical shift differences between the signal exhibiting the lowest chemical shift and another in the chemical shift range of 100 to 180 ppm of about 51.5, 49.8, and 45.0±0.1 ppm.

The pharmaceutical compositions, preferably tablets, of the invention contain imatinib or a pharmaceutical acceptable salt thereof, preferably imatinib mesylate, in a mixture with one or more excipients. Excipients are added to the composition for a variety of purposes as described below. Preferably, the pharmaceutical composition of the present invention comprises a dosage form containing from about 50 mg to about 500 mg imatinib, more preferably, from about 100 mg to about 400 mg, even more preferably about 100 mg or 400 mg imatinib.

The present invention also provides processes for preparing a pharmaceutical composition, preferably a tablet, containing imatinib or a pharmaceutical acceptable salt thereof, preferably imatinib mesylate in an amount of about 23-29% w/w, preferably of 25-29% w/w, more preferably of about 28-29% w/w.

One process of the invention for preparing such pharmaceutical composition is dry granulation. The dry granulation may comprise blending the composition containing the active ingredient and the excipients; compacting the blend into a slug or a sheet; comminuting the slug or the sheet into compacted granules; and compressing the compacted granules into a tablet containing imatinib or a pharmaceutical acceptable salt thereof, preferably imatinib mesylate in an amount of about 23-29% w/w.

Another process of the invention for preparing the pharmaceutical composition is direct compression (dry blending). The direct compression may comprise blending the composition containing the active ingredient and the excipients; and compressing it directly into a tablet containing imatinib or a pharmaceutical acceptable salt thereof, preferably imatinib mesylate in an amount of about 23-29% w/w. The compression is directly into a compacted dosage form using direct compression techniques. Direct compression is an easy, simple and applicable for industrial scale.

Diluents increase the bulk of a solid pharmaceutical composition and can make a pharmaceutical dosage form containing the composition easier for the patient and caregiver to handle. Diluents for solid compositions include, for example, microcrystalline cellulose (e.g. AVICEL®), microfine cellulose, lactose, starch, pregelatinized starch, calcium carbonate, calcium sulfate, sugar, dextrates, dextrin, dextrose, dibasic calcium phosphate dihydrate, tribasic calcium phosphate, kaolin, magnesium carbonate, magnesium oxide, maltodextrin, mannitol, polymethacrylates (e.g. EUDRAGIT®), potassium chloride, powdered cellulose, sodium chloride, sorbitol and talc. Most preferably the diluents are selected from the group consisting of: Mannitol, calcium carbonate, Starlac, lactose, and di-basic calcium phosphate, most preferably the diluent is Starlac (82-88% Lactose monohydrate and 12-18% Maize starch).

Solid pharmaceutical compositions that are compacted into a dosage form like a tablet can include excipients whose functions include helping to bind the active ingredient and other excipients together after compression. Binders for solid pharmaceutical compositions include at least one of acacia, alginic acid, carbomer (e.g. carbopol), carboxymethylcellulose sodium, dextrin, ethyl cellulose, gelatin, guar gum, hydrogenated vegetable oil, hydroxyethyl cellulose, hydroxypropyl cellulose (e.g. KLUCEL®), hydroxypropyl methyl cellulose (e.g. METHOCEL®), liquid glucose, magnesium aluminum silicate, maltodextrin, methylcellulose, polymethacrylates, povidone (e.g. KOLLIDON®, PLASDONE®), pregelatinized starch, sodium alginate, or starch. More preferably the binders are selected from hydroxypropylcellulose, povidone (e.g. KOLLIDON®, PLASDONE®), or starch, most preferably the binder is povidone (e.g. KOLLIDON®, PLASDONE®).

The dissolution rate of a compacted solid pharmaceutical composition in the patient's stomach can be increased by the addition of a disintegrant to the composition. Disintegrants include, but are not limited to, alginic acid, carboxymethylcellulose calcium, carboxymethylcellulose sodium (e.g. AC-DI-SOL @PRIMELLOSE®), colloidal silicon dioxide, croscarmellose sodium, crospovidone (e.g. KOLLIDON®, POLYPLASDONE®), guar gum, magnesium aluminum silicate, methyl cellulose, microcrystalline cellulose, polacrilin potassium, powdered cellulose, pregelatinized starch, sodium alginate, sodium starch glycolate (e.g. EXPLOTAB®) or starch. Most preferably the disintegrants are selected from carboxymethylcellulose sodium (e.g. AC-DI-SOL @PRIMELLOSE®), crospovidone or sodium starch glycolate, most preferably the disintegrant is crospovidone or carboxy methyl cellulose or mixtures thereof.

