Understanding excipient functionality in a formulation

Pharmaceutical Excipient Characterization

Abstract

The aim of formulation development is to design a product and its manufacturing process to consistently deliver the intended Quality Target Product Profile (QTPP). This involves determining the Critical Quality Attributes (CQAs) for the Active Pharmaceutical Ingredient (API) and excipients that define the performance of the product.

Introduction

The aim of formulation development is to design a product and its manufacturing process to consistently deliver the intended Quality Target Product Profile (QTPP). This involves determining the Critical Quality Attributes (CQAs) for the Active Pharmaceutical Ingredient (API) and excipients that define the performance of the product. These are generally identified through an assessment of the extent to which the variation in a specific attribute, for example particle size, can impact the drug product’s quality and performance.

With reference to the excipient, guidance from the FDA and USP encourages identification of the CQAs for excipients and the setting of associated quality controls [1]. Changes in the physical characteristics of an excipient may impact its interaction with other formulation components and thereby have a major impact on the QTPP.

Analytical strategies

The analysis of formulation blends using microscope images is widely employed during the initial stages of product development in order to understand how the physical properties of the excipient correlate with product performance.

Once the CQAs associated with the excipient have been identified, a routine quality control strategy is developed and validated using techniques such as laser diffraction for particle size analysis.