Skewness and kurtosis values of force-time profiles obtained from compression of lactose, glucose and mannitol granules

Two parameters, skewness and kurtosis, normally used to describe a distribution were utilized in characterizing the force-time profiles of the upper punch of a rotary press, obtained in the main compression of lactose, glucose or mannitol granules prepared with different amounts of binder solution. Calculation of these parameters includes all measured data points of the main compression and therefore they describe the shape of the whole curve in figures. Skewness measures the magnitude of sidedness of the curve and kurtosis describes the heaviness of the tails of the curve. The skewness and kurtosis values of three diluents differed from each other. The force-time curves of mannitol tablets were skewest to the left and those of lactose tablets less skew, when the amount of granulation liquid was 90 ml kg(-1). With 120 ml kg(-1), the profiles obtained from glucose tablets were skewer than those from mannitol tablets. The skewer the profile, the more deformation of granules occured during consolidation. The differences in the kurtosis values were due to changes in the magnitude of tailing. With increasing skewness to the left, kurtosis increased. The amount of granulation liquid was also found to affect the skewness and kurtosis values of profiles obtained from glucose tablets.