Preparation of injectable auto-forming alginate gel containing simvastatin with amorphous calcium phosphate as a controlled release medium and their therapeutic effect in osteoporosis model rat
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Highly soluble amorphous calcium phosphate powder (ACP) was added to the alginate gel as a buffering agent, in an attempt to enable widely controlled release while avoiding an acidification of the gel-environment. Therapeutic effects of the ACP-containing alginate gel which slowly releases a drug, simvastatin, on osteoporosis model rats were examined. A model drug, simvastatin, incorporated in the alginate gel with ACP up to 0.5%, was continuously released for a long time under the acidic condition. The release rate was controlled by the amount of ACP, serving as a buffer to suppress acidity. When the alginate solution intramuscularly injected in the rat, a soft gel was formed in the injected site. Simvastatin released from the gel containing 0.5% of ACP showed high therapeutic effect on osteoporosis rat. Thus, the present injectable long-sustained release system is expected to be a novel drug delivery controlling device.
KeywordsAlginate Simvastatin Bone Mineral Content Simulated Body Fluid Sodium Alginate
This work was partly supported by the Japan Society for the Promotion of Science (nos. 21700494).
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