2.4. Preparation of Powder for Liquisolid and Conventional Tablets Several olmesartan liquisolid formulations were prepared at two different drug concentrations of 20 and 40% (w/w) in liquid vehicles. Each formulation contains three different carriers, Avicel PH 102, Fujicalin and Neusilin and Aerosil as coating material at carrier/coat ratio of 5, 10, and
15. The appropriate amounts of carrier and coating materials used for each formulation depend upon Lfof that formulation. The drug-vehicle liquid system was Inhibitors,research,lifescience,medical produced by mixing olmesartan (20mg/tablet) in nonvolatile liquid vehicle using mortar and pestle. To this liquid medication, the calculated amount of the carrier was added by continuous mixing in the mortar. Then, Inhibitors,research,lifescience,medical coating material was carefully
added and mixed until mortar contents start to look dry. In the last stage of the preparation, a 6% (w/w) croscarmellose as a disintegrant was added and mixed. All liquisolid preparations were compacted into tablets using a ten-station rotary compression machine (Rimek, Karnavati Engineering, India) using flat-faced punch with a compression force that FG-4592 datasheet provide acceptable tablet hardness. Composition of liquids solid compacts batches is shown in Table 1. Table 1 Formulations of olmesartan liquisolid compacts. 2.5. PrecompressionStudies Flowabilityofliquisolid Inhibitors,research,lifescience,medical admixture is important in formulation of tablet dosage form on industrial scale. Therefore, it was essential to study the flowability of these liquisolid powder admixtures prior to compression. Flowability can Inhibitors,research,lifescience,medical be evaluated using parameters such as Carr’s index, angle of repose, and Hausner’s ratio. 2.6. Angle of Repose The angle of repose of powder blend Inhibitors,research,lifescience,medical was determined by fixed height funnel method. Angle of repose
(θ) was calculated using the following equation: θ=tan−1 hr, (2) where h and r are the height and radius of powder cone. 2.7. Compressibility Index The compressibility index of the powder blend was determined by Carr’s compressibility index [10]. The formula for Carr’s index is as below: Carr’s index (%) =[(Tapped density−Bulk density)×100]Tapped density. (3) 2.8. Thymidine kinase Hausner’s Ratio Hausner’s ratio was calculated from the equation: Hausner’s ratio=Tapped densityBulk density. (4) 2.9. Differential Scanning Calorimetry Differential Scanning Calorimetry study was carried out using calibrated Shimadzu DSC-60 (Shimadzu, Kyoto, Japan) instrument. DSC thermograms of pure drug olmesartan, and powder mixture for optimized liquisolid preparations were obtained. DSC aluminium cells were used as sample holder, and blank DSC aluminium cell was used as reference. 2-3mg sample was used for analysis. Thermograms were recorded over the range of 20°C–300°C at a constant rate of 20°C per minute under nitrogen purge at 20mL/min. 2.10.