Case Study 608 DVS and iGC Pharmaceutical Disorder Overview
This review paper from Surface Measurement Systems explains how vapor sorption techniques—Dynamic Vapor Sorption (DVS) and Inverse Gas Chromatography Surface Energy Analysis (IGC SEA)—can be applied to assess the thermodynamic stability and disorder of pharmaceutical solids. It outlines the spectrum of solid forms (stable crystals, metastable polymorphs, hydrates/solvates, defect‑rich crystals, partially or fully amorphous materials) and demonstrates how DVS and IGC SEA provide complementary information on surface energy, solubility parameters, glass transition, and moisture‑induced phase changes. The document presents experimental principles, illustrative data (surface energy vs particle size, polymorph surface energies, hydrate/solvate isotherms, amorphous content calibration curves, glass transition temperature versus relative humidity, and surface energy distribution profiles), and discusses the practical implications for formulation, processing, and storage. It also highlights recent methodological advances such as finite‑concentration IGC SEA for energetic heterogeneity and the ability to quantify amorphous fractions below 0.5 % using gravimetric sorption.
Topics
Thermodynamic Stability Landscape of Pharmaceutical Solids
Defines the hierarchy of solid forms—from the lowest‑energy crystal to metastable polymorphs, hydrates/solvates, defect‑laden crystals, and amorphous phases—and explains why disorder matters for drug performance.