A Base-Triggerable Catanionic Mixed Lipid System: Isothermal Titration Calorimetric and Single-Crystal X-ray Diffraction Studies

Abstract

Lipid-based, base-triggerable systems will be useful for colon specific targeted delivery of drugs and pharmaceuticals. In light of this, a catanionic surfactant system, composed of O-lauroylethanolamine hydrochloride (OLEA·HCl) and sodium dodecyl sulfate (SDS), has been designed. The aggregates formed by near equimolar mixtures of OLEA·HCl-SDS have shown lability at basic pH, indicating that the system may be useful for developing colon specific drug delivery system(s). Turbidimetric and isothermal titration calorimetric studies revealed that OLEA·HCl forms a 1:1 (mol/mol) complex with SDS. The three-dimensional structure of the equimolar OLEA-SDS complex has been solved by single-crystal X-ray diffraction. Analysis of the molecular packing and intermolecular interactions in the crystal lattice revealed a hydrogen bonding belt in the headgroup region of the complex and dispersion interactions among the acyl chains as the main factors stabilizing the complex. These observations will be useful in understanding specific interactions between lipids in more complex systems, e.g., biomembranes.

Self-Assembly, Supramolecular Organization, and Phase Behavior of l-Alanine Alkyl Esters (n = 9–18) and Characterization of Equimolar l-Alanine Lauryl Ester/Lauryl Sulfate Catanionic Complex

“…Throughout the experiment, the solution in the reaction cell was stirred at a speed of 300 rpm. Generally, the first injection was found to be imprecise; therefore, a 5 μL injection was added, and the resultant point was deleted before the analysis of the rest of the data to a “one set of sites” model using the MicroCal Origin software provided by the ITC manufacturer as described earlier . The analysis yields values of stoichiometry of binding ( n ), binding constant ( K b ), and enthalpy of binding (Δ H b ).…”

“…Electrostatics plays a key role in their interaction with biomacromolecules. − Catanionic mixtures have been also used as stationary phases for electrokinetic separations . A number of catanionic systems have been demonstrated to form vesicles, and new systems are being discovered. − …”

Mechanism for the Reduced Dissolution of Ritonavir Tablets by Sodium Lauryl Sulfate

“…Similar interaction was observed in 9-aminoacridinium dodecyl sulfate, 2-(dodecanoyloxy) ethanaminium dodecyl sulfate, and 1-octylquinolinium dodecyl sulfate. [31][32][33] Corresponding to the 2 thiazole groups to RTV, 2 types of ionic species of RTV may exist in the solution, RTV þ and RTV 2þ . Based on Henderson-Hasselbalch equation, 3…”

Crystallographic and Energetic Insights into Reduced Dissolution and Physical Stability of a Drug–Surfactant Salt: The Case of Norfloxacin Lauryl Sulfate

“…In this study, we provide more direct evidence of proton transfer between the drug cation and LS – anion through an analysis of crystal structure, from which molecular insights into the changes in pharmaceutical properties, such as solubility and dissolution rate, could be gained. Crystal structures of a handful of complexes between LS – and organic molecules have been reported, including berberine, 9-aminoacridine (a cationic dye), O- lauroylethanolamine, and quinolinium and isoquinolinium (ionic liquid crystals) . However, most reported drug–lauryl sulfate complexes are amorphous, except for trimethoprim and metformin, which precipitated out as crystalline solids. , Single-crystal structures of trimethoprim and metformin complexes with LS – have not been reported.…”