Synthesis and functionalization of dextran-based single-chain nanoparticles in aqueous media.

Water-dispersible dextran-based single-chain polymer nanoparticles (SCPNs) were prepared in aqueous media and under mild conditions. Radiolabeling of the resulting biocompatible materials allowed the study of lung deposition of aqueous aerosols after intratracheal nebulization by means of single-photon emission computed tomography (SPECT), demonstrating their potential use as imaging contrast agents.

Effect of aging on the release of salbutamol sulfate from lipid matrices.

The aim of the present work was to evaluate the influence of aging that might condition the release of salbutamol sulfate from oral formulations (lipid matrices) using Gelucire as lipid excipients. Gelucires are essentially characterized by their melting point and their hydrophilic-lipophilic balance. The release profiles of salbutamol sulfate from the capsules elaborated were dependent on the type of Gelucires, fast release, in the case of Gelucire 35/10, a slower release for Gelucire 48/09 and a slow release for Gelucire 46/07. Differential scanning calorimetry was used to study the physical state of drugs in the matrices. Gelucires may exhibit aging effects, whereby a range of physical properties may change upon storage. In the case of Gelucire 35/10, which presents a fast release of salbutamol sulfate, storage produces a decrease in the values of dissolution constant for all capsule sizes. Gelucire 48/09 showed a slower release rate than Gelucire 35/10, and after 1 year of storage, a decrease in the salbutamol dissolution rate for capsule number 3 and 4 was observed. Gelucire 46/07 presented the slowest dissolution rate, but there were not statistically significant differences. These results show that the faster the dissolution rate, and the larger the capsule size, the higher is the influence of storage.

Non-conventional yeasts as hosts for heterologous protein production.

Yeasts are an attractive group of lower eukaryotic microorganisms, some of which are used in several industrial processes that include brewing, baking and the production of a variety of biochemical compounds. More recently, yeasts have been developed as host organisms for the production of foreign (heterologous) proteins. Saccharomyces cerevisiae has usually been the yeast of choice, but an increasing number of alternative non-Saccharomyces yeasts has now become accessible for modern molecular genetics techniques. Some of them exhibit certain favourable traits such as high-level secretion or very strong and tightly regulated promoters, offering significant advantages over traditional bakers' yeast. In the present work, the current status of Kluyveromyces lactis, Yarrowia lipolytica, Hansenula polymorpha and Pichia pastoris (the best-known alternative yeast systems) is reviewed. The advantages and limitations of these systems are discussed in relation to S. cerevisiae.