Solubility of digitoxin in supercritical CO2: Experimental study and modeling.

In this communication, the solubility of digitoxin drug in supercritical CO2 was studied at different operating conditions (311 < T (K) < 343, 120 < P (bar) < 300). The results revealed digitoxin drug solubility (in mole fraction) was between 0.095 × 10-5 to 1.12 × 10-5. In the case of thermodynamic solubility modeling, cubic and non-cubic equation of states i.e. SAFT (statistical associating fluid theory), SRK (Soave-Redlich-Kwong) and sPC-SAFT (simplified perturbed chain SAFT) EoSs and six density-based correlations (Chrastil, Kumar-Johnston (KJ), Mendez-Santiago-Teja (MST), Garlapati and Madras (GM), Bartle et al. and Sung-Shim models) were considered. All used equations indicated reasonable behavior with appropriate accuracy for the solubility of the digitoxin drug. Meanwhile, sPC-SAFT EoS and Kumar-Johnston correlation with AARD% set to 8.96 % and 6.25 %, respectively exhibited greater accuracy in fitting the solubility data. Moreover, total, solvation and vaporization enthalpies of the digitoxin/supercritical carbon dioxide binary mixture were calculated based on KJ, Chrastil and Bartle et al. models.

Association of Tumor Necrosis Factor-α and Myeloperoxidase enzyme with Severe Asthma: A comparative study.

Background: Tumor necrosis factor-alpha (TNF-α) may stimulate airway hyperresponsiveness in asthma, which is also affected by neutrophils activity. The latter can be determined indirectly by evaluating myeloperoxidase (MPO) activity. The insufficient studies that investigated the combined association of serum TNF-α and MPO with asthma was objective of this study. Methods: A case-control study included 110-asthmatics besides 92-controls. All participants underwent venous sampling for TNF-α and MPO immunoassays. A percentage of predicted "forced expiratory volume in one second (FEV1%)", and the "peak expiratory flow rate (PEF/L)" of all participants were verified. The statistical analyses had done using SPSS V-25. The accuracy, specificity, sensitivity, and significance of both biomarkers to distinguish asthma examined "under the ROC-curves". Results: High TNF-α levels observed among the controls(p-0.006), opposing the higher MPO levels among the patients(p-0.00). There were nonsignificant variations of two biomarkers between the treatment groups and nonsignificant correlations of MPO with FEV1 and PEF. There was a significant correlation of MPO with the TNF-α levels of all participants. The TNF-α showed lower sensitivity, specificity, and accuracy to diagnose asthma. There were no MPO differences according to asthma levels. The TNF-α was higher among the severe asthmatics significantly. Discussion: TNF-α may be a contributory particle for neutrophilic inflammation of severe asthma. MPO levels were significantly higher among asthmatics, whereas TNF-α levels were lower. TNF-α levels were higher among those with severe compared to mild/moderate asthma. The MPO level has a significant predictive capacity compared to TNF-α for distinguishing asthma from healthy subjects.