Response Surface Optimization for Simultanous Estimation of Sofosbuvir and Velpatasvir in Human Plasma Sample

An efficient column friendly, buffer free, highly sensitive, cost effective RP-HPLC method was developed by considering the criticality of different method parameters on analytical attributes like tailing factor, resolution and retention time in preliminary risk analysis and screening designs. The Pareto analysis of screening design highlighted the need for optimization of resolution and its influencers (capacity factor and theoretical plates) for both the drugs to imbibe quality in the method. The suggested method of optimization design was developed using ZODIAC C18 ODS (250 mm × 4.6 mm, 5 μm) column in isocratic mode using mobile phase acetonitrile : methanol : water in the ratio of 60:10:30 at a flow rate of 0.8 mL/min and UV detection wavelength of 262 nm. The retention times of drugs were found to be 3.488 minutes for sofosbuvir, 5.387 minutes for velpatasvir. The linear regression analysis data for the calibration plots showed good linear relationship with r2=0.997 for sofosbuvir, r2=0.988 for velpatasvir, in the working concentration range of 1000-5000 ng/mL, 250-1250 ng/mL respectively. The AQbD devised method was applied for quantification of drugs in plasma and validated as suggested in ICH M10 guidelines.

Optimizing Support Locations in the Roof–Column Structural System

The roof–column structural system is utilized for many engineering and architectural applications due to its structural efficiency. However, it typically requires column locations to be predetermined, and involves a tedious trial-and-error adjusting process to fulfil both engineering and architectural requirements. Finding efficient column distributions with the aid of computational methods, such as structural optimization, is an ongoing challenge. Existing methods are limited, with continuum methods involving the generation of undesired complex shapes, and discrete methods involving a time-consuming process for optimizing columns’ spatial order. This paper presents a new optimization method to design the distribution of a given number of vertical supporting columns under a roof structure. A computational algorithm was developed on the basis of the optimality-criterion (OC) method to preserve and removed candidate columns pre-embedded with design requirements. Three substrategies are presented to improve optimizer performance. The effectiveness of the new method was validated with a range of roof–column structural models. Treating column locations as design variables provides opportunities to significantly improve structural performance.

COLUMN SORPTION OF TOXIC IONS IN VARIOUS QUARTZ SAND - PACKED COLUMNS

In this study the adsorption of As(V), Cu(II) and Zn(II) ions from multi-species model solution was tested in dynamic conditions in sand columns containing a thin layer of bentonite (B), iron-based sludge (IS) and synthetic magnetic particles (MP). Adsorption experiments were performed in order to evaluate the removal efficiency and selectivity of the individual layers in the column. The model solution with concentration of 10 mg/L Cu(II), Zn(II) and As(V) ions of each representing the real wastewater concentration was percolated through the columns of different beddings. In columns filled only with QS/B and QS/IS the removal effect for Cu(II) and Zn(II) ions was comparable while for As(V) ions more efficient column was IS bearing. The columns with B/IS and B/MP layer showed opposite effect for removal of individual ions. While IS layer showed higher affinity towards Cu(II) and Zn(II) the MP layer enhanced the removal of As(V). The highest removal effect for all ions was obtained by QS/B/MP column. For As(V) the removal effect achieved 90 % after 4 percolation cycles. After the third percolation cycle the removal effect of QS/B/IS column decreased from 100% to 58, 90 and 77 %, for As(V), Cu(II) and Zn(II) ions, respectively. By repeating of the percolation cycles the removal of As(V) by QS/B/MP column slight decreased, up to 90 % after four runs. In spite that after the third cycle almost 100 % of As(V) was removed. For Cu(II) and Zn(II) the decrease from 100 % to 76 and 62 % was detected after four cycles, respectively.

A simple single-stage extraction method for Mo separation from geological samples for isotopic analysis by MC-ICP-MS

Simple, fast and efficient column separation of Mo from geological sample matrices using the TRU resin.