The Study On Metformin Hydrochloride Microspheres And Rosiglitazone Maleate Floating Microspheres

In this paper,metformin hydrochloride and rosiglitazone maleate were selected as model drugs. The sustained-release microspheres and floating microspheres were respectively prepared with EC as the carrier material by the emulsion-solvent diffusion method, which to aim at sloving sudden release of hydrophilicity drugs (MH) and prolonging residence time in the stomach helps in absorption of the drugs (RM).Ultraviolet spetrophotometry method was developed for determination of the content from the MH microspheres and selected to examine the drug release in vitro in distilled water; High performance liquid chrmatograhy method was developed for assaying the content from the RM floating microspheres and in vitro release which selected to examine the drug release in pH1.0 hydrochloric acid as the medium. Analytical methods above were proved to be stable, reliable and sensitive.Before formulation design, the solubility in different media and the partition coefficient of MH and RM were investigated, respectively. MH and RM microspheres were prepared by double emulsion (W/O/W) method with Ethyl cellulose (EC) as the carrier material. To evaluate the in vitro release behavior and the stability during encapsulation process and in vitro release, the optimal formulation was verified by orthogonal design based on the results of single factor experiment. The results showed that the prepared microspheres had a complete spherical shape and dispersive quality. Compared with the reference formulations, the self-made microspheres may sustained release of drugs better. The mean diameter, drug loaded percent (DL) and encapsulation efficiency (EE) of MH microspheres and RM floating microspheres rewere (122.1±1.5)μm and (410.1±3.7)μm; (8.43±0.22) % and (9.31±0.31) %; (86.08±1.97) % and (89.55±1.65) %. The floating percentage of RM microspheres was (91.43±1.51) %.Stability studies of MH and RM on light, temperature and moisture were determined, and accelerated test was taken on estimating the stability of the microspheres. The results showed that appearance, DL, release rate and floating percentage of the microspheres were stable under 75%±5% RH, 40℃±2℃.