RESUMEN
OBJECTIVE:To prepare nifedipine (NF) hollow controlled-release microspheres and evaluate the quality. METH-ODS:Solvent diffusion volatilization method was used to prepare microspheres,using comprehensive scores of cumulative release in 2,12,24 h(Q2 h,Q12 h,Q24 h)as indexes,orthogonal test was designed to screen the carrier material ethyl cellulose(EC),poly-vinyl pyrrolidone(PVP)and main drug NF amounts;appearance,particle size distribution,drug loading,floating and cumulative release of the microspheres prepared by optimal formulation were evaluated and compared of in vitro release behavior with imported preparation of Nifedipine controlled-release tablets (Adalat?). RESULTS:The optimal formulation was as follow as NF 3.00 g, PVP 1.60 g,EC 15.65 g. Prepared NF hollow controlled-release microspheres were spherical in shape with particle size distribution of 24-40 mesh and drug loading of 8.66%;24 h floating rate in release medium was 97.93%,Q2 h,Q12 h,Q24 h were 20.49%, 52.90%,91.00%(RSD<10%,n=3). Compared with the imported preparation,similarity factor f2 values of cumulative release were higher than 50,showing in vitro drug-release was consistent with the zero-order kinetic equation (r=0.9993);n of Rit-ger-Peppas equation (r=0.9807) was 0.478. CONCLUSIONS:Prepare NF hollow controlled-release microspheres show similar drug-release behavior with the imported preparation,the drug is released by the combination of diffusion and erosion.