GB2223943A - Oral disage forms of omega-3 polyunsaturated acids - Google Patents

Abstract

Omega-3 polyunsaturated acids, especially EPA and/or DHA, in free acid form or as pharmaceutically acceptable salts are presented in enteric dosage forms to overcome the problems of belching and the risk of oxidation in the stomach associated with the oral administration of said acids. The acids can be used alone or with other active principles, especially linolenic acid, gamma-linolenic acid, and/or dihomo-gamma-linolenic acid. Preferably, the enteric dosage form is an enterically coated capsule such as a soft or, especially, hard gelatine capsule.

Description

CRAWL DOSAGE FORMS ()E OME(sA-3 POLYUNSATURATED A(:ILS The present invention relates to the oral aaministration of omega-3 polyunsaturateo acias especially, but not exclusively, all-cis-5,8,11,14,17-eicosapentaenoic acid (i.e. all-cis-fatty acia 20:5 omega-3; EPA) and/or 22:6 omega-3-docosahexaenioc acia (LHA). In particular, it provides enteric dosage forms of omeya-3 polyunsaturatea acids.

It has been known for many years that the low occurrence of aetherosclerotic cardiovascular diseases amonyst Greenland Eskimos ana the low mortality rate of cardiovascular patients in Scandinavia is attributable to the consumption of relatively high amounts of fish oil. The relevant active inyredients in fish oil have been identified as the omega-3 polyunsaturated aciasEPA and DHA, which are present in their triglyceride and/or other esteritied forms. The use of EPA in free acid form or as a pharmaceutically acceptable salt, ester or amide is disclosed in GB-A-1604554 and GB-A-2033745.Further, US-A-4097602 disclosed the inhibition of blooa platelet aggregation by administration of EPA in its free acid form or as a salt or lower alkyl ester. kore recently, US-A-4526902 disclosed the prophlyaxis of thrombo-embolic conditions by simultaneous aoministration of EPA ana/or DhA with one or more of linoleic, yamma-linolenic or dihomo-gamma-linolenic acid. The said acids can be present as the free acid or as pharmaceutically acceptable salts, or esters or amides thereof.

Formulations usea or proposea for the administration of EPA and/or l)hA include oral, rectal, topical, vaginal, intrapulmonary and parenteral formulations. Usually, oral formulations have been employea, especially soft gelatine capsules. However, a problem associated with such oral administration is belching resulting in an unpleasant fishy smell ana taste following disintegration or dissolution of the oral formulation in the stomach. Such a problem previously was well established in the administration of cod liver oil capsules which, because of the vitaminA and D content of the oil, have been used for many decades as a dietary' supplement.

When EPA and/or DHA are administered in the form of a derivative thereof, usually an alkyl ester or triglyceride, it must be converted into the free fatty acid before beiny absorbea by the boat. The conversion of ester is carried out in the stomach by the pancreatic enzyme Lipase. However, not all patients produce sufficient Lipase to properly convert the derivative into free tatty acid form. For example, the production of Lipase may be reduced, or even eliminated, as a result of disease or due to alcohol, smoking, stress etc. Accordingly, there is good reason to prefer to use EPA and/or LHA in the free acid form.

however, because of their polyunsaturation the free fatty acids are prone to rapid oxidation, which problem is not encountered with the esters. Although antioxidants, e.g. gamma-tocopherol, are used to prevent or at least reduce oxidation, the presentInventor suspects that significant oxidation of the acid takes place in the stomach thereby reducing the availability of the fatty acids.

The teaching and practice in the art to aate has been that the free acid is administered orally in the same manner as the esters.

The present Inventor has appreciatec that the long standing problem of belching with the accompanying fishy smell and taste associated with the oral administration of EPA and/or DHA and the risk of oxidation in the stomach can simply and readily be overcome by use of an enteric dosage form (i.e. a dosage form which, when taken orally, will pass through the stomach substantially without release of the active principle but which will release the active principle in the intestine). Although enteric dosage forms are widely used, there was, to the best of our knowledge, no previous proposal that omega-3 polyunsaturated free acias should be presented in enteric dosage form ana it had not been appreciated that there was any reason or advantage arising from the use of that form.Thus, the present invention resiaes in the enteric presentation of omega-3 polyunsaturatea free acias as aistinct front enteric dosage forms in general.

The present invention provides an enteric dosage form containing as an active principle an omega-3 polyunsaturated acid in free acid form or as a pharmaceutically acceptable salt thereof. Further, the invention provides the use of said enteric dosage forms in the treatment or prophylaxis of thrombo-embolic conditions. It also provides said enteric dosage forms for the treatment of other conditions for which omega-3 polyunsaturatea acias in their free or precursor form, such as their glyceride or alkyl esters, are indicatea. Such conditions incluae rheumatoid arthritis, diabetes mellitus, migraine, psoriasis, cancer, ana hypercholesterolaemia ana as a dietetic.

As indicated previously, it is preferred that the omega-3 polyunsaturated acid is EPA, DHA or a mixture thereof. It is present in free acid form or as a pharmaceutically acceptable salt thereof and can be present as the sole active principle or with other active principles, especially linoleic acid, gamma-linolenic acid and/or dihomo-gamma-linolenic acid in free acid or salt form.

c)rnega-3 pc,lyunsaturatea acias are reaaily oxioised and hence an antioxidant usually will be present. The presently preferred antioxidant is gamma-tocopherol but other pharmacoloyically acceptable antioxidants can be used, tor example butylated hydroxy anisole, butylatea hydroxy toluene, propyl gallate or a quinone.

lhe enteric aosage form may also contain one or more pharmaceutically acceptable excipients depending upon the precise nature of the dosage form.

Suitably, the enteric dosage form can be an enterically coated tablets containing the omega-3 polyunsaturated acid in a microencapsulated form or loaded on a suitable absorbent. However, it is preferred that the enteric dosage form is an enterically coated capsule, especially a soft or, more especially, hard gelatine capsule.

Enteric coatings are widely used in the pharmaceutical industry and are formed of substances which are relatively insoluble in the acid medium of the stomach but disintegrate in the medium of the small intestine. Suitable enteric coatings incluae cellulose acetate phthalate and polymethacrylate.

Usually, the omega-3 polyunsaturated acid will be administered in a daily dosage of 20 to 50 ing/kg, especially 30-40 mg/kg. The actual dose will vary depending inter alia on the identity of the omega-3 polyunsaturated acid and the nature and degree of the disorder being treatea. Usually, each unit dose will contain 250 to 1000 mg, especially 400 to 800 mg.

Ihe following is a description, by way of example only, of a presently preferred embodiment of the invention.

ExampleTransparent hard gelatine capsules (size 0), consisting of 14% water and 86% gelatine were each filled with 500 mg of a fish oil concentrate (EPACHOL 60U) supplied by Messes. E;PA Limitea (Winosor, Ontario,Canada). The concentrate contains about 32% by weight free EPA, about 28% by weight free DhA and 0.02% by weight gamma-tocopherol. It does not contain any cholesterol, cetoleic acid or saturatea fatty acias and is an oily liquid of brown colour having a characteristic odour.It has the following physico-chemical properties:acid value 160iodine value 340peroxide value 3saponification value 190saponifiable matter 1.25relative density 0.935refractive index 1.49 The filled gelatine capsules were placed in a coating tower where they were carriea in a heatea (55"C) air stream whilst being sprayed with an enteric coating solution. lhe coating solution had the following composition by weight:cellulose acetate phthalate BPC 40 mgethyl phthalate BPC 12 mgmethylene chloride 616 mgi ethyl alcohol 95% I.E. 128 mg.

Sufficient coating solution was applied to proviae a theoretical coating of 6 mg/2, which is an excess of that theoretically required in order to allow for losses auring the coating process.

Claims (3)

1. An enteric dosage form containing as an active principle an omega-3 polyunsaturated acid in free acid form or as a pharmaceutically acceptable salt thereof.

2. An enteric dosage form as claimed in Claim 1, wherein said acid is EPA, DHA or a mixture thereof.

3. An enteric dosage form as claimed in Claim 1 orClaim 2, wherein said acid is present in free acid form 4 An enteric dosage form as claimed in any one of the preceding claims, wherein said acid or salt is present as the sole active principle.

5 An enteric dosage form as claimed in any one ofClaims 1 to 4, wherein said acid or salt is present with another active principle selected from linoleic acid, gamma-linolenic acid, and/or dihomo-gamma-linolenic acid in free acid form or as a pharmaceutically acceptable salt thereof.

6 An enteric dosage form as claimed in any one of the preceding claims containing an antioxidant amount of gamma-tocopherol.

7 An enteric aosage torm as claimed in any one of the preceding claims which is an enterically coated tablet containing the said acid or salt in a microencapsulated form or loaaed on an absorbent.

8 An enteric dosage form as claimea in any one ofClaims 1 to 6 which is an enterically coated capsule.

9 An enteric dosage form as claimed in Claim 8, wherein the capsule is a soft gelatine capsule.

10 An enteric aosage form as claimed in Claim 8, wherein the capsule is a hard gelatine capsule.

11 An enteric dosage form as claimed in any one of the preceding claims, wherein each unit dose contains 250 to 1000 mg of said omega-3 acid or salt.

12 An enteric dosage form as claimed in Claim 11, wherein each unit dose contains 400 to 800 mg of said omega-3 acid or salt.

13 An enteric dosage form substantially as hereinbefore described in the Example.

14 Ihe use of an enteric dosage form as claimed in any one of the preceding claims in the treatment or prophylaxis of thrombo-embolic conditions.

15 The use of an enteric dosage form as claimed in any one of Claims 1 to 13 for the treatment of rheumatoid arthritis.

16 The use of an enteric dosage form as claimed in any one of Claims 1 to 13 for the treatment of diabetes mellitus.

17 The use of an enteric dosage form as claimed in any one of Claims 1 to 13 for the treatment of migraine.

18 The use of an enteric dosage form as claimed in any one of Claims 1 to 13 for the treatment of psoriasis.

19 The use of an enteric dosage form as claimed in any one of Claims 1 to 13 for the treatment of cancer.

20 The use of an enteric dosage form as claimed in any one of Claims 1 to 13 for the treatment of hypercholesterolaemia.

21 The use of an enteric dosage form as claimed in any one of Claims 1 to 13 as a dietetic.