Mechanistic understanding of the link between Sodium Starch Glycolate properties and the performance of tablets made by wet granulation.

The impact of varying Sodium Starch Glycolate (SSG) grade and wet granulation intensity on the mechanism of disintegration and dissolution of mannitol-based Immediate Release (IR) placebo tablets was investigated. MRI and 1H NMR provided mechanistic insight, and revealed a four-fold range in both tablet disintegration and dissolution rates. MRI was used to quantify the rates of change in tablet volumes and the data fitted to a hydration/erosion model. Reduced levels of cross-linking change SSG from a swelling to a gelling matrix. The tablet hydration and dissolution rates are related to the viscosity at the tablet-solution interface, with high viscosities limiting mass transport.

Prediction of isotope patterns for partially deuterated analytes in HPLC/MS.

A probability model is given which accurately predicts the electrospray mass patterns of substance P arising from full or incomplete deuterium exchange in solution. For accurate determination of the number of exchangeable protons the solvent should have a deuterium purity of at least 98%. At 25 degrees C several minutes are required before the degree of exchange reaches the equilibrium value.

Effect of ionic strength on perfusive flow in capillary electrochromatography columns packed with wide-pore stationary phases.

The use of wide-pore stationary phases in capillary electrochromatography has shown exceptional increases in separation efficiency in conjunction with high electroosmotic flow. These effects are due to the perfusive flow mechanism which is primarily controlled by the ionic strength of the mobile phase. Good correlation between calculated values of electrochemical double-layer thickness and efficiency data have also been obtained. Reduced plate height values of <0.5 have been observed with pore sizes of 4000 A. In addition, electroosmotic flow mobility twice that of 3 microm Spherisorb ODS-1 has been obtained.