Exploring the Value of GPC/SEC in Polysaccharide Characterization

Using GPC/SEC for Excipient Characterization

The properties of polymeric excipients can directly affect the clinical efficacy, safety, and quality of a finished pharmaceutical product and are routinely identified as critical quality attributes (CQAs). This article looks at how gel permeation/size‑exclusion chromatography (GPC/SEC) can be applied to measure characteristics such as molecular weight (MW), MW distribution and structure, and degree of branching. Case study data for the measurement of poly-lactic acid (PLA) and poly‑lactic glycolic acid (PLGA) highlights the detailed information that can be accessed.

Abstract

The properties of polymeric excipients can directly affect the clinical efficacy, safety, and quality of a finished pharmaceutical product and are routinely identified as critical quality attributes (CQAs). This article looks at how gel permeation/size exclusion chromatography (GPC/SEC) can be applied to measure characteristics such as molecular weight, distribution, structure, and degree of branching.

Introduction

Polymeric excipients are an important addition to the sophisticated tableting blends of today. Ingredients such as poly‑lactic acid (PLA), poly-lactic glycolic acid (PLGA), and hydroxyl methyl cellulose and its derivatives enable formulators to achieve closely controlled drug release profiles using a growing range of manufacturing techniques that includes spray drying, hot‑melt extrusion, and lipid‑based drug delivery. The properties of these polymers can directly affect the clinical efficacy, safety, and quality of the finished pharmaceutical product and are therefore often identified as critical quality attributes (CQAs). CQAs for polymer excipients typically include molecular weight (MW), MW distribution, and structural characteristics such as degree of branching.

Gel permeation/size-exclusion chromatography (GPC/SEC) is a powerful technique for the characterization of polymers and other macromolecules. In this article we examine its application in the analysis of polymeric excipients. Case study data for the measurement of PLA/PLGA highlights the detailed information that can be accessed.

The Vital Role of Excipients

The workflows associated with the development of oral solid dosage forms, whether innovator or generic, are increasingly well established and are rooted in a Quality by Design (QbD) approach.¹ These workflows emphasize the need for detailed characterization of the excipient, as well as the active ingredient, both alone and within the blend. The resulting information supports the development of a detailed understanding of how the drug product will behave and of a specification for each component that will ensure successful drug delivery and the necessary quality control.