An inert atmosphere was maintained by purging nitrogen gas at a flow rate of 50 ml/min. The prepared microparticles of all batches were accurately Roxadustat cost weighed. The measured weight of prepared microspheres was divided by total amount of all the excipients and drug used in preparation of the microspheres, which give the total percentage yield of microspheres. The percentage yield was then calculated by using the formula: Percentyield=(Amountofmicrospheresobtained/Theoreticalamount)×100 The theoretical amount is the sum of weight of all the non-volatile solid ingredients used in the process. The flow characteristics of different

microparticles were studied by measuring the angle of repose employing fixed funnel

method. The angle of repose was calculated by using the following formula. Tanθ=h/rwhereθ=tan−1(h/r)Where, h = height of pile, r = radius of the base of the pile, θ = angle of repose. Bulk density and tapped density were measured by using 10 ml of graduated cylinder. The pre weighed sample was placed in a cylinder; its initial volume was recorded (bulk volume) and subjected to tapings for 100 times. Then the final volume (tapped volume) was noted down. Bulk density and tapped density were calculated from the following formula. Bulkdensity=massofmicroparticles/bulkvolume Tappeddensity=massofmicroparticles/tappedvolume www.selleckchem.com/products/abt-199.html Compressibility index (CI) or Carr’s index value of microparticles was computed according to the following equation: Carr’sindex(%)=[(tappeddensity−bulkdensity)/tappeddensity]×100

Hausner ratio of microparticles was determined by comparing the tapped density to the bulk density using the equation: Hausner’s ratio = tapped density/bulk density. For size distribution analysis, 250 mg of the microparticles of different sizes in a batch were separated by sieving, using a range of standard sieves. The amounts retained on different sieves were weighed. The mean particle size of the microparticles was calculated by the formula.10 Meanparticlesize=∑(Meanparticlesizeofthefraction×Weightfraction)∑(Weightfraction) An accurately weighed portion of microparticles equivalent to 5 mg of Glibenclamide were Resminostat weighed and transferred in to a mortar. Powdered and dissolved in 100 ml of pH 7.4 phosphate buffer, suitably diluted and the absorbance of the resulting solution was measured at 228 nm.11 Entrapment efficiency was calculated using the formula.12 Entrapmentefficiency=EstimatedpercentdrugcontentTheoreticalpercentdrugcontent×100 Estimated percent drug content was determined from the analysis of microparticles and the theoretical percent drug content was calculated from the employed core: coat ratio in the formulation of microparticles. Morphology and surface characteristics were studied by Scanning Electron Microscopy. The samples for the SEM analysis were prepared by sprinkling the microparticles on one side of the double adhesive stub.