Dynamic Perfusion Computed Tomography for the Assessment of Concomitant Coronary Artery Disease in Patients with a History of Percutaneous Transluminal Angioplasty for Chronic Limb-Threatening Ischemia-A Pilot Study.

BACKGROUND: Chronic limb-threatening ischemia (CLTI) is associated with high rates of long-term cardiovascular mortality. Exercise stress testing to detect obstructive coronary artery disease (CAD) can be difficult in this subset of patients due to inability to undergo exercise testing, presence of balanced ischemia and severe coronary artery calcification (CAC). AIM: To test the feasibility of regadenoson stress dynamic perfusion computed tomography (DPCT) in CLTI patients. METHODS: Between 2018 and 2023, coronary computed tomography angiography (CTA) and, in the case of a calcium score higher than 400, DPCT, were performed in 25 CLTI patients with a history of endovascular revascularization. RESULTS: Of the 25 patients, 19 had a calcium score higher than 400, requiring DPCT image acquisition. Obstructive CAD could be ruled out in 10 of the 25 patients. Of the 15 CTA/DPCT+ patients, 13 proceeded to coronary angiography (CAG). Revascularization was necessary in all 13 patients. In these 13 patients, vessel-based sensitivity and specificity of coronary CTA/DPCT as compared to invasive evaluation was 75%, respectively. At follow-up (27 ± 21 months) there was no statistically significant difference in all-cause mortality between CTA/DPCT- positive and -negative patients (p = 0.065). CONCLUSIONS: Despite a high prevalence of severe CAC, coronary CTA complemented by DPCT may be a feasible method to detect obstructive and functionally significant CAD in CLTI patients.

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.

Physicochemical characterisation and investigation of the bonding mechanisms of API-titanate nanotube composites as new drug carrier systems.

Titanate nanotube (TNT) has recently been explored as a new carrier material for active pharmaceutical ingredients (API). The aim of the present work was to reveal the physicochemical properties of API-TNT composites, focusing on the interactions between the TNTs and the incorporated APIs. Drugs belonging to different Biopharmaceutical Classification System (BCS) classes were loaded into TNTs: diltiazem hydrochloride (BCS I.), diclofenac sodium (BCS II.), atenolol (BCS III.) and hydrochlorothiazide (BCS IV.). Experimental results demonstrated that it is feasible for spiral cross-sectioned titanate nanotubes to carry drugs and maintain their bioactivity. The structural properties of the composites were characterized by a range of analytical techniques, including FT-IR, DSC, TG-MS, etc. The interactions between APIs and TNTs were identified as electrostatic attractions, mainly dominated by hydrogen bonds. Based on the results, it can be stated that the strength of the association depends on the hydrogen donor strength of the API. The drug release of incorporated APIs was evaluated from compressed tablets and compared to that of pure APIs. Differences noticed in the dissolution profiles due to incorporation showed a correlation with the strength of interactions between the APIs and the TNTs observed in the above analytical studies.

[Titanate nanotubes in the therapy]. / Titanát nanocsövek a gyógyászatban.

The demand for revealing the medical advantages offered by nanotechnology is increasing more and more. Titanate nanotubes deserve consideration in many aspects. Their production is easy, cost-effective and environmentally friendly. Due to their special physico-chemical properties, titanate nanotubes can play an important role in different fields of therapy, such as medical diagnostics, implantology, or even as cancer treatment. The aim of our work is to present the titanate nanotubes and give an overview on their medical applicability through the results of previous researches.