Abstract

Background: Cystic fibrosis (CF) and CF-related liver disease can lead to disturbances in bile acid metabolism.
Aim: This study determined serum bile acid concentrations in CF to define their usefulness in liver disease assessment.
Methods: Primary, secondary and conjugated bile acid levels were measured in three CF groups (25 patients each) exhibiting: liver cirrhosis, other liver disease, no liver disease, and in 25 healthy subjects (HS).
Results: Bile acid levels were higher in CF patients than in HS, except for glycodeoxycholic acid (GDCA). However, bile acid concentrations did not differ between patients with cirrhosis and other liver involvement. GDCA and deoxycholic acid (DCA) differentiated CF patients with non-cirrhotic liver disease from those without liver disease (GDCA-AUC: 0.924, 95%CI 0.822–1.000, p<0.001; DCA-AUC: 0.867, 95%CI: 0.731–1.000, p<0.001). Principal component analysis revealed that in CF liver disease was related to GDCA, GGTP activity, severe genotype and pancreatic insufficiency.
Conclusions: A CF-specific bile acid profile was defined and shown to relate to liver disease. GDCA differentiates patients with non-cirrhotic liver involvement from those with no detectable liver disease. Hence, GDCA is a candidate for validation as a biomarker of non-cirrhotic progression of liver disease in CF.

Highlights

• Kinetic performance comparison of protein reversed-phase columns.
• Model proteins of various size, NISTmAb and NISTmAb fragments as test analytes.
• Core-shell, fully porous & monolithic columns compared using gradient kinetic plots.
• Kinetic plots allow convenient comparison in terms of speed or max. plate numbers.
• 400/450 Å core-shell columns showed the best performance due to a thin shell.

Highlights

• Therapeutic protein complexes separated at superheated conditions.
• Complex dissociation is complete at superheated conditions.
• On-column degradation can be limited by fast gradients and ultrashort columns.

Highlights

• New stationary phases with low hydrophobicity were tested for protein separations
• The new ES-LH stationary phase showed excellent protein recovery
• The ES-LH and C1 materials were found to be less retentive than commercial phases
• The ES-LH phase showed novel selectivity due to its unique surface chemistry

In-process control (IPC) is an important task during chemical syntheses in pharmaceutical industry. Despite the fact that each chemical reaction is unique, the most common analytical technique used for IPC analysis is high performance liquid chromatography (HPLC). Today, the so-called “Quality by Design” (QbD) principle is often being applied rather than “Trial and Error” approach for HPLC method development. The QbD approach requires only for a very few experimental measurements to find the appropriate stationary phase and optimal chromatographic conditions such as the composition of mobile phase, gradient steepness or time (tG), temperature (T), and mobile phase pH. In this study, the applicability of a multifactorial liquid chromatographic optimization software was studied in an extended knowledge space. Using state-of-the-art ultra-high performance liquid chromatography (UHPLC), the analysis time can significantly be shortened. By using UHPLC, it is possible to analyse the composition of the reaction mixture within few minutes. In this work, a mixture of route of synthesis of apixaban was analysed on short narrow bore column (50 × 2.1 mm, packed with sub-2 µm particles) resulting in short analysis time. The aim of the study was to cover a relatively narrow range of method parameters (tG
, T, pH) in order to find a robust working point (zone). The results of the virtual (modeled) robustness testing were systematically compared to experimental measurements and Design of Experiments (DoE) based predictions.