However, limitations of multiple dosing and risk of triggering gastrointestinal symptoms make its dose optimization difficult. The present study was designed to develop the oral sustained release metformin hydrochloride tablet formulation using lipophilic waxes viz. hydrogenated castor oil, stearic acid and glyceryl monostearate

either alone or their combinations. The in vitro dissolution study was carried out using USP 22 apparatus I, basket method. The drug release kinetics demonstrated that hydrogenated castor oil sustained the release of metformin greater MK5108 concentration than stearic acid and glyceryl monostearate when used alone. Combination of hydrogenated castor oil with stearic acid (1:1) sustained the drug release (75.69 +/- 0.76%) greater than hydrogenated castor oil with glyceryl monostearate (86.45 +/- 0.96%) and stearic acid with glyceryl monostearate (92.29 +/- 0.76%) combinations. Kinetic modeling of in-vitro dissolution profiles revealed that metformin release ranges from AZD8055 PI3K/Akt/mTOR inhibitor diffusion controlled or Fickian transport to anomalous type or non-Fickian transport mechanisms. Applying Korsmeyer equation to in-vitro drug release data indicated that diffusion along with erosion could be the

mechanism of drug release.”
“The aim of this study was to improve mechanical properties of polypropylene/cycloolefin copolymer (PP/COC) blends by processing-induced formation of long COC fibers. According to the available literature, the fibrous morphology in PP/COC blends was observed just once by coincidence. For this reason, we focused our attention on finding processing conditions yielding PP/COC fibrous morphology in a well-defined, reproducible

way. A number of PP/COC blends were prepared by both compression molding and injection molding (IM). Neat polymers were characterized by rheological measurements, whereas phase morphology of the resulting 3-Methyladenine PI3K/Akt/mTOR inhibitor PP/COC blends was characterized by means of scanning electron microscopy (SEM). The longest COC fibers were achieved in the injection molded PP/COC blends with compositions 75/25 and 70/30 wt %. Elastic modulus and yield strength of all blends were measured as functions of the blend composition using an Instron tensile tester; statistically significant improvement of the yield strength due to fibrous morphology was proved. Moreover, two different models were applied in the analysis of mechanical properties: (i) the equivalent box model for isotropic blends and (ii) the Halpin-Tsai model for long fiber composites. In all PP/COC blends prepared by IM, the COC fibers were oriented in the processing direction, as documented by SEM micrographs, and acted as a reinforcing component, as evidenced by stress-strain measurements. (C) 2011 Wiley Periodicals, Inc.