EMA's March 2026 Q&A on 3D-printed solid oral doses accepts inline NIR and Raman spectroscopy for unit-level rejection, anchoring personalised micro-batches in the QbD and RTRT framework.
QbD is the broader regulatory philosophy that PAT serves. A primer on the ICH and FDA documents that built it, the vocabulary it introduced, and how process analytics fits inside it.
March-May 2026 in ACS Analytical Chemistry: three threads for process analytics - close-focus Raman probes for turbid streams, deep-learning chemometrics, and open-source spectroscopy tooling.
Twenty years of guidance documents - 2004 FDA PAT guidance, ICH Q8 through Q14, ASTM E2363 - turned a fragmented vocabulary into a working framework. A reading guide.
USP chapters 858 (Raman Spectroscopy) and informational 1858 replaced chapter 1120 on 1 August 2020. Almost six years on, handheld identity testing is the workhorse application; compendial method adoption is uneven.
ICH Q14 reached Step 4 in November 2023. Thirty months on, the EU, FDA, Swissmedic and China NMPA have it on the books, but the ISPE readiness survey shows enhanced-approach adoption sitting at 19%.
Spectra are not answers. The bridge between a 1,000-channel spectrum and a number you can act on is chemometrics - a small toolbox of multivariate methods, used the same way for forty years.
Both methods take a 1,000-channel spectrum and compress it into a handful of latent variables. They are not interchangeable. PCA describes; PLS predicts. The decision is older than most of the software.
ICH Q14 sets the framework. ASTM E1655 sets the practice. The intersection - what an inspector actually wants to see in a chemometric validation file - is a short, specific list.