POWDER FLOWABILITY AS A FUNCTIONALITY PARAMETER OF THE EXCIPIENT GALENIQ 720 Original Article KARINA IVONNE FUENTES-GONZÁLEZ, LEOPOLDO VILLAFUERTE-ROBLES 1 Received: 27 Feb 2014 Revised and Accepted: 01 May 2014 Department of Pharmacy, National School of Biological Sciences, National Polytechnic Institute of Mexico, D. F. Mexico, Unidad Profesional Adolfo López Mateos. Col. Industrial Vallejo, C. P. 07738, D. F. México. Email: lvillaro@encb.ipn.mx ABSTRACT Objective: The purpose of the work was the assessment of the GalenIQ 720 flowability as a functionality parameter of the excipient, comparing two different methods. Methods: The evaluated parameters were the powder flow through different size orifices and the compressibility index, as absolute values and as values relative to Helmcel 200. The parameters determined with pure excipients and in mixtures with a model drug, metronidazole. Results: The compressibility index is a specific measurement for each powders blend that allows the assessment of its overall flow properties. Flowability, expressed as the flow rate, shows so many different results as orifices are being tested. Both methods exhibit comparable results only by wide orifice sizes where the interaction with de orifice walls is minimized. The flow rate increases progressively, mostly in a potential relationship, with an increasing orifice diameter. The flow rate of GalenIQ 720 attains a maximum with 0.4-0.8% magnesium stearate. Formulations containing GalenIQ 720 show about 2.8 times greater flowability than those containing Helmcel 200 while the flowability of GalenIQ 720 is about 8.7 times greater than that of Helmcel. The presence of metronidazole attenuates the differences observed by the flowability of pure excipients and its spread. Conclusion: Both methods consistently show a comparable improvement of metronidazole flowability with GalenIQ 720 and a deterioration of the same with Helmcel 200. The knowledge of the individual materials flowability allows the inference of their effect on the flowability of their mixtures but not the magnitude of this effect. Keywords: Powder flow, Compressibility index, Surrogate functionality, Explicit functionality, Relative functionality, Metronidazole, Lubricants. INTRODUCTION Solid dosage forms are heterogeneous systems composed of particles with different physical and chemical properties. The performance of such systems by blending, powder flow and compaction is critical for manufacturing, transport and scaling-up of the products. Powders are the most used materials in the pharmaceutical industry and are difficult to be characterized. This is attributed to their own heterogeneity and tendency to segregate in the course of their processing and transport. This makes difficult the prediction of their functionality [1]. Pharmaceutical products have very strict requirements in terms of content uniformity, consistency, stability during storage, transport and shelf life, which requires an exceptional degree of control in the manufacturing process [2]. During manufacture active ingredients and excipients are subjected to mechanical tensions, for example during charging and discharging, grinding, mixing, extrusion, fluidizing, dispensing, compression and coating. Therefore, a concern during the formulation is the understanding of the potential response of the solids to mechanical stresses throughout the development of a product and in the production line. Understanding, characterizing and predicting the properties of the powders are important aspects in the pharmaceutical industry in the development and manufacture [3]. The manufacture of pharmaceutical solid dosage forms involves several processes. These processes are very sensitive to powder characteristics such as flowability and apparent density, parameters being to a certain extent interrelated and which affect the quality of the final product [4]. The powder flow is a key factor in the series of processes involved in the manufacture of pharmaceuticals such as direct compression tablets and hard gelatin capsules. These products must achieve an optimal powder flow in order to obtain end products with an acceptable content uniformity, weight variation and physical consistency. Knowledge and subsequent control of the characteristics of the powders is very important in the development and processing of solid dosage forms [5]. The active ingredients are a major constraint in the formulation. Excipients and the manufacturing process are selected to address the deficiencies that may present the drug. This emphasizes the functionality of each excipient and the benefits obtained from each unit operation during manufacture [6]. Excipients are a very diverse group of materials with a wide range in their properties. They are used in many different products to provide different functionalities, depending on particular applications. The functionality has been defined as a desirable property of a material that helps in manufacturing, facilitating it and improving the quality or performance of pharmaceutical products. In the context of the formulations and pharmaceutical products, each formulation has its particular functionality requirements. One way to verify the functionality of an excipient is the identification of surrogate tests that have some relation to the required functionality. Such tests have been defined as characteristics related to functionality or performance tests [7]. In general, the utility of testing functionality includes: a) determining the properties of materials, for purposes of quality control, b) predicting the performance of materials in a formulation using surrogate functionality and c) comparing the functionality of excipients of different origin and different physical or chemical characteristics [8]. The selection of properties that define the functionality of the excipients is considered a critical activity. In the development of a International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 6, Issue 9, 2014 Innovare Academic Sciences