This guidance provides recommendations to applicants to aid the development, validation, and use of near infrared (NIR)-based analytical procedures in evaluating the identity, strength, quality, purity, and potency of drug substances and drug products. The recommendations apply to new drug applications (NDAs), abbreviated new drug applications (ANDAs), and supplemental NDAs and ANDAs for small molecule drugs. The principles in this guidance also apply to drug substances and drug products covered in Type II drug master files. FDA intends to issue recommendations specific to NIR methods used for biological products under biologics license applications in a future revision to this guidance. This guidance provides recommendations to applicants for applying the concepts described in the guidance for industry PAT — A Framework for Innovative Pharmaceutical Development, Manufacturing, and Quality Assurance (September 2004) (PAT guidance) and the International Council for Harmonisation (ICH) guidance for industry Q2(R1) Validation of Analytical Procedures: Text and Methodology (November 2005) to NIR analytical procedures that use chemometric models. This guidance also provides recommendations for submitting NIR documentation in applications.