Investigation of the Compressibility and Compactibility of Titanate Nanotube-API Composites.

The present work aims to reveal the pharma-industrial benefits of the use of hydrothermally synthesised titanate nanotube (TNT) carriers in the manufacturing of nano-sized active pharmaceutical ingredients (APIs). Based on this purpose, the compressibility and compactibility of various APIs (diltiazem hydrochloride, diclofenac sodium, atenolol and hydrochlorothiazide) and their 1:1 composites formed with TNTs were investigated in a comparative study, using a Lloyd 6000R uniaxial press instrumented with a force gauge and a linear variable differential transformer extensometer. The tablet compression was performed without the use of any excipients, thus providing the precise energetic characterisation of the materials' behaviour under pressure. In addition to the powder functionality test, the post-compressional properties of the tablets were also determined and evaluated. The results of the energetic analysis demonstrated that the use of TNTs as drug carriers is beneficial in every step of the tabletting process: besides providing better flowability and more favourable particle rearrangement, it highly decreases the elastic recovery of the APIs and results in ideal plastic deformation. Moreover, the post-compressional properties of the TNT⁻API composites were found to be exceptional (e.g., great tablet hardness and tensile strength), affirming the above results and proving the potential in the use of TNT carriers for drug manufacturing.