{
  "abstract": "The relationship between the nanoscale free volume of pharmaceutical polymer films and their hydration behavior remains poorly understood. Eight pharmaceutical polymers were screened at three concentration levels within a quality-by-design framework; only two poly(vinyl alcohol) grades (PVA EG-30P and EG-40P), hydroxypropyl cellulose (HPC), and sodium alginate (Na-alginate) formed continuous films. These were characterized by positron annihilation lifetime spectroscopy (PALS), loss on drying (LOD), and swelling analysis. PALS clearly differentiated HPC, Na-alginate, and PVA, whereas the two PVA grades were similar and the concentration had only a minor effect. HPC showed the largest free volume holes (86.7–89.5 Å3), and Na-alginate the smallest holes (36.9–39.6 Å3) together with the highest LOD (20.2–21.6%). Across the 12 polymer–concentration combinations, the free volume hole volume correlated inversely with LOD (Spearman ρ = −0.85) but not with the equilibrium swelling index, as both HPC and Na-alginate swelled considerably more than PVA. Thus, PALS discriminates film-forming pharmaceutical polymers and reflects their residual water content, but the free volume of the air-dried films does not predict their swelling capacity.",
  "abstract_shown": true,
  "affiliations": [
    "University Pharmacy Department of Pharmacy Administration, Semmelweis University, 7-9 Hőgyes Street, 1092 Budapest, Hungary",
    "Center for Pharmacology and Drug Research & Development, Semmelweis University, 1085 Budapest, Hungary",
    "Department of Nuclear Chemistry, Institute of Chemistry, Faculty of Science, Eötvös Loránd University, 1518 Budapest, Hungary",
    "Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Semmelweis University, 7-9 Hőgyes Street, 1092 Budapest, Hungary"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Mariam Majida Shokoya"
    },
    {
      "affs": [
        2
      ],
      "name": "Károly Süvegh",
      "orcid": "0000-0001-8147-0546"
    },
    {
      "affs": [
        1,
        3
      ],
      "name": "Zsófia Vilimi"
    },
    {
      "affs": [
        1,
        3
      ],
      "name": "Nikolett Kállai-Szabó",
      "orcid": "0000-0002-8164-3993"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Romána Zelkó",
      "orcid": "0000-0002-5419-9137"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "István Sebe"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1scbjtgmydm8k.bib",
  "cited_by": 0,
  "doi": "10.3390/ijms27219518",
  "fulltext_url": null,
  "id": "1scbjtgmydm8k",
  "issns": [
    "1422-0067"
  ],
  "landing_url": "https://www.mdpi.com/1422-0067/27/21/9518",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2211|Muon and positron interactions and applications"
    ]
  ],
  "openalex": "W7223919466",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-24",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/1scbjtgmydm8k.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:57Z",
      "native_id": "10.3390/ijms27219518",
      "source": "crossref",
      "url": "https://www.mdpi.com/1422-0067/27/21/9518"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "issn:1422-0067",
      "subfield": "general"
    }
  ],
  "title": "Analysis of Local Free Volume and Hydration in Pharmaceutical Polymer Films Using Positron Annihilation Lifetime Spectroscopy",
  "title_text": "Analysis of Local Free Volume and Hydration in Pharmaceutical Polymer Films Using Positron Annihilation Lifetime Spectroscopy",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:57Z",
  "url": "https://research.draconitic.com/paper/1scbjtgmydm8k",
  "venue": "International Journal of Molecular Sciences",
  "versions": []
}