Resection to Exploration Ratios and Associated Outcomes in Patients with Pancreatic Ductal Adenocarcinoma.

OBJECTIVE: To investigate resection/exploration ratios (RER), reasons for omission of pancreatectomy, and survival outcomes in patients undergoing surgical exploration with resection intent for pancreatic ductal adenocarcinoma (PDAC). SUMMARY BACKGROUND DATA: While surgical indications for PDAC are expanding, information about intraoperative attrition is lacking. METHODS: The RER was calculated in PDAC patients undergoing exploration from 2018 through 2020. Factors associated with uncompleted resection and survival were identified using multivariable models. RESULTS: In total, 681 patients were included. Upfront explorations were 296 (43.7%), and post-neoadjuvant explorations were 385 (56.3%). The overall RER was 89.7% (90.5% in the upfront setting and 89.1% post-neoadjuvant treatment). In this latter subgroup, the RER decreased from 96.1% in resectable disease to 86.6% in borderline resectable disease and 61.9% in locally advanced disease. The primary reasons for uncompleted resection were occult metastases in presumed resectable/borderline resectable disease (without difference between upfront and post-neoadjuvant operations) and local unresectability in locally advanced disease. No preoperative variable was associated with uncompleted resection in upfront explorations, while anatomical staging informed the likelihood of surgical attrition following neoadjuvant treatment. Uncompleted resection was invariably associated with a median survival of around one year. The median post-pancreatectomy survival was 36.9 months in the upfront setting and 29.5 months following neoadjuvant treatment. The median survival from diagnosis in patients receiving post-neoadjuvant resection was 34.5 months. CONCLUSIONS: This analysis provided contemporary information about resection rates, reasons for intraoperative attrition, and survival outcomes in the entire spectrum of PDAC patients selected for surgical exploration at an experienced institution.

Terminal sterilization of BisGMA-TEGDMA thermoset materials and their bioactive surfaces by supercritical CO2.

The development of biomaterials endowed with bioactive features relies on a simultaneous insight into a proper terminal sterilization process. FDA recommendations on sterility of biomaterials are very strict: a sterility assurance level (SAL) of 10(-6) must be guaranteed for biomaterials to be used in human implants. In the present work, we have explored the potential of supercritical CO(2) (scCO(2)) in the presence of H(2)O(2) as a low-temperature sterilization process for thermoset materials and their bioactive surfaces. Different conditions allowing for terminal sterilization have been screened and a treatment time-amount of H(2)O(2) relationship proposed. The selected terminal sterilization conditions did not notably modify the mechanical properties of the thermoset nor of their fiber-reinforced composites. This was confirmed by µCT analyses performed prior to and after the treatment. On the contrary, terminal sterilization in the presence of H(2)O(2) induced a slight decrease in the surface hardness. The treatment of the thermoset material with scCO(2) led to a reduction in the residual unreacted monomers content, as determined by means of high performance liquid chromatography (HPLC) analyses. Finally, it was found that a thermoset coated with a polysaccharide layer containing silver nanoparticles maintained a very high antimicrobial efficacy even after the scCO(2)-based terminal sterilization.

Applications of supercritical fluids to enhance the dissolution behaviors of Furosemide by generation of microparticles and solid dispersions.

The 'classical' loop diuretic drug Furosemide has been used as a model compound to investigate the possibility of enhancing the dissolution rate of poorly water-soluble drugs using supercritical anti-solvent techniques (SASs). In the present study we report upon the in vitro bioavailability improvement of Furosemide through particle size reduction as well as formation of solid dispersions (SDs) using the hydrophilic polymer Crospovidone. Supercritical carbon dioxide was used as the processing medium for these experiments. In order to successfully design a CO(2) antisolvent process, preliminary studies of Furosemide microparticles generation were conducted using Peng Robinson's Equation of State. These preliminary studies indicated using acetone as a solvent with pressures of 100 and 200bar and a temperature of 313K would yield optimum results. These operative conditions were then adopted for the SDs. Micronization by means of SAS at 200bar resulted in a significant reduction of crystallites, particle size, as well as improved dissolution rate in comparison with untreated drug. Furosemide recrystallized by SAS at 100bar and using traditional solvent evaporation. Moreover, changes in polymorphic form were observed in the 200bar samples. The physicochemical characterization of Furosemide:crospovidone SDs (1:1 and 1:2 w/w, respectively) generated by SAS revealed the presence of the drug amorphously dispersed in the 1:2 w/w sample at 100bar still remaining stable after 6months. This sample exhibits the best in vitro dissolution performance in the simulated gastric fluid (pH 1.2), in comparison with the same SD obtained by traditional method. No interactions between drug and polymer were observed. These results, together with the presence of the selected carrier, confirm that the use of Supercritical fluids antisolvent technology is a valid mean to increase the dissolution rate of poorly soluble drugs. Theoretical in vivo-in vitro relation was predicted by means of a pharmacokinetics mathematical model.

Characterization of solid dispersions of itraconazole and vitamin E TPGS prepared by microwave technology.

BACKGROUND: This study describes the influence of microwave irradiation (MW) on the preparation and properties of solvent-free solid dispersions (SDs) employing vitamin E D-α-tocopheryl polyethylene glycol (TPGS) 1000 succinate, with itraconazole as a model drug. MATERIALS AND METHODS: Itraconazole is characterized by low aqueous solubility and vitamin E TPGS was chosen as the surfactant carrier for the formulation of MW solid dispersions in different ratios. Their physicochemical characteristics were investigated by means of powder x-ray diffraction (PXRD), differential scanning calorimetry (DSC), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and hot-stage microscopy. Comparison with the corresponding physical mixtures and the drug alone allowed the relationship between influence of the technological process on physicochemical and morphological properties of the systems to be examined. RESULTS: PXRD data confirmed the absence of phase transitions in the solid state of the drug subjected to MW alone. On the other hand, an amorphous form of the drug was obtained in the solid dispersion with the highest content of carrier investigated (1:3 w/w). All the SDs showed an improvement in the solubility and dissolution profile of the drug, with the best results obtained in the case of the 1:3 w/w SD. This was related to an interaction between the drug and the carrier with a complex that formed due to favorable H bonds, as demonstrated by DRIFT analysis. CONCLUSION: It was demonstrated that the amorphization of the drug led to an increase in wettability and a significant improvement in bioavailability. Therefore, SDs obtained by MW technique using vitamin E TPGS as carrier provide a promising way to increase the dissolution rate and solubility of poorly bioavailable drugs.