Related Experiment Video
Updated: Dec 7, 2025

Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study
Published on: August 15, 2016
Molecular recognizable ion-paired complex formation between diclofenac/indomethacin and famotidine/cimetidine
Takahiro Kasai1, Kanako Shiono1, Yuta Otsuka1
1Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
Abstract:
This study focused on the physicochemical interactions between acidic and basic drugs in aqueous solutions. Their ion pair interactions were evaluated in an in vitro study. The model non-steroid anti-inflammatory drugs (NSAIDs), indomethacin (INM) and diclofenac (DIC), were used as acidic and hydrophobic drugs, whereas cimetidine (CIM), famotidine (FAM), and imidazole (IMD) were used as basic additives with heterocyclic moieties. The drug mixtures were evaluated by thermal analysis, dissolution test, nuclear magnetic resonance (NMR) spectroscopy, and mass spectroscopy. The fusion enthalpy of DIC-CIM, INM-CIM, and INM-arginine (ARG) sample was calculated based on melting temperature transformation. The DIC mixture with CIM, IMD, antipyrine (ANT), and ARG showed enhanced solubility, whereas the DIC-FAM mixture sample showed a decreased solubility. Electrospray ionization mass spectroscopy was carried out to detect binary mixtures. The interactions in DIC-FAM mixture sample were found between the carboxyl group of DIC and the amine groups of FAM by NMR. These findings were suggested that DIC-FAM mixture samples construct ion pair complexes based on the theory of Bjerrum. Moreover, the acid model drug and basic model drug also can be constructed 1:1 complexes that affects their solubility in the solvent of water type.
More Related Videos
10:20Method for Identifying Small Molecule Inhibitors of the Protein-protein Interaction Between HCN1 and TRIP8b
Published on: November 11, 2016
05:08Solubility of Hydrophobic Compounds in Aqueous Solution Using Combinations of Self-assembling Peptide and Amino Acid
Published on: September 20, 2017
Related Concept Videos
Acid Suppressive Drugs for Peptic Ulcer Disease: Histamine H2-Receptor Antagonists
Drug-Receptor Bonds
In...
Factors Influencing Drug Absorption: Drug Dissolution
Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct...
Factors Affecting Dissolution: Drug pKa, Lipophilicity and GI pH
A drug's pKa and the pH of the gastrointestinal (GI) tract play crucial roles...
Factors Influencing Drug Absorption: Physicochemical Parameters
Enhanced drug absorption can be achieved by reducing particle sizes and increasing surface areas, thereby facilitating...