Glidants can be added to improve the flow properties of non-compacted solid composition and improve the accuracy of dosing. Excipients that can function as glidants include colloidal silicon dioxide, magnesium trisilicate, powdered cellulose, starch, talc, and/or tribasic calcium phosphate. Most preferably the glidants are selected from talc, colloidal silicon dioxide, silicone dioxide NF most preferably the glidants is silicon dioxide NF.

When a dosage form such as a tablet is made by compaction of a powdered composition, the composition is subjected to pressure from a punch and dye. Some excipients and active ingredients have a tendency to adhere to the surfaces of the punch and dye, which can cause the product to have pitting and other surface irregularities. A lubricant can be added to the composition to reduce adhesion and ease release of the product form the dye. Lubricants include, but are not limited to, magnesium stearate, calcium stearate, glyceryl monostearate, glyceryl palmitostearate, hydrogenated castor oil, hydrogenated vegetable oil, mineral oil, polyethylene glycol, sodium benzoate, sodium lauryl sulfate, sodium stearyl fumarate, stearic acid, talc, and/or zinc stearate. Most preferably, the lubricants are selected from the group consisting of: sodium stearyl fumarate, magnesium stearate and talc. Most preferably the lubricants are selected from the group consisting of magnesium stearate, sodium stearyl fumarate and a mixture thereof.

Flavoring agents and flavor enhancers make the dosage form more palatable to the patient. Common flavoring agents and flavor enhancers for pharmaceutical products that can be included in the composition of the present invention include, but are not limited to, maltol, vanillin, ethyl vanillin, menthol, citric acid, fumaric acid, ethyl maltol, or tartaric acid.

Solid compositions can also be dyed using any pharmaceutically acceptable colorant to improve their appearance and/or facilitate patient identification of the product and unit dosage level.

Selection of excipients and the amounts to use can be readily determined by the formulation scientist based upon experience and consideration of standard procedures and reference works in the field.

In a preferred embodiment, the tablets in accordance with the present invention comprise; from about 23% to 29% w/w, more preferably from about 25% to about 29% w/w, imatinib mesylate; from 10 to 60% w/w, more preferably from about 25% to about 60% w/w, of a diluent, filler or bulking agent, preferably lactose, more preferably starlac (82-88% Lactose monohydrate and 12-18% Maize starch); from 4 to 30% w/w, more preferably from about 10% to about 25% w/w, of a disintegrant, preferably crospovidone; from 0.2 to 5% w/w of a glidant, preferably silicon dioxide; and from 0.1 to 4% w/w, more preferably from about 0.5% to about 2% w/w, of a lubricant, preferably selected from magnesium stearate or sodium stearyl fumurate or the mixture thereof.

More preferably, each tablet contains about;

119.5 mg imatinib mesylate

106.5 mg Starlac (82-88% Lactose monohydrate and 12-18% Maize starch)

52.0 mg crospovidone NF

22.50 mg Croscarmellose Sodium (Primellose),

2.0 mg Silicon Dioxide

102.5 mg A-Tab (Calcium Phosphate Dibasic)

3.5 mg magnesium stearate.

4.0 mg Sodium Stearyl Fumarate.

Having described the invention with reference to certain preferred embodiments, other embodiments will become apparent to one skilled in the art from consideration of the specification. The invention is further defined by reference to the following examples describing in detail the preparation of the composition and methods of use of the invention. It will be apparent to those skilled in the art that many modifications, both to materials and methods, may be practiced without departing from the scope of the invention.

The following examples are given for the purpose of illustrating the invention and shall not be construed as limiting the scope or spirit of the invention. The examples below demonstrate the advantage of the tablets having 23-29% Imatinib Mesylate, compared to tablets having about 60% of Imatinib Mesylate, in terms of hardness and friability.

EXAMPLES XRD Measurements

XRD diffraction was performed on X-Ray powder diffractometer: PanAlytical X'pert Pro powder diffractometer, Cu-tube, scanning parameters: CuKα radiation, λ=1.5418 Å. Continuous scan at a rate of: 0.02° 2theta/0.3 sec.

13C NMR Measurements

The CP/MAS 13C NMR measurements were made at Bruker Avance 500 NMR US/WB spectrometer in 4-mm ZrO2 rotor. Magic angle spinning (MAS) speed was 10 kHz. As used herein, the term “13C NMR chemical shifts” refers to the shifts measured under above specified conditions, however, these shifts can slightly differ instrument to instrument and can be shifted either upfield or downfield due to the different instrumental setup and calibration used. Nevertheless the sequence of individual peaks remains identical.

Example 1 Tablets Containing 23-29% Imatinib Mesylate (100 & 400 Mg Tablets) Prepared by Dry Granulation

MATERIAL 100, 400 mg % Part I Imatinib Mesylate 28.44 Silicone dioxide (Syloid 244 FP) 0.47 Starlac (Lactose Monohydrate 82-88% 25.22 Maize Starch 12-18%) A-Tab (Calcium Phosphate Dibs Anh) 24.39 Primilose(Croscarmellose Sodium) 2.67 Crospovidone 6.18 Part II Sodium Stearyl Fumarate (PRUV) 0.95 Part III Crospovidone 6.18 Primelose (Croscarmelose Sodium) 2.67 Part IV Magnesium Stearate 0.83

Manufacturing process of Imatinib Mesylate tablets by dry granulation:

  • 1. Sieve components of Part I through sieve #30 mesh and transfer to Flow BIN.
  • 2. Sieve component of part II through #50 mesh, transfer to Flow Bin from step 1 and mix for 20 minutes.
  • 3. Compress the mix from step 2 in to slugs.
  • 4. Mill the slugs from step 3 through Frewitt and transfer to Flow Bin. And mix for 10 minutes.
  • 5. Sieve components of Part III through sieve #30 mesh and transfer to Flow BIN from step 4 and mix for 15 minutes.
  • 6. Sieve component of part IV through sieve # 50 mesh, transfer to Flow Bin from step 5 and mix for 3 minutes to get the final blend.
  • 7. Compress final blend from step 6 in to tablet cores (412 mg/tab for 100 mg dosage strength and 1,648 mg/tab for 400 mg dosage strength).

Cosmetic Coating:

1. Suspend 21S3894 ORANGE into 95% Ethanol under specified conditions.
2. Apply suspension onto core tablets.

TABLE I Hardness and friability for the composition of example 1. Weight (mg) Hardness (scu) Friability (%) 1 414 21 0.0 2 411 18 3 409 19 4 416 21 0.0 5 422 21 6 405 20 7 406 21 8 411 25 0.0 9 425 21 10 414 21 min 405 18 max 425 25

Example 2 Tablets Containing 23-29% Imatinib Mesylate (100 & 400 Mg Tablets) Prepared by Direct Compression

MATERIAL mg/100 mg tablet Part I Imatinib Mesylate 119.5 Lactose MNHDR (DCL-14) 125.0 Crospovidone 62.0 Avicel PH 102 42.7 Klucel 12.8 Part II Avicel PH 102 42.7 Aerosil 200 3.0 Part III Magnesium Stearate 4.3

Manufacturing process of Imatinib Mesylate tablets by dry granulation:

1. Mix components of Part I,
2. Sieve components of Part II through sieve #30 mesh,
3. Add materials of step 2 to the mixture of step 1 and mix for 10 minutes,
4. Sieve component of part III through #50 mesh,
5. Add materials of step 4 to the mixture of step 3 and mix for 5 minutes to get the final blend, and
6. Compress the final blend from step 5 in to tablet cores (412 mg/tab for 100 mg dosage strength and 1,648 mg/tab for 400 mg dosage strength).

TABLE II Hardness and friability for the composition of example 2 Weight (mg) Hardness (scu) Friability (%) 1 414 21 0.0 2 411 18 3 409 19 4 416 21 0.0 5 422 21 6 405 20 7 406 21 8 411 25 0.0 9 425 21 10  414 21 min 405 18 max 425 25

Example 3 Tablets Containing about 63% Imatinib Mesylate—Dry Granulation (Comparative Example) Imatinib Mesylate 100 mg Tablets:

mg per 1,000 Cores core Raw Materials kg g mg PART I (Slugging Mix) 26.55 Starlac 26 55 2.8 Primellose 2 80 119.5 Imatinib Mesylate 119 500 0.5 Silicon Dioxide NF(Syloid 500 244) 25.0 A-Tab (Calcium Phosphate 25 000 Dibasic Anhydrous) 5.2 Kollidonh CL(Crospovidone 5 200 NF) Part II 1.0 Sodium Stearyl Fumarate 1 000 (Pruv) 180.55 Theoretical End Weight 180 550 for Slugging Mix Part III 3.0 Kollidon CL(Crospovidone) 3 000 3.45 Primellose 3 450 Part IV 3.0 Magnesium Stearate NF/BP 3 000 190.0 Theoretical End Weight 190 000

Example 4 Tablets Containing about 60% Imatinib Mesylate—Direct Compression (Comparative Example)

MATERIAL weight Part I Imatinib Mesylate 119.5 (Lactose Monohydrate) 30.17 Crospovidone 18.5 Avicel PH 102 8.0 Klucel 3.0 Part II Avicel PH 102 8.0 Aerosil 200 1.33 Magnesium Staearate 1.5

Example 5 Hardness and Friability of Tablets Containing about 60% Imatinib as Prepared in Examples 3 and 4

Weight (mg) Hardness (scu) Friability (%) 1 160 4 2.5 2 180 5 3 120 3 3.0 4 210 5 5 160 4 6 150 3 7 190 2 5.0 8 110 2 9 140 3 10 190 4

Claims

1. A pharmaceutical composition comprising imatinib mesylate in an amount of about 23-29% w/w of the total composition.

2. The pharmaceutical composition of claim 1, wherein the imatinib mesylate is a crystalline imatinib mesylate form V or crystalline imatinib mesylate form X.

3. The pharmaceutical composition of claim 2, wherein imatinib mesylate is crystalline imatinib mesylate form X.

4. The pharmaceutical composition of claim 1, comprising imatinib mesylate in an amount of about 25-29% w/w of the total composition.

5. The pharmaceutical composition of claim 4, comprising imatinib mesylate in an amount of about 28-29% w/w of the total composition.

6. The pharmaceutical composition of claim 1 in the form of a tablet.

7. The pharmaceutical composition of claim 6, wherein the hardness of the tablet is at least about 10 scu.

8. The pharmaceutical composition of claim 7, wherein the hardness of the tablet is at least about 15 scu.

9. The pharmaceutical composition of claim 8, wherein the hardness of the tablet is about 15 scu to about 30 scu.

10. The pharmaceutical composition of claim 6, wherein the tablet has a friability of less than 1%.

11. The pharmaceutical composition of claim 10, wherein the tablet has a friability of less than 0.1%.

12. The pharmaceutical composition of claim 6, wherein the tablet comprises a dosage of about 50 mg to about 500 mg imatinib.

13. The pharmaceutical composition of claim 12, comprising a dosage selected from a 100 mg dosage and a 400 mg dosage of imatinib.

14. The pharmaceutical composition of claim 1, comprising imatinib mesylate in an amount from about 23 to about 29% w/w; from about 10 to about 60% w/w of a diluent; from about 4 to about 30% w/w of a disintegrant; from about 0.2 to about 5% w/w of a glidant; and from about 0.1 to about 4% w/w of a lubricant.

15. The pharmaceutical composition of claim 14, wherein the diluent is a lactose monohydrate (Starlac), the disintegrant is selected from crospovidone, carboxymethylcellulose sodium and a mixture thereof, the glidant is silicon dioxide, and the lubricant is magnesium stearate, sodium stearyl fumarate or a mixture thereof.

16. The pharmaceutical composition of claim 14, comprising imatinib mesylate in an amount from about 23 to about 29% w/w; from about 25 to about 60% w/w of the diluent; from about 10 to about 25% w/w of the disintegrant; from about 0.2 to about 5% w/w of the glidant; and from about 0.5 to about 2% w/w of the lubricant.

17. The pharmaceutical composition of claim 6, comprising about 119.5 mg imatinib mesylate; about 106.5 mg of a lactose monohydrate (Starlac); about 52 mg crospovidone; about 22.5 mg croscarmellose sodium (Primellose); about 2 mg silicon dioxide; about 102.5 mg calcium phosphate dibasic (A-Tab); about 3.5 mg magnesium stearate; and about 4 mg sodium stearyl fumarate.

18. A process of preparing a pharmaceutical composition of claim 1 containing imatinib mesylate in an amount of about 23-29% w/w of the total composition comprising: combining imatinib and at least one pharmaceutical acceptable excipient to form mixture and tabletting the mixture into a pharmaceutical composition in the form of a tablet.

19. The process of claim 18, wherein the imatinib mesylate is crystalline imatinib mesylate form V or form X.

20. The process of claim 18, wherein tabletting comprises a method selected from dry granulation, and direct compaction of a mixture comprising imatinib.

21. The process of claim 20, wherein tabletting comprises dry granulation.

22. The process of claim 20, wherein tabletting comprises direct compression.

23. The process of claim 18, further comprising coating the pharmaceutical composition in the form of a tablet with a cosmetic coating.

Patent History
Publication number: 20090087489
Type: Application
Filed: Sep 25, 2008
Publication Date: Apr 2, 2009
Inventors: Bella Gerber (Petah-Tiqva), Zvika Doani (Tel-Mond)
Application Number: 12/238,314
Classifications
Current U.S. Class: Coated Pills Or Tablets (424/474); Plural Diazine Rings (544/295); Additional Six-membered Hetero Ring Consisting Of Five Ring Carbons And One Ring Nitrogen Attached Directly Or Indirectly To The 1,3-diazine By Nonionic Bonding (514/252.18)
International Classification: A61K 9/28 (20060101); C07D 403/14 (20060101); A61P 35/00 (20060101); A61P 9/00 (20060101); A61K 31/496 (20060101);