In the present investigation, the dissolution rate improvement of glimepiride was carried out by preparing solid dispersions (SDs) using melting technique with poloxamer 188, a copolymer nonionic surfactant. Prepared SDs were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and evaluated for solubility, in vitro drug release, dissolution efficiency and in vivo drug absorption by intraperitoneal glucose tolerance test (IPGTT). All the SDs had shown good flow properties. Loss of their individual surface properties during melting and solidification as reveled by SEM studies indicated the formation of effective SDs. X-ray diffraction studies showed decrease in crystallinity of glimepiride in SDs as compared to the pure glimepiride. All the formulations prepared by melting technique have shown significant enhancement of dissolution rate when compared to pure glimepiride. The dissolution rate of glimepiride increases as the amount of polymer (poloxamer 188) increases in SDs. Moreover, IPGTT indicated that the SDs of glimepiride-poloxamer 188 markedly reduces the blood glucose concentration in Swiss Albino mice. Thus, the present study demonstrated that a copolymer nonionic surfactant, poloxamer 188 provides a promising way to prepare solid dispersion with glimepiride which increases the solubility, dissolution rate and oral bioavailabilty of glimepiride.
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