Crystal Engineering in the Pharmaceutical Sciences

A special issue of Pharmaceuticals (ISSN 1424-8247). This special issue belongs to the section "Medicinal Chemistry".

Deadline for manuscript submissions: 25 August 2026 | Viewed by 901

Special Issue Editor


E-Mail Website
Guest Editor
Department of Industrial and Physical Pharmacy, School of Pharmacy and Pharmaceutical Sciences, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47906, USA
Interests: solid state chemistry; pair distribution function; synchrotron x-ray diffraction; solid nanoparticles; drug quality; polymorphs; salts; cocrystals; amorphous forms
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

As Desiraju noted, “crystal engineering”—a term coined more than sixty years ago—remains central to solid-state chemistry and the development, manufacturing, and control of pharmaceuticals. It focuses on understanding intermolecular interactions and crystal packing, and using this knowledge to design solids with desirable physical and chemical properties; in this way, it is closely linked to pharmaceutical development and formulation design. Crystal engineering is especially important for salts and cocrystals. For salts, a key concern is the risk of disproportionation; for cocrystals, questions include whether they can be prepared reproducibly, whether they are stable, and whether they deliver advantageous properties. In parallel, liposomal products and lipid-based nanocarriers provide complementary strategies for engineering drug microenvironments and performance. Avoiding late-appearing or hidden polymorphs—and using crystal-structure prediction to aid the discovery of all relevant polymorphs—remains a major area of focus. Finally, applications of crystal engineering to manufacturing pharmaceutical solids in space are of particular interest.

Prof. Dr. Stephen Robert Byrn
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Pharmaceuticals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • intermolecular interactions
  • cocrystals
  • salts
  • disproportionation
  • crystal structure prediction
  • space manufacturing

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (1 paper)

Order results
Result details
Select all
Export citation of selected articles as:

Research

18 pages, 2343 KB  
Article
The Molecular Structures of Liquid and Glassy Nifedipine and Felodipine and Their Incorporation into PVP
by Chris J. Benmore, Stephen K. Wilke, Samrat Amin, Richard Weber, Pamela A. Smith, Stephen R. Byrn, Olivia Gibbons, Ethan Earl, Stephen Davidowski and Jeffery L. Yarger
Pharmaceuticals 2026, 19(4), 638; https://doi.org/10.3390/ph19040638 - 18 Apr 2026
Viewed by 478
Abstract
Background: Amorphous drug formulations are commonly used to improve the solubility and bioavailability of poorly soluble molecular pharmaceuticals, yet less is known about their molecular conformations and local bonding interactions than their crystalline phases. Methods: High-energy X-ray diffraction structure factor measurements [...] Read more.
Background: Amorphous drug formulations are commonly used to improve the solubility and bioavailability of poorly soluble molecular pharmaceuticals, yet less is known about their molecular conformations and local bonding interactions than their crystalline phases. Methods: High-energy X-ray diffraction structure factor measurements have been made on liquid and glassy nifedipine (NIF), felodipine (FEL), NIF 1:3 polyvinylpyrrolidone (PVP), and FEL 1:3 PVP wt.% mixtures. The corresponding X-ray pair distribution functions have been interpreted using empirical potential structure refinement using different models and density functional theory conformer calculations. Results: In both NIF and FEL, the NH···O inter-molecular hydrogen bonds between the pyridyl nitrogen and ester carbonyls are found to be considerably weaker than those observed in the crystalline polymorphs. For nifedipine, it is proposed that either inter-molecular NH…ON nitro bonds are present and/or a fraction (<20%) of conformational changes, with the aryl ring flipped, occur in the liquid state. For felodipine, the models indicate significant disorder associated with the methyl and ethyl side chains in the liquid state, with the main peak intensity at 3.0 Å arising from intra-molecular Cl-Cl atom pairs. When nifedipine molecules are incorporated into PVP, our models show they possess stronger NH···O bonds to the PVP polymer than felodipine molecules, which have stronger affinity for bonding to the polymer than to other felodipine molecules. Conclusions: The amorphous forms of both NIF and FEL show much weaker hydrogen bonding than found in their crystalline phases. Liquid NIF also exhibits configurations which are not observed in the crystal phases. Full article
(This article belongs to the Special Issue Crystal Engineering in the Pharmaceutical Sciences)
Show Figures

Graphical abstract

Back to TopTop