The present invention provides a microsphere with a slow-release period from about two weeks to about four weeks following administration, to enable a higher content of a drug to be included, to suppress an initial burst of the drug, and to maintain an optimal, effective blood concentration during the slow-release period. In a microsphere containing a drug and polylactic acid/glycolic acid (PLGA) copolymer, the amount of PLGA copolymer per part by weight of the drug is from about 3 to about 10 parts by weight； the average particle size of the microsphere is from about 20 to about 50 μm； and (3) the PLGA copolymer has a weight-average molecular weight from about 10,000 to about 50,000 and a PLGA compositional ratio from about 75/25 to about 50/50. The microsphere promotes the production of various endogenous repair factors useful against various tissue disorders.
