Determination of the optimal blend time for lumartem tablets using the double cone blender
Abstract
Mixing is probably the most widely performed unit operation in pharmaceutical manufacturing, in fact, it is difficult to find a product where mixing is not involved in some stages of the process, It is difficult to determine what degree of mixing is required in particular circumstances and ways to assess the same blending operation could be affected by the physical properties of the materials to be mixed, blending time, rotation speed and percentage of blender capacity. Poor uniformity of the blend is obtained especially during the mixing of low dose drug with large amount of excipient. During the manufacture of Lumartem, which is a low dose drug i.e. the ratios of the active pharmaceutical ingredients are small, at Kampala pharmaceutical industries, a number of batches failed due to poor blend uniformity resulting from insufficient blending time i.e. less blend time and or over blending time. The company suffered financial losses due to rework of poor-quality product. Therefore, a study was performed to determine the optimal blending time for Lumartem. A rotating double cone blender fixed around a fixed axis at rotating speed of 40rpm was used for the blending process. Samples were withdrawn from three locations that is; top, middle and bottom of the blender at different time points of 20, 25,30, 35 and 45 minutes for three batches using a side sampling thief probe. Assay of the active pharmaceutical ingredients was determined using High Performance Liquid Chromatography (HPLC). The results obtained indicated that blend content uniformity is significantly affected by time as the relative standard deviation of both Artemether and Lumefantrine decreased as the blending process approached the optimal blending time and increased as the blending process was reproaching the optimal blending time. For this study the optimal blending time for Artemether was 35 minutes whereas for Lumefantrine was 45 minutes therefore the optimal blending time for Lumartem was found to be 40minutes. The optimal blend time for Lumartem was found to be 40mins basing on the blend time of the actives present in the drug