Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Patent
1998-01-09
2000-11-21
Page, Thurman K.
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
497499, 497497, A61K 958, A61K 962
Patent
active
061499420
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a novel stable pharmaceutical pellet formulation containing omeprazole and to a process for the preparation of this formulation.
The pharmaceutical effects of omeprazole on the organism has been extensively researched and are widely known. On the other hand, the longer-term stability of pharmaceutical formulations containing omeprazole has so far proved troublesome. Because the stability of omeprazole is influenced by organic solvents and moisture and its conversion is promoted by reagents giving an acid reaction or hindered by reagents giving an alkaline reaction, an oral omeprazole formulation must be protected with an enteric coating against the action of stomach acid so that it can develop its effect in the small intestine.
Conventionally, however, enteric coatings contain components giving a acid reaction, so, in contact therewith, omeprazole would be continuously decomposed and hence, over time, would change its appearance as well as lose its effect.
To reduce these disadvantages, attempts have been made e.g. to provide pharmaceutical omeprazole formulations with two coatings, the inner coating being intended to form a barrier against the outer, enteric coating which decomposes the omeprazole, and against penetrating moisture.
It has been found, however, that the stability of such pharmaceutical formulations still does not satisfy the desired criteria and that coating the formulation twice greatly increases the cost of the manufacturing process.
The object of the present invention is therefore to provide a stable pharmaceutical formulation with a core containing omeprazole as the active ingredient, and a single coating, which formulation avoids the above-mentioned disadvantages.
Surprisingly, it has now been found that the addition of TiO.sub.2 to the core and optionally to the enteric coating greatly improves the storage stability of the omeprazole formulation according to the invention compared with formulations of the state of the art, and that the use of a separate intermediate layer acting as a barrier can thereby be avoided.
The above object is therefore achieved by the provision of a pharmaceutical pellet formulation with a core containing omeprazole in the form of its free base as the active ingredient, and with an enteric coating, in which formulation the core and optionally the coating contain TiO.sub.2 and other adjuncts.
Examples of suitable adjuncts for the pellet formulation according to the invention are binders, sedimentation retarders and pH correctors.
The active ingredient omeprazole is used in the form of its free base. Either the omeprazole is used as starter cores in the form of coarse crystals, preferably in the particle size range 0.2-0.5 mm or 0.4-1 mm, or the omeprazole in the form of fine crystals (e.g. <50 micrometers or <10 micrometers) or coarse crystals (e.g. <250 micrometers), in a suspension with adjuncts, is applied to starter cores, e.g. consisting of sugar (sucrose), which optionally contain additives such as sodium a carboxymethyl starch, polyvinylpyrrolidone, gelatine or other compounds known to those skilled in the art.
The suspension or solution applied to the starter cores contains omeprazole and adjuncts, especially at least one binder, at least one sedimentation retarder, pH correctors and optionally at least one dyestuff and/or pigment and/or lake, lubricants/antiadhesive agents and suspension stabilizers/thickeners, and TiO.sub.2 as a stabilizer for improving the storage stability, in water or a mixture of water and one or more conventional organic solvents, or in an organic solvent.
Examples of suitable binders are sodium carboxymethyl starch, polyvinylpyrrolidone, gelatine, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, xanthan, carrageenan products, polyvinyl acetate, sodium carboxymethyl cellulose, ethyl cellulose, starch mucilage or liquefied waxes, either individually or in combination with one another.
Examples of suitable sedimentation retarders are highly disperse silicon dioxide, starch mucilage, mucilag
REFERENCES:
patent: 5045321 (1991-09-01), Makino et al.
patent: 5538954 (1996-07-01), Koch et al.
patent: 5869097 (1999-02-01), Wong et al.
Scheiwe Max Werner
Villiger Thomas
Fubara Blessing
Melpha AG
Page Thurman K.
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