OBJECTIVE:To optimize the formulation of Mirabegron sustained-release tablets. METHODS:Using polyethylene oxide(PEO)and hydroxypropylmethyl cellulose(HPMC K4M)as the sustained release matrix,Mirabegron sustained-release tab-lets were prepared by powder direct compression technology. Using 1,3,5,7 h accumulative release rate as indexes,the amounts of PEO,HPMC K4M and OPADRY? were optimized by composite design-response surface method,and then validated. Accumula-tive release rates of sustained-release tablet and original tablet (MyrbetriqTM) were compared in different pH mediums (water,pH 1.0 simulated gastric fluid,pH 4.5 acetate buffer solution,pH 6.8 phosphate buffer solution) at different rotation rates (100,50 r/min),and similiar factor f2 was calculated to fit drug release model of sustained-release tablet. RESULTS:In the optimized firmu-lation each Mirabegron sustained-release tablet contained mirabegron 25 mg,PEO 108.02 mg,HPMC K4M 21.69 mg,OPADRY? 2.27%. Relative error of accumulative release rates at 1,3,5,7 h to predicted value were 4.78%,3.48%,0.69% and -1.41%, respectively. f2 of release curves of sustained-release tablet and original tablet were higher than 65 in different pH medium at differ-ent rotation rates. The drug release of sustained-release tablet was fitted to zero-order release equation. CONCLUSIONS:Mirabe-gron sustained-release tablet by optimized technology is similar to original tablet in drug release behavior.

Rabbit bone marrow-derived mesenchymal stem cells(MSCs) are multipotent. We studied the adipogenic and osteogenic differentiation potent using adipogenic supplement (AS) or osteogenic supplement (OS) in vitro. Specific markers of this induced adipogenic and osteogenic lineage were identified. The findings showed that the rabbit MSCs are capable of differentiating into adipogenic and osteogenic lineages spontaneously. On the 21st day, approximately 75% rabbit MSCs were induced to adipogenic or osteogenic cells in medium containing AS or OS, respectively. These results demonstrated that the differentiation of MSCs could be regulated in vitro. The underlying molecular mechanisms of adipogenic or osteogenic differentiation await elucidation.
Adipose Tissue ; cytology ; Animals ; Bone and Bones ; cytology ; Cell Differentiation ; Cell Lineage ; In Vitro Techniques ; Mesoderm ; cytology ; Rabbits ; Stem Cells ; cytology