Blending and characterization of pharmaceutical powders

Abstract

Blending is a critical part of pharmaceutical manufacturing. It consists of two parts, the actual mixing of powdered ingredients to a desired degree of homogeneity and the analytical testing to confirm the same. Blending equipment and formulation considerations are discussed, along with potential mechanisms for a loss of quality of blends. A general description of the role of blending and its impact on the quality of finished dosage forms is presented. Traditional and on-line methods for assessing the quality of blends are described. Though widely accepted, traditional blend uniformity testing (thief sampling) has a number of potential weaknesses. On-line techniques such as near-infrared spectroscopy, Raman spectroscopy and light-induced fluorescence are considered as alternatives to traditional testing. The characteristics of the technology and potential challenges of analysis and implementation are discussed for these on-line methods.