Evaluating the discriminatory power of a dissolution assay for rosuvastatin calcium capsules: Solid-state properties and dissolution media

We propose to evaluate the dissolution properties of rosuvastatin calcium (ROSC) capsules in different media to characterize the discriminatory power of the assay method. Dissolution assays were performed in media with different pH, and including the surfactant sodium dodecyl sulfate (SDS). Several immediaterelease formulations were manufactured using the commercial raw material characterized as amorphous solid. The hydrophobic adjutant magnesium stearate was employed in some formulations due to its negative effect in the wettability and dissolution efficacy of solid dosages. These formulations showed the lower dissolution efficacy values in media without surfactant; however, when SDS was added to the medium, the dissolution efficacy increased, and the discriminatory power was lost. In spite of micellar solubilization does not increase the ROSC solubility, it modifies the discriminatory power of the assay method, increasing the wettability of the powder mixtures. The crystalline form M of ROSC was recrystallized in our laboratory, and it showed lower solubility in water than amorphous solid. However, its dissolution properties were not influenced by SDS. These results are important to develop dissolution assays for other hydrophilic drugs with increased water solubility, once that dissolution media with surfactants increase the wettability of the formulations, leading to an overrated dissolution rate

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved