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US 5,271,945 AGranted
Sustained release microcapsule for water soluble drug
AssigneeTakeda Chemical Industries, Ltd.
InventorsToshio Yoshioka, Hiroaki Okada, Yasuaki Ogawa
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Abstract
Sustained release microcapsules including a water soluble drug and an organic basic substance as a drug retaining substance of this invention not only have a high rate of incorporation (trapping rate), but also show little initial release so that they can be administered safely and bring about persistent, stable sustained release.
Claims5
A sustained release microcapsule, comprising:
- a) a wall made of a biocompatible polymer having acidic residues, selected from the group consisting of a homopolymer of lactic acid and a copolymer of lactic acid and glycolic acid;
- b) a water-soluble neutral or basic polypeptide within the microcapsule, the concentration of the water-soluble neutral or basic polypeptide in the internal water phase being from 0.1% to 80% (W/W);
- and
- c) an organic basic substance for regulating the release of the polypeptide which:
- 1) has a pKa at least 8.0;
- 2) is selected from the group consisting of N-methylglucamine, diethanolamine, arginine, lysine and histidine;
- 3) interacts with the acidic residues of the wall of the biocompatible polymer;
- 4) does not interact with the water-soluble neutral or basic polypeptide;
- 5) is added to the internal water phase at a concentration from 0.5% to 75% (W/W).
6 more elements
Dependencies are inferred from the claim text.