Chemometric Determination of the Acidity Constant of Etodolac Using PARAFAC and MCR-ALS Modeling of UV-pH Spectral Dataset

Asiye Ü., Kanakaraj L., Erdal D.

ChemistrySelect, vol.10, no.43, 2025 (SCI-Expanded, Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 10 Issue: 43
  • Publication Date: 2025
  • Doi Number: 10.1002/slct.202503407
  • Journal Name: ChemistrySelect
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core
  • Keywords: Chemometric pKa determination, Etodolac, MCR-ALS model, PARAFAC model, Spectrophotometry, UV-pH absorbance dataset
  • Ankara Yıldırım Beyazıt University Affiliated: Yes

Abstract

The acidity constant (pKa) is a fundamental physicochemical parameter that affects a drug's solubility, permeability, and bioavailability. In this study, chemometric modeling strategies, parallel factor analysis (PARAFAC), and multivariate curve resolution–alternating least squares (MCR-ALS), were applied to UV-pH absorbance data of the nonsteroidal anti-inflammatory drug etodolac. Spectral measurements across varying concentrations and buffer media were modeled to resolve acidic and basic species profiles. The calculated pKa values, 4.64 (PARAFAC) and 4.55 (MCR-ALS), showed strong agreement and confirmed the reliability of these approaches. The results highlight the potential of multiway and bilinear modeling as rapid, titration-free alternatives for precise pKa determination in pharmaceutical analysis.