Compound for treating cartilage diseases

The present invention aims to improve cartilage obstacles without side effects, and a compound of formula (A) having such activity is thus provided. The compound can be injected into the intra-articular parts of the disease affected area, and additionally, the compound remains in, and sustained release of the compound occurs in the intra-articular parts of the disease affected area. The compond as shown in formula (I) satisfies the aforesaid conditions above. (The codes of the above formula (I) are shown in the specification). Even at the dosage required for exerting cartilage regeneration, the compound of the present invention does not show repeating side effects. Therefore, the compound of the present invention is very useful for safe and effective prevention and/ or treatment of cartilage obstacles. Further, the suspension prepared from the compound of the present invention can be injected into the patient without the need for surgery thus reducing the burden of the patients. As such, the compound of the p