The concepts of Pharmaceutical Powder Mixing: the View point of Theory and Practice

Majority of the active ingredients and adjuvants used for the manufacture of pharmaceutical dosage forms constitutes in the powder form. The market for solid dosage forms involving powder processing is large and is growing day by day. Handling and processing of powders is central to pharmaceutical operations. But it poses numerous problems due to their unpredictable and irregular behavior. Main purpose of solids mixing is to obtain a product with acceptable homogeneity. In this study mechanisms of powders mixing and role of segregation is studied briefly. Homogeneity is a key factor to accept quality of tablets in pharmaceutical companies, so amlodipine tablet is considered as a case studywhich is mixture of seven different components in powder form. In this work effect of wet mixing with different quantities of solvent is compared with dry mixing. All samples were evaluated by scanning electron microscope to study the exterior shape and the physical aspects of samples. It was found that wet mixing will granulate the ingredients and results show that it causes a reduction in segregation. Also quality of mixing methods were compare by measuring concentration of amlodipine besylate using spectrophotometry technique at 237 nm. For each method, eight random samples were evaluated and homogeneity is reported as RSD (Relative Standard Deviation) parameter. Results indicate that dry mixing has not acceptable homogeneity while by addition of solvent, proper RSD was observed.

Keywords:

Powder mixing , Amlodipine tablet , Segregation , Quality of mixing , Wet mixing