Flow Through Diffusion Cell Method: A Better Approach to Study Drug Release Behavior as Compared to Traditional Dissolution Test Method

Co‐polymeric hydrogels consisting of N‐vinyl‐2‐pyrrolidone (NVP) and acrylic acid (AAc) were synthesized and evaluated for release of a model drug, i.e., vitamin B₁₂. Release studies in simulated gastric fluid (pH 1.2) and intestinal fluid (pH 7.4), at 37°C, showed the hydrogels to be pH sensitive. An in vitro release study by ‘traditional dissolution test’ (TDT) showed that percent drug released from the hydrogel was nearly 8.6±2.1 and 83.2±4.8 in the media of pH 1.2 and 6.8, respectively. However, in order to incorporate in vivo GI conditions such as acidic pH and high water content in the stomach, low water content and the presence of a semi–solid mass in the large intestine, a new test model, called flow through diffusion cell (FTDC) was also used. The two approaches yielded almost different release profiles. The gels were characterized by thermogravimetric analysis and FTIR spectroscopy.     

A Rapid and Sensitive Strip‐Based Quick Test for Nerve Agents Tabun,Sarin, and Soman Using BODIPY‐Modified Silica Materials

Test strips that in combination with a portable fluorescence reader or digital camera can rapidly and selectively detect chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB), and Soman (GD) and their simulants in the gas phase have been developed. The strips contain spots of a hybrid indicator material consisting of a fluorescent BODIPY indicator covalently anchored into the channels of mesoporous SBA silica microparticles. The fluorescence quenching response allows the sensitive detection of CWAs in the μg m^?3 range in a few seconds.     

Voltammetric Peak Area as Instrumental Datum. A Possibility to Improve the Determination at Ultratrace Level Concentration of Platinum Group Metals (PGMs) and Lead. Application to Particulate Matter

Peak area as instrumental datum for determining the concentration of metals in solution instead of peak height is proposed for analytical voltammetric determinations. In the case of species present at ultratrace concentration level or having low reversibility degree of the electrodic processes, the employment of peak area permits to achieve limits of detection lower even more of one order of magnitude. The present work shows the possibility of determining at ultratrace level concentration Pd(II), Pt(II), Rh(III) and Pb(II) by voltammetry in particulate matter; these species, linked to vehicle emissions, show to have, in the supporting electrolytes employed, a very high irreversibility degree of the electrodic processes